1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/slab.h>
  3#include <linux/kernel.h>
  4#include <linux/bitops.h>
  5#include <linux/cpumask.h>
  6#include <linux/export.h>
  7#include <linux/memblock.h>
  8#include <linux/numa.h>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  9
 10/**
 11 * cpumask_next_wrap - helper to implement for_each_cpu_wrap
 12 * @n: the cpu prior to the place to search
 13 * @mask: the cpumask pointer
 14 * @start: the start point of the iteration
 15 * @wrap: assume @n crossing @start terminates the iteration
 16 *
 17 * Return: >= nr_cpu_ids on completion
 18 *
 19 * Note: the @wrap argument is required for the start condition when
 20 * we cannot assume @start is set in @mask.
 21 */
 22unsigned int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap)
 23{
 24	unsigned int next;
 25
 26again:
 27	next = cpumask_next(n, mask);
 28
 29	if (wrap && n < start && next >= start) {
 30		return nr_cpumask_bits;
 31
 32	} else if (next >= nr_cpumask_bits) {
 33		wrap = true;
 34		n = -1;
 35		goto again;
 36	}
 37
 38	return next;
 39}
 40EXPORT_SYMBOL(cpumask_next_wrap);
 41
 42/* These are not inline because of header tangles. */
 43#ifdef CONFIG_CPUMASK_OFFSTACK
 44/**
 45 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
 46 * @mask: pointer to cpumask_var_t where the cpumask is returned
 47 * @flags: GFP_ flags
 48 * @node: memory node from which to allocate or %NUMA_NO_NODE
 49 *
 50 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
 51 * a nop returning a constant 1 (in <linux/cpumask.h>).
 52 *
 53 * Return: TRUE if memory allocation succeeded, FALSE otherwise.
 54 *
 55 * In addition, mask will be NULL if this fails.  Note that gcc is
 56 * usually smart enough to know that mask can never be NULL if
 57 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
 58 * too.
 59 */
 60bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
 61{
 62	*mask = kmalloc_node(cpumask_size(), flags, node);
 63
 64#ifdef CONFIG_DEBUG_PER_CPU_MAPS
 65	if (!*mask) {
 66		printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
 67		dump_stack();
 68	}
 69#endif
 70
 71	return *mask != NULL;
 72}
 73EXPORT_SYMBOL(alloc_cpumask_var_node);
 74
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 75/**
 76 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
 77 * @mask: pointer to cpumask_var_t where the cpumask is returned
 78 *
 79 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
 80 * a nop (in <linux/cpumask.h>).
 81 * Either returns an allocated (zero-filled) cpumask, or causes the
 82 * system to panic.
 83 */
 84void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
 85{
 86	*mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES);
 87	if (!*mask)
 88		panic("%s: Failed to allocate %u bytes\n", __func__,
 89		      cpumask_size());
 90}
 91
 92/**
 93 * free_cpumask_var - frees memory allocated for a struct cpumask.
 94 * @mask: cpumask to free
 95 *
 96 * This is safe on a NULL mask.
 97 */
 98void free_cpumask_var(cpumask_var_t mask)
 99{
100	kfree(mask);
101}
102EXPORT_SYMBOL(free_cpumask_var);
103
104/**
105 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
106 * @mask: cpumask to free
107 */
108void __init free_bootmem_cpumask_var(cpumask_var_t mask)
109{
110	memblock_free(mask, cpumask_size());
111}
112#endif
113
114/**
115 * cpumask_local_spread - select the i'th cpu based on NUMA distances
116 * @i: index number
117 * @node: local numa_node
118 *
119 * Return: online CPU according to a numa aware policy; local cpus are returned
120 * first, followed by non-local ones, then it wraps around.
121 *
122 * For those who wants to enumerate all CPUs based on their NUMA distances,
123 * i.e. call this function in a loop, like:
124 *
125 * for (i = 0; i < num_online_cpus(); i++) {
126 *	cpu = cpumask_local_spread(i, node);
127 *	do_something(cpu);
128 * }
129 *
130 * There's a better alternative based on for_each()-like iterators:
131 *
132 *	for_each_numa_hop_mask(mask, node) {
133 *		for_each_cpu_andnot(cpu, mask, prev)
134 *			do_something(cpu);
135 *		prev = mask;
136 *	}
137 *
138 * It's simpler and more verbose than above. Complexity of iterator-based
139 * enumeration is O(sched_domains_numa_levels * nr_cpu_ids), while
140 * cpumask_local_spread() when called for each cpu is
141 * O(sched_domains_numa_levels * nr_cpu_ids * log(nr_cpu_ids)).
142 */
143unsigned int cpumask_local_spread(unsigned int i, int node)
144{
145	unsigned int cpu;
 
146
 
 
147	/* Wrap: we always want a cpu. */
148	i %= num_online_cpus();
149
150	cpu = sched_numa_find_nth_cpu(cpu_online_mask, i, node);
151
152	WARN_ON(cpu >= nr_cpu_ids);
153	return cpu;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
154}
155EXPORT_SYMBOL(cpumask_local_spread);
156
157static DEFINE_PER_CPU(int, distribute_cpu_mask_prev);
158
159/**
160 * cpumask_any_and_distribute - Return an arbitrary cpu within src1p & src2p.
161 * @src1p: first &cpumask for intersection
162 * @src2p: second &cpumask for intersection
163 *
164 * Iterated calls using the same srcp1 and srcp2 will be distributed within
165 * their intersection.
166 *
167 * Return: >= nr_cpu_ids if the intersection is empty.
168 */
169unsigned int cpumask_any_and_distribute(const struct cpumask *src1p,
170			       const struct cpumask *src2p)
171{
172	unsigned int next, prev;
173
174	/* NOTE: our first selection will skip 0. */
175	prev = __this_cpu_read(distribute_cpu_mask_prev);
176
177	next = find_next_and_bit_wrap(cpumask_bits(src1p), cpumask_bits(src2p),
178					nr_cpumask_bits, prev + 1);
179	if (next < nr_cpu_ids)
180		__this_cpu_write(distribute_cpu_mask_prev, next);
181
182	return next;
183}
184EXPORT_SYMBOL(cpumask_any_and_distribute);
185
186/**
187 * cpumask_any_distribute - Return an arbitrary cpu from srcp
188 * @srcp: &cpumask for selection
189 *
190 * Return: >= nr_cpu_ids if the intersection is empty.
191 */
192unsigned int cpumask_any_distribute(const struct cpumask *srcp)
193{
194	unsigned int next, prev;
195
196	/* NOTE: our first selection will skip 0. */
197	prev = __this_cpu_read(distribute_cpu_mask_prev);
198	next = find_next_bit_wrap(cpumask_bits(srcp), nr_cpumask_bits, prev + 1);
199	if (next < nr_cpu_ids)
200		__this_cpu_write(distribute_cpu_mask_prev, next);
201
202	return next;
203}
204EXPORT_SYMBOL(cpumask_any_distribute);

  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/slab.h>
  3#include <linux/kernel.h>
  4#include <linux/bitops.h>
  5#include <linux/cpumask.h>
  6#include <linux/export.h>
  7#include <linux/memblock.h>
  8#include <linux/numa.h>
  9#include <linux/sched/isolation.h>
 10
 11/**
 12 * cpumask_next - get the next cpu in a cpumask
 13 * @n: the cpu prior to the place to search (ie. return will be > @n)
 14 * @srcp: the cpumask pointer
 15 *
 16 * Returns >= nr_cpu_ids if no further cpus set.
 17 */
 18unsigned int cpumask_next(int n, const struct cpumask *srcp)
 19{
 20	/* -1 is a legal arg here. */
 21	if (n != -1)
 22		cpumask_check(n);
 23	return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1);
 24}
 25EXPORT_SYMBOL(cpumask_next);
 26
 27/**
 28 * cpumask_next_and - get the next cpu in *src1p & *src2p
 29 * @n: the cpu prior to the place to search (ie. return will be > @n)
 30 * @src1p: the first cpumask pointer
 31 * @src2p: the second cpumask pointer
 32 *
 33 * Returns >= nr_cpu_ids if no further cpus set in both.
 34 */
 35int cpumask_next_and(int n, const struct cpumask *src1p,
 36		     const struct cpumask *src2p)
 37{
 38	/* -1 is a legal arg here. */
 39	if (n != -1)
 40		cpumask_check(n);
 41	return find_next_and_bit(cpumask_bits(src1p), cpumask_bits(src2p),
 42		nr_cpumask_bits, n + 1);
 43}
 44EXPORT_SYMBOL(cpumask_next_and);
 45
 46/**
 47 * cpumask_any_but - return a "random" in a cpumask, but not this one.
 48 * @mask: the cpumask to search
 49 * @cpu: the cpu to ignore.
 50 *
 51 * Often used to find any cpu but smp_processor_id() in a mask.
 52 * Returns >= nr_cpu_ids if no cpus set.
 53 */
 54int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
 55{
 56	unsigned int i;
 57
 58	cpumask_check(cpu);
 59	for_each_cpu(i, mask)
 60		if (i != cpu)
 61			break;
 62	return i;
 63}
 64EXPORT_SYMBOL(cpumask_any_but);
 65
 66/**
 67 * cpumask_next_wrap - helper to implement for_each_cpu_wrap
 68 * @n: the cpu prior to the place to search
 69 * @mask: the cpumask pointer
 70 * @start: the start point of the iteration
 71 * @wrap: assume @n crossing @start terminates the iteration
 72 *
 73 * Returns >= nr_cpu_ids on completion
 74 *
 75 * Note: the @wrap argument is required for the start condition when
 76 * we cannot assume @start is set in @mask.
 77 */
 78int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap)
 79{
 80	int next;
 81
 82again:
 83	next = cpumask_next(n, mask);
 84
 85	if (wrap && n < start && next >= start) {
 86		return nr_cpumask_bits;
 87
 88	} else if (next >= nr_cpumask_bits) {
 89		wrap = true;
 90		n = -1;
 91		goto again;
 92	}
 93
 94	return next;
 95}
 96EXPORT_SYMBOL(cpumask_next_wrap);
 97
 98/* These are not inline because of header tangles. */
 99#ifdef CONFIG_CPUMASK_OFFSTACK
100/**
101 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
102 * @mask: pointer to cpumask_var_t where the cpumask is returned
103 * @flags: GFP_ flags
 
104 *
105 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
106 * a nop returning a constant 1 (in <linux/cpumask.h>)
107 * Returns TRUE if memory allocation succeeded, FALSE otherwise.
 
108 *
109 * In addition, mask will be NULL if this fails.  Note that gcc is
110 * usually smart enough to know that mask can never be NULL if
111 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
112 * too.
113 */
114bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
115{
116	*mask = kmalloc_node(cpumask_size(), flags, node);
117
118#ifdef CONFIG_DEBUG_PER_CPU_MAPS
119	if (!*mask) {
120		printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
121		dump_stack();
122	}
123#endif
124
125	return *mask != NULL;
126}
127EXPORT_SYMBOL(alloc_cpumask_var_node);
128
129bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
130{
131	return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
132}
133EXPORT_SYMBOL(zalloc_cpumask_var_node);
134
135/**
136 * alloc_cpumask_var - allocate a struct cpumask
137 * @mask: pointer to cpumask_var_t where the cpumask is returned
138 * @flags: GFP_ flags
139 *
140 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
141 * a nop returning a constant 1 (in <linux/cpumask.h>).
142 *
143 * See alloc_cpumask_var_node.
144 */
145bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
146{
147	return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);
148}
149EXPORT_SYMBOL(alloc_cpumask_var);
150
151bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
152{
153	return alloc_cpumask_var(mask, flags | __GFP_ZERO);
154}
155EXPORT_SYMBOL(zalloc_cpumask_var);
156
157/**
158 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
159 * @mask: pointer to cpumask_var_t where the cpumask is returned
160 *
161 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
162 * a nop (in <linux/cpumask.h>).
163 * Either returns an allocated (zero-filled) cpumask, or causes the
164 * system to panic.
165 */
166void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
167{
168	*mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES);
169	if (!*mask)
170		panic("%s: Failed to allocate %u bytes\n", __func__,
171		      cpumask_size());
172}
173
174/**
175 * free_cpumask_var - frees memory allocated for a struct cpumask.
176 * @mask: cpumask to free
177 *
178 * This is safe on a NULL mask.
179 */
180void free_cpumask_var(cpumask_var_t mask)
181{
182	kfree(mask);
183}
184EXPORT_SYMBOL(free_cpumask_var);
185
186/**
187 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
188 * @mask: cpumask to free
189 */
190void __init free_bootmem_cpumask_var(cpumask_var_t mask)
191{
192	memblock_free_early(__pa(mask), cpumask_size());
193}
194#endif
195
196/**
197 * cpumask_local_spread - select the i'th cpu with local numa cpu's first
198 * @i: index number
199 * @node: local numa_node
200 *
201 * This function selects an online CPU according to a numa aware policy;
202 * local cpus are returned first, followed by non-local ones, then it
203 * wraps around.
 
 
204 *
205 * It's not very efficient, but useful for setup.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
206 */
207unsigned int cpumask_local_spread(unsigned int i, int node)
208{
209	int cpu, hk_flags;
210	const struct cpumask *mask;
211
212	hk_flags = HK_FLAG_DOMAIN | HK_FLAG_MANAGED_IRQ;
213	mask = housekeeping_cpumask(hk_flags);
214	/* Wrap: we always want a cpu. */
215	i %= cpumask_weight(mask);
216
217	if (node == NUMA_NO_NODE) {
218		for_each_cpu(cpu, mask) {
219			if (i-- == 0)
220				return cpu;
221		}
222	} else {
223		/* NUMA first. */
224		for_each_cpu_and(cpu, cpumask_of_node(node), mask) {
225			if (i-- == 0)
226				return cpu;
227		}
228
229		for_each_cpu(cpu, mask) {
230			/* Skip NUMA nodes, done above. */
231			if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
232				continue;
233
234			if (i-- == 0)
235				return cpu;
236		}
237	}
238	BUG();
239}
240EXPORT_SYMBOL(cpumask_local_spread);
241
242static DEFINE_PER_CPU(int, distribute_cpu_mask_prev);
243
244/**
245 * Returns an arbitrary cpu within srcp1 & srcp2.
 
 
246 *
247 * Iterated calls using the same srcp1 and srcp2 will be distributed within
248 * their intersection.
249 *
250 * Returns >= nr_cpu_ids if the intersection is empty.
251 */
252int cpumask_any_and_distribute(const struct cpumask *src1p,
253			       const struct cpumask *src2p)
254{
255	int next, prev;
256
257	/* NOTE: our first selection will skip 0. */
258	prev = __this_cpu_read(distribute_cpu_mask_prev);
259
260	next = cpumask_next_and(prev, src1p, src2p);
261	if (next >= nr_cpu_ids)
262		next = cpumask_first_and(src1p, src2p);
 
263
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
264	if (next < nr_cpu_ids)
265		__this_cpu_write(distribute_cpu_mask_prev, next);
266
267	return next;
268}
269EXPORT_SYMBOL(cpumask_any_and_distribute);