1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _MM_PERCPU_INTERNAL_H
  3#define _MM_PERCPU_INTERNAL_H
  4
  5#include <linux/types.h>
  6#include <linux/percpu.h>
  7#include <linux/memcontrol.h>
  8
  9/*
 10 * pcpu_block_md is the metadata block struct.
 11 * Each chunk's bitmap is split into a number of full blocks.
 12 * All units are in terms of bits.
 13 *
 14 * The scan hint is the largest known contiguous area before the contig hint.
 15 * It is not necessarily the actual largest contig hint though.  There is an
 16 * invariant that the scan_hint_start > contig_hint_start iff
 17 * scan_hint == contig_hint.  This is necessary because when scanning forward,
 18 * we don't know if a new contig hint would be better than the current one.
 19 */
 20struct pcpu_block_md {
 21	int			scan_hint;	/* scan hint for block */
 22	int			scan_hint_start; /* block relative starting
 23						    position of the scan hint */
 24	int                     contig_hint;    /* contig hint for block */
 25	int                     contig_hint_start; /* block relative starting
 26						      position of the contig hint */
 27	int                     left_free;      /* size of free space along
 28						   the left side of the block */
 29	int                     right_free;     /* size of free space along
 30						   the right side of the block */
 31	int                     first_free;     /* block position of first free */
 32	int			nr_bits;	/* total bits responsible for */
 33};
 34
 35struct pcpu_chunk {
 36#ifdef CONFIG_PERCPU_STATS
 37	int			nr_alloc;	/* # of allocations */
 38	size_t			max_alloc_size; /* largest allocation size */
 39#endif
 40
 41	struct list_head	list;		/* linked to pcpu_slot lists */
 42	int			free_bytes;	/* free bytes in the chunk */
 43	struct pcpu_block_md	chunk_md;
 44	unsigned long		*bound_map;	/* boundary map */
 45
 46	/*
 47	 * base_addr is the base address of this chunk.
 48	 * To reduce false sharing, current layout is optimized to make sure
 49	 * base_addr locate in the different cacheline with free_bytes and
 50	 * chunk_md.
 51	 */
 52	void			*base_addr ____cacheline_aligned_in_smp;
 53
 54	unsigned long		*alloc_map;	/* allocation map */
 55	struct pcpu_block_md	*md_blocks;	/* metadata blocks */
 56
 57	void			*data;		/* chunk data */
 58	bool			immutable;	/* no [de]population allowed */
 59	bool			isolated;	/* isolated from active chunk
 60						   slots */
 61	int			start_offset;	/* the overlap with the previous
 62						   region to have a page aligned
 63						   base_addr */
 64	int			end_offset;	/* additional area required to
 65						   have the region end page
 66						   aligned */
 67#ifdef CONFIG_MEMCG_KMEM
 68	struct obj_cgroup	**obj_cgroups;	/* vector of object cgroups */
 69#endif
 70
 71	int			nr_pages;	/* # of pages served by this chunk */
 72	int			nr_populated;	/* # of populated pages */
 73	int                     nr_empty_pop_pages; /* # of empty populated pages */
 74	unsigned long		populated[];	/* populated bitmap */
 75};
 76
 77extern spinlock_t pcpu_lock;
 78
 79extern struct list_head *pcpu_chunk_lists;
 80extern int pcpu_nr_slots;
 81extern int pcpu_sidelined_slot;
 82extern int pcpu_to_depopulate_slot;
 83extern int pcpu_nr_empty_pop_pages;
 84
 85extern struct pcpu_chunk *pcpu_first_chunk;
 86extern struct pcpu_chunk *pcpu_reserved_chunk;
 87
 88/**
 89 * pcpu_chunk_nr_blocks - converts nr_pages to # of md_blocks
 90 * @chunk: chunk of interest
 91 *
 92 * This conversion is from the number of physical pages that the chunk
 93 * serves to the number of bitmap blocks used.
 94 */
 95static inline int pcpu_chunk_nr_blocks(struct pcpu_chunk *chunk)
 96{
 97	return chunk->nr_pages * PAGE_SIZE / PCPU_BITMAP_BLOCK_SIZE;
 98}
 99
100/**
101 * pcpu_nr_pages_to_map_bits - converts the pages to size of bitmap
102 * @pages: number of physical pages
103 *
104 * This conversion is from physical pages to the number of bits
105 * required in the bitmap.
106 */
107static inline int pcpu_nr_pages_to_map_bits(int pages)
108{
109	return pages * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE;
110}
111
112/**
113 * pcpu_chunk_map_bits - helper to convert nr_pages to size of bitmap
114 * @chunk: chunk of interest
115 *
116 * This conversion is from the number of physical pages that the chunk
117 * serves to the number of bits in the bitmap.
118 */
119static inline int pcpu_chunk_map_bits(struct pcpu_chunk *chunk)
120{
121	return pcpu_nr_pages_to_map_bits(chunk->nr_pages);
122}
123
124/**
125 * pcpu_obj_full_size - helper to calculate size of each accounted object
126 * @size: size of area to allocate in bytes
127 *
128 * For each accounted object there is an extra space which is used to store
129 * obj_cgroup membership if kmemcg is not disabled. Charge it too.
130 */
131static inline size_t pcpu_obj_full_size(size_t size)
132{
133	size_t extra_size = 0;
134
135#ifdef CONFIG_MEMCG_KMEM
136	if (!mem_cgroup_kmem_disabled())
137		extra_size += size / PCPU_MIN_ALLOC_SIZE * sizeof(struct obj_cgroup *);
138#endif
139
140	return size * num_possible_cpus() + extra_size;
141}
142
143#ifdef CONFIG_PERCPU_STATS
144
145#include <linux/spinlock.h>
146
147struct percpu_stats {
148	u64 nr_alloc;		/* lifetime # of allocations */
149	u64 nr_dealloc;		/* lifetime # of deallocations */
150	u64 nr_cur_alloc;	/* current # of allocations */
151	u64 nr_max_alloc;	/* max # of live allocations */
152	u32 nr_chunks;		/* current # of live chunks */
153	u32 nr_max_chunks;	/* max # of live chunks */
154	size_t min_alloc_size;	/* min allocation size */
155	size_t max_alloc_size;	/* max allocation size */
156};
157
158extern struct percpu_stats pcpu_stats;
159extern struct pcpu_alloc_info pcpu_stats_ai;
160
161/*
162 * For debug purposes. We don't care about the flexible array.
163 */
164static inline void pcpu_stats_save_ai(const struct pcpu_alloc_info *ai)
165{
166	memcpy(&pcpu_stats_ai, ai, sizeof(struct pcpu_alloc_info));
167
168	/* initialize min_alloc_size to unit_size */
169	pcpu_stats.min_alloc_size = pcpu_stats_ai.unit_size;
170}
171
172/*
173 * pcpu_stats_area_alloc - increment area allocation stats
174 * @chunk: the location of the area being allocated
175 * @size: size of area to allocate in bytes
176 *
177 * CONTEXT:
178 * pcpu_lock.
179 */
180static inline void pcpu_stats_area_alloc(struct pcpu_chunk *chunk, size_t size)
181{
182	lockdep_assert_held(&pcpu_lock);
183
184	pcpu_stats.nr_alloc++;
185	pcpu_stats.nr_cur_alloc++;
186	pcpu_stats.nr_max_alloc =
187		max(pcpu_stats.nr_max_alloc, pcpu_stats.nr_cur_alloc);
188	pcpu_stats.min_alloc_size =
189		min(pcpu_stats.min_alloc_size, size);
190	pcpu_stats.max_alloc_size =
191		max(pcpu_stats.max_alloc_size, size);
192
193	chunk->nr_alloc++;
194	chunk->max_alloc_size = max(chunk->max_alloc_size, size);
195}
196
197/*
198 * pcpu_stats_area_dealloc - decrement allocation stats
199 * @chunk: the location of the area being deallocated
200 *
201 * CONTEXT:
202 * pcpu_lock.
203 */
204static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
205{
206	lockdep_assert_held(&pcpu_lock);
207
208	pcpu_stats.nr_dealloc++;
209	pcpu_stats.nr_cur_alloc--;
210
211	chunk->nr_alloc--;
212}
213
214/*
215 * pcpu_stats_chunk_alloc - increment chunk stats
216 */
217static inline void pcpu_stats_chunk_alloc(void)
218{
219	unsigned long flags;
220	spin_lock_irqsave(&pcpu_lock, flags);
221
222	pcpu_stats.nr_chunks++;
223	pcpu_stats.nr_max_chunks =
224		max(pcpu_stats.nr_max_chunks, pcpu_stats.nr_chunks);
225
226	spin_unlock_irqrestore(&pcpu_lock, flags);
227}
228
229/*
230 * pcpu_stats_chunk_dealloc - decrement chunk stats
231 */
232static inline void pcpu_stats_chunk_dealloc(void)
233{
234	unsigned long flags;
235	spin_lock_irqsave(&pcpu_lock, flags);
236
237	pcpu_stats.nr_chunks--;
238
239	spin_unlock_irqrestore(&pcpu_lock, flags);
240}
241
242#else
243
244static inline void pcpu_stats_save_ai(const struct pcpu_alloc_info *ai)
245{
246}
247
248static inline void pcpu_stats_area_alloc(struct pcpu_chunk *chunk, size_t size)
249{
250}
251
252static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
253{
254}
255
256static inline void pcpu_stats_chunk_alloc(void)
257{
258}
259
260static inline void pcpu_stats_chunk_dealloc(void)
261{
262}
263
264#endif /* !CONFIG_PERCPU_STATS */
265
266#endif