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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * mm/percpu.c - percpu memory allocator
4 *
5 * Copyright (C) 2009 SUSE Linux Products GmbH
6 * Copyright (C) 2009 Tejun Heo <tj@kernel.org>
7 *
8 * Copyright (C) 2017 Facebook Inc.
9 * Copyright (C) 2017 Dennis Zhou <dennisszhou@gmail.com>
10 *
11 * The percpu allocator handles both static and dynamic areas. Percpu
12 * areas are allocated in chunks which are divided into units. There is
13 * a 1-to-1 mapping for units to possible cpus. These units are grouped
14 * based on NUMA properties of the machine.
15 *
16 * c0 c1 c2
17 * ------------------- ------------------- ------------
18 * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
19 * ------------------- ...... ------------------- .... ------------
20 *
21 * Allocation is done by offsets into a unit's address space. Ie., an
22 * area of 512 bytes at 6k in c1 occupies 512 bytes at 6k in c1:u0,
23 * c1:u1, c1:u2, etc. On NUMA machines, the mapping may be non-linear
24 * and even sparse. Access is handled by configuring percpu base
25 * registers according to the cpu to unit mappings and offsetting the
26 * base address using pcpu_unit_size.
27 *
28 * There is special consideration for the first chunk which must handle
29 * the static percpu variables in the kernel image as allocation services
30 * are not online yet. In short, the first chunk is structured like so:
31 *
32 * <Static | [Reserved] | Dynamic>
33 *
34 * The static data is copied from the original section managed by the
35 * linker. The reserved section, if non-zero, primarily manages static
36 * percpu variables from kernel modules. Finally, the dynamic section
37 * takes care of normal allocations.
38 *
39 * The allocator organizes chunks into lists according to free size and
40 * tries to allocate from the fullest chunk first. Each chunk is managed
41 * by a bitmap with metadata blocks. The allocation map is updated on
42 * every allocation and free to reflect the current state while the boundary
43 * map is only updated on allocation. Each metadata block contains
44 * information to help mitigate the need to iterate over large portions
45 * of the bitmap. The reverse mapping from page to chunk is stored in
46 * the page's index. Lastly, units are lazily backed and grow in unison.
47 *
48 * There is a unique conversion that goes on here between bytes and bits.
49 * Each bit represents a fragment of size PCPU_MIN_ALLOC_SIZE. The chunk
50 * tracks the number of pages it is responsible for in nr_pages. Helper
51 * functions are used to convert from between the bytes, bits, and blocks.
52 * All hints are managed in bits unless explicitly stated.
53 *
54 * To use this allocator, arch code should do the following:
55 *
56 * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
57 * regular address to percpu pointer and back if they need to be
58 * different from the default
59 *
60 * - use pcpu_setup_first_chunk() during percpu area initialization to
61 * setup the first chunk containing the kernel static percpu area
62 */
63
64#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
65
66#include <linux/bitmap.h>
67#include <linux/memblock.h>
68#include <linux/err.h>
69#include <linux/lcm.h>
70#include <linux/list.h>
71#include <linux/log2.h>
72#include <linux/mm.h>
73#include <linux/module.h>
74#include <linux/mutex.h>
75#include <linux/percpu.h>
76#include <linux/pfn.h>
77#include <linux/slab.h>
78#include <linux/spinlock.h>
79#include <linux/vmalloc.h>
80#include <linux/workqueue.h>
81#include <linux/kmemleak.h>
82#include <linux/sched.h>
83
84#include <asm/cacheflush.h>
85#include <asm/sections.h>
86#include <asm/tlbflush.h>
87#include <asm/io.h>
88
89#define CREATE_TRACE_POINTS
90#include <trace/events/percpu.h>
91
92#include "percpu-internal.h"
93
94/* the slots are sorted by free bytes left, 1-31 bytes share the same slot */
95#define PCPU_SLOT_BASE_SHIFT 5
96/* chunks in slots below this are subject to being sidelined on failed alloc */
97#define PCPU_SLOT_FAIL_THRESHOLD 3
98
99#define PCPU_EMPTY_POP_PAGES_LOW 2
100#define PCPU_EMPTY_POP_PAGES_HIGH 4
101
102#ifdef CONFIG_SMP
103/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
104#ifndef __addr_to_pcpu_ptr
105#define __addr_to_pcpu_ptr(addr) \
106 (void __percpu *)((unsigned long)(addr) - \
107 (unsigned long)pcpu_base_addr + \
108 (unsigned long)__per_cpu_start)
109#endif
110#ifndef __pcpu_ptr_to_addr
111#define __pcpu_ptr_to_addr(ptr) \
112 (void __force *)((unsigned long)(ptr) + \
113 (unsigned long)pcpu_base_addr - \
114 (unsigned long)__per_cpu_start)
115#endif
116#else /* CONFIG_SMP */
117/* on UP, it's always identity mapped */
118#define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
119#define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
120#endif /* CONFIG_SMP */
121
122static int pcpu_unit_pages __ro_after_init;
123static int pcpu_unit_size __ro_after_init;
124static int pcpu_nr_units __ro_after_init;
125static int pcpu_atom_size __ro_after_init;
126int pcpu_nr_slots __ro_after_init;
127static size_t pcpu_chunk_struct_size __ro_after_init;
128
129/* cpus with the lowest and highest unit addresses */
130static unsigned int pcpu_low_unit_cpu __ro_after_init;
131static unsigned int pcpu_high_unit_cpu __ro_after_init;
132
133/* the address of the first chunk which starts with the kernel static area */
134void *pcpu_base_addr __ro_after_init;
135EXPORT_SYMBOL_GPL(pcpu_base_addr);
136
137static const int *pcpu_unit_map __ro_after_init; /* cpu -> unit */
138const unsigned long *pcpu_unit_offsets __ro_after_init; /* cpu -> unit offset */
139
140/* group information, used for vm allocation */
141static int pcpu_nr_groups __ro_after_init;
142static const unsigned long *pcpu_group_offsets __ro_after_init;
143static const size_t *pcpu_group_sizes __ro_after_init;
144
145/*
146 * The first chunk which always exists. Note that unlike other
147 * chunks, this one can be allocated and mapped in several different
148 * ways and thus often doesn't live in the vmalloc area.
149 */
150struct pcpu_chunk *pcpu_first_chunk __ro_after_init;
151
152/*
153 * Optional reserved chunk. This chunk reserves part of the first
154 * chunk and serves it for reserved allocations. When the reserved
155 * region doesn't exist, the following variable is NULL.
156 */
157struct pcpu_chunk *pcpu_reserved_chunk __ro_after_init;
158
159DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
160static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop, map ext */
161
162struct list_head *pcpu_slot __ro_after_init; /* chunk list slots */
163
164/* chunks which need their map areas extended, protected by pcpu_lock */
165static LIST_HEAD(pcpu_map_extend_chunks);
166
167/*
168 * The number of empty populated pages, protected by pcpu_lock. The
169 * reserved chunk doesn't contribute to the count.
170 */
171int pcpu_nr_empty_pop_pages;
172
173/*
174 * The number of populated pages in use by the allocator, protected by
175 * pcpu_lock. This number is kept per a unit per chunk (i.e. when a page gets
176 * allocated/deallocated, it is allocated/deallocated in all units of a chunk
177 * and increments/decrements this count by 1).
178 */
179static unsigned long pcpu_nr_populated;
180
181/*
182 * Balance work is used to populate or destroy chunks asynchronously. We
183 * try to keep the number of populated free pages between
184 * PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one
185 * empty chunk.
186 */
187static void pcpu_balance_workfn(struct work_struct *work);
188static DECLARE_WORK(pcpu_balance_work, pcpu_balance_workfn);
189static bool pcpu_async_enabled __read_mostly;
190static bool pcpu_atomic_alloc_failed;
191
192static void pcpu_schedule_balance_work(void)
193{
194 if (pcpu_async_enabled)
195 schedule_work(&pcpu_balance_work);
196}
197
198/**
199 * pcpu_addr_in_chunk - check if the address is served from this chunk
200 * @chunk: chunk of interest
201 * @addr: percpu address
202 *
203 * RETURNS:
204 * True if the address is served from this chunk.
205 */
206static bool pcpu_addr_in_chunk(struct pcpu_chunk *chunk, void *addr)
207{
208 void *start_addr, *end_addr;
209
210 if (!chunk)
211 return false;
212
213 start_addr = chunk->base_addr + chunk->start_offset;
214 end_addr = chunk->base_addr + chunk->nr_pages * PAGE_SIZE -
215 chunk->end_offset;
216
217 return addr >= start_addr && addr < end_addr;
218}
219
220static int __pcpu_size_to_slot(int size)
221{
222 int highbit = fls(size); /* size is in bytes */
223 return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
224}
225
226static int pcpu_size_to_slot(int size)
227{
228 if (size == pcpu_unit_size)
229 return pcpu_nr_slots - 1;
230 return __pcpu_size_to_slot(size);
231}
232
233static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
234{
235 const struct pcpu_block_md *chunk_md = &chunk->chunk_md;
236
237 if (chunk->free_bytes < PCPU_MIN_ALLOC_SIZE ||
238 chunk_md->contig_hint == 0)
239 return 0;
240
241 return pcpu_size_to_slot(chunk_md->contig_hint * PCPU_MIN_ALLOC_SIZE);
242}
243
244/* set the pointer to a chunk in a page struct */
245static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
246{
247 page->index = (unsigned long)pcpu;
248}
249
250/* obtain pointer to a chunk from a page struct */
251static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
252{
253 return (struct pcpu_chunk *)page->index;
254}
255
256static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
257{
258 return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
259}
260
261static unsigned long pcpu_unit_page_offset(unsigned int cpu, int page_idx)
262{
263 return pcpu_unit_offsets[cpu] + (page_idx << PAGE_SHIFT);
264}
265
266static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
267 unsigned int cpu, int page_idx)
268{
269 return (unsigned long)chunk->base_addr +
270 pcpu_unit_page_offset(cpu, page_idx);
271}
272
273static void pcpu_next_unpop(unsigned long *bitmap, int *rs, int *re, int end)
274{
275 *rs = find_next_zero_bit(bitmap, end, *rs);
276 *re = find_next_bit(bitmap, end, *rs + 1);
277}
278
279static void pcpu_next_pop(unsigned long *bitmap, int *rs, int *re, int end)
280{
281 *rs = find_next_bit(bitmap, end, *rs);
282 *re = find_next_zero_bit(bitmap, end, *rs + 1);
283}
284
285/*
286 * Bitmap region iterators. Iterates over the bitmap between
287 * [@start, @end) in @chunk. @rs and @re should be integer variables
288 * and will be set to start and end index of the current free region.
289 */
290#define pcpu_for_each_unpop_region(bitmap, rs, re, start, end) \
291 for ((rs) = (start), pcpu_next_unpop((bitmap), &(rs), &(re), (end)); \
292 (rs) < (re); \
293 (rs) = (re) + 1, pcpu_next_unpop((bitmap), &(rs), &(re), (end)))
294
295#define pcpu_for_each_pop_region(bitmap, rs, re, start, end) \
296 for ((rs) = (start), pcpu_next_pop((bitmap), &(rs), &(re), (end)); \
297 (rs) < (re); \
298 (rs) = (re) + 1, pcpu_next_pop((bitmap), &(rs), &(re), (end)))
299
300/*
301 * The following are helper functions to help access bitmaps and convert
302 * between bitmap offsets to address offsets.
303 */
304static unsigned long *pcpu_index_alloc_map(struct pcpu_chunk *chunk, int index)
305{
306 return chunk->alloc_map +
307 (index * PCPU_BITMAP_BLOCK_BITS / BITS_PER_LONG);
308}
309
310static unsigned long pcpu_off_to_block_index(int off)
311{
312 return off / PCPU_BITMAP_BLOCK_BITS;
313}
314
315static unsigned long pcpu_off_to_block_off(int off)
316{
317 return off & (PCPU_BITMAP_BLOCK_BITS - 1);
318}
319
320static unsigned long pcpu_block_off_to_off(int index, int off)
321{
322 return index * PCPU_BITMAP_BLOCK_BITS + off;
323}
324
325/*
326 * pcpu_next_hint - determine which hint to use
327 * @block: block of interest
328 * @alloc_bits: size of allocation
329 *
330 * This determines if we should scan based on the scan_hint or first_free.
331 * In general, we want to scan from first_free to fulfill allocations by
332 * first fit. However, if we know a scan_hint at position scan_hint_start
333 * cannot fulfill an allocation, we can begin scanning from there knowing
334 * the contig_hint will be our fallback.
335 */
336static int pcpu_next_hint(struct pcpu_block_md *block, int alloc_bits)
337{
338 /*
339 * The three conditions below determine if we can skip past the
340 * scan_hint. First, does the scan hint exist. Second, is the
341 * contig_hint after the scan_hint (possibly not true iff
342 * contig_hint == scan_hint). Third, is the allocation request
343 * larger than the scan_hint.
344 */
345 if (block->scan_hint &&
346 block->contig_hint_start > block->scan_hint_start &&
347 alloc_bits > block->scan_hint)
348 return block->scan_hint_start + block->scan_hint;
349
350 return block->first_free;
351}
352
353/**
354 * pcpu_next_md_free_region - finds the next hint free area
355 * @chunk: chunk of interest
356 * @bit_off: chunk offset
357 * @bits: size of free area
358 *
359 * Helper function for pcpu_for_each_md_free_region. It checks
360 * block->contig_hint and performs aggregation across blocks to find the
361 * next hint. It modifies bit_off and bits in-place to be consumed in the
362 * loop.
363 */
364static void pcpu_next_md_free_region(struct pcpu_chunk *chunk, int *bit_off,
365 int *bits)
366{
367 int i = pcpu_off_to_block_index(*bit_off);
368 int block_off = pcpu_off_to_block_off(*bit_off);
369 struct pcpu_block_md *block;
370
371 *bits = 0;
372 for (block = chunk->md_blocks + i; i < pcpu_chunk_nr_blocks(chunk);
373 block++, i++) {
374 /* handles contig area across blocks */
375 if (*bits) {
376 *bits += block->left_free;
377 if (block->left_free == PCPU_BITMAP_BLOCK_BITS)
378 continue;
379 return;
380 }
381
382 /*
383 * This checks three things. First is there a contig_hint to
384 * check. Second, have we checked this hint before by
385 * comparing the block_off. Third, is this the same as the
386 * right contig hint. In the last case, it spills over into
387 * the next block and should be handled by the contig area
388 * across blocks code.
389 */
390 *bits = block->contig_hint;
391 if (*bits && block->contig_hint_start >= block_off &&
392 *bits + block->contig_hint_start < PCPU_BITMAP_BLOCK_BITS) {
393 *bit_off = pcpu_block_off_to_off(i,
394 block->contig_hint_start);
395 return;
396 }
397 /* reset to satisfy the second predicate above */
398 block_off = 0;
399
400 *bits = block->right_free;
401 *bit_off = (i + 1) * PCPU_BITMAP_BLOCK_BITS - block->right_free;
402 }
403}
404
405/**
406 * pcpu_next_fit_region - finds fit areas for a given allocation request
407 * @chunk: chunk of interest
408 * @alloc_bits: size of allocation
409 * @align: alignment of area (max PAGE_SIZE)
410 * @bit_off: chunk offset
411 * @bits: size of free area
412 *
413 * Finds the next free region that is viable for use with a given size and
414 * alignment. This only returns if there is a valid area to be used for this
415 * allocation. block->first_free is returned if the allocation request fits
416 * within the block to see if the request can be fulfilled prior to the contig
417 * hint.
418 */
419static void pcpu_next_fit_region(struct pcpu_chunk *chunk, int alloc_bits,
420 int align, int *bit_off, int *bits)
421{
422 int i = pcpu_off_to_block_index(*bit_off);
423 int block_off = pcpu_off_to_block_off(*bit_off);
424 struct pcpu_block_md *block;
425
426 *bits = 0;
427 for (block = chunk->md_blocks + i; i < pcpu_chunk_nr_blocks(chunk);
428 block++, i++) {
429 /* handles contig area across blocks */
430 if (*bits) {
431 *bits += block->left_free;
432 if (*bits >= alloc_bits)
433 return;
434 if (block->left_free == PCPU_BITMAP_BLOCK_BITS)
435 continue;
436 }
437
438 /* check block->contig_hint */
439 *bits = ALIGN(block->contig_hint_start, align) -
440 block->contig_hint_start;
441 /*
442 * This uses the block offset to determine if this has been
443 * checked in the prior iteration.
444 */
445 if (block->contig_hint &&
446 block->contig_hint_start >= block_off &&
447 block->contig_hint >= *bits + alloc_bits) {
448 int start = pcpu_next_hint(block, alloc_bits);
449
450 *bits += alloc_bits + block->contig_hint_start -
451 start;
452 *bit_off = pcpu_block_off_to_off(i, start);
453 return;
454 }
455 /* reset to satisfy the second predicate above */
456 block_off = 0;
457
458 *bit_off = ALIGN(PCPU_BITMAP_BLOCK_BITS - block->right_free,
459 align);
460 *bits = PCPU_BITMAP_BLOCK_BITS - *bit_off;
461 *bit_off = pcpu_block_off_to_off(i, *bit_off);
462 if (*bits >= alloc_bits)
463 return;
464 }
465
466 /* no valid offsets were found - fail condition */
467 *bit_off = pcpu_chunk_map_bits(chunk);
468}
469
470/*
471 * Metadata free area iterators. These perform aggregation of free areas
472 * based on the metadata blocks and return the offset @bit_off and size in
473 * bits of the free area @bits. pcpu_for_each_fit_region only returns when
474 * a fit is found for the allocation request.
475 */
476#define pcpu_for_each_md_free_region(chunk, bit_off, bits) \
477 for (pcpu_next_md_free_region((chunk), &(bit_off), &(bits)); \
478 (bit_off) < pcpu_chunk_map_bits((chunk)); \
479 (bit_off) += (bits) + 1, \
480 pcpu_next_md_free_region((chunk), &(bit_off), &(bits)))
481
482#define pcpu_for_each_fit_region(chunk, alloc_bits, align, bit_off, bits) \
483 for (pcpu_next_fit_region((chunk), (alloc_bits), (align), &(bit_off), \
484 &(bits)); \
485 (bit_off) < pcpu_chunk_map_bits((chunk)); \
486 (bit_off) += (bits), \
487 pcpu_next_fit_region((chunk), (alloc_bits), (align), &(bit_off), \
488 &(bits)))
489
490/**
491 * pcpu_mem_zalloc - allocate memory
492 * @size: bytes to allocate
493 * @gfp: allocation flags
494 *
495 * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
496 * kzalloc() is used; otherwise, the equivalent of vzalloc() is used.
497 * This is to facilitate passing through whitelisted flags. The
498 * returned memory is always zeroed.
499 *
500 * RETURNS:
501 * Pointer to the allocated area on success, NULL on failure.
502 */
503static void *pcpu_mem_zalloc(size_t size, gfp_t gfp)
504{
505 if (WARN_ON_ONCE(!slab_is_available()))
506 return NULL;
507
508 if (size <= PAGE_SIZE)
509 return kzalloc(size, gfp);
510 else
511 return __vmalloc(size, gfp | __GFP_ZERO, PAGE_KERNEL);
512}
513
514/**
515 * pcpu_mem_free - free memory
516 * @ptr: memory to free
517 *
518 * Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc().
519 */
520static void pcpu_mem_free(void *ptr)
521{
522 kvfree(ptr);
523}
524
525static void __pcpu_chunk_move(struct pcpu_chunk *chunk, int slot,
526 bool move_front)
527{
528 if (chunk != pcpu_reserved_chunk) {
529 if (move_front)
530 list_move(&chunk->list, &pcpu_slot[slot]);
531 else
532 list_move_tail(&chunk->list, &pcpu_slot[slot]);
533 }
534}
535
536static void pcpu_chunk_move(struct pcpu_chunk *chunk, int slot)
537{
538 __pcpu_chunk_move(chunk, slot, true);
539}
540
541/**
542 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
543 * @chunk: chunk of interest
544 * @oslot: the previous slot it was on
545 *
546 * This function is called after an allocation or free changed @chunk.
547 * New slot according to the changed state is determined and @chunk is
548 * moved to the slot. Note that the reserved chunk is never put on
549 * chunk slots.
550 *
551 * CONTEXT:
552 * pcpu_lock.
553 */
554static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
555{
556 int nslot = pcpu_chunk_slot(chunk);
557
558 if (oslot != nslot)
559 __pcpu_chunk_move(chunk, nslot, oslot < nslot);
560}
561
562/*
563 * pcpu_update_empty_pages - update empty page counters
564 * @chunk: chunk of interest
565 * @nr: nr of empty pages
566 *
567 * This is used to keep track of the empty pages now based on the premise
568 * a md_block covers a page. The hint update functions recognize if a block
569 * is made full or broken to calculate deltas for keeping track of free pages.
570 */
571static inline void pcpu_update_empty_pages(struct pcpu_chunk *chunk, int nr)
572{
573 chunk->nr_empty_pop_pages += nr;
574 if (chunk != pcpu_reserved_chunk)
575 pcpu_nr_empty_pop_pages += nr;
576}
577
578/*
579 * pcpu_region_overlap - determines if two regions overlap
580 * @a: start of first region, inclusive
581 * @b: end of first region, exclusive
582 * @x: start of second region, inclusive
583 * @y: end of second region, exclusive
584 *
585 * This is used to determine if the hint region [a, b) overlaps with the
586 * allocated region [x, y).
587 */
588static inline bool pcpu_region_overlap(int a, int b, int x, int y)
589{
590 return (a < y) && (x < b);
591}
592
593/**
594 * pcpu_block_update - updates a block given a free area
595 * @block: block of interest
596 * @start: start offset in block
597 * @end: end offset in block
598 *
599 * Updates a block given a known free area. The region [start, end) is
600 * expected to be the entirety of the free area within a block. Chooses
601 * the best starting offset if the contig hints are equal.
602 */
603static void pcpu_block_update(struct pcpu_block_md *block, int start, int end)
604{
605 int contig = end - start;
606
607 block->first_free = min(block->first_free, start);
608 if (start == 0)
609 block->left_free = contig;
610
611 if (end == block->nr_bits)
612 block->right_free = contig;
613
614 if (contig > block->contig_hint) {
615 /* promote the old contig_hint to be the new scan_hint */
616 if (start > block->contig_hint_start) {
617 if (block->contig_hint > block->scan_hint) {
618 block->scan_hint_start =
619 block->contig_hint_start;
620 block->scan_hint = block->contig_hint;
621 } else if (start < block->scan_hint_start) {
622 /*
623 * The old contig_hint == scan_hint. But, the
624 * new contig is larger so hold the invariant
625 * scan_hint_start < contig_hint_start.
626 */
627 block->scan_hint = 0;
628 }
629 } else {
630 block->scan_hint = 0;
631 }
632 block->contig_hint_start = start;
633 block->contig_hint = contig;
634 } else if (contig == block->contig_hint) {
635 if (block->contig_hint_start &&
636 (!start ||
637 __ffs(start) > __ffs(block->contig_hint_start))) {
638 /* start has a better alignment so use it */
639 block->contig_hint_start = start;
640 if (start < block->scan_hint_start &&
641 block->contig_hint > block->scan_hint)
642 block->scan_hint = 0;
643 } else if (start > block->scan_hint_start ||
644 block->contig_hint > block->scan_hint) {
645 /*
646 * Knowing contig == contig_hint, update the scan_hint
647 * if it is farther than or larger than the current
648 * scan_hint.
649 */
650 block->scan_hint_start = start;
651 block->scan_hint = contig;
652 }
653 } else {
654 /*
655 * The region is smaller than the contig_hint. So only update
656 * the scan_hint if it is larger than or equal and farther than
657 * the current scan_hint.
658 */
659 if ((start < block->contig_hint_start &&
660 (contig > block->scan_hint ||
661 (contig == block->scan_hint &&
662 start > block->scan_hint_start)))) {
663 block->scan_hint_start = start;
664 block->scan_hint = contig;
665 }
666 }
667}
668
669/*
670 * pcpu_block_update_scan - update a block given a free area from a scan
671 * @chunk: chunk of interest
672 * @bit_off: chunk offset
673 * @bits: size of free area
674 *
675 * Finding the final allocation spot first goes through pcpu_find_block_fit()
676 * to find a block that can hold the allocation and then pcpu_alloc_area()
677 * where a scan is used. When allocations require specific alignments,
678 * we can inadvertently create holes which will not be seen in the alloc
679 * or free paths.
680 *
681 * This takes a given free area hole and updates a block as it may change the
682 * scan_hint. We need to scan backwards to ensure we don't miss free bits
683 * from alignment.
684 */
685static void pcpu_block_update_scan(struct pcpu_chunk *chunk, int bit_off,
686 int bits)
687{
688 int s_off = pcpu_off_to_block_off(bit_off);
689 int e_off = s_off + bits;
690 int s_index, l_bit;
691 struct pcpu_block_md *block;
692
693 if (e_off > PCPU_BITMAP_BLOCK_BITS)
694 return;
695
696 s_index = pcpu_off_to_block_index(bit_off);
697 block = chunk->md_blocks + s_index;
698
699 /* scan backwards in case of alignment skipping free bits */
700 l_bit = find_last_bit(pcpu_index_alloc_map(chunk, s_index), s_off);
701 s_off = (s_off == l_bit) ? 0 : l_bit + 1;
702
703 pcpu_block_update(block, s_off, e_off);
704}
705
706/**
707 * pcpu_chunk_refresh_hint - updates metadata about a chunk
708 * @chunk: chunk of interest
709 * @full_scan: if we should scan from the beginning
710 *
711 * Iterates over the metadata blocks to find the largest contig area.
712 * A full scan can be avoided on the allocation path as this is triggered
713 * if we broke the contig_hint. In doing so, the scan_hint will be before
714 * the contig_hint or after if the scan_hint == contig_hint. This cannot
715 * be prevented on freeing as we want to find the largest area possibly
716 * spanning blocks.
717 */
718static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk, bool full_scan)
719{
720 struct pcpu_block_md *chunk_md = &chunk->chunk_md;
721 int bit_off, bits;
722
723 /* promote scan_hint to contig_hint */
724 if (!full_scan && chunk_md->scan_hint) {
725 bit_off = chunk_md->scan_hint_start + chunk_md->scan_hint;
726 chunk_md->contig_hint_start = chunk_md->scan_hint_start;
727 chunk_md->contig_hint = chunk_md->scan_hint;
728 chunk_md->scan_hint = 0;
729 } else {
730 bit_off = chunk_md->first_free;
731 chunk_md->contig_hint = 0;
732 }
733
734 bits = 0;
735 pcpu_for_each_md_free_region(chunk, bit_off, bits) {
736 pcpu_block_update(chunk_md, bit_off, bit_off + bits);
737 }
738}
739
740/**
741 * pcpu_block_refresh_hint
742 * @chunk: chunk of interest
743 * @index: index of the metadata block
744 *
745 * Scans over the block beginning at first_free and updates the block
746 * metadata accordingly.
747 */
748static void pcpu_block_refresh_hint(struct pcpu_chunk *chunk, int index)
749{
750 struct pcpu_block_md *block = chunk->md_blocks + index;
751 unsigned long *alloc_map = pcpu_index_alloc_map(chunk, index);
752 int rs, re, start; /* region start, region end */
753
754 /* promote scan_hint to contig_hint */
755 if (block->scan_hint) {
756 start = block->scan_hint_start + block->scan_hint;
757 block->contig_hint_start = block->scan_hint_start;
758 block->contig_hint = block->scan_hint;
759 block->scan_hint = 0;
760 } else {
761 start = block->first_free;
762 block->contig_hint = 0;
763 }
764
765 block->right_free = 0;
766
767 /* iterate over free areas and update the contig hints */
768 pcpu_for_each_unpop_region(alloc_map, rs, re, start,
769 PCPU_BITMAP_BLOCK_BITS) {
770 pcpu_block_update(block, rs, re);
771 }
772}
773
774/**
775 * pcpu_block_update_hint_alloc - update hint on allocation path
776 * @chunk: chunk of interest
777 * @bit_off: chunk offset
778 * @bits: size of request
779 *
780 * Updates metadata for the allocation path. The metadata only has to be
781 * refreshed by a full scan iff the chunk's contig hint is broken. Block level
782 * scans are required if the block's contig hint is broken.
783 */
784static void pcpu_block_update_hint_alloc(struct pcpu_chunk *chunk, int bit_off,
785 int bits)
786{
787 struct pcpu_block_md *chunk_md = &chunk->chunk_md;
788 int nr_empty_pages = 0;
789 struct pcpu_block_md *s_block, *e_block, *block;
790 int s_index, e_index; /* block indexes of the freed allocation */
791 int s_off, e_off; /* block offsets of the freed allocation */
792
793 /*
794 * Calculate per block offsets.
795 * The calculation uses an inclusive range, but the resulting offsets
796 * are [start, end). e_index always points to the last block in the
797 * range.
798 */
799 s_index = pcpu_off_to_block_index(bit_off);
800 e_index = pcpu_off_to_block_index(bit_off + bits - 1);
801 s_off = pcpu_off_to_block_off(bit_off);
802 e_off = pcpu_off_to_block_off(bit_off + bits - 1) + 1;
803
804 s_block = chunk->md_blocks + s_index;
805 e_block = chunk->md_blocks + e_index;
806
807 /*
808 * Update s_block.
809 * block->first_free must be updated if the allocation takes its place.
810 * If the allocation breaks the contig_hint, a scan is required to
811 * restore this hint.
812 */
813 if (s_block->contig_hint == PCPU_BITMAP_BLOCK_BITS)
814 nr_empty_pages++;
815
816 if (s_off == s_block->first_free)
817 s_block->first_free = find_next_zero_bit(
818 pcpu_index_alloc_map(chunk, s_index),
819 PCPU_BITMAP_BLOCK_BITS,
820 s_off + bits);
821
822 if (pcpu_region_overlap(s_block->scan_hint_start,
823 s_block->scan_hint_start + s_block->scan_hint,
824 s_off,
825 s_off + bits))
826 s_block->scan_hint = 0;
827
828 if (pcpu_region_overlap(s_block->contig_hint_start,
829 s_block->contig_hint_start +
830 s_block->contig_hint,
831 s_off,
832 s_off + bits)) {
833 /* block contig hint is broken - scan to fix it */
834 if (!s_off)
835 s_block->left_free = 0;
836 pcpu_block_refresh_hint(chunk, s_index);
837 } else {
838 /* update left and right contig manually */
839 s_block->left_free = min(s_block->left_free, s_off);
840 if (s_index == e_index)
841 s_block->right_free = min_t(int, s_block->right_free,
842 PCPU_BITMAP_BLOCK_BITS - e_off);
843 else
844 s_block->right_free = 0;
845 }
846
847 /*
848 * Update e_block.
849 */
850 if (s_index != e_index) {
851 if (e_block->contig_hint == PCPU_BITMAP_BLOCK_BITS)
852 nr_empty_pages++;
853
854 /*
855 * When the allocation is across blocks, the end is along
856 * the left part of the e_block.
857 */
858 e_block->first_free = find_next_zero_bit(
859 pcpu_index_alloc_map(chunk, e_index),
860 PCPU_BITMAP_BLOCK_BITS, e_off);
861
862 if (e_off == PCPU_BITMAP_BLOCK_BITS) {
863 /* reset the block */
864 e_block++;
865 } else {
866 if (e_off > e_block->scan_hint_start)
867 e_block->scan_hint = 0;
868
869 e_block->left_free = 0;
870 if (e_off > e_block->contig_hint_start) {
871 /* contig hint is broken - scan to fix it */
872 pcpu_block_refresh_hint(chunk, e_index);
873 } else {
874 e_block->right_free =
875 min_t(int, e_block->right_free,
876 PCPU_BITMAP_BLOCK_BITS - e_off);
877 }
878 }
879
880 /* update in-between md_blocks */
881 nr_empty_pages += (e_index - s_index - 1);
882 for (block = s_block + 1; block < e_block; block++) {
883 block->scan_hint = 0;
884 block->contig_hint = 0;
885 block->left_free = 0;
886 block->right_free = 0;
887 }
888 }
889
890 if (nr_empty_pages)
891 pcpu_update_empty_pages(chunk, -nr_empty_pages);
892
893 if (pcpu_region_overlap(chunk_md->scan_hint_start,
894 chunk_md->scan_hint_start +
895 chunk_md->scan_hint,
896 bit_off,
897 bit_off + bits))
898 chunk_md->scan_hint = 0;
899
900 /*
901 * The only time a full chunk scan is required is if the chunk
902 * contig hint is broken. Otherwise, it means a smaller space
903 * was used and therefore the chunk contig hint is still correct.
904 */
905 if (pcpu_region_overlap(chunk_md->contig_hint_start,
906 chunk_md->contig_hint_start +
907 chunk_md->contig_hint,
908 bit_off,
909 bit_off + bits))
910 pcpu_chunk_refresh_hint(chunk, false);
911}
912
913/**
914 * pcpu_block_update_hint_free - updates the block hints on the free path
915 * @chunk: chunk of interest
916 * @bit_off: chunk offset
917 * @bits: size of request
918 *
919 * Updates metadata for the allocation path. This avoids a blind block
920 * refresh by making use of the block contig hints. If this fails, it scans
921 * forward and backward to determine the extent of the free area. This is
922 * capped at the boundary of blocks.
923 *
924 * A chunk update is triggered if a page becomes free, a block becomes free,
925 * or the free spans across blocks. This tradeoff is to minimize iterating
926 * over the block metadata to update chunk_md->contig_hint.
927 * chunk_md->contig_hint may be off by up to a page, but it will never be more
928 * than the available space. If the contig hint is contained in one block, it
929 * will be accurate.
930 */
931static void pcpu_block_update_hint_free(struct pcpu_chunk *chunk, int bit_off,
932 int bits)
933{
934 int nr_empty_pages = 0;
935 struct pcpu_block_md *s_block, *e_block, *block;
936 int s_index, e_index; /* block indexes of the freed allocation */
937 int s_off, e_off; /* block offsets of the freed allocation */
938 int start, end; /* start and end of the whole free area */
939
940 /*
941 * Calculate per block offsets.
942 * The calculation uses an inclusive range, but the resulting offsets
943 * are [start, end). e_index always points to the last block in the
944 * range.
945 */
946 s_index = pcpu_off_to_block_index(bit_off);
947 e_index = pcpu_off_to_block_index(bit_off + bits - 1);
948 s_off = pcpu_off_to_block_off(bit_off);
949 e_off = pcpu_off_to_block_off(bit_off + bits - 1) + 1;
950
951 s_block = chunk->md_blocks + s_index;
952 e_block = chunk->md_blocks + e_index;
953
954 /*
955 * Check if the freed area aligns with the block->contig_hint.
956 * If it does, then the scan to find the beginning/end of the
957 * larger free area can be avoided.
958 *
959 * start and end refer to beginning and end of the free area
960 * within each their respective blocks. This is not necessarily
961 * the entire free area as it may span blocks past the beginning
962 * or end of the block.
963 */
964 start = s_off;
965 if (s_off == s_block->contig_hint + s_block->contig_hint_start) {
966 start = s_block->contig_hint_start;
967 } else {
968 /*
969 * Scan backwards to find the extent of the free area.
970 * find_last_bit returns the starting bit, so if the start bit
971 * is returned, that means there was no last bit and the
972 * remainder of the chunk is free.
973 */
974 int l_bit = find_last_bit(pcpu_index_alloc_map(chunk, s_index),
975 start);
976 start = (start == l_bit) ? 0 : l_bit + 1;
977 }
978
979 end = e_off;
980 if (e_off == e_block->contig_hint_start)
981 end = e_block->contig_hint_start + e_block->contig_hint;
982 else
983 end = find_next_bit(pcpu_index_alloc_map(chunk, e_index),
984 PCPU_BITMAP_BLOCK_BITS, end);
985
986 /* update s_block */
987 e_off = (s_index == e_index) ? end : PCPU_BITMAP_BLOCK_BITS;
988 if (!start && e_off == PCPU_BITMAP_BLOCK_BITS)
989 nr_empty_pages++;
990 pcpu_block_update(s_block, start, e_off);
991
992 /* freeing in the same block */
993 if (s_index != e_index) {
994 /* update e_block */
995 if (end == PCPU_BITMAP_BLOCK_BITS)
996 nr_empty_pages++;
997 pcpu_block_update(e_block, 0, end);
998
999 /* reset md_blocks in the middle */
1000 nr_empty_pages += (e_index - s_index - 1);
1001 for (block = s_block + 1; block < e_block; block++) {
1002 block->first_free = 0;
1003 block->scan_hint = 0;
1004 block->contig_hint_start = 0;
1005 block->contig_hint = PCPU_BITMAP_BLOCK_BITS;
1006 block->left_free = PCPU_BITMAP_BLOCK_BITS;
1007 block->right_free = PCPU_BITMAP_BLOCK_BITS;
1008 }
1009 }
1010
1011 if (nr_empty_pages)
1012 pcpu_update_empty_pages(chunk, nr_empty_pages);
1013
1014 /*
1015 * Refresh chunk metadata when the free makes a block free or spans
1016 * across blocks. The contig_hint may be off by up to a page, but if
1017 * the contig_hint is contained in a block, it will be accurate with
1018 * the else condition below.
1019 */
1020 if (((end - start) >= PCPU_BITMAP_BLOCK_BITS) || s_index != e_index)
1021 pcpu_chunk_refresh_hint(chunk, true);
1022 else
1023 pcpu_block_update(&chunk->chunk_md,
1024 pcpu_block_off_to_off(s_index, start),
1025 end);
1026}
1027
1028/**
1029 * pcpu_is_populated - determines if the region is populated
1030 * @chunk: chunk of interest
1031 * @bit_off: chunk offset
1032 * @bits: size of area
1033 * @next_off: return value for the next offset to start searching
1034 *
1035 * For atomic allocations, check if the backing pages are populated.
1036 *
1037 * RETURNS:
1038 * Bool if the backing pages are populated.
1039 * next_index is to skip over unpopulated blocks in pcpu_find_block_fit.
1040 */
1041static bool pcpu_is_populated(struct pcpu_chunk *chunk, int bit_off, int bits,
1042 int *next_off)
1043{
1044 int page_start, page_end, rs, re;
1045
1046 page_start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE);
1047 page_end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE);
1048
1049 rs = page_start;
1050 pcpu_next_unpop(chunk->populated, &rs, &re, page_end);
1051 if (rs >= page_end)
1052 return true;
1053
1054 *next_off = re * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE;
1055 return false;
1056}
1057
1058/**
1059 * pcpu_find_block_fit - finds the block index to start searching
1060 * @chunk: chunk of interest
1061 * @alloc_bits: size of request in allocation units
1062 * @align: alignment of area (max PAGE_SIZE bytes)
1063 * @pop_only: use populated regions only
1064 *
1065 * Given a chunk and an allocation spec, find the offset to begin searching
1066 * for a free region. This iterates over the bitmap metadata blocks to
1067 * find an offset that will be guaranteed to fit the requirements. It is
1068 * not quite first fit as if the allocation does not fit in the contig hint
1069 * of a block or chunk, it is skipped. This errs on the side of caution
1070 * to prevent excess iteration. Poor alignment can cause the allocator to
1071 * skip over blocks and chunks that have valid free areas.
1072 *
1073 * RETURNS:
1074 * The offset in the bitmap to begin searching.
1075 * -1 if no offset is found.
1076 */
1077static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits,
1078 size_t align, bool pop_only)
1079{
1080 struct pcpu_block_md *chunk_md = &chunk->chunk_md;
1081 int bit_off, bits, next_off;
1082
1083 /*
1084 * Check to see if the allocation can fit in the chunk's contig hint.
1085 * This is an optimization to prevent scanning by assuming if it
1086 * cannot fit in the global hint, there is memory pressure and creating
1087 * a new chunk would happen soon.
1088 */
1089 bit_off = ALIGN(chunk_md->contig_hint_start, align) -
1090 chunk_md->contig_hint_start;
1091 if (bit_off + alloc_bits > chunk_md->contig_hint)
1092 return -1;
1093
1094 bit_off = pcpu_next_hint(chunk_md, alloc_bits);
1095 bits = 0;
1096 pcpu_for_each_fit_region(chunk, alloc_bits, align, bit_off, bits) {
1097 if (!pop_only || pcpu_is_populated(chunk, bit_off, bits,
1098 &next_off))
1099 break;
1100
1101 bit_off = next_off;
1102 bits = 0;
1103 }
1104
1105 if (bit_off == pcpu_chunk_map_bits(chunk))
1106 return -1;
1107
1108 return bit_off;
1109}
1110
1111/*
1112 * pcpu_find_zero_area - modified from bitmap_find_next_zero_area_off()
1113 * @map: the address to base the search on
1114 * @size: the bitmap size in bits
1115 * @start: the bitnumber to start searching at
1116 * @nr: the number of zeroed bits we're looking for
1117 * @align_mask: alignment mask for zero area
1118 * @largest_off: offset of the largest area skipped
1119 * @largest_bits: size of the largest area skipped
1120 *
1121 * The @align_mask should be one less than a power of 2.
1122 *
1123 * This is a modified version of bitmap_find_next_zero_area_off() to remember
1124 * the largest area that was skipped. This is imperfect, but in general is
1125 * good enough. The largest remembered region is the largest failed region
1126 * seen. This does not include anything we possibly skipped due to alignment.
1127 * pcpu_block_update_scan() does scan backwards to try and recover what was
1128 * lost to alignment. While this can cause scanning to miss earlier possible
1129 * free areas, smaller allocations will eventually fill those holes.
1130 */
1131static unsigned long pcpu_find_zero_area(unsigned long *map,
1132 unsigned long size,
1133 unsigned long start,
1134 unsigned long nr,
1135 unsigned long align_mask,
1136 unsigned long *largest_off,
1137 unsigned long *largest_bits)
1138{
1139 unsigned long index, end, i, area_off, area_bits;
1140again:
1141 index = find_next_zero_bit(map, size, start);
1142
1143 /* Align allocation */
1144 index = __ALIGN_MASK(index, align_mask);
1145 area_off = index;
1146
1147 end = index + nr;
1148 if (end > size)
1149 return end;
1150 i = find_next_bit(map, end, index);
1151 if (i < end) {
1152 area_bits = i - area_off;
1153 /* remember largest unused area with best alignment */
1154 if (area_bits > *largest_bits ||
1155 (area_bits == *largest_bits && *largest_off &&
1156 (!area_off || __ffs(area_off) > __ffs(*largest_off)))) {
1157 *largest_off = area_off;
1158 *largest_bits = area_bits;
1159 }
1160
1161 start = i + 1;
1162 goto again;
1163 }
1164 return index;
1165}
1166
1167/**
1168 * pcpu_alloc_area - allocates an area from a pcpu_chunk
1169 * @chunk: chunk of interest
1170 * @alloc_bits: size of request in allocation units
1171 * @align: alignment of area (max PAGE_SIZE)
1172 * @start: bit_off to start searching
1173 *
1174 * This function takes in a @start offset to begin searching to fit an
1175 * allocation of @alloc_bits with alignment @align. It needs to scan
1176 * the allocation map because if it fits within the block's contig hint,
1177 * @start will be block->first_free. This is an attempt to fill the
1178 * allocation prior to breaking the contig hint. The allocation and
1179 * boundary maps are updated accordingly if it confirms a valid
1180 * free area.
1181 *
1182 * RETURNS:
1183 * Allocated addr offset in @chunk on success.
1184 * -1 if no matching area is found.
1185 */
1186static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits,
1187 size_t align, int start)
1188{
1189 struct pcpu_block_md *chunk_md = &chunk->chunk_md;
1190 size_t align_mask = (align) ? (align - 1) : 0;
1191 unsigned long area_off = 0, area_bits = 0;
1192 int bit_off, end, oslot;
1193
1194 lockdep_assert_held(&pcpu_lock);
1195
1196 oslot = pcpu_chunk_slot(chunk);
1197
1198 /*
1199 * Search to find a fit.
1200 */
1201 end = min_t(int, start + alloc_bits + PCPU_BITMAP_BLOCK_BITS,
1202 pcpu_chunk_map_bits(chunk));
1203 bit_off = pcpu_find_zero_area(chunk->alloc_map, end, start, alloc_bits,
1204 align_mask, &area_off, &area_bits);
1205 if (bit_off >= end)
1206 return -1;
1207
1208 if (area_bits)
1209 pcpu_block_update_scan(chunk, area_off, area_bits);
1210
1211 /* update alloc map */
1212 bitmap_set(chunk->alloc_map, bit_off, alloc_bits);
1213
1214 /* update boundary map */
1215 set_bit(bit_off, chunk->bound_map);
1216 bitmap_clear(chunk->bound_map, bit_off + 1, alloc_bits - 1);
1217 set_bit(bit_off + alloc_bits, chunk->bound_map);
1218
1219 chunk->free_bytes -= alloc_bits * PCPU_MIN_ALLOC_SIZE;
1220
1221 /* update first free bit */
1222 if (bit_off == chunk_md->first_free)
1223 chunk_md->first_free = find_next_zero_bit(
1224 chunk->alloc_map,
1225 pcpu_chunk_map_bits(chunk),
1226 bit_off + alloc_bits);
1227
1228 pcpu_block_update_hint_alloc(chunk, bit_off, alloc_bits);
1229
1230 pcpu_chunk_relocate(chunk, oslot);
1231
1232 return bit_off * PCPU_MIN_ALLOC_SIZE;
1233}
1234
1235/**
1236 * pcpu_free_area - frees the corresponding offset
1237 * @chunk: chunk of interest
1238 * @off: addr offset into chunk
1239 *
1240 * This function determines the size of an allocation to free using
1241 * the boundary bitmap and clears the allocation map.
1242 */
1243static void pcpu_free_area(struct pcpu_chunk *chunk, int off)
1244{
1245 struct pcpu_block_md *chunk_md = &chunk->chunk_md;
1246 int bit_off, bits, end, oslot;
1247
1248 lockdep_assert_held(&pcpu_lock);
1249 pcpu_stats_area_dealloc(chunk);
1250
1251 oslot = pcpu_chunk_slot(chunk);
1252
1253 bit_off = off / PCPU_MIN_ALLOC_SIZE;
1254
1255 /* find end index */
1256 end = find_next_bit(chunk->bound_map, pcpu_chunk_map_bits(chunk),
1257 bit_off + 1);
1258 bits = end - bit_off;
1259 bitmap_clear(chunk->alloc_map, bit_off, bits);
1260
1261 /* update metadata */
1262 chunk->free_bytes += bits * PCPU_MIN_ALLOC_SIZE;
1263
1264 /* update first free bit */
1265 chunk_md->first_free = min(chunk_md->first_free, bit_off);
1266
1267 pcpu_block_update_hint_free(chunk, bit_off, bits);
1268
1269 pcpu_chunk_relocate(chunk, oslot);
1270}
1271
1272static void pcpu_init_md_block(struct pcpu_block_md *block, int nr_bits)
1273{
1274 block->scan_hint = 0;
1275 block->contig_hint = nr_bits;
1276 block->left_free = nr_bits;
1277 block->right_free = nr_bits;
1278 block->first_free = 0;
1279 block->nr_bits = nr_bits;
1280}
1281
1282static void pcpu_init_md_blocks(struct pcpu_chunk *chunk)
1283{
1284 struct pcpu_block_md *md_block;
1285
1286 /* init the chunk's block */
1287 pcpu_init_md_block(&chunk->chunk_md, pcpu_chunk_map_bits(chunk));
1288
1289 for (md_block = chunk->md_blocks;
1290 md_block != chunk->md_blocks + pcpu_chunk_nr_blocks(chunk);
1291 md_block++)
1292 pcpu_init_md_block(md_block, PCPU_BITMAP_BLOCK_BITS);
1293}
1294
1295/**
1296 * pcpu_alloc_first_chunk - creates chunks that serve the first chunk
1297 * @tmp_addr: the start of the region served
1298 * @map_size: size of the region served
1299 *
1300 * This is responsible for creating the chunks that serve the first chunk. The
1301 * base_addr is page aligned down of @tmp_addr while the region end is page
1302 * aligned up. Offsets are kept track of to determine the region served. All
1303 * this is done to appease the bitmap allocator in avoiding partial blocks.
1304 *
1305 * RETURNS:
1306 * Chunk serving the region at @tmp_addr of @map_size.
1307 */
1308static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr,
1309 int map_size)
1310{
1311 struct pcpu_chunk *chunk;
1312 unsigned long aligned_addr, lcm_align;
1313 int start_offset, offset_bits, region_size, region_bits;
1314 size_t alloc_size;
1315
1316 /* region calculations */
1317 aligned_addr = tmp_addr & PAGE_MASK;
1318
1319 start_offset = tmp_addr - aligned_addr;
1320
1321 /*
1322 * Align the end of the region with the LCM of PAGE_SIZE and
1323 * PCPU_BITMAP_BLOCK_SIZE. One of these constants is a multiple of
1324 * the other.
1325 */
1326 lcm_align = lcm(PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE);
1327 region_size = ALIGN(start_offset + map_size, lcm_align);
1328
1329 /* allocate chunk */
1330 alloc_size = sizeof(struct pcpu_chunk) +
1331 BITS_TO_LONGS(region_size >> PAGE_SHIFT);
1332 chunk = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
1333 if (!chunk)
1334 panic("%s: Failed to allocate %zu bytes\n", __func__,
1335 alloc_size);
1336
1337 INIT_LIST_HEAD(&chunk->list);
1338
1339 chunk->base_addr = (void *)aligned_addr;
1340 chunk->start_offset = start_offset;
1341 chunk->end_offset = region_size - chunk->start_offset - map_size;
1342
1343 chunk->nr_pages = region_size >> PAGE_SHIFT;
1344 region_bits = pcpu_chunk_map_bits(chunk);
1345
1346 alloc_size = BITS_TO_LONGS(region_bits) * sizeof(chunk->alloc_map[0]);
1347 chunk->alloc_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
1348 if (!chunk->alloc_map)
1349 panic("%s: Failed to allocate %zu bytes\n", __func__,
1350 alloc_size);
1351
1352 alloc_size =
1353 BITS_TO_LONGS(region_bits + 1) * sizeof(chunk->bound_map[0]);
1354 chunk->bound_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
1355 if (!chunk->bound_map)
1356 panic("%s: Failed to allocate %zu bytes\n", __func__,
1357 alloc_size);
1358
1359 alloc_size = pcpu_chunk_nr_blocks(chunk) * sizeof(chunk->md_blocks[0]);
1360 chunk->md_blocks = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
1361 if (!chunk->md_blocks)
1362 panic("%s: Failed to allocate %zu bytes\n", __func__,
1363 alloc_size);
1364
1365 pcpu_init_md_blocks(chunk);
1366
1367 /* manage populated page bitmap */
1368 chunk->immutable = true;
1369 bitmap_fill(chunk->populated, chunk->nr_pages);
1370 chunk->nr_populated = chunk->nr_pages;
1371 chunk->nr_empty_pop_pages = chunk->nr_pages;
1372
1373 chunk->free_bytes = map_size;
1374
1375 if (chunk->start_offset) {
1376 /* hide the beginning of the bitmap */
1377 offset_bits = chunk->start_offset / PCPU_MIN_ALLOC_SIZE;
1378 bitmap_set(chunk->alloc_map, 0, offset_bits);
1379 set_bit(0, chunk->bound_map);
1380 set_bit(offset_bits, chunk->bound_map);
1381
1382 chunk->chunk_md.first_free = offset_bits;
1383
1384 pcpu_block_update_hint_alloc(chunk, 0, offset_bits);
1385 }
1386
1387 if (chunk->end_offset) {
1388 /* hide the end of the bitmap */
1389 offset_bits = chunk->end_offset / PCPU_MIN_ALLOC_SIZE;
1390 bitmap_set(chunk->alloc_map,
1391 pcpu_chunk_map_bits(chunk) - offset_bits,
1392 offset_bits);
1393 set_bit((start_offset + map_size) / PCPU_MIN_ALLOC_SIZE,
1394 chunk->bound_map);
1395 set_bit(region_bits, chunk->bound_map);
1396
1397 pcpu_block_update_hint_alloc(chunk, pcpu_chunk_map_bits(chunk)
1398 - offset_bits, offset_bits);
1399 }
1400
1401 return chunk;
1402}
1403
1404static struct pcpu_chunk *pcpu_alloc_chunk(gfp_t gfp)
1405{
1406 struct pcpu_chunk *chunk;
1407 int region_bits;
1408
1409 chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size, gfp);
1410 if (!chunk)
1411 return NULL;
1412
1413 INIT_LIST_HEAD(&chunk->list);
1414 chunk->nr_pages = pcpu_unit_pages;
1415 region_bits = pcpu_chunk_map_bits(chunk);
1416
1417 chunk->alloc_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits) *
1418 sizeof(chunk->alloc_map[0]), gfp);
1419 if (!chunk->alloc_map)
1420 goto alloc_map_fail;
1421
1422 chunk->bound_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits + 1) *
1423 sizeof(chunk->bound_map[0]), gfp);
1424 if (!chunk->bound_map)
1425 goto bound_map_fail;
1426
1427 chunk->md_blocks = pcpu_mem_zalloc(pcpu_chunk_nr_blocks(chunk) *
1428 sizeof(chunk->md_blocks[0]), gfp);
1429 if (!chunk->md_blocks)
1430 goto md_blocks_fail;
1431
1432 pcpu_init_md_blocks(chunk);
1433
1434 /* init metadata */
1435 chunk->free_bytes = chunk->nr_pages * PAGE_SIZE;
1436
1437 return chunk;
1438
1439md_blocks_fail:
1440 pcpu_mem_free(chunk->bound_map);
1441bound_map_fail:
1442 pcpu_mem_free(chunk->alloc_map);
1443alloc_map_fail:
1444 pcpu_mem_free(chunk);
1445
1446 return NULL;
1447}
1448
1449static void pcpu_free_chunk(struct pcpu_chunk *chunk)
1450{
1451 if (!chunk)
1452 return;
1453 pcpu_mem_free(chunk->md_blocks);
1454 pcpu_mem_free(chunk->bound_map);
1455 pcpu_mem_free(chunk->alloc_map);
1456 pcpu_mem_free(chunk);
1457}
1458
1459/**
1460 * pcpu_chunk_populated - post-population bookkeeping
1461 * @chunk: pcpu_chunk which got populated
1462 * @page_start: the start page
1463 * @page_end: the end page
1464 *
1465 * Pages in [@page_start,@page_end) have been populated to @chunk. Update
1466 * the bookkeeping information accordingly. Must be called after each
1467 * successful population.
1468 *
1469 * If this is @for_alloc, do not increment pcpu_nr_empty_pop_pages because it
1470 * is to serve an allocation in that area.
1471 */
1472static void pcpu_chunk_populated(struct pcpu_chunk *chunk, int page_start,
1473 int page_end)
1474{
1475 int nr = page_end - page_start;
1476
1477 lockdep_assert_held(&pcpu_lock);
1478
1479 bitmap_set(chunk->populated, page_start, nr);
1480 chunk->nr_populated += nr;
1481 pcpu_nr_populated += nr;
1482
1483 pcpu_update_empty_pages(chunk, nr);
1484}
1485
1486/**
1487 * pcpu_chunk_depopulated - post-depopulation bookkeeping
1488 * @chunk: pcpu_chunk which got depopulated
1489 * @page_start: the start page
1490 * @page_end: the end page
1491 *
1492 * Pages in [@page_start,@page_end) have been depopulated from @chunk.
1493 * Update the bookkeeping information accordingly. Must be called after
1494 * each successful depopulation.
1495 */
1496static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk,
1497 int page_start, int page_end)
1498{
1499 int nr = page_end - page_start;
1500
1501 lockdep_assert_held(&pcpu_lock);
1502
1503 bitmap_clear(chunk->populated, page_start, nr);
1504 chunk->nr_populated -= nr;
1505 pcpu_nr_populated -= nr;
1506
1507 pcpu_update_empty_pages(chunk, -nr);
1508}
1509
1510/*
1511 * Chunk management implementation.
1512 *
1513 * To allow different implementations, chunk alloc/free and
1514 * [de]population are implemented in a separate file which is pulled
1515 * into this file and compiled together. The following functions
1516 * should be implemented.
1517 *
1518 * pcpu_populate_chunk - populate the specified range of a chunk
1519 * pcpu_depopulate_chunk - depopulate the specified range of a chunk
1520 * pcpu_create_chunk - create a new chunk
1521 * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
1522 * pcpu_addr_to_page - translate address to physical address
1523 * pcpu_verify_alloc_info - check alloc_info is acceptable during init
1524 */
1525static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
1526 int page_start, int page_end, gfp_t gfp);
1527static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
1528 int page_start, int page_end);
1529static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp);
1530static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
1531static struct page *pcpu_addr_to_page(void *addr);
1532static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
1533
1534#ifdef CONFIG_NEED_PER_CPU_KM
1535#include "percpu-km.c"
1536#else
1537#include "percpu-vm.c"
1538#endif
1539
1540/**
1541 * pcpu_chunk_addr_search - determine chunk containing specified address
1542 * @addr: address for which the chunk needs to be determined.
1543 *
1544 * This is an internal function that handles all but static allocations.
1545 * Static percpu address values should never be passed into the allocator.
1546 *
1547 * RETURNS:
1548 * The address of the found chunk.
1549 */
1550static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
1551{
1552 /* is it in the dynamic region (first chunk)? */
1553 if (pcpu_addr_in_chunk(pcpu_first_chunk, addr))
1554 return pcpu_first_chunk;
1555
1556 /* is it in the reserved region? */
1557 if (pcpu_addr_in_chunk(pcpu_reserved_chunk, addr))
1558 return pcpu_reserved_chunk;
1559
1560 /*
1561 * The address is relative to unit0 which might be unused and
1562 * thus unmapped. Offset the address to the unit space of the
1563 * current processor before looking it up in the vmalloc
1564 * space. Note that any possible cpu id can be used here, so
1565 * there's no need to worry about preemption or cpu hotplug.
1566 */
1567 addr += pcpu_unit_offsets[raw_smp_processor_id()];
1568 return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
1569}
1570
1571/**
1572 * pcpu_alloc - the percpu allocator
1573 * @size: size of area to allocate in bytes
1574 * @align: alignment of area (max PAGE_SIZE)
1575 * @reserved: allocate from the reserved chunk if available
1576 * @gfp: allocation flags
1577 *
1578 * Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't
1579 * contain %GFP_KERNEL, the allocation is atomic. If @gfp has __GFP_NOWARN
1580 * then no warning will be triggered on invalid or failed allocation
1581 * requests.
1582 *
1583 * RETURNS:
1584 * Percpu pointer to the allocated area on success, NULL on failure.
1585 */
1586static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
1587 gfp_t gfp)
1588{
1589 /* whitelisted flags that can be passed to the backing allocators */
1590 gfp_t pcpu_gfp = gfp & (GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
1591 bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;
1592 bool do_warn = !(gfp & __GFP_NOWARN);
1593 static int warn_limit = 10;
1594 struct pcpu_chunk *chunk, *next;
1595 const char *err;
1596 int slot, off, cpu, ret;
1597 unsigned long flags;
1598 void __percpu *ptr;
1599 size_t bits, bit_align;
1600
1601 /*
1602 * There is now a minimum allocation size of PCPU_MIN_ALLOC_SIZE,
1603 * therefore alignment must be a minimum of that many bytes.
1604 * An allocation may have internal fragmentation from rounding up
1605 * of up to PCPU_MIN_ALLOC_SIZE - 1 bytes.
1606 */
1607 if (unlikely(align < PCPU_MIN_ALLOC_SIZE))
1608 align = PCPU_MIN_ALLOC_SIZE;
1609
1610 size = ALIGN(size, PCPU_MIN_ALLOC_SIZE);
1611 bits = size >> PCPU_MIN_ALLOC_SHIFT;
1612 bit_align = align >> PCPU_MIN_ALLOC_SHIFT;
1613
1614 if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE ||
1615 !is_power_of_2(align))) {
1616 WARN(do_warn, "illegal size (%zu) or align (%zu) for percpu allocation\n",
1617 size, align);
1618 return NULL;
1619 }
1620
1621 if (!is_atomic) {
1622 /*
1623 * pcpu_balance_workfn() allocates memory under this mutex,
1624 * and it may wait for memory reclaim. Allow current task
1625 * to become OOM victim, in case of memory pressure.
1626 */
1627 if (gfp & __GFP_NOFAIL)
1628 mutex_lock(&pcpu_alloc_mutex);
1629 else if (mutex_lock_killable(&pcpu_alloc_mutex))
1630 return NULL;
1631 }
1632
1633 spin_lock_irqsave(&pcpu_lock, flags);
1634
1635 /* serve reserved allocations from the reserved chunk if available */
1636 if (reserved && pcpu_reserved_chunk) {
1637 chunk = pcpu_reserved_chunk;
1638
1639 off = pcpu_find_block_fit(chunk, bits, bit_align, is_atomic);
1640 if (off < 0) {
1641 err = "alloc from reserved chunk failed";
1642 goto fail_unlock;
1643 }
1644
1645 off = pcpu_alloc_area(chunk, bits, bit_align, off);
1646 if (off >= 0)
1647 goto area_found;
1648
1649 err = "alloc from reserved chunk failed";
1650 goto fail_unlock;
1651 }
1652
1653restart:
1654 /* search through normal chunks */
1655 for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
1656 list_for_each_entry_safe(chunk, next, &pcpu_slot[slot], list) {
1657 off = pcpu_find_block_fit(chunk, bits, bit_align,
1658 is_atomic);
1659 if (off < 0) {
1660 if (slot < PCPU_SLOT_FAIL_THRESHOLD)
1661 pcpu_chunk_move(chunk, 0);
1662 continue;
1663 }
1664
1665 off = pcpu_alloc_area(chunk, bits, bit_align, off);
1666 if (off >= 0)
1667 goto area_found;
1668
1669 }
1670 }
1671
1672 spin_unlock_irqrestore(&pcpu_lock, flags);
1673
1674 /*
1675 * No space left. Create a new chunk. We don't want multiple
1676 * tasks to create chunks simultaneously. Serialize and create iff
1677 * there's still no empty chunk after grabbing the mutex.
1678 */
1679 if (is_atomic) {
1680 err = "atomic alloc failed, no space left";
1681 goto fail;
1682 }
1683
1684 if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
1685 chunk = pcpu_create_chunk(pcpu_gfp);
1686 if (!chunk) {
1687 err = "failed to allocate new chunk";
1688 goto fail;
1689 }
1690
1691 spin_lock_irqsave(&pcpu_lock, flags);
1692 pcpu_chunk_relocate(chunk, -1);
1693 } else {
1694 spin_lock_irqsave(&pcpu_lock, flags);
1695 }
1696
1697 goto restart;
1698
1699area_found:
1700 pcpu_stats_area_alloc(chunk, size);
1701 spin_unlock_irqrestore(&pcpu_lock, flags);
1702
1703 /* populate if not all pages are already there */
1704 if (!is_atomic) {
1705 int page_start, page_end, rs, re;
1706
1707 page_start = PFN_DOWN(off);
1708 page_end = PFN_UP(off + size);
1709
1710 pcpu_for_each_unpop_region(chunk->populated, rs, re,
1711 page_start, page_end) {
1712 WARN_ON(chunk->immutable);
1713
1714 ret = pcpu_populate_chunk(chunk, rs, re, pcpu_gfp);
1715
1716 spin_lock_irqsave(&pcpu_lock, flags);
1717 if (ret) {
1718 pcpu_free_area(chunk, off);
1719 err = "failed to populate";
1720 goto fail_unlock;
1721 }
1722 pcpu_chunk_populated(chunk, rs, re);
1723 spin_unlock_irqrestore(&pcpu_lock, flags);
1724 }
1725
1726 mutex_unlock(&pcpu_alloc_mutex);
1727 }
1728
1729 if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
1730 pcpu_schedule_balance_work();
1731
1732 /* clear the areas and return address relative to base address */
1733 for_each_possible_cpu(cpu)
1734 memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
1735
1736 ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
1737 kmemleak_alloc_percpu(ptr, size, gfp);
1738
1739 trace_percpu_alloc_percpu(reserved, is_atomic, size, align,
1740 chunk->base_addr, off, ptr);
1741
1742 return ptr;
1743
1744fail_unlock:
1745 spin_unlock_irqrestore(&pcpu_lock, flags);
1746fail:
1747 trace_percpu_alloc_percpu_fail(reserved, is_atomic, size, align);
1748
1749 if (!is_atomic && do_warn && warn_limit) {
1750 pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n",
1751 size, align, is_atomic, err);
1752 dump_stack();
1753 if (!--warn_limit)
1754 pr_info("limit reached, disable warning\n");
1755 }
1756 if (is_atomic) {
1757 /* see the flag handling in pcpu_blance_workfn() */
1758 pcpu_atomic_alloc_failed = true;
1759 pcpu_schedule_balance_work();
1760 } else {
1761 mutex_unlock(&pcpu_alloc_mutex);
1762 }
1763 return NULL;
1764}
1765
1766/**
1767 * __alloc_percpu_gfp - allocate dynamic percpu area
1768 * @size: size of area to allocate in bytes
1769 * @align: alignment of area (max PAGE_SIZE)
1770 * @gfp: allocation flags
1771 *
1772 * Allocate zero-filled percpu area of @size bytes aligned at @align. If
1773 * @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can
1774 * be called from any context but is a lot more likely to fail. If @gfp
1775 * has __GFP_NOWARN then no warning will be triggered on invalid or failed
1776 * allocation requests.
1777 *
1778 * RETURNS:
1779 * Percpu pointer to the allocated area on success, NULL on failure.
1780 */
1781void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp)
1782{
1783 return pcpu_alloc(size, align, false, gfp);
1784}
1785EXPORT_SYMBOL_GPL(__alloc_percpu_gfp);
1786
1787/**
1788 * __alloc_percpu - allocate dynamic percpu area
1789 * @size: size of area to allocate in bytes
1790 * @align: alignment of area (max PAGE_SIZE)
1791 *
1792 * Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL).
1793 */
1794void __percpu *__alloc_percpu(size_t size, size_t align)
1795{
1796 return pcpu_alloc(size, align, false, GFP_KERNEL);
1797}
1798EXPORT_SYMBOL_GPL(__alloc_percpu);
1799
1800/**
1801 * __alloc_reserved_percpu - allocate reserved percpu area
1802 * @size: size of area to allocate in bytes
1803 * @align: alignment of area (max PAGE_SIZE)
1804 *
1805 * Allocate zero-filled percpu area of @size bytes aligned at @align
1806 * from reserved percpu area if arch has set it up; otherwise,
1807 * allocation is served from the same dynamic area. Might sleep.
1808 * Might trigger writeouts.
1809 *
1810 * CONTEXT:
1811 * Does GFP_KERNEL allocation.
1812 *
1813 * RETURNS:
1814 * Percpu pointer to the allocated area on success, NULL on failure.
1815 */
1816void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
1817{
1818 return pcpu_alloc(size, align, true, GFP_KERNEL);
1819}
1820
1821/**
1822 * pcpu_balance_workfn - manage the amount of free chunks and populated pages
1823 * @work: unused
1824 *
1825 * Reclaim all fully free chunks except for the first one. This is also
1826 * responsible for maintaining the pool of empty populated pages. However,
1827 * it is possible that this is called when physical memory is scarce causing
1828 * OOM killer to be triggered. We should avoid doing so until an actual
1829 * allocation causes the failure as it is possible that requests can be
1830 * serviced from already backed regions.
1831 */
1832static void pcpu_balance_workfn(struct work_struct *work)
1833{
1834 /* gfp flags passed to underlying allocators */
1835 const gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
1836 LIST_HEAD(to_free);
1837 struct list_head *free_head = &pcpu_slot[pcpu_nr_slots - 1];
1838 struct pcpu_chunk *chunk, *next;
1839 int slot, nr_to_pop, ret;
1840
1841 /*
1842 * There's no reason to keep around multiple unused chunks and VM
1843 * areas can be scarce. Destroy all free chunks except for one.
1844 */
1845 mutex_lock(&pcpu_alloc_mutex);
1846 spin_lock_irq(&pcpu_lock);
1847
1848 list_for_each_entry_safe(chunk, next, free_head, list) {
1849 WARN_ON(chunk->immutable);
1850
1851 /* spare the first one */
1852 if (chunk == list_first_entry(free_head, struct pcpu_chunk, list))
1853 continue;
1854
1855 list_move(&chunk->list, &to_free);
1856 }
1857
1858 spin_unlock_irq(&pcpu_lock);
1859
1860 list_for_each_entry_safe(chunk, next, &to_free, list) {
1861 int rs, re;
1862
1863 pcpu_for_each_pop_region(chunk->populated, rs, re, 0,
1864 chunk->nr_pages) {
1865 pcpu_depopulate_chunk(chunk, rs, re);
1866 spin_lock_irq(&pcpu_lock);
1867 pcpu_chunk_depopulated(chunk, rs, re);
1868 spin_unlock_irq(&pcpu_lock);
1869 }
1870 pcpu_destroy_chunk(chunk);
1871 cond_resched();
1872 }
1873
1874 /*
1875 * Ensure there are certain number of free populated pages for
1876 * atomic allocs. Fill up from the most packed so that atomic
1877 * allocs don't increase fragmentation. If atomic allocation
1878 * failed previously, always populate the maximum amount. This
1879 * should prevent atomic allocs larger than PAGE_SIZE from keeping
1880 * failing indefinitely; however, large atomic allocs are not
1881 * something we support properly and can be highly unreliable and
1882 * inefficient.
1883 */
1884retry_pop:
1885 if (pcpu_atomic_alloc_failed) {
1886 nr_to_pop = PCPU_EMPTY_POP_PAGES_HIGH;
1887 /* best effort anyway, don't worry about synchronization */
1888 pcpu_atomic_alloc_failed = false;
1889 } else {
1890 nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH -
1891 pcpu_nr_empty_pop_pages,
1892 0, PCPU_EMPTY_POP_PAGES_HIGH);
1893 }
1894
1895 for (slot = pcpu_size_to_slot(PAGE_SIZE); slot < pcpu_nr_slots; slot++) {
1896 int nr_unpop = 0, rs, re;
1897
1898 if (!nr_to_pop)
1899 break;
1900
1901 spin_lock_irq(&pcpu_lock);
1902 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
1903 nr_unpop = chunk->nr_pages - chunk->nr_populated;
1904 if (nr_unpop)
1905 break;
1906 }
1907 spin_unlock_irq(&pcpu_lock);
1908
1909 if (!nr_unpop)
1910 continue;
1911
1912 /* @chunk can't go away while pcpu_alloc_mutex is held */
1913 pcpu_for_each_unpop_region(chunk->populated, rs, re, 0,
1914 chunk->nr_pages) {
1915 int nr = min(re - rs, nr_to_pop);
1916
1917 ret = pcpu_populate_chunk(chunk, rs, rs + nr, gfp);
1918 if (!ret) {
1919 nr_to_pop -= nr;
1920 spin_lock_irq(&pcpu_lock);
1921 pcpu_chunk_populated(chunk, rs, rs + nr);
1922 spin_unlock_irq(&pcpu_lock);
1923 } else {
1924 nr_to_pop = 0;
1925 }
1926
1927 if (!nr_to_pop)
1928 break;
1929 }
1930 }
1931
1932 if (nr_to_pop) {
1933 /* ran out of chunks to populate, create a new one and retry */
1934 chunk = pcpu_create_chunk(gfp);
1935 if (chunk) {
1936 spin_lock_irq(&pcpu_lock);
1937 pcpu_chunk_relocate(chunk, -1);
1938 spin_unlock_irq(&pcpu_lock);
1939 goto retry_pop;
1940 }
1941 }
1942
1943 mutex_unlock(&pcpu_alloc_mutex);
1944}
1945
1946/**
1947 * free_percpu - free percpu area
1948 * @ptr: pointer to area to free
1949 *
1950 * Free percpu area @ptr.
1951 *
1952 * CONTEXT:
1953 * Can be called from atomic context.
1954 */
1955void free_percpu(void __percpu *ptr)
1956{
1957 void *addr;
1958 struct pcpu_chunk *chunk;
1959 unsigned long flags;
1960 int off;
1961 bool need_balance = false;
1962
1963 if (!ptr)
1964 return;
1965
1966 kmemleak_free_percpu(ptr);
1967
1968 addr = __pcpu_ptr_to_addr(ptr);
1969
1970 spin_lock_irqsave(&pcpu_lock, flags);
1971
1972 chunk = pcpu_chunk_addr_search(addr);
1973 off = addr - chunk->base_addr;
1974
1975 pcpu_free_area(chunk, off);
1976
1977 /* if there are more than one fully free chunks, wake up grim reaper */
1978 if (chunk->free_bytes == pcpu_unit_size) {
1979 struct pcpu_chunk *pos;
1980
1981 list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
1982 if (pos != chunk) {
1983 need_balance = true;
1984 break;
1985 }
1986 }
1987
1988 trace_percpu_free_percpu(chunk->base_addr, off, ptr);
1989
1990 spin_unlock_irqrestore(&pcpu_lock, flags);
1991
1992 if (need_balance)
1993 pcpu_schedule_balance_work();
1994}
1995EXPORT_SYMBOL_GPL(free_percpu);
1996
1997bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr)
1998{
1999#ifdef CONFIG_SMP
2000 const size_t static_size = __per_cpu_end - __per_cpu_start;
2001 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
2002 unsigned int cpu;
2003
2004 for_each_possible_cpu(cpu) {
2005 void *start = per_cpu_ptr(base, cpu);
2006 void *va = (void *)addr;
2007
2008 if (va >= start && va < start + static_size) {
2009 if (can_addr) {
2010 *can_addr = (unsigned long) (va - start);
2011 *can_addr += (unsigned long)
2012 per_cpu_ptr(base, get_boot_cpu_id());
2013 }
2014 return true;
2015 }
2016 }
2017#endif
2018 /* on UP, can't distinguish from other static vars, always false */
2019 return false;
2020}
2021
2022/**
2023 * is_kernel_percpu_address - test whether address is from static percpu area
2024 * @addr: address to test
2025 *
2026 * Test whether @addr belongs to in-kernel static percpu area. Module
2027 * static percpu areas are not considered. For those, use
2028 * is_module_percpu_address().
2029 *
2030 * RETURNS:
2031 * %true if @addr is from in-kernel static percpu area, %false otherwise.
2032 */
2033bool is_kernel_percpu_address(unsigned long addr)
2034{
2035 return __is_kernel_percpu_address(addr, NULL);
2036}
2037
2038/**
2039 * per_cpu_ptr_to_phys - convert translated percpu address to physical address
2040 * @addr: the address to be converted to physical address
2041 *
2042 * Given @addr which is dereferenceable address obtained via one of
2043 * percpu access macros, this function translates it into its physical
2044 * address. The caller is responsible for ensuring @addr stays valid
2045 * until this function finishes.
2046 *
2047 * percpu allocator has special setup for the first chunk, which currently
2048 * supports either embedding in linear address space or vmalloc mapping,
2049 * and, from the second one, the backing allocator (currently either vm or
2050 * km) provides translation.
2051 *
2052 * The addr can be translated simply without checking if it falls into the
2053 * first chunk. But the current code reflects better how percpu allocator
2054 * actually works, and the verification can discover both bugs in percpu
2055 * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
2056 * code.
2057 *
2058 * RETURNS:
2059 * The physical address for @addr.
2060 */
2061phys_addr_t per_cpu_ptr_to_phys(void *addr)
2062{
2063 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
2064 bool in_first_chunk = false;
2065 unsigned long first_low, first_high;
2066 unsigned int cpu;
2067
2068 /*
2069 * The following test on unit_low/high isn't strictly
2070 * necessary but will speed up lookups of addresses which
2071 * aren't in the first chunk.
2072 *
2073 * The address check is against full chunk sizes. pcpu_base_addr
2074 * points to the beginning of the first chunk including the
2075 * static region. Assumes good intent as the first chunk may
2076 * not be full (ie. < pcpu_unit_pages in size).
2077 */
2078 first_low = (unsigned long)pcpu_base_addr +
2079 pcpu_unit_page_offset(pcpu_low_unit_cpu, 0);
2080 first_high = (unsigned long)pcpu_base_addr +
2081 pcpu_unit_page_offset(pcpu_high_unit_cpu, pcpu_unit_pages);
2082 if ((unsigned long)addr >= first_low &&
2083 (unsigned long)addr < first_high) {
2084 for_each_possible_cpu(cpu) {
2085 void *start = per_cpu_ptr(base, cpu);
2086
2087 if (addr >= start && addr < start + pcpu_unit_size) {
2088 in_first_chunk = true;
2089 break;
2090 }
2091 }
2092 }
2093
2094 if (in_first_chunk) {
2095 if (!is_vmalloc_addr(addr))
2096 return __pa(addr);
2097 else
2098 return page_to_phys(vmalloc_to_page(addr)) +
2099 offset_in_page(addr);
2100 } else
2101 return page_to_phys(pcpu_addr_to_page(addr)) +
2102 offset_in_page(addr);
2103}
2104
2105/**
2106 * pcpu_alloc_alloc_info - allocate percpu allocation info
2107 * @nr_groups: the number of groups
2108 * @nr_units: the number of units
2109 *
2110 * Allocate ai which is large enough for @nr_groups groups containing
2111 * @nr_units units. The returned ai's groups[0].cpu_map points to the
2112 * cpu_map array which is long enough for @nr_units and filled with
2113 * NR_CPUS. It's the caller's responsibility to initialize cpu_map
2114 * pointer of other groups.
2115 *
2116 * RETURNS:
2117 * Pointer to the allocated pcpu_alloc_info on success, NULL on
2118 * failure.
2119 */
2120struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
2121 int nr_units)
2122{
2123 struct pcpu_alloc_info *ai;
2124 size_t base_size, ai_size;
2125 void *ptr;
2126 int unit;
2127
2128 base_size = ALIGN(struct_size(ai, groups, nr_groups),
2129 __alignof__(ai->groups[0].cpu_map[0]));
2130 ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
2131
2132 ptr = memblock_alloc(PFN_ALIGN(ai_size), PAGE_SIZE);
2133 if (!ptr)
2134 return NULL;
2135 ai = ptr;
2136 ptr += base_size;
2137
2138 ai->groups[0].cpu_map = ptr;
2139
2140 for (unit = 0; unit < nr_units; unit++)
2141 ai->groups[0].cpu_map[unit] = NR_CPUS;
2142
2143 ai->nr_groups = nr_groups;
2144 ai->__ai_size = PFN_ALIGN(ai_size);
2145
2146 return ai;
2147}
2148
2149/**
2150 * pcpu_free_alloc_info - free percpu allocation info
2151 * @ai: pcpu_alloc_info to free
2152 *
2153 * Free @ai which was allocated by pcpu_alloc_alloc_info().
2154 */
2155void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
2156{
2157 memblock_free_early(__pa(ai), ai->__ai_size);
2158}
2159
2160/**
2161 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
2162 * @lvl: loglevel
2163 * @ai: allocation info to dump
2164 *
2165 * Print out information about @ai using loglevel @lvl.
2166 */
2167static void pcpu_dump_alloc_info(const char *lvl,
2168 const struct pcpu_alloc_info *ai)
2169{
2170 int group_width = 1, cpu_width = 1, width;
2171 char empty_str[] = "--------";
2172 int alloc = 0, alloc_end = 0;
2173 int group, v;
2174 int upa, apl; /* units per alloc, allocs per line */
2175
2176 v = ai->nr_groups;
2177 while (v /= 10)
2178 group_width++;
2179
2180 v = num_possible_cpus();
2181 while (v /= 10)
2182 cpu_width++;
2183 empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
2184
2185 upa = ai->alloc_size / ai->unit_size;
2186 width = upa * (cpu_width + 1) + group_width + 3;
2187 apl = rounddown_pow_of_two(max(60 / width, 1));
2188
2189 printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
2190 lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
2191 ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
2192
2193 for (group = 0; group < ai->nr_groups; group++) {
2194 const struct pcpu_group_info *gi = &ai->groups[group];
2195 int unit = 0, unit_end = 0;
2196
2197 BUG_ON(gi->nr_units % upa);
2198 for (alloc_end += gi->nr_units / upa;
2199 alloc < alloc_end; alloc++) {
2200 if (!(alloc % apl)) {
2201 pr_cont("\n");
2202 printk("%spcpu-alloc: ", lvl);
2203 }
2204 pr_cont("[%0*d] ", group_width, group);
2205
2206 for (unit_end += upa; unit < unit_end; unit++)
2207 if (gi->cpu_map[unit] != NR_CPUS)
2208 pr_cont("%0*d ",
2209 cpu_width, gi->cpu_map[unit]);
2210 else
2211 pr_cont("%s ", empty_str);
2212 }
2213 }
2214 pr_cont("\n");
2215}
2216
2217/**
2218 * pcpu_setup_first_chunk - initialize the first percpu chunk
2219 * @ai: pcpu_alloc_info describing how to percpu area is shaped
2220 * @base_addr: mapped address
2221 *
2222 * Initialize the first percpu chunk which contains the kernel static
2223 * percpu area. This function is to be called from arch percpu area
2224 * setup path.
2225 *
2226 * @ai contains all information necessary to initialize the first
2227 * chunk and prime the dynamic percpu allocator.
2228 *
2229 * @ai->static_size is the size of static percpu area.
2230 *
2231 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
2232 * reserve after the static area in the first chunk. This reserves
2233 * the first chunk such that it's available only through reserved
2234 * percpu allocation. This is primarily used to serve module percpu
2235 * static areas on architectures where the addressing model has
2236 * limited offset range for symbol relocations to guarantee module
2237 * percpu symbols fall inside the relocatable range.
2238 *
2239 * @ai->dyn_size determines the number of bytes available for dynamic
2240 * allocation in the first chunk. The area between @ai->static_size +
2241 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
2242 *
2243 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
2244 * and equal to or larger than @ai->static_size + @ai->reserved_size +
2245 * @ai->dyn_size.
2246 *
2247 * @ai->atom_size is the allocation atom size and used as alignment
2248 * for vm areas.
2249 *
2250 * @ai->alloc_size is the allocation size and always multiple of
2251 * @ai->atom_size. This is larger than @ai->atom_size if
2252 * @ai->unit_size is larger than @ai->atom_size.
2253 *
2254 * @ai->nr_groups and @ai->groups describe virtual memory layout of
2255 * percpu areas. Units which should be colocated are put into the
2256 * same group. Dynamic VM areas will be allocated according to these
2257 * groupings. If @ai->nr_groups is zero, a single group containing
2258 * all units is assumed.
2259 *
2260 * The caller should have mapped the first chunk at @base_addr and
2261 * copied static data to each unit.
2262 *
2263 * The first chunk will always contain a static and a dynamic region.
2264 * However, the static region is not managed by any chunk. If the first
2265 * chunk also contains a reserved region, it is served by two chunks -
2266 * one for the reserved region and one for the dynamic region. They
2267 * share the same vm, but use offset regions in the area allocation map.
2268 * The chunk serving the dynamic region is circulated in the chunk slots
2269 * and available for dynamic allocation like any other chunk.
2270 */
2271void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
2272 void *base_addr)
2273{
2274 size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
2275 size_t static_size, dyn_size;
2276 struct pcpu_chunk *chunk;
2277 unsigned long *group_offsets;
2278 size_t *group_sizes;
2279 unsigned long *unit_off;
2280 unsigned int cpu;
2281 int *unit_map;
2282 int group, unit, i;
2283 int map_size;
2284 unsigned long tmp_addr;
2285 size_t alloc_size;
2286
2287#define PCPU_SETUP_BUG_ON(cond) do { \
2288 if (unlikely(cond)) { \
2289 pr_emerg("failed to initialize, %s\n", #cond); \
2290 pr_emerg("cpu_possible_mask=%*pb\n", \
2291 cpumask_pr_args(cpu_possible_mask)); \
2292 pcpu_dump_alloc_info(KERN_EMERG, ai); \
2293 BUG(); \
2294 } \
2295} while (0)
2296
2297 /* sanity checks */
2298 PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
2299#ifdef CONFIG_SMP
2300 PCPU_SETUP_BUG_ON(!ai->static_size);
2301 PCPU_SETUP_BUG_ON(offset_in_page(__per_cpu_start));
2302#endif
2303 PCPU_SETUP_BUG_ON(!base_addr);
2304 PCPU_SETUP_BUG_ON(offset_in_page(base_addr));
2305 PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
2306 PCPU_SETUP_BUG_ON(offset_in_page(ai->unit_size));
2307 PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
2308 PCPU_SETUP_BUG_ON(!IS_ALIGNED(ai->unit_size, PCPU_BITMAP_BLOCK_SIZE));
2309 PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
2310 PCPU_SETUP_BUG_ON(!ai->dyn_size);
2311 PCPU_SETUP_BUG_ON(!IS_ALIGNED(ai->reserved_size, PCPU_MIN_ALLOC_SIZE));
2312 PCPU_SETUP_BUG_ON(!(IS_ALIGNED(PCPU_BITMAP_BLOCK_SIZE, PAGE_SIZE) ||
2313 IS_ALIGNED(PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE)));
2314 PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
2315
2316 /* process group information and build config tables accordingly */
2317 alloc_size = ai->nr_groups * sizeof(group_offsets[0]);
2318 group_offsets = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
2319 if (!group_offsets)
2320 panic("%s: Failed to allocate %zu bytes\n", __func__,
2321 alloc_size);
2322
2323 alloc_size = ai->nr_groups * sizeof(group_sizes[0]);
2324 group_sizes = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
2325 if (!group_sizes)
2326 panic("%s: Failed to allocate %zu bytes\n", __func__,
2327 alloc_size);
2328
2329 alloc_size = nr_cpu_ids * sizeof(unit_map[0]);
2330 unit_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
2331 if (!unit_map)
2332 panic("%s: Failed to allocate %zu bytes\n", __func__,
2333 alloc_size);
2334
2335 alloc_size = nr_cpu_ids * sizeof(unit_off[0]);
2336 unit_off = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
2337 if (!unit_off)
2338 panic("%s: Failed to allocate %zu bytes\n", __func__,
2339 alloc_size);
2340
2341 for (cpu = 0; cpu < nr_cpu_ids; cpu++)
2342 unit_map[cpu] = UINT_MAX;
2343
2344 pcpu_low_unit_cpu = NR_CPUS;
2345 pcpu_high_unit_cpu = NR_CPUS;
2346
2347 for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
2348 const struct pcpu_group_info *gi = &ai->groups[group];
2349
2350 group_offsets[group] = gi->base_offset;
2351 group_sizes[group] = gi->nr_units * ai->unit_size;
2352
2353 for (i = 0; i < gi->nr_units; i++) {
2354 cpu = gi->cpu_map[i];
2355 if (cpu == NR_CPUS)
2356 continue;
2357
2358 PCPU_SETUP_BUG_ON(cpu >= nr_cpu_ids);
2359 PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
2360 PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
2361
2362 unit_map[cpu] = unit + i;
2363 unit_off[cpu] = gi->base_offset + i * ai->unit_size;
2364
2365 /* determine low/high unit_cpu */
2366 if (pcpu_low_unit_cpu == NR_CPUS ||
2367 unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
2368 pcpu_low_unit_cpu = cpu;
2369 if (pcpu_high_unit_cpu == NR_CPUS ||
2370 unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
2371 pcpu_high_unit_cpu = cpu;
2372 }
2373 }
2374 pcpu_nr_units = unit;
2375
2376 for_each_possible_cpu(cpu)
2377 PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
2378
2379 /* we're done parsing the input, undefine BUG macro and dump config */
2380#undef PCPU_SETUP_BUG_ON
2381 pcpu_dump_alloc_info(KERN_DEBUG, ai);
2382
2383 pcpu_nr_groups = ai->nr_groups;
2384 pcpu_group_offsets = group_offsets;
2385 pcpu_group_sizes = group_sizes;
2386 pcpu_unit_map = unit_map;
2387 pcpu_unit_offsets = unit_off;
2388
2389 /* determine basic parameters */
2390 pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
2391 pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
2392 pcpu_atom_size = ai->atom_size;
2393 pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
2394 BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
2395
2396 pcpu_stats_save_ai(ai);
2397
2398 /*
2399 * Allocate chunk slots. The additional last slot is for
2400 * empty chunks.
2401 */
2402 pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
2403 pcpu_slot = memblock_alloc(pcpu_nr_slots * sizeof(pcpu_slot[0]),
2404 SMP_CACHE_BYTES);
2405 if (!pcpu_slot)
2406 panic("%s: Failed to allocate %zu bytes\n", __func__,
2407 pcpu_nr_slots * sizeof(pcpu_slot[0]));
2408 for (i = 0; i < pcpu_nr_slots; i++)
2409 INIT_LIST_HEAD(&pcpu_slot[i]);
2410
2411 /*
2412 * The end of the static region needs to be aligned with the
2413 * minimum allocation size as this offsets the reserved and
2414 * dynamic region. The first chunk ends page aligned by
2415 * expanding the dynamic region, therefore the dynamic region
2416 * can be shrunk to compensate while still staying above the
2417 * configured sizes.
2418 */
2419 static_size = ALIGN(ai->static_size, PCPU_MIN_ALLOC_SIZE);
2420 dyn_size = ai->dyn_size - (static_size - ai->static_size);
2421
2422 /*
2423 * Initialize first chunk.
2424 * If the reserved_size is non-zero, this initializes the reserved
2425 * chunk. If the reserved_size is zero, the reserved chunk is NULL
2426 * and the dynamic region is initialized here. The first chunk,
2427 * pcpu_first_chunk, will always point to the chunk that serves
2428 * the dynamic region.
2429 */
2430 tmp_addr = (unsigned long)base_addr + static_size;
2431 map_size = ai->reserved_size ?: dyn_size;
2432 chunk = pcpu_alloc_first_chunk(tmp_addr, map_size);
2433
2434 /* init dynamic chunk if necessary */
2435 if (ai->reserved_size) {
2436 pcpu_reserved_chunk = chunk;
2437
2438 tmp_addr = (unsigned long)base_addr + static_size +
2439 ai->reserved_size;
2440 map_size = dyn_size;
2441 chunk = pcpu_alloc_first_chunk(tmp_addr, map_size);
2442 }
2443
2444 /* link the first chunk in */
2445 pcpu_first_chunk = chunk;
2446 pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages;
2447 pcpu_chunk_relocate(pcpu_first_chunk, -1);
2448
2449 /* include all regions of the first chunk */
2450 pcpu_nr_populated += PFN_DOWN(size_sum);
2451
2452 pcpu_stats_chunk_alloc();
2453 trace_percpu_create_chunk(base_addr);
2454
2455 /* we're done */
2456 pcpu_base_addr = base_addr;
2457}
2458
2459#ifdef CONFIG_SMP
2460
2461const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = {
2462 [PCPU_FC_AUTO] = "auto",
2463 [PCPU_FC_EMBED] = "embed",
2464 [PCPU_FC_PAGE] = "page",
2465};
2466
2467enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
2468
2469static int __init percpu_alloc_setup(char *str)
2470{
2471 if (!str)
2472 return -EINVAL;
2473
2474 if (0)
2475 /* nada */;
2476#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
2477 else if (!strcmp(str, "embed"))
2478 pcpu_chosen_fc = PCPU_FC_EMBED;
2479#endif
2480#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
2481 else if (!strcmp(str, "page"))
2482 pcpu_chosen_fc = PCPU_FC_PAGE;
2483#endif
2484 else
2485 pr_warn("unknown allocator %s specified\n", str);
2486
2487 return 0;
2488}
2489early_param("percpu_alloc", percpu_alloc_setup);
2490
2491/*
2492 * pcpu_embed_first_chunk() is used by the generic percpu setup.
2493 * Build it if needed by the arch config or the generic setup is going
2494 * to be used.
2495 */
2496#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
2497 !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
2498#define BUILD_EMBED_FIRST_CHUNK
2499#endif
2500
2501/* build pcpu_page_first_chunk() iff needed by the arch config */
2502#if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
2503#define BUILD_PAGE_FIRST_CHUNK
2504#endif
2505
2506/* pcpu_build_alloc_info() is used by both embed and page first chunk */
2507#if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
2508/**
2509 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
2510 * @reserved_size: the size of reserved percpu area in bytes
2511 * @dyn_size: minimum free size for dynamic allocation in bytes
2512 * @atom_size: allocation atom size
2513 * @cpu_distance_fn: callback to determine distance between cpus, optional
2514 *
2515 * This function determines grouping of units, their mappings to cpus
2516 * and other parameters considering needed percpu size, allocation
2517 * atom size and distances between CPUs.
2518 *
2519 * Groups are always multiples of atom size and CPUs which are of
2520 * LOCAL_DISTANCE both ways are grouped together and share space for
2521 * units in the same group. The returned configuration is guaranteed
2522 * to have CPUs on different nodes on different groups and >=75% usage
2523 * of allocated virtual address space.
2524 *
2525 * RETURNS:
2526 * On success, pointer to the new allocation_info is returned. On
2527 * failure, ERR_PTR value is returned.
2528 */
2529static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
2530 size_t reserved_size, size_t dyn_size,
2531 size_t atom_size,
2532 pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
2533{
2534 static int group_map[NR_CPUS] __initdata;
2535 static int group_cnt[NR_CPUS] __initdata;
2536 const size_t static_size = __per_cpu_end - __per_cpu_start;
2537 int nr_groups = 1, nr_units = 0;
2538 size_t size_sum, min_unit_size, alloc_size;
2539 int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
2540 int last_allocs, group, unit;
2541 unsigned int cpu, tcpu;
2542 struct pcpu_alloc_info *ai;
2543 unsigned int *cpu_map;
2544
2545 /* this function may be called multiple times */
2546 memset(group_map, 0, sizeof(group_map));
2547 memset(group_cnt, 0, sizeof(group_cnt));
2548
2549 /* calculate size_sum and ensure dyn_size is enough for early alloc */
2550 size_sum = PFN_ALIGN(static_size + reserved_size +
2551 max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
2552 dyn_size = size_sum - static_size - reserved_size;
2553
2554 /*
2555 * Determine min_unit_size, alloc_size and max_upa such that
2556 * alloc_size is multiple of atom_size and is the smallest
2557 * which can accommodate 4k aligned segments which are equal to
2558 * or larger than min_unit_size.
2559 */
2560 min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
2561
2562 /* determine the maximum # of units that can fit in an allocation */
2563 alloc_size = roundup(min_unit_size, atom_size);
2564 upa = alloc_size / min_unit_size;
2565 while (alloc_size % upa || (offset_in_page(alloc_size / upa)))
2566 upa--;
2567 max_upa = upa;
2568
2569 /* group cpus according to their proximity */
2570 for_each_possible_cpu(cpu) {
2571 group = 0;
2572 next_group:
2573 for_each_possible_cpu(tcpu) {
2574 if (cpu == tcpu)
2575 break;
2576 if (group_map[tcpu] == group && cpu_distance_fn &&
2577 (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
2578 cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
2579 group++;
2580 nr_groups = max(nr_groups, group + 1);
2581 goto next_group;
2582 }
2583 }
2584 group_map[cpu] = group;
2585 group_cnt[group]++;
2586 }
2587
2588 /*
2589 * Wasted space is caused by a ratio imbalance of upa to group_cnt.
2590 * Expand the unit_size until we use >= 75% of the units allocated.
2591 * Related to atom_size, which could be much larger than the unit_size.
2592 */
2593 last_allocs = INT_MAX;
2594 for (upa = max_upa; upa; upa--) {
2595 int allocs = 0, wasted = 0;
2596
2597 if (alloc_size % upa || (offset_in_page(alloc_size / upa)))
2598 continue;
2599
2600 for (group = 0; group < nr_groups; group++) {
2601 int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
2602 allocs += this_allocs;
2603 wasted += this_allocs * upa - group_cnt[group];
2604 }
2605
2606 /*
2607 * Don't accept if wastage is over 1/3. The
2608 * greater-than comparison ensures upa==1 always
2609 * passes the following check.
2610 */
2611 if (wasted > num_possible_cpus() / 3)
2612 continue;
2613
2614 /* and then don't consume more memory */
2615 if (allocs > last_allocs)
2616 break;
2617 last_allocs = allocs;
2618 best_upa = upa;
2619 }
2620 upa = best_upa;
2621
2622 /* allocate and fill alloc_info */
2623 for (group = 0; group < nr_groups; group++)
2624 nr_units += roundup(group_cnt[group], upa);
2625
2626 ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
2627 if (!ai)
2628 return ERR_PTR(-ENOMEM);
2629 cpu_map = ai->groups[0].cpu_map;
2630
2631 for (group = 0; group < nr_groups; group++) {
2632 ai->groups[group].cpu_map = cpu_map;
2633 cpu_map += roundup(group_cnt[group], upa);
2634 }
2635
2636 ai->static_size = static_size;
2637 ai->reserved_size = reserved_size;
2638 ai->dyn_size = dyn_size;
2639 ai->unit_size = alloc_size / upa;
2640 ai->atom_size = atom_size;
2641 ai->alloc_size = alloc_size;
2642
2643 for (group = 0, unit = 0; group < nr_groups; group++) {
2644 struct pcpu_group_info *gi = &ai->groups[group];
2645
2646 /*
2647 * Initialize base_offset as if all groups are located
2648 * back-to-back. The caller should update this to
2649 * reflect actual allocation.
2650 */
2651 gi->base_offset = unit * ai->unit_size;
2652
2653 for_each_possible_cpu(cpu)
2654 if (group_map[cpu] == group)
2655 gi->cpu_map[gi->nr_units++] = cpu;
2656 gi->nr_units = roundup(gi->nr_units, upa);
2657 unit += gi->nr_units;
2658 }
2659 BUG_ON(unit != nr_units);
2660
2661 return ai;
2662}
2663#endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
2664
2665#if defined(BUILD_EMBED_FIRST_CHUNK)
2666/**
2667 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
2668 * @reserved_size: the size of reserved percpu area in bytes
2669 * @dyn_size: minimum free size for dynamic allocation in bytes
2670 * @atom_size: allocation atom size
2671 * @cpu_distance_fn: callback to determine distance between cpus, optional
2672 * @alloc_fn: function to allocate percpu page
2673 * @free_fn: function to free percpu page
2674 *
2675 * This is a helper to ease setting up embedded first percpu chunk and
2676 * can be called where pcpu_setup_first_chunk() is expected.
2677 *
2678 * If this function is used to setup the first chunk, it is allocated
2679 * by calling @alloc_fn and used as-is without being mapped into
2680 * vmalloc area. Allocations are always whole multiples of @atom_size
2681 * aligned to @atom_size.
2682 *
2683 * This enables the first chunk to piggy back on the linear physical
2684 * mapping which often uses larger page size. Please note that this
2685 * can result in very sparse cpu->unit mapping on NUMA machines thus
2686 * requiring large vmalloc address space. Don't use this allocator if
2687 * vmalloc space is not orders of magnitude larger than distances
2688 * between node memory addresses (ie. 32bit NUMA machines).
2689 *
2690 * @dyn_size specifies the minimum dynamic area size.
2691 *
2692 * If the needed size is smaller than the minimum or specified unit
2693 * size, the leftover is returned using @free_fn.
2694 *
2695 * RETURNS:
2696 * 0 on success, -errno on failure.
2697 */
2698int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
2699 size_t atom_size,
2700 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
2701 pcpu_fc_alloc_fn_t alloc_fn,
2702 pcpu_fc_free_fn_t free_fn)
2703{
2704 void *base = (void *)ULONG_MAX;
2705 void **areas = NULL;
2706 struct pcpu_alloc_info *ai;
2707 size_t size_sum, areas_size;
2708 unsigned long max_distance;
2709 int group, i, highest_group, rc = 0;
2710
2711 ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
2712 cpu_distance_fn);
2713 if (IS_ERR(ai))
2714 return PTR_ERR(ai);
2715
2716 size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
2717 areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
2718
2719 areas = memblock_alloc(areas_size, SMP_CACHE_BYTES);
2720 if (!areas) {
2721 rc = -ENOMEM;
2722 goto out_free;
2723 }
2724
2725 /* allocate, copy and determine base address & max_distance */
2726 highest_group = 0;
2727 for (group = 0; group < ai->nr_groups; group++) {
2728 struct pcpu_group_info *gi = &ai->groups[group];
2729 unsigned int cpu = NR_CPUS;
2730 void *ptr;
2731
2732 for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
2733 cpu = gi->cpu_map[i];
2734 BUG_ON(cpu == NR_CPUS);
2735
2736 /* allocate space for the whole group */
2737 ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
2738 if (!ptr) {
2739 rc = -ENOMEM;
2740 goto out_free_areas;
2741 }
2742 /* kmemleak tracks the percpu allocations separately */
2743 kmemleak_free(ptr);
2744 areas[group] = ptr;
2745
2746 base = min(ptr, base);
2747 if (ptr > areas[highest_group])
2748 highest_group = group;
2749 }
2750 max_distance = areas[highest_group] - base;
2751 max_distance += ai->unit_size * ai->groups[highest_group].nr_units;
2752
2753 /* warn if maximum distance is further than 75% of vmalloc space */
2754 if (max_distance > VMALLOC_TOTAL * 3 / 4) {
2755 pr_warn("max_distance=0x%lx too large for vmalloc space 0x%lx\n",
2756 max_distance, VMALLOC_TOTAL);
2757#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
2758 /* and fail if we have fallback */
2759 rc = -EINVAL;
2760 goto out_free_areas;
2761#endif
2762 }
2763
2764 /*
2765 * Copy data and free unused parts. This should happen after all
2766 * allocations are complete; otherwise, we may end up with
2767 * overlapping groups.
2768 */
2769 for (group = 0; group < ai->nr_groups; group++) {
2770 struct pcpu_group_info *gi = &ai->groups[group];
2771 void *ptr = areas[group];
2772
2773 for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
2774 if (gi->cpu_map[i] == NR_CPUS) {
2775 /* unused unit, free whole */
2776 free_fn(ptr, ai->unit_size);
2777 continue;
2778 }
2779 /* copy and return the unused part */
2780 memcpy(ptr, __per_cpu_load, ai->static_size);
2781 free_fn(ptr + size_sum, ai->unit_size - size_sum);
2782 }
2783 }
2784
2785 /* base address is now known, determine group base offsets */
2786 for (group = 0; group < ai->nr_groups; group++) {
2787 ai->groups[group].base_offset = areas[group] - base;
2788 }
2789
2790 pr_info("Embedded %zu pages/cpu s%zu r%zu d%zu u%zu\n",
2791 PFN_DOWN(size_sum), ai->static_size, ai->reserved_size,
2792 ai->dyn_size, ai->unit_size);
2793
2794 pcpu_setup_first_chunk(ai, base);
2795 goto out_free;
2796
2797out_free_areas:
2798 for (group = 0; group < ai->nr_groups; group++)
2799 if (areas[group])
2800 free_fn(areas[group],
2801 ai->groups[group].nr_units * ai->unit_size);
2802out_free:
2803 pcpu_free_alloc_info(ai);
2804 if (areas)
2805 memblock_free_early(__pa(areas), areas_size);
2806 return rc;
2807}
2808#endif /* BUILD_EMBED_FIRST_CHUNK */
2809
2810#ifdef BUILD_PAGE_FIRST_CHUNK
2811/**
2812 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
2813 * @reserved_size: the size of reserved percpu area in bytes
2814 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
2815 * @free_fn: function to free percpu page, always called with PAGE_SIZE
2816 * @populate_pte_fn: function to populate pte
2817 *
2818 * This is a helper to ease setting up page-remapped first percpu
2819 * chunk and can be called where pcpu_setup_first_chunk() is expected.
2820 *
2821 * This is the basic allocator. Static percpu area is allocated
2822 * page-by-page into vmalloc area.
2823 *
2824 * RETURNS:
2825 * 0 on success, -errno on failure.
2826 */
2827int __init pcpu_page_first_chunk(size_t reserved_size,
2828 pcpu_fc_alloc_fn_t alloc_fn,
2829 pcpu_fc_free_fn_t free_fn,
2830 pcpu_fc_populate_pte_fn_t populate_pte_fn)
2831{
2832 static struct vm_struct vm;
2833 struct pcpu_alloc_info *ai;
2834 char psize_str[16];
2835 int unit_pages;
2836 size_t pages_size;
2837 struct page **pages;
2838 int unit, i, j, rc = 0;
2839 int upa;
2840 int nr_g0_units;
2841
2842 snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
2843
2844 ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
2845 if (IS_ERR(ai))
2846 return PTR_ERR(ai);
2847 BUG_ON(ai->nr_groups != 1);
2848 upa = ai->alloc_size/ai->unit_size;
2849 nr_g0_units = roundup(num_possible_cpus(), upa);
2850 if (WARN_ON(ai->groups[0].nr_units != nr_g0_units)) {
2851 pcpu_free_alloc_info(ai);
2852 return -EINVAL;
2853 }
2854
2855 unit_pages = ai->unit_size >> PAGE_SHIFT;
2856
2857 /* unaligned allocations can't be freed, round up to page size */
2858 pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
2859 sizeof(pages[0]));
2860 pages = memblock_alloc(pages_size, SMP_CACHE_BYTES);
2861 if (!pages)
2862 panic("%s: Failed to allocate %zu bytes\n", __func__,
2863 pages_size);
2864
2865 /* allocate pages */
2866 j = 0;
2867 for (unit = 0; unit < num_possible_cpus(); unit++) {
2868 unsigned int cpu = ai->groups[0].cpu_map[unit];
2869 for (i = 0; i < unit_pages; i++) {
2870 void *ptr;
2871
2872 ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
2873 if (!ptr) {
2874 pr_warn("failed to allocate %s page for cpu%u\n",
2875 psize_str, cpu);
2876 goto enomem;
2877 }
2878 /* kmemleak tracks the percpu allocations separately */
2879 kmemleak_free(ptr);
2880 pages[j++] = virt_to_page(ptr);
2881 }
2882 }
2883
2884 /* allocate vm area, map the pages and copy static data */
2885 vm.flags = VM_ALLOC;
2886 vm.size = num_possible_cpus() * ai->unit_size;
2887 vm_area_register_early(&vm, PAGE_SIZE);
2888
2889 for (unit = 0; unit < num_possible_cpus(); unit++) {
2890 unsigned long unit_addr =
2891 (unsigned long)vm.addr + unit * ai->unit_size;
2892
2893 for (i = 0; i < unit_pages; i++)
2894 populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
2895
2896 /* pte already populated, the following shouldn't fail */
2897 rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
2898 unit_pages);
2899 if (rc < 0)
2900 panic("failed to map percpu area, err=%d\n", rc);
2901
2902 /*
2903 * FIXME: Archs with virtual cache should flush local
2904 * cache for the linear mapping here - something
2905 * equivalent to flush_cache_vmap() on the local cpu.
2906 * flush_cache_vmap() can't be used as most supporting
2907 * data structures are not set up yet.
2908 */
2909
2910 /* copy static data */
2911 memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
2912 }
2913
2914 /* we're ready, commit */
2915 pr_info("%d %s pages/cpu s%zu r%zu d%zu\n",
2916 unit_pages, psize_str, ai->static_size,
2917 ai->reserved_size, ai->dyn_size);
2918
2919 pcpu_setup_first_chunk(ai, vm.addr);
2920 goto out_free_ar;
2921
2922enomem:
2923 while (--j >= 0)
2924 free_fn(page_address(pages[j]), PAGE_SIZE);
2925 rc = -ENOMEM;
2926out_free_ar:
2927 memblock_free_early(__pa(pages), pages_size);
2928 pcpu_free_alloc_info(ai);
2929 return rc;
2930}
2931#endif /* BUILD_PAGE_FIRST_CHUNK */
2932
2933#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
2934/*
2935 * Generic SMP percpu area setup.
2936 *
2937 * The embedding helper is used because its behavior closely resembles
2938 * the original non-dynamic generic percpu area setup. This is
2939 * important because many archs have addressing restrictions and might
2940 * fail if the percpu area is located far away from the previous
2941 * location. As an added bonus, in non-NUMA cases, embedding is
2942 * generally a good idea TLB-wise because percpu area can piggy back
2943 * on the physical linear memory mapping which uses large page
2944 * mappings on applicable archs.
2945 */
2946unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
2947EXPORT_SYMBOL(__per_cpu_offset);
2948
2949static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
2950 size_t align)
2951{
2952 return memblock_alloc_from(size, align, __pa(MAX_DMA_ADDRESS));
2953}
2954
2955static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
2956{
2957 memblock_free_early(__pa(ptr), size);
2958}
2959
2960void __init setup_per_cpu_areas(void)
2961{
2962 unsigned long delta;
2963 unsigned int cpu;
2964 int rc;
2965
2966 /*
2967 * Always reserve area for module percpu variables. That's
2968 * what the legacy allocator did.
2969 */
2970 rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
2971 PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
2972 pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
2973 if (rc < 0)
2974 panic("Failed to initialize percpu areas.");
2975
2976 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
2977 for_each_possible_cpu(cpu)
2978 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
2979}
2980#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
2981
2982#else /* CONFIG_SMP */
2983
2984/*
2985 * UP percpu area setup.
2986 *
2987 * UP always uses km-based percpu allocator with identity mapping.
2988 * Static percpu variables are indistinguishable from the usual static
2989 * variables and don't require any special preparation.
2990 */
2991void __init setup_per_cpu_areas(void)
2992{
2993 const size_t unit_size =
2994 roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
2995 PERCPU_DYNAMIC_RESERVE));
2996 struct pcpu_alloc_info *ai;
2997 void *fc;
2998
2999 ai = pcpu_alloc_alloc_info(1, 1);
3000 fc = memblock_alloc_from(unit_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
3001 if (!ai || !fc)
3002 panic("Failed to allocate memory for percpu areas.");
3003 /* kmemleak tracks the percpu allocations separately */
3004 kmemleak_free(fc);
3005
3006 ai->dyn_size = unit_size;
3007 ai->unit_size = unit_size;
3008 ai->atom_size = unit_size;
3009 ai->alloc_size = unit_size;
3010 ai->groups[0].nr_units = 1;
3011 ai->groups[0].cpu_map[0] = 0;
3012
3013 pcpu_setup_first_chunk(ai, fc);
3014 pcpu_free_alloc_info(ai);
3015}
3016
3017#endif /* CONFIG_SMP */
3018
3019/*
3020 * pcpu_nr_pages - calculate total number of populated backing pages
3021 *
3022 * This reflects the number of pages populated to back chunks. Metadata is
3023 * excluded in the number exposed in meminfo as the number of backing pages
3024 * scales with the number of cpus and can quickly outweigh the memory used for
3025 * metadata. It also keeps this calculation nice and simple.
3026 *
3027 * RETURNS:
3028 * Total number of populated backing pages in use by the allocator.
3029 */
3030unsigned long pcpu_nr_pages(void)
3031{
3032 return pcpu_nr_populated * pcpu_nr_units;
3033}
3034
3035/*
3036 * Percpu allocator is initialized early during boot when neither slab or
3037 * workqueue is available. Plug async management until everything is up
3038 * and running.
3039 */
3040static int __init percpu_enable_async(void)
3041{
3042 pcpu_async_enabled = true;
3043 return 0;
3044}
3045subsys_initcall(percpu_enable_async);
1/*
2 * mm/percpu.c - percpu memory allocator
3 *
4 * Copyright (C) 2009 SUSE Linux Products GmbH
5 * Copyright (C) 2009 Tejun Heo <tj@kernel.org>
6 *
7 * This file is released under the GPLv2.
8 *
9 * This is percpu allocator which can handle both static and dynamic
10 * areas. Percpu areas are allocated in chunks. Each chunk is
11 * consisted of boot-time determined number of units and the first
12 * chunk is used for static percpu variables in the kernel image
13 * (special boot time alloc/init handling necessary as these areas
14 * need to be brought up before allocation services are running).
15 * Unit grows as necessary and all units grow or shrink in unison.
16 * When a chunk is filled up, another chunk is allocated.
17 *
18 * c0 c1 c2
19 * ------------------- ------------------- ------------
20 * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
21 * ------------------- ...... ------------------- .... ------------
22 *
23 * Allocation is done in offset-size areas of single unit space. Ie,
24 * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
25 * c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to
26 * cpus. On NUMA, the mapping can be non-linear and even sparse.
27 * Percpu access can be done by configuring percpu base registers
28 * according to cpu to unit mapping and pcpu_unit_size.
29 *
30 * There are usually many small percpu allocations many of them being
31 * as small as 4 bytes. The allocator organizes chunks into lists
32 * according to free size and tries to allocate from the fullest one.
33 * Each chunk keeps the maximum contiguous area size hint which is
34 * guaranteed to be equal to or larger than the maximum contiguous
35 * area in the chunk. This helps the allocator not to iterate the
36 * chunk maps unnecessarily.
37 *
38 * Allocation state in each chunk is kept using an array of integers
39 * on chunk->map. A positive value in the map represents a free
40 * region and negative allocated. Allocation inside a chunk is done
41 * by scanning this map sequentially and serving the first matching
42 * entry. This is mostly copied from the percpu_modalloc() allocator.
43 * Chunks can be determined from the address using the index field
44 * in the page struct. The index field contains a pointer to the chunk.
45 *
46 * To use this allocator, arch code should do the followings.
47 *
48 * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
49 * regular address to percpu pointer and back if they need to be
50 * different from the default
51 *
52 * - use pcpu_setup_first_chunk() during percpu area initialization to
53 * setup the first chunk containing the kernel static percpu area
54 */
55
56#include <linux/bitmap.h>
57#include <linux/bootmem.h>
58#include <linux/err.h>
59#include <linux/list.h>
60#include <linux/log2.h>
61#include <linux/mm.h>
62#include <linux/module.h>
63#include <linux/mutex.h>
64#include <linux/percpu.h>
65#include <linux/pfn.h>
66#include <linux/slab.h>
67#include <linux/spinlock.h>
68#include <linux/vmalloc.h>
69#include <linux/workqueue.h>
70#include <linux/kmemleak.h>
71
72#include <asm/cacheflush.h>
73#include <asm/sections.h>
74#include <asm/tlbflush.h>
75#include <asm/io.h>
76
77#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
78#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
79
80#ifdef CONFIG_SMP
81/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
82#ifndef __addr_to_pcpu_ptr
83#define __addr_to_pcpu_ptr(addr) \
84 (void __percpu *)((unsigned long)(addr) - \
85 (unsigned long)pcpu_base_addr + \
86 (unsigned long)__per_cpu_start)
87#endif
88#ifndef __pcpu_ptr_to_addr
89#define __pcpu_ptr_to_addr(ptr) \
90 (void __force *)((unsigned long)(ptr) + \
91 (unsigned long)pcpu_base_addr - \
92 (unsigned long)__per_cpu_start)
93#endif
94#else /* CONFIG_SMP */
95/* on UP, it's always identity mapped */
96#define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
97#define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
98#endif /* CONFIG_SMP */
99
100struct pcpu_chunk {
101 struct list_head list; /* linked to pcpu_slot lists */
102 int free_size; /* free bytes in the chunk */
103 int contig_hint; /* max contiguous size hint */
104 void *base_addr; /* base address of this chunk */
105 int map_used; /* # of map entries used before the sentry */
106 int map_alloc; /* # of map entries allocated */
107 int *map; /* allocation map */
108 void *data; /* chunk data */
109 int first_free; /* no free below this */
110 bool immutable; /* no [de]population allowed */
111 unsigned long populated[]; /* populated bitmap */
112};
113
114static int pcpu_unit_pages __read_mostly;
115static int pcpu_unit_size __read_mostly;
116static int pcpu_nr_units __read_mostly;
117static int pcpu_atom_size __read_mostly;
118static int pcpu_nr_slots __read_mostly;
119static size_t pcpu_chunk_struct_size __read_mostly;
120
121/* cpus with the lowest and highest unit addresses */
122static unsigned int pcpu_low_unit_cpu __read_mostly;
123static unsigned int pcpu_high_unit_cpu __read_mostly;
124
125/* the address of the first chunk which starts with the kernel static area */
126void *pcpu_base_addr __read_mostly;
127EXPORT_SYMBOL_GPL(pcpu_base_addr);
128
129static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
130const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */
131
132/* group information, used for vm allocation */
133static int pcpu_nr_groups __read_mostly;
134static const unsigned long *pcpu_group_offsets __read_mostly;
135static const size_t *pcpu_group_sizes __read_mostly;
136
137/*
138 * The first chunk which always exists. Note that unlike other
139 * chunks, this one can be allocated and mapped in several different
140 * ways and thus often doesn't live in the vmalloc area.
141 */
142static struct pcpu_chunk *pcpu_first_chunk;
143
144/*
145 * Optional reserved chunk. This chunk reserves part of the first
146 * chunk and serves it for reserved allocations. The amount of
147 * reserved offset is in pcpu_reserved_chunk_limit. When reserved
148 * area doesn't exist, the following variables contain NULL and 0
149 * respectively.
150 */
151static struct pcpu_chunk *pcpu_reserved_chunk;
152static int pcpu_reserved_chunk_limit;
153
154/*
155 * Synchronization rules.
156 *
157 * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former
158 * protects allocation/reclaim paths, chunks, populated bitmap and
159 * vmalloc mapping. The latter is a spinlock and protects the index
160 * data structures - chunk slots, chunks and area maps in chunks.
161 *
162 * During allocation, pcpu_alloc_mutex is kept locked all the time and
163 * pcpu_lock is grabbed and released as necessary. All actual memory
164 * allocations are done using GFP_KERNEL with pcpu_lock released. In
165 * general, percpu memory can't be allocated with irq off but
166 * irqsave/restore are still used in alloc path so that it can be used
167 * from early init path - sched_init() specifically.
168 *
169 * Free path accesses and alters only the index data structures, so it
170 * can be safely called from atomic context. When memory needs to be
171 * returned to the system, free path schedules reclaim_work which
172 * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be
173 * reclaimed, release both locks and frees the chunks. Note that it's
174 * necessary to grab both locks to remove a chunk from circulation as
175 * allocation path might be referencing the chunk with only
176 * pcpu_alloc_mutex locked.
177 */
178static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */
179static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */
180
181static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
182
183/* reclaim work to release fully free chunks, scheduled from free path */
184static void pcpu_reclaim(struct work_struct *work);
185static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim);
186
187static bool pcpu_addr_in_first_chunk(void *addr)
188{
189 void *first_start = pcpu_first_chunk->base_addr;
190
191 return addr >= first_start && addr < first_start + pcpu_unit_size;
192}
193
194static bool pcpu_addr_in_reserved_chunk(void *addr)
195{
196 void *first_start = pcpu_first_chunk->base_addr;
197
198 return addr >= first_start &&
199 addr < first_start + pcpu_reserved_chunk_limit;
200}
201
202static int __pcpu_size_to_slot(int size)
203{
204 int highbit = fls(size); /* size is in bytes */
205 return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
206}
207
208static int pcpu_size_to_slot(int size)
209{
210 if (size == pcpu_unit_size)
211 return pcpu_nr_slots - 1;
212 return __pcpu_size_to_slot(size);
213}
214
215static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
216{
217 if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
218 return 0;
219
220 return pcpu_size_to_slot(chunk->free_size);
221}
222
223/* set the pointer to a chunk in a page struct */
224static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
225{
226 page->index = (unsigned long)pcpu;
227}
228
229/* obtain pointer to a chunk from a page struct */
230static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
231{
232 return (struct pcpu_chunk *)page->index;
233}
234
235static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
236{
237 return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
238}
239
240static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
241 unsigned int cpu, int page_idx)
242{
243 return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
244 (page_idx << PAGE_SHIFT);
245}
246
247static void __maybe_unused pcpu_next_unpop(struct pcpu_chunk *chunk,
248 int *rs, int *re, int end)
249{
250 *rs = find_next_zero_bit(chunk->populated, end, *rs);
251 *re = find_next_bit(chunk->populated, end, *rs + 1);
252}
253
254static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk,
255 int *rs, int *re, int end)
256{
257 *rs = find_next_bit(chunk->populated, end, *rs);
258 *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
259}
260
261/*
262 * (Un)populated page region iterators. Iterate over (un)populated
263 * page regions between @start and @end in @chunk. @rs and @re should
264 * be integer variables and will be set to start and end page index of
265 * the current region.
266 */
267#define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
268 for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
269 (rs) < (re); \
270 (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
271
272#define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
273 for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
274 (rs) < (re); \
275 (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
276
277/**
278 * pcpu_mem_zalloc - allocate memory
279 * @size: bytes to allocate
280 *
281 * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
282 * kzalloc() is used; otherwise, vzalloc() is used. The returned
283 * memory is always zeroed.
284 *
285 * CONTEXT:
286 * Does GFP_KERNEL allocation.
287 *
288 * RETURNS:
289 * Pointer to the allocated area on success, NULL on failure.
290 */
291static void *pcpu_mem_zalloc(size_t size)
292{
293 if (WARN_ON_ONCE(!slab_is_available()))
294 return NULL;
295
296 if (size <= PAGE_SIZE)
297 return kzalloc(size, GFP_KERNEL);
298 else
299 return vzalloc(size);
300}
301
302/**
303 * pcpu_mem_free - free memory
304 * @ptr: memory to free
305 * @size: size of the area
306 *
307 * Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc().
308 */
309static void pcpu_mem_free(void *ptr, size_t size)
310{
311 if (size <= PAGE_SIZE)
312 kfree(ptr);
313 else
314 vfree(ptr);
315}
316
317/**
318 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
319 * @chunk: chunk of interest
320 * @oslot: the previous slot it was on
321 *
322 * This function is called after an allocation or free changed @chunk.
323 * New slot according to the changed state is determined and @chunk is
324 * moved to the slot. Note that the reserved chunk is never put on
325 * chunk slots.
326 *
327 * CONTEXT:
328 * pcpu_lock.
329 */
330static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
331{
332 int nslot = pcpu_chunk_slot(chunk);
333
334 if (chunk != pcpu_reserved_chunk && oslot != nslot) {
335 if (oslot < nslot)
336 list_move(&chunk->list, &pcpu_slot[nslot]);
337 else
338 list_move_tail(&chunk->list, &pcpu_slot[nslot]);
339 }
340}
341
342/**
343 * pcpu_need_to_extend - determine whether chunk area map needs to be extended
344 * @chunk: chunk of interest
345 *
346 * Determine whether area map of @chunk needs to be extended to
347 * accommodate a new allocation.
348 *
349 * CONTEXT:
350 * pcpu_lock.
351 *
352 * RETURNS:
353 * New target map allocation length if extension is necessary, 0
354 * otherwise.
355 */
356static int pcpu_need_to_extend(struct pcpu_chunk *chunk)
357{
358 int new_alloc;
359
360 if (chunk->map_alloc >= chunk->map_used + 3)
361 return 0;
362
363 new_alloc = PCPU_DFL_MAP_ALLOC;
364 while (new_alloc < chunk->map_used + 3)
365 new_alloc *= 2;
366
367 return new_alloc;
368}
369
370/**
371 * pcpu_extend_area_map - extend area map of a chunk
372 * @chunk: chunk of interest
373 * @new_alloc: new target allocation length of the area map
374 *
375 * Extend area map of @chunk to have @new_alloc entries.
376 *
377 * CONTEXT:
378 * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock.
379 *
380 * RETURNS:
381 * 0 on success, -errno on failure.
382 */
383static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
384{
385 int *old = NULL, *new = NULL;
386 size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
387 unsigned long flags;
388
389 new = pcpu_mem_zalloc(new_size);
390 if (!new)
391 return -ENOMEM;
392
393 /* acquire pcpu_lock and switch to new area map */
394 spin_lock_irqsave(&pcpu_lock, flags);
395
396 if (new_alloc <= chunk->map_alloc)
397 goto out_unlock;
398
399 old_size = chunk->map_alloc * sizeof(chunk->map[0]);
400 old = chunk->map;
401
402 memcpy(new, old, old_size);
403
404 chunk->map_alloc = new_alloc;
405 chunk->map = new;
406 new = NULL;
407
408out_unlock:
409 spin_unlock_irqrestore(&pcpu_lock, flags);
410
411 /*
412 * pcpu_mem_free() might end up calling vfree() which uses
413 * IRQ-unsafe lock and thus can't be called under pcpu_lock.
414 */
415 pcpu_mem_free(old, old_size);
416 pcpu_mem_free(new, new_size);
417
418 return 0;
419}
420
421/**
422 * pcpu_alloc_area - allocate area from a pcpu_chunk
423 * @chunk: chunk of interest
424 * @size: wanted size in bytes
425 * @align: wanted align
426 *
427 * Try to allocate @size bytes area aligned at @align from @chunk.
428 * Note that this function only allocates the offset. It doesn't
429 * populate or map the area.
430 *
431 * @chunk->map must have at least two free slots.
432 *
433 * CONTEXT:
434 * pcpu_lock.
435 *
436 * RETURNS:
437 * Allocated offset in @chunk on success, -1 if no matching area is
438 * found.
439 */
440static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
441{
442 int oslot = pcpu_chunk_slot(chunk);
443 int max_contig = 0;
444 int i, off;
445 bool seen_free = false;
446 int *p;
447
448 for (i = chunk->first_free, p = chunk->map + i; i < chunk->map_used; i++, p++) {
449 int head, tail;
450 int this_size;
451
452 off = *p;
453 if (off & 1)
454 continue;
455
456 /* extra for alignment requirement */
457 head = ALIGN(off, align) - off;
458
459 this_size = (p[1] & ~1) - off;
460 if (this_size < head + size) {
461 if (!seen_free) {
462 chunk->first_free = i;
463 seen_free = true;
464 }
465 max_contig = max(this_size, max_contig);
466 continue;
467 }
468
469 /*
470 * If head is small or the previous block is free,
471 * merge'em. Note that 'small' is defined as smaller
472 * than sizeof(int), which is very small but isn't too
473 * uncommon for percpu allocations.
474 */
475 if (head && (head < sizeof(int) || !(p[-1] & 1))) {
476 *p = off += head;
477 if (p[-1] & 1)
478 chunk->free_size -= head;
479 else
480 max_contig = max(*p - p[-1], max_contig);
481 this_size -= head;
482 head = 0;
483 }
484
485 /* if tail is small, just keep it around */
486 tail = this_size - head - size;
487 if (tail < sizeof(int)) {
488 tail = 0;
489 size = this_size - head;
490 }
491
492 /* split if warranted */
493 if (head || tail) {
494 int nr_extra = !!head + !!tail;
495
496 /* insert new subblocks */
497 memmove(p + nr_extra + 1, p + 1,
498 sizeof(chunk->map[0]) * (chunk->map_used - i));
499 chunk->map_used += nr_extra;
500
501 if (head) {
502 if (!seen_free) {
503 chunk->first_free = i;
504 seen_free = true;
505 }
506 *++p = off += head;
507 ++i;
508 max_contig = max(head, max_contig);
509 }
510 if (tail) {
511 p[1] = off + size;
512 max_contig = max(tail, max_contig);
513 }
514 }
515
516 if (!seen_free)
517 chunk->first_free = i + 1;
518
519 /* update hint and mark allocated */
520 if (i + 1 == chunk->map_used)
521 chunk->contig_hint = max_contig; /* fully scanned */
522 else
523 chunk->contig_hint = max(chunk->contig_hint,
524 max_contig);
525
526 chunk->free_size -= size;
527 *p |= 1;
528
529 pcpu_chunk_relocate(chunk, oslot);
530 return off;
531 }
532
533 chunk->contig_hint = max_contig; /* fully scanned */
534 pcpu_chunk_relocate(chunk, oslot);
535
536 /* tell the upper layer that this chunk has no matching area */
537 return -1;
538}
539
540/**
541 * pcpu_free_area - free area to a pcpu_chunk
542 * @chunk: chunk of interest
543 * @freeme: offset of area to free
544 *
545 * Free area starting from @freeme to @chunk. Note that this function
546 * only modifies the allocation map. It doesn't depopulate or unmap
547 * the area.
548 *
549 * CONTEXT:
550 * pcpu_lock.
551 */
552static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
553{
554 int oslot = pcpu_chunk_slot(chunk);
555 int off = 0;
556 unsigned i, j;
557 int to_free = 0;
558 int *p;
559
560 freeme |= 1; /* we are searching for <given offset, in use> pair */
561
562 i = 0;
563 j = chunk->map_used;
564 while (i != j) {
565 unsigned k = (i + j) / 2;
566 off = chunk->map[k];
567 if (off < freeme)
568 i = k + 1;
569 else if (off > freeme)
570 j = k;
571 else
572 i = j = k;
573 }
574 BUG_ON(off != freeme);
575
576 if (i < chunk->first_free)
577 chunk->first_free = i;
578
579 p = chunk->map + i;
580 *p = off &= ~1;
581 chunk->free_size += (p[1] & ~1) - off;
582
583 /* merge with next? */
584 if (!(p[1] & 1))
585 to_free++;
586 /* merge with previous? */
587 if (i > 0 && !(p[-1] & 1)) {
588 to_free++;
589 i--;
590 p--;
591 }
592 if (to_free) {
593 chunk->map_used -= to_free;
594 memmove(p + 1, p + 1 + to_free,
595 (chunk->map_used - i) * sizeof(chunk->map[0]));
596 }
597
598 chunk->contig_hint = max(chunk->map[i + 1] - chunk->map[i] - 1, chunk->contig_hint);
599 pcpu_chunk_relocate(chunk, oslot);
600}
601
602static struct pcpu_chunk *pcpu_alloc_chunk(void)
603{
604 struct pcpu_chunk *chunk;
605
606 chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size);
607 if (!chunk)
608 return NULL;
609
610 chunk->map = pcpu_mem_zalloc(PCPU_DFL_MAP_ALLOC *
611 sizeof(chunk->map[0]));
612 if (!chunk->map) {
613 pcpu_mem_free(chunk, pcpu_chunk_struct_size);
614 return NULL;
615 }
616
617 chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
618 chunk->map[0] = 0;
619 chunk->map[1] = pcpu_unit_size | 1;
620 chunk->map_used = 1;
621
622 INIT_LIST_HEAD(&chunk->list);
623 chunk->free_size = pcpu_unit_size;
624 chunk->contig_hint = pcpu_unit_size;
625
626 return chunk;
627}
628
629static void pcpu_free_chunk(struct pcpu_chunk *chunk)
630{
631 if (!chunk)
632 return;
633 pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
634 pcpu_mem_free(chunk, pcpu_chunk_struct_size);
635}
636
637/*
638 * Chunk management implementation.
639 *
640 * To allow different implementations, chunk alloc/free and
641 * [de]population are implemented in a separate file which is pulled
642 * into this file and compiled together. The following functions
643 * should be implemented.
644 *
645 * pcpu_populate_chunk - populate the specified range of a chunk
646 * pcpu_depopulate_chunk - depopulate the specified range of a chunk
647 * pcpu_create_chunk - create a new chunk
648 * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
649 * pcpu_addr_to_page - translate address to physical address
650 * pcpu_verify_alloc_info - check alloc_info is acceptable during init
651 */
652static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size);
653static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size);
654static struct pcpu_chunk *pcpu_create_chunk(void);
655static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
656static struct page *pcpu_addr_to_page(void *addr);
657static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
658
659#ifdef CONFIG_NEED_PER_CPU_KM
660#include "percpu-km.c"
661#else
662#include "percpu-vm.c"
663#endif
664
665/**
666 * pcpu_chunk_addr_search - determine chunk containing specified address
667 * @addr: address for which the chunk needs to be determined.
668 *
669 * RETURNS:
670 * The address of the found chunk.
671 */
672static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
673{
674 /* is it in the first chunk? */
675 if (pcpu_addr_in_first_chunk(addr)) {
676 /* is it in the reserved area? */
677 if (pcpu_addr_in_reserved_chunk(addr))
678 return pcpu_reserved_chunk;
679 return pcpu_first_chunk;
680 }
681
682 /*
683 * The address is relative to unit0 which might be unused and
684 * thus unmapped. Offset the address to the unit space of the
685 * current processor before looking it up in the vmalloc
686 * space. Note that any possible cpu id can be used here, so
687 * there's no need to worry about preemption or cpu hotplug.
688 */
689 addr += pcpu_unit_offsets[raw_smp_processor_id()];
690 return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
691}
692
693/**
694 * pcpu_alloc - the percpu allocator
695 * @size: size of area to allocate in bytes
696 * @align: alignment of area (max PAGE_SIZE)
697 * @reserved: allocate from the reserved chunk if available
698 *
699 * Allocate percpu area of @size bytes aligned at @align.
700 *
701 * CONTEXT:
702 * Does GFP_KERNEL allocation.
703 *
704 * RETURNS:
705 * Percpu pointer to the allocated area on success, NULL on failure.
706 */
707static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
708{
709 static int warn_limit = 10;
710 struct pcpu_chunk *chunk;
711 const char *err;
712 int slot, off, new_alloc;
713 unsigned long flags;
714 void __percpu *ptr;
715
716 /*
717 * We want the lowest bit of offset available for in-use/free
718 * indicator, so force >= 16bit alignment and make size even.
719 */
720 if (unlikely(align < 2))
721 align = 2;
722
723 if (unlikely(size & 1))
724 size++;
725
726 if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
727 WARN(true, "illegal size (%zu) or align (%zu) for "
728 "percpu allocation\n", size, align);
729 return NULL;
730 }
731
732 mutex_lock(&pcpu_alloc_mutex);
733 spin_lock_irqsave(&pcpu_lock, flags);
734
735 /* serve reserved allocations from the reserved chunk if available */
736 if (reserved && pcpu_reserved_chunk) {
737 chunk = pcpu_reserved_chunk;
738
739 if (size > chunk->contig_hint) {
740 err = "alloc from reserved chunk failed";
741 goto fail_unlock;
742 }
743
744 while ((new_alloc = pcpu_need_to_extend(chunk))) {
745 spin_unlock_irqrestore(&pcpu_lock, flags);
746 if (pcpu_extend_area_map(chunk, new_alloc) < 0) {
747 err = "failed to extend area map of reserved chunk";
748 goto fail_unlock_mutex;
749 }
750 spin_lock_irqsave(&pcpu_lock, flags);
751 }
752
753 off = pcpu_alloc_area(chunk, size, align);
754 if (off >= 0)
755 goto area_found;
756
757 err = "alloc from reserved chunk failed";
758 goto fail_unlock;
759 }
760
761restart:
762 /* search through normal chunks */
763 for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
764 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
765 if (size > chunk->contig_hint)
766 continue;
767
768 new_alloc = pcpu_need_to_extend(chunk);
769 if (new_alloc) {
770 spin_unlock_irqrestore(&pcpu_lock, flags);
771 if (pcpu_extend_area_map(chunk,
772 new_alloc) < 0) {
773 err = "failed to extend area map";
774 goto fail_unlock_mutex;
775 }
776 spin_lock_irqsave(&pcpu_lock, flags);
777 /*
778 * pcpu_lock has been dropped, need to
779 * restart cpu_slot list walking.
780 */
781 goto restart;
782 }
783
784 off = pcpu_alloc_area(chunk, size, align);
785 if (off >= 0)
786 goto area_found;
787 }
788 }
789
790 /* hmmm... no space left, create a new chunk */
791 spin_unlock_irqrestore(&pcpu_lock, flags);
792
793 chunk = pcpu_create_chunk();
794 if (!chunk) {
795 err = "failed to allocate new chunk";
796 goto fail_unlock_mutex;
797 }
798
799 spin_lock_irqsave(&pcpu_lock, flags);
800 pcpu_chunk_relocate(chunk, -1);
801 goto restart;
802
803area_found:
804 spin_unlock_irqrestore(&pcpu_lock, flags);
805
806 /* populate, map and clear the area */
807 if (pcpu_populate_chunk(chunk, off, size)) {
808 spin_lock_irqsave(&pcpu_lock, flags);
809 pcpu_free_area(chunk, off);
810 err = "failed to populate";
811 goto fail_unlock;
812 }
813
814 mutex_unlock(&pcpu_alloc_mutex);
815
816 /* return address relative to base address */
817 ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
818 kmemleak_alloc_percpu(ptr, size);
819 return ptr;
820
821fail_unlock:
822 spin_unlock_irqrestore(&pcpu_lock, flags);
823fail_unlock_mutex:
824 mutex_unlock(&pcpu_alloc_mutex);
825 if (warn_limit) {
826 pr_warning("PERCPU: allocation failed, size=%zu align=%zu, "
827 "%s\n", size, align, err);
828 dump_stack();
829 if (!--warn_limit)
830 pr_info("PERCPU: limit reached, disable warning\n");
831 }
832 return NULL;
833}
834
835/**
836 * __alloc_percpu - allocate dynamic percpu area
837 * @size: size of area to allocate in bytes
838 * @align: alignment of area (max PAGE_SIZE)
839 *
840 * Allocate zero-filled percpu area of @size bytes aligned at @align.
841 * Might sleep. Might trigger writeouts.
842 *
843 * CONTEXT:
844 * Does GFP_KERNEL allocation.
845 *
846 * RETURNS:
847 * Percpu pointer to the allocated area on success, NULL on failure.
848 */
849void __percpu *__alloc_percpu(size_t size, size_t align)
850{
851 return pcpu_alloc(size, align, false);
852}
853EXPORT_SYMBOL_GPL(__alloc_percpu);
854
855/**
856 * __alloc_reserved_percpu - allocate reserved percpu area
857 * @size: size of area to allocate in bytes
858 * @align: alignment of area (max PAGE_SIZE)
859 *
860 * Allocate zero-filled percpu area of @size bytes aligned at @align
861 * from reserved percpu area if arch has set it up; otherwise,
862 * allocation is served from the same dynamic area. Might sleep.
863 * Might trigger writeouts.
864 *
865 * CONTEXT:
866 * Does GFP_KERNEL allocation.
867 *
868 * RETURNS:
869 * Percpu pointer to the allocated area on success, NULL on failure.
870 */
871void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
872{
873 return pcpu_alloc(size, align, true);
874}
875
876/**
877 * pcpu_reclaim - reclaim fully free chunks, workqueue function
878 * @work: unused
879 *
880 * Reclaim all fully free chunks except for the first one.
881 *
882 * CONTEXT:
883 * workqueue context.
884 */
885static void pcpu_reclaim(struct work_struct *work)
886{
887 LIST_HEAD(todo);
888 struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1];
889 struct pcpu_chunk *chunk, *next;
890
891 mutex_lock(&pcpu_alloc_mutex);
892 spin_lock_irq(&pcpu_lock);
893
894 list_for_each_entry_safe(chunk, next, head, list) {
895 WARN_ON(chunk->immutable);
896
897 /* spare the first one */
898 if (chunk == list_first_entry(head, struct pcpu_chunk, list))
899 continue;
900
901 list_move(&chunk->list, &todo);
902 }
903
904 spin_unlock_irq(&pcpu_lock);
905
906 list_for_each_entry_safe(chunk, next, &todo, list) {
907 pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
908 pcpu_destroy_chunk(chunk);
909 }
910
911 mutex_unlock(&pcpu_alloc_mutex);
912}
913
914/**
915 * free_percpu - free percpu area
916 * @ptr: pointer to area to free
917 *
918 * Free percpu area @ptr.
919 *
920 * CONTEXT:
921 * Can be called from atomic context.
922 */
923void free_percpu(void __percpu *ptr)
924{
925 void *addr;
926 struct pcpu_chunk *chunk;
927 unsigned long flags;
928 int off;
929
930 if (!ptr)
931 return;
932
933 kmemleak_free_percpu(ptr);
934
935 addr = __pcpu_ptr_to_addr(ptr);
936
937 spin_lock_irqsave(&pcpu_lock, flags);
938
939 chunk = pcpu_chunk_addr_search(addr);
940 off = addr - chunk->base_addr;
941
942 pcpu_free_area(chunk, off);
943
944 /* if there are more than one fully free chunks, wake up grim reaper */
945 if (chunk->free_size == pcpu_unit_size) {
946 struct pcpu_chunk *pos;
947
948 list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
949 if (pos != chunk) {
950 schedule_work(&pcpu_reclaim_work);
951 break;
952 }
953 }
954
955 spin_unlock_irqrestore(&pcpu_lock, flags);
956}
957EXPORT_SYMBOL_GPL(free_percpu);
958
959/**
960 * is_kernel_percpu_address - test whether address is from static percpu area
961 * @addr: address to test
962 *
963 * Test whether @addr belongs to in-kernel static percpu area. Module
964 * static percpu areas are not considered. For those, use
965 * is_module_percpu_address().
966 *
967 * RETURNS:
968 * %true if @addr is from in-kernel static percpu area, %false otherwise.
969 */
970bool is_kernel_percpu_address(unsigned long addr)
971{
972#ifdef CONFIG_SMP
973 const size_t static_size = __per_cpu_end - __per_cpu_start;
974 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
975 unsigned int cpu;
976
977 for_each_possible_cpu(cpu) {
978 void *start = per_cpu_ptr(base, cpu);
979
980 if ((void *)addr >= start && (void *)addr < start + static_size)
981 return true;
982 }
983#endif
984 /* on UP, can't distinguish from other static vars, always false */
985 return false;
986}
987
988/**
989 * per_cpu_ptr_to_phys - convert translated percpu address to physical address
990 * @addr: the address to be converted to physical address
991 *
992 * Given @addr which is dereferenceable address obtained via one of
993 * percpu access macros, this function translates it into its physical
994 * address. The caller is responsible for ensuring @addr stays valid
995 * until this function finishes.
996 *
997 * percpu allocator has special setup for the first chunk, which currently
998 * supports either embedding in linear address space or vmalloc mapping,
999 * and, from the second one, the backing allocator (currently either vm or
1000 * km) provides translation.
1001 *
1002 * The addr can be tranlated simply without checking if it falls into the
1003 * first chunk. But the current code reflects better how percpu allocator
1004 * actually works, and the verification can discover both bugs in percpu
1005 * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
1006 * code.
1007 *
1008 * RETURNS:
1009 * The physical address for @addr.
1010 */
1011phys_addr_t per_cpu_ptr_to_phys(void *addr)
1012{
1013 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
1014 bool in_first_chunk = false;
1015 unsigned long first_low, first_high;
1016 unsigned int cpu;
1017
1018 /*
1019 * The following test on unit_low/high isn't strictly
1020 * necessary but will speed up lookups of addresses which
1021 * aren't in the first chunk.
1022 */
1023 first_low = pcpu_chunk_addr(pcpu_first_chunk, pcpu_low_unit_cpu, 0);
1024 first_high = pcpu_chunk_addr(pcpu_first_chunk, pcpu_high_unit_cpu,
1025 pcpu_unit_pages);
1026 if ((unsigned long)addr >= first_low &&
1027 (unsigned long)addr < first_high) {
1028 for_each_possible_cpu(cpu) {
1029 void *start = per_cpu_ptr(base, cpu);
1030
1031 if (addr >= start && addr < start + pcpu_unit_size) {
1032 in_first_chunk = true;
1033 break;
1034 }
1035 }
1036 }
1037
1038 if (in_first_chunk) {
1039 if (!is_vmalloc_addr(addr))
1040 return __pa(addr);
1041 else
1042 return page_to_phys(vmalloc_to_page(addr)) +
1043 offset_in_page(addr);
1044 } else
1045 return page_to_phys(pcpu_addr_to_page(addr)) +
1046 offset_in_page(addr);
1047}
1048
1049/**
1050 * pcpu_alloc_alloc_info - allocate percpu allocation info
1051 * @nr_groups: the number of groups
1052 * @nr_units: the number of units
1053 *
1054 * Allocate ai which is large enough for @nr_groups groups containing
1055 * @nr_units units. The returned ai's groups[0].cpu_map points to the
1056 * cpu_map array which is long enough for @nr_units and filled with
1057 * NR_CPUS. It's the caller's responsibility to initialize cpu_map
1058 * pointer of other groups.
1059 *
1060 * RETURNS:
1061 * Pointer to the allocated pcpu_alloc_info on success, NULL on
1062 * failure.
1063 */
1064struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
1065 int nr_units)
1066{
1067 struct pcpu_alloc_info *ai;
1068 size_t base_size, ai_size;
1069 void *ptr;
1070 int unit;
1071
1072 base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
1073 __alignof__(ai->groups[0].cpu_map[0]));
1074 ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
1075
1076 ptr = memblock_virt_alloc_nopanic(PFN_ALIGN(ai_size), 0);
1077 if (!ptr)
1078 return NULL;
1079 ai = ptr;
1080 ptr += base_size;
1081
1082 ai->groups[0].cpu_map = ptr;
1083
1084 for (unit = 0; unit < nr_units; unit++)
1085 ai->groups[0].cpu_map[unit] = NR_CPUS;
1086
1087 ai->nr_groups = nr_groups;
1088 ai->__ai_size = PFN_ALIGN(ai_size);
1089
1090 return ai;
1091}
1092
1093/**
1094 * pcpu_free_alloc_info - free percpu allocation info
1095 * @ai: pcpu_alloc_info to free
1096 *
1097 * Free @ai which was allocated by pcpu_alloc_alloc_info().
1098 */
1099void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
1100{
1101 memblock_free_early(__pa(ai), ai->__ai_size);
1102}
1103
1104/**
1105 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
1106 * @lvl: loglevel
1107 * @ai: allocation info to dump
1108 *
1109 * Print out information about @ai using loglevel @lvl.
1110 */
1111static void pcpu_dump_alloc_info(const char *lvl,
1112 const struct pcpu_alloc_info *ai)
1113{
1114 int group_width = 1, cpu_width = 1, width;
1115 char empty_str[] = "--------";
1116 int alloc = 0, alloc_end = 0;
1117 int group, v;
1118 int upa, apl; /* units per alloc, allocs per line */
1119
1120 v = ai->nr_groups;
1121 while (v /= 10)
1122 group_width++;
1123
1124 v = num_possible_cpus();
1125 while (v /= 10)
1126 cpu_width++;
1127 empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
1128
1129 upa = ai->alloc_size / ai->unit_size;
1130 width = upa * (cpu_width + 1) + group_width + 3;
1131 apl = rounddown_pow_of_two(max(60 / width, 1));
1132
1133 printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
1134 lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
1135 ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
1136
1137 for (group = 0; group < ai->nr_groups; group++) {
1138 const struct pcpu_group_info *gi = &ai->groups[group];
1139 int unit = 0, unit_end = 0;
1140
1141 BUG_ON(gi->nr_units % upa);
1142 for (alloc_end += gi->nr_units / upa;
1143 alloc < alloc_end; alloc++) {
1144 if (!(alloc % apl)) {
1145 printk(KERN_CONT "\n");
1146 printk("%spcpu-alloc: ", lvl);
1147 }
1148 printk(KERN_CONT "[%0*d] ", group_width, group);
1149
1150 for (unit_end += upa; unit < unit_end; unit++)
1151 if (gi->cpu_map[unit] != NR_CPUS)
1152 printk(KERN_CONT "%0*d ", cpu_width,
1153 gi->cpu_map[unit]);
1154 else
1155 printk(KERN_CONT "%s ", empty_str);
1156 }
1157 }
1158 printk(KERN_CONT "\n");
1159}
1160
1161/**
1162 * pcpu_setup_first_chunk - initialize the first percpu chunk
1163 * @ai: pcpu_alloc_info describing how to percpu area is shaped
1164 * @base_addr: mapped address
1165 *
1166 * Initialize the first percpu chunk which contains the kernel static
1167 * perpcu area. This function is to be called from arch percpu area
1168 * setup path.
1169 *
1170 * @ai contains all information necessary to initialize the first
1171 * chunk and prime the dynamic percpu allocator.
1172 *
1173 * @ai->static_size is the size of static percpu area.
1174 *
1175 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
1176 * reserve after the static area in the first chunk. This reserves
1177 * the first chunk such that it's available only through reserved
1178 * percpu allocation. This is primarily used to serve module percpu
1179 * static areas on architectures where the addressing model has
1180 * limited offset range for symbol relocations to guarantee module
1181 * percpu symbols fall inside the relocatable range.
1182 *
1183 * @ai->dyn_size determines the number of bytes available for dynamic
1184 * allocation in the first chunk. The area between @ai->static_size +
1185 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
1186 *
1187 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
1188 * and equal to or larger than @ai->static_size + @ai->reserved_size +
1189 * @ai->dyn_size.
1190 *
1191 * @ai->atom_size is the allocation atom size and used as alignment
1192 * for vm areas.
1193 *
1194 * @ai->alloc_size is the allocation size and always multiple of
1195 * @ai->atom_size. This is larger than @ai->atom_size if
1196 * @ai->unit_size is larger than @ai->atom_size.
1197 *
1198 * @ai->nr_groups and @ai->groups describe virtual memory layout of
1199 * percpu areas. Units which should be colocated are put into the
1200 * same group. Dynamic VM areas will be allocated according to these
1201 * groupings. If @ai->nr_groups is zero, a single group containing
1202 * all units is assumed.
1203 *
1204 * The caller should have mapped the first chunk at @base_addr and
1205 * copied static data to each unit.
1206 *
1207 * If the first chunk ends up with both reserved and dynamic areas, it
1208 * is served by two chunks - one to serve the core static and reserved
1209 * areas and the other for the dynamic area. They share the same vm
1210 * and page map but uses different area allocation map to stay away
1211 * from each other. The latter chunk is circulated in the chunk slots
1212 * and available for dynamic allocation like any other chunks.
1213 *
1214 * RETURNS:
1215 * 0 on success, -errno on failure.
1216 */
1217int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
1218 void *base_addr)
1219{
1220 static char cpus_buf[4096] __initdata;
1221 static int smap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
1222 static int dmap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
1223 size_t dyn_size = ai->dyn_size;
1224 size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
1225 struct pcpu_chunk *schunk, *dchunk = NULL;
1226 unsigned long *group_offsets;
1227 size_t *group_sizes;
1228 unsigned long *unit_off;
1229 unsigned int cpu;
1230 int *unit_map;
1231 int group, unit, i;
1232
1233 cpumask_scnprintf(cpus_buf, sizeof(cpus_buf), cpu_possible_mask);
1234
1235#define PCPU_SETUP_BUG_ON(cond) do { \
1236 if (unlikely(cond)) { \
1237 pr_emerg("PERCPU: failed to initialize, %s", #cond); \
1238 pr_emerg("PERCPU: cpu_possible_mask=%s\n", cpus_buf); \
1239 pcpu_dump_alloc_info(KERN_EMERG, ai); \
1240 BUG(); \
1241 } \
1242} while (0)
1243
1244 /* sanity checks */
1245 PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
1246#ifdef CONFIG_SMP
1247 PCPU_SETUP_BUG_ON(!ai->static_size);
1248 PCPU_SETUP_BUG_ON((unsigned long)__per_cpu_start & ~PAGE_MASK);
1249#endif
1250 PCPU_SETUP_BUG_ON(!base_addr);
1251 PCPU_SETUP_BUG_ON((unsigned long)base_addr & ~PAGE_MASK);
1252 PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
1253 PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
1254 PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
1255 PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
1256 PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
1257
1258 /* process group information and build config tables accordingly */
1259 group_offsets = memblock_virt_alloc(ai->nr_groups *
1260 sizeof(group_offsets[0]), 0);
1261 group_sizes = memblock_virt_alloc(ai->nr_groups *
1262 sizeof(group_sizes[0]), 0);
1263 unit_map = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_map[0]), 0);
1264 unit_off = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_off[0]), 0);
1265
1266 for (cpu = 0; cpu < nr_cpu_ids; cpu++)
1267 unit_map[cpu] = UINT_MAX;
1268
1269 pcpu_low_unit_cpu = NR_CPUS;
1270 pcpu_high_unit_cpu = NR_CPUS;
1271
1272 for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
1273 const struct pcpu_group_info *gi = &ai->groups[group];
1274
1275 group_offsets[group] = gi->base_offset;
1276 group_sizes[group] = gi->nr_units * ai->unit_size;
1277
1278 for (i = 0; i < gi->nr_units; i++) {
1279 cpu = gi->cpu_map[i];
1280 if (cpu == NR_CPUS)
1281 continue;
1282
1283 PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids);
1284 PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
1285 PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
1286
1287 unit_map[cpu] = unit + i;
1288 unit_off[cpu] = gi->base_offset + i * ai->unit_size;
1289
1290 /* determine low/high unit_cpu */
1291 if (pcpu_low_unit_cpu == NR_CPUS ||
1292 unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
1293 pcpu_low_unit_cpu = cpu;
1294 if (pcpu_high_unit_cpu == NR_CPUS ||
1295 unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
1296 pcpu_high_unit_cpu = cpu;
1297 }
1298 }
1299 pcpu_nr_units = unit;
1300
1301 for_each_possible_cpu(cpu)
1302 PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
1303
1304 /* we're done parsing the input, undefine BUG macro and dump config */
1305#undef PCPU_SETUP_BUG_ON
1306 pcpu_dump_alloc_info(KERN_DEBUG, ai);
1307
1308 pcpu_nr_groups = ai->nr_groups;
1309 pcpu_group_offsets = group_offsets;
1310 pcpu_group_sizes = group_sizes;
1311 pcpu_unit_map = unit_map;
1312 pcpu_unit_offsets = unit_off;
1313
1314 /* determine basic parameters */
1315 pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
1316 pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
1317 pcpu_atom_size = ai->atom_size;
1318 pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
1319 BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
1320
1321 /*
1322 * Allocate chunk slots. The additional last slot is for
1323 * empty chunks.
1324 */
1325 pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
1326 pcpu_slot = memblock_virt_alloc(
1327 pcpu_nr_slots * sizeof(pcpu_slot[0]), 0);
1328 for (i = 0; i < pcpu_nr_slots; i++)
1329 INIT_LIST_HEAD(&pcpu_slot[i]);
1330
1331 /*
1332 * Initialize static chunk. If reserved_size is zero, the
1333 * static chunk covers static area + dynamic allocation area
1334 * in the first chunk. If reserved_size is not zero, it
1335 * covers static area + reserved area (mostly used for module
1336 * static percpu allocation).
1337 */
1338 schunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
1339 INIT_LIST_HEAD(&schunk->list);
1340 schunk->base_addr = base_addr;
1341 schunk->map = smap;
1342 schunk->map_alloc = ARRAY_SIZE(smap);
1343 schunk->immutable = true;
1344 bitmap_fill(schunk->populated, pcpu_unit_pages);
1345
1346 if (ai->reserved_size) {
1347 schunk->free_size = ai->reserved_size;
1348 pcpu_reserved_chunk = schunk;
1349 pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
1350 } else {
1351 schunk->free_size = dyn_size;
1352 dyn_size = 0; /* dynamic area covered */
1353 }
1354 schunk->contig_hint = schunk->free_size;
1355
1356 schunk->map[0] = 1;
1357 schunk->map[1] = ai->static_size;
1358 schunk->map_used = 1;
1359 if (schunk->free_size)
1360 schunk->map[++schunk->map_used] = 1 | (ai->static_size + schunk->free_size);
1361 else
1362 schunk->map[1] |= 1;
1363
1364 /* init dynamic chunk if necessary */
1365 if (dyn_size) {
1366 dchunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
1367 INIT_LIST_HEAD(&dchunk->list);
1368 dchunk->base_addr = base_addr;
1369 dchunk->map = dmap;
1370 dchunk->map_alloc = ARRAY_SIZE(dmap);
1371 dchunk->immutable = true;
1372 bitmap_fill(dchunk->populated, pcpu_unit_pages);
1373
1374 dchunk->contig_hint = dchunk->free_size = dyn_size;
1375 dchunk->map[0] = 1;
1376 dchunk->map[1] = pcpu_reserved_chunk_limit;
1377 dchunk->map[2] = (pcpu_reserved_chunk_limit + dchunk->free_size) | 1;
1378 dchunk->map_used = 2;
1379 }
1380
1381 /* link the first chunk in */
1382 pcpu_first_chunk = dchunk ?: schunk;
1383 pcpu_chunk_relocate(pcpu_first_chunk, -1);
1384
1385 /* we're done */
1386 pcpu_base_addr = base_addr;
1387 return 0;
1388}
1389
1390#ifdef CONFIG_SMP
1391
1392const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = {
1393 [PCPU_FC_AUTO] = "auto",
1394 [PCPU_FC_EMBED] = "embed",
1395 [PCPU_FC_PAGE] = "page",
1396};
1397
1398enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
1399
1400static int __init percpu_alloc_setup(char *str)
1401{
1402 if (!str)
1403 return -EINVAL;
1404
1405 if (0)
1406 /* nada */;
1407#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
1408 else if (!strcmp(str, "embed"))
1409 pcpu_chosen_fc = PCPU_FC_EMBED;
1410#endif
1411#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1412 else if (!strcmp(str, "page"))
1413 pcpu_chosen_fc = PCPU_FC_PAGE;
1414#endif
1415 else
1416 pr_warning("PERCPU: unknown allocator %s specified\n", str);
1417
1418 return 0;
1419}
1420early_param("percpu_alloc", percpu_alloc_setup);
1421
1422/*
1423 * pcpu_embed_first_chunk() is used by the generic percpu setup.
1424 * Build it if needed by the arch config or the generic setup is going
1425 * to be used.
1426 */
1427#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
1428 !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
1429#define BUILD_EMBED_FIRST_CHUNK
1430#endif
1431
1432/* build pcpu_page_first_chunk() iff needed by the arch config */
1433#if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
1434#define BUILD_PAGE_FIRST_CHUNK
1435#endif
1436
1437/* pcpu_build_alloc_info() is used by both embed and page first chunk */
1438#if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
1439/**
1440 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
1441 * @reserved_size: the size of reserved percpu area in bytes
1442 * @dyn_size: minimum free size for dynamic allocation in bytes
1443 * @atom_size: allocation atom size
1444 * @cpu_distance_fn: callback to determine distance between cpus, optional
1445 *
1446 * This function determines grouping of units, their mappings to cpus
1447 * and other parameters considering needed percpu size, allocation
1448 * atom size and distances between CPUs.
1449 *
1450 * Groups are always mutliples of atom size and CPUs which are of
1451 * LOCAL_DISTANCE both ways are grouped together and share space for
1452 * units in the same group. The returned configuration is guaranteed
1453 * to have CPUs on different nodes on different groups and >=75% usage
1454 * of allocated virtual address space.
1455 *
1456 * RETURNS:
1457 * On success, pointer to the new allocation_info is returned. On
1458 * failure, ERR_PTR value is returned.
1459 */
1460static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
1461 size_t reserved_size, size_t dyn_size,
1462 size_t atom_size,
1463 pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
1464{
1465 static int group_map[NR_CPUS] __initdata;
1466 static int group_cnt[NR_CPUS] __initdata;
1467 const size_t static_size = __per_cpu_end - __per_cpu_start;
1468 int nr_groups = 1, nr_units = 0;
1469 size_t size_sum, min_unit_size, alloc_size;
1470 int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
1471 int last_allocs, group, unit;
1472 unsigned int cpu, tcpu;
1473 struct pcpu_alloc_info *ai;
1474 unsigned int *cpu_map;
1475
1476 /* this function may be called multiple times */
1477 memset(group_map, 0, sizeof(group_map));
1478 memset(group_cnt, 0, sizeof(group_cnt));
1479
1480 /* calculate size_sum and ensure dyn_size is enough for early alloc */
1481 size_sum = PFN_ALIGN(static_size + reserved_size +
1482 max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
1483 dyn_size = size_sum - static_size - reserved_size;
1484
1485 /*
1486 * Determine min_unit_size, alloc_size and max_upa such that
1487 * alloc_size is multiple of atom_size and is the smallest
1488 * which can accommodate 4k aligned segments which are equal to
1489 * or larger than min_unit_size.
1490 */
1491 min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
1492
1493 alloc_size = roundup(min_unit_size, atom_size);
1494 upa = alloc_size / min_unit_size;
1495 while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1496 upa--;
1497 max_upa = upa;
1498
1499 /* group cpus according to their proximity */
1500 for_each_possible_cpu(cpu) {
1501 group = 0;
1502 next_group:
1503 for_each_possible_cpu(tcpu) {
1504 if (cpu == tcpu)
1505 break;
1506 if (group_map[tcpu] == group && cpu_distance_fn &&
1507 (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
1508 cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
1509 group++;
1510 nr_groups = max(nr_groups, group + 1);
1511 goto next_group;
1512 }
1513 }
1514 group_map[cpu] = group;
1515 group_cnt[group]++;
1516 }
1517
1518 /*
1519 * Expand unit size until address space usage goes over 75%
1520 * and then as much as possible without using more address
1521 * space.
1522 */
1523 last_allocs = INT_MAX;
1524 for (upa = max_upa; upa; upa--) {
1525 int allocs = 0, wasted = 0;
1526
1527 if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1528 continue;
1529
1530 for (group = 0; group < nr_groups; group++) {
1531 int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
1532 allocs += this_allocs;
1533 wasted += this_allocs * upa - group_cnt[group];
1534 }
1535
1536 /*
1537 * Don't accept if wastage is over 1/3. The
1538 * greater-than comparison ensures upa==1 always
1539 * passes the following check.
1540 */
1541 if (wasted > num_possible_cpus() / 3)
1542 continue;
1543
1544 /* and then don't consume more memory */
1545 if (allocs > last_allocs)
1546 break;
1547 last_allocs = allocs;
1548 best_upa = upa;
1549 }
1550 upa = best_upa;
1551
1552 /* allocate and fill alloc_info */
1553 for (group = 0; group < nr_groups; group++)
1554 nr_units += roundup(group_cnt[group], upa);
1555
1556 ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
1557 if (!ai)
1558 return ERR_PTR(-ENOMEM);
1559 cpu_map = ai->groups[0].cpu_map;
1560
1561 for (group = 0; group < nr_groups; group++) {
1562 ai->groups[group].cpu_map = cpu_map;
1563 cpu_map += roundup(group_cnt[group], upa);
1564 }
1565
1566 ai->static_size = static_size;
1567 ai->reserved_size = reserved_size;
1568 ai->dyn_size = dyn_size;
1569 ai->unit_size = alloc_size / upa;
1570 ai->atom_size = atom_size;
1571 ai->alloc_size = alloc_size;
1572
1573 for (group = 0, unit = 0; group_cnt[group]; group++) {
1574 struct pcpu_group_info *gi = &ai->groups[group];
1575
1576 /*
1577 * Initialize base_offset as if all groups are located
1578 * back-to-back. The caller should update this to
1579 * reflect actual allocation.
1580 */
1581 gi->base_offset = unit * ai->unit_size;
1582
1583 for_each_possible_cpu(cpu)
1584 if (group_map[cpu] == group)
1585 gi->cpu_map[gi->nr_units++] = cpu;
1586 gi->nr_units = roundup(gi->nr_units, upa);
1587 unit += gi->nr_units;
1588 }
1589 BUG_ON(unit != nr_units);
1590
1591 return ai;
1592}
1593#endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
1594
1595#if defined(BUILD_EMBED_FIRST_CHUNK)
1596/**
1597 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
1598 * @reserved_size: the size of reserved percpu area in bytes
1599 * @dyn_size: minimum free size for dynamic allocation in bytes
1600 * @atom_size: allocation atom size
1601 * @cpu_distance_fn: callback to determine distance between cpus, optional
1602 * @alloc_fn: function to allocate percpu page
1603 * @free_fn: function to free percpu page
1604 *
1605 * This is a helper to ease setting up embedded first percpu chunk and
1606 * can be called where pcpu_setup_first_chunk() is expected.
1607 *
1608 * If this function is used to setup the first chunk, it is allocated
1609 * by calling @alloc_fn and used as-is without being mapped into
1610 * vmalloc area. Allocations are always whole multiples of @atom_size
1611 * aligned to @atom_size.
1612 *
1613 * This enables the first chunk to piggy back on the linear physical
1614 * mapping which often uses larger page size. Please note that this
1615 * can result in very sparse cpu->unit mapping on NUMA machines thus
1616 * requiring large vmalloc address space. Don't use this allocator if
1617 * vmalloc space is not orders of magnitude larger than distances
1618 * between node memory addresses (ie. 32bit NUMA machines).
1619 *
1620 * @dyn_size specifies the minimum dynamic area size.
1621 *
1622 * If the needed size is smaller than the minimum or specified unit
1623 * size, the leftover is returned using @free_fn.
1624 *
1625 * RETURNS:
1626 * 0 on success, -errno on failure.
1627 */
1628int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
1629 size_t atom_size,
1630 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
1631 pcpu_fc_alloc_fn_t alloc_fn,
1632 pcpu_fc_free_fn_t free_fn)
1633{
1634 void *base = (void *)ULONG_MAX;
1635 void **areas = NULL;
1636 struct pcpu_alloc_info *ai;
1637 size_t size_sum, areas_size, max_distance;
1638 int group, i, rc;
1639
1640 ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
1641 cpu_distance_fn);
1642 if (IS_ERR(ai))
1643 return PTR_ERR(ai);
1644
1645 size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
1646 areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
1647
1648 areas = memblock_virt_alloc_nopanic(areas_size, 0);
1649 if (!areas) {
1650 rc = -ENOMEM;
1651 goto out_free;
1652 }
1653
1654 /* allocate, copy and determine base address */
1655 for (group = 0; group < ai->nr_groups; group++) {
1656 struct pcpu_group_info *gi = &ai->groups[group];
1657 unsigned int cpu = NR_CPUS;
1658 void *ptr;
1659
1660 for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
1661 cpu = gi->cpu_map[i];
1662 BUG_ON(cpu == NR_CPUS);
1663
1664 /* allocate space for the whole group */
1665 ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
1666 if (!ptr) {
1667 rc = -ENOMEM;
1668 goto out_free_areas;
1669 }
1670 /* kmemleak tracks the percpu allocations separately */
1671 kmemleak_free(ptr);
1672 areas[group] = ptr;
1673
1674 base = min(ptr, base);
1675 }
1676
1677 /*
1678 * Copy data and free unused parts. This should happen after all
1679 * allocations are complete; otherwise, we may end up with
1680 * overlapping groups.
1681 */
1682 for (group = 0; group < ai->nr_groups; group++) {
1683 struct pcpu_group_info *gi = &ai->groups[group];
1684 void *ptr = areas[group];
1685
1686 for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
1687 if (gi->cpu_map[i] == NR_CPUS) {
1688 /* unused unit, free whole */
1689 free_fn(ptr, ai->unit_size);
1690 continue;
1691 }
1692 /* copy and return the unused part */
1693 memcpy(ptr, __per_cpu_load, ai->static_size);
1694 free_fn(ptr + size_sum, ai->unit_size - size_sum);
1695 }
1696 }
1697
1698 /* base address is now known, determine group base offsets */
1699 max_distance = 0;
1700 for (group = 0; group < ai->nr_groups; group++) {
1701 ai->groups[group].base_offset = areas[group] - base;
1702 max_distance = max_t(size_t, max_distance,
1703 ai->groups[group].base_offset);
1704 }
1705 max_distance += ai->unit_size;
1706
1707 /* warn if maximum distance is further than 75% of vmalloc space */
1708 if (max_distance > VMALLOC_TOTAL * 3 / 4) {
1709 pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc "
1710 "space 0x%lx\n", max_distance,
1711 VMALLOC_TOTAL);
1712#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1713 /* and fail if we have fallback */
1714 rc = -EINVAL;
1715 goto out_free;
1716#endif
1717 }
1718
1719 pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
1720 PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
1721 ai->dyn_size, ai->unit_size);
1722
1723 rc = pcpu_setup_first_chunk(ai, base);
1724 goto out_free;
1725
1726out_free_areas:
1727 for (group = 0; group < ai->nr_groups; group++)
1728 if (areas[group])
1729 free_fn(areas[group],
1730 ai->groups[group].nr_units * ai->unit_size);
1731out_free:
1732 pcpu_free_alloc_info(ai);
1733 if (areas)
1734 memblock_free_early(__pa(areas), areas_size);
1735 return rc;
1736}
1737#endif /* BUILD_EMBED_FIRST_CHUNK */
1738
1739#ifdef BUILD_PAGE_FIRST_CHUNK
1740/**
1741 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
1742 * @reserved_size: the size of reserved percpu area in bytes
1743 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
1744 * @free_fn: function to free percpu page, always called with PAGE_SIZE
1745 * @populate_pte_fn: function to populate pte
1746 *
1747 * This is a helper to ease setting up page-remapped first percpu
1748 * chunk and can be called where pcpu_setup_first_chunk() is expected.
1749 *
1750 * This is the basic allocator. Static percpu area is allocated
1751 * page-by-page into vmalloc area.
1752 *
1753 * RETURNS:
1754 * 0 on success, -errno on failure.
1755 */
1756int __init pcpu_page_first_chunk(size_t reserved_size,
1757 pcpu_fc_alloc_fn_t alloc_fn,
1758 pcpu_fc_free_fn_t free_fn,
1759 pcpu_fc_populate_pte_fn_t populate_pte_fn)
1760{
1761 static struct vm_struct vm;
1762 struct pcpu_alloc_info *ai;
1763 char psize_str[16];
1764 int unit_pages;
1765 size_t pages_size;
1766 struct page **pages;
1767 int unit, i, j, rc;
1768
1769 snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
1770
1771 ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
1772 if (IS_ERR(ai))
1773 return PTR_ERR(ai);
1774 BUG_ON(ai->nr_groups != 1);
1775 BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
1776
1777 unit_pages = ai->unit_size >> PAGE_SHIFT;
1778
1779 /* unaligned allocations can't be freed, round up to page size */
1780 pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
1781 sizeof(pages[0]));
1782 pages = memblock_virt_alloc(pages_size, 0);
1783
1784 /* allocate pages */
1785 j = 0;
1786 for (unit = 0; unit < num_possible_cpus(); unit++)
1787 for (i = 0; i < unit_pages; i++) {
1788 unsigned int cpu = ai->groups[0].cpu_map[unit];
1789 void *ptr;
1790
1791 ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
1792 if (!ptr) {
1793 pr_warning("PERCPU: failed to allocate %s page "
1794 "for cpu%u\n", psize_str, cpu);
1795 goto enomem;
1796 }
1797 /* kmemleak tracks the percpu allocations separately */
1798 kmemleak_free(ptr);
1799 pages[j++] = virt_to_page(ptr);
1800 }
1801
1802 /* allocate vm area, map the pages and copy static data */
1803 vm.flags = VM_ALLOC;
1804 vm.size = num_possible_cpus() * ai->unit_size;
1805 vm_area_register_early(&vm, PAGE_SIZE);
1806
1807 for (unit = 0; unit < num_possible_cpus(); unit++) {
1808 unsigned long unit_addr =
1809 (unsigned long)vm.addr + unit * ai->unit_size;
1810
1811 for (i = 0; i < unit_pages; i++)
1812 populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
1813
1814 /* pte already populated, the following shouldn't fail */
1815 rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
1816 unit_pages);
1817 if (rc < 0)
1818 panic("failed to map percpu area, err=%d\n", rc);
1819
1820 /*
1821 * FIXME: Archs with virtual cache should flush local
1822 * cache for the linear mapping here - something
1823 * equivalent to flush_cache_vmap() on the local cpu.
1824 * flush_cache_vmap() can't be used as most supporting
1825 * data structures are not set up yet.
1826 */
1827
1828 /* copy static data */
1829 memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
1830 }
1831
1832 /* we're ready, commit */
1833 pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
1834 unit_pages, psize_str, vm.addr, ai->static_size,
1835 ai->reserved_size, ai->dyn_size);
1836
1837 rc = pcpu_setup_first_chunk(ai, vm.addr);
1838 goto out_free_ar;
1839
1840enomem:
1841 while (--j >= 0)
1842 free_fn(page_address(pages[j]), PAGE_SIZE);
1843 rc = -ENOMEM;
1844out_free_ar:
1845 memblock_free_early(__pa(pages), pages_size);
1846 pcpu_free_alloc_info(ai);
1847 return rc;
1848}
1849#endif /* BUILD_PAGE_FIRST_CHUNK */
1850
1851#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
1852/*
1853 * Generic SMP percpu area setup.
1854 *
1855 * The embedding helper is used because its behavior closely resembles
1856 * the original non-dynamic generic percpu area setup. This is
1857 * important because many archs have addressing restrictions and might
1858 * fail if the percpu area is located far away from the previous
1859 * location. As an added bonus, in non-NUMA cases, embedding is
1860 * generally a good idea TLB-wise because percpu area can piggy back
1861 * on the physical linear memory mapping which uses large page
1862 * mappings on applicable archs.
1863 */
1864unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
1865EXPORT_SYMBOL(__per_cpu_offset);
1866
1867static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
1868 size_t align)
1869{
1870 return memblock_virt_alloc_from_nopanic(
1871 size, align, __pa(MAX_DMA_ADDRESS));
1872}
1873
1874static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
1875{
1876 memblock_free_early(__pa(ptr), size);
1877}
1878
1879void __init setup_per_cpu_areas(void)
1880{
1881 unsigned long delta;
1882 unsigned int cpu;
1883 int rc;
1884
1885 /*
1886 * Always reserve area for module percpu variables. That's
1887 * what the legacy allocator did.
1888 */
1889 rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
1890 PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
1891 pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
1892 if (rc < 0)
1893 panic("Failed to initialize percpu areas.");
1894
1895 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
1896 for_each_possible_cpu(cpu)
1897 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
1898}
1899#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
1900
1901#else /* CONFIG_SMP */
1902
1903/*
1904 * UP percpu area setup.
1905 *
1906 * UP always uses km-based percpu allocator with identity mapping.
1907 * Static percpu variables are indistinguishable from the usual static
1908 * variables and don't require any special preparation.
1909 */
1910void __init setup_per_cpu_areas(void)
1911{
1912 const size_t unit_size =
1913 roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
1914 PERCPU_DYNAMIC_RESERVE));
1915 struct pcpu_alloc_info *ai;
1916 void *fc;
1917
1918 ai = pcpu_alloc_alloc_info(1, 1);
1919 fc = memblock_virt_alloc_from_nopanic(unit_size,
1920 PAGE_SIZE,
1921 __pa(MAX_DMA_ADDRESS));
1922 if (!ai || !fc)
1923 panic("Failed to allocate memory for percpu areas.");
1924 /* kmemleak tracks the percpu allocations separately */
1925 kmemleak_free(fc);
1926
1927 ai->dyn_size = unit_size;
1928 ai->unit_size = unit_size;
1929 ai->atom_size = unit_size;
1930 ai->alloc_size = unit_size;
1931 ai->groups[0].nr_units = 1;
1932 ai->groups[0].cpu_map[0] = 0;
1933
1934 if (pcpu_setup_first_chunk(ai, fc) < 0)
1935 panic("Failed to initialize percpu areas.");
1936}
1937
1938#endif /* CONFIG_SMP */
1939
1940/*
1941 * First and reserved chunks are initialized with temporary allocation
1942 * map in initdata so that they can be used before slab is online.
1943 * This function is called after slab is brought up and replaces those
1944 * with properly allocated maps.
1945 */
1946void __init percpu_init_late(void)
1947{
1948 struct pcpu_chunk *target_chunks[] =
1949 { pcpu_first_chunk, pcpu_reserved_chunk, NULL };
1950 struct pcpu_chunk *chunk;
1951 unsigned long flags;
1952 int i;
1953
1954 for (i = 0; (chunk = target_chunks[i]); i++) {
1955 int *map;
1956 const size_t size = PERCPU_DYNAMIC_EARLY_SLOTS * sizeof(map[0]);
1957
1958 BUILD_BUG_ON(size > PAGE_SIZE);
1959
1960 map = pcpu_mem_zalloc(size);
1961 BUG_ON(!map);
1962
1963 spin_lock_irqsave(&pcpu_lock, flags);
1964 memcpy(map, chunk->map, size);
1965 chunk->map = map;
1966 spin_unlock_irqrestore(&pcpu_lock, flags);
1967 }
1968}