2 * mm/percpu.c - percpu memory allocator
4 * Copyright (C) 2009 SUSE Linux Products GmbH
5 * Copyright (C) 2009 Tejun Heo <tj@kernel.org>
7 * This file is released under the GPLv2.
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.
19 * ------------------- ------------------- ------------
20 * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
21 * ------------------- ...... ------------------- .... ------------
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.
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.
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.
46 * To use this allocator, arch code should do the followings.
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
52 * - use pcpu_setup_first_chunk() during percpu area initialization to
53 * setup the first chunk containing the kernel static percpu area
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>
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>
72 #include <asm/cacheflush.h>
73 #include <asm/sections.h>
74 #include <asm/tlbflush.h>
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 #define PCPU_ATOMIC_MAP_MARGIN_LOW 32
80 #define PCPU_ATOMIC_MAP_MARGIN_HIGH 64
81 #define PCPU_EMPTY_POP_PAGES_LOW 2
82 #define PCPU_EMPTY_POP_PAGES_HIGH 4
85 /* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
86 #ifndef __addr_to_pcpu_ptr
87 #define __addr_to_pcpu_ptr(addr) \
88 (void __percpu *)((unsigned long)(addr) - \
89 (unsigned long)pcpu_base_addr + \
90 (unsigned long)__per_cpu_start)
92 #ifndef __pcpu_ptr_to_addr
93 #define __pcpu_ptr_to_addr(ptr) \
94 (void __force *)((unsigned long)(ptr) + \
95 (unsigned long)pcpu_base_addr - \
96 (unsigned long)__per_cpu_start)
98 #else /* CONFIG_SMP */
99 /* on UP, it's always identity mapped */
100 #define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
101 #define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
102 #endif /* CONFIG_SMP */
105 struct list_head list; /* linked to pcpu_slot lists */
106 int free_size; /* free bytes in the chunk */
107 int contig_hint; /* max contiguous size hint */
108 void *base_addr; /* base address of this chunk */
110 int map_used; /* # of map entries used before the sentry */
111 int map_alloc; /* # of map entries allocated */
112 int *map; /* allocation map */
113 struct work_struct map_extend_work;/* async ->map[] extension */
115 void *data; /* chunk data */
116 int first_free; /* no free below this */
117 bool immutable; /* no [de]population allowed */
118 int nr_populated; /* # of populated pages */
119 unsigned long populated[]; /* populated bitmap */
122 static int pcpu_unit_pages __read_mostly;
123 static int pcpu_unit_size __read_mostly;
124 static int pcpu_nr_units __read_mostly;
125 static int pcpu_atom_size __read_mostly;
126 static int pcpu_nr_slots __read_mostly;
127 static size_t pcpu_chunk_struct_size __read_mostly;
129 /* cpus with the lowest and highest unit addresses */
130 static unsigned int pcpu_low_unit_cpu __read_mostly;
131 static unsigned int pcpu_high_unit_cpu __read_mostly;
133 /* the address of the first chunk which starts with the kernel static area */
134 void *pcpu_base_addr __read_mostly;
135 EXPORT_SYMBOL_GPL(pcpu_base_addr);
137 static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
138 const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */
140 /* group information, used for vm allocation */
141 static int pcpu_nr_groups __read_mostly;
142 static const unsigned long *pcpu_group_offsets __read_mostly;
143 static const size_t *pcpu_group_sizes __read_mostly;
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.
150 static struct pcpu_chunk *pcpu_first_chunk;
153 * Optional reserved chunk. This chunk reserves part of the first
154 * chunk and serves it for reserved allocations. The amount of
155 * reserved offset is in pcpu_reserved_chunk_limit. When reserved
156 * area doesn't exist, the following variables contain NULL and 0
159 static struct pcpu_chunk *pcpu_reserved_chunk;
160 static int pcpu_reserved_chunk_limit;
162 static DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
163 static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop */
165 static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
168 * The number of empty populated pages, protected by pcpu_lock. The
169 * reserved chunk doesn't contribute to the count.
171 static int pcpu_nr_empty_pop_pages;
174 * Balance work is used to populate or destroy chunks asynchronously. We
175 * try to keep the number of populated free pages between
176 * PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one
179 static void pcpu_balance_workfn(struct work_struct *work);
180 static DECLARE_WORK(pcpu_balance_work, pcpu_balance_workfn);
181 static bool pcpu_async_enabled __read_mostly;
182 static bool pcpu_atomic_alloc_failed;
184 static void pcpu_schedule_balance_work(void)
186 if (pcpu_async_enabled)
187 schedule_work(&pcpu_balance_work);
190 static bool pcpu_addr_in_first_chunk(void *addr)
192 void *first_start = pcpu_first_chunk->base_addr;
194 return addr >= first_start && addr < first_start + pcpu_unit_size;
197 static bool pcpu_addr_in_reserved_chunk(void *addr)
199 void *first_start = pcpu_first_chunk->base_addr;
201 return addr >= first_start &&
202 addr < first_start + pcpu_reserved_chunk_limit;
205 static int __pcpu_size_to_slot(int size)
207 int highbit = fls(size); /* size is in bytes */
208 return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
211 static int pcpu_size_to_slot(int size)
213 if (size == pcpu_unit_size)
214 return pcpu_nr_slots - 1;
215 return __pcpu_size_to_slot(size);
218 static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
220 if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
223 return pcpu_size_to_slot(chunk->free_size);
226 /* set the pointer to a chunk in a page struct */
227 static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
229 page->index = (unsigned long)pcpu;
232 /* obtain pointer to a chunk from a page struct */
233 static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
235 return (struct pcpu_chunk *)page->index;
238 static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
240 return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
243 static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
244 unsigned int cpu, int page_idx)
246 return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
247 (page_idx << PAGE_SHIFT);
250 static void __maybe_unused pcpu_next_unpop(struct pcpu_chunk *chunk,
251 int *rs, int *re, int end)
253 *rs = find_next_zero_bit(chunk->populated, end, *rs);
254 *re = find_next_bit(chunk->populated, end, *rs + 1);
257 static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk,
258 int *rs, int *re, int end)
260 *rs = find_next_bit(chunk->populated, end, *rs);
261 *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
265 * (Un)populated page region iterators. Iterate over (un)populated
266 * page regions between @start and @end in @chunk. @rs and @re should
267 * be integer variables and will be set to start and end page index of
268 * the current region.
270 #define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
271 for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
273 (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
275 #define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
276 for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
278 (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
281 * pcpu_mem_zalloc - allocate memory
282 * @size: bytes to allocate
284 * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
285 * kzalloc() is used; otherwise, vzalloc() is used. The returned
286 * memory is always zeroed.
289 * Does GFP_KERNEL allocation.
292 * Pointer to the allocated area on success, NULL on failure.
294 static void *pcpu_mem_zalloc(size_t size)
296 if (WARN_ON_ONCE(!slab_is_available()))
299 if (size <= PAGE_SIZE)
300 return kzalloc(size, GFP_KERNEL);
302 return vzalloc(size);
306 * pcpu_mem_free - free memory
307 * @ptr: memory to free
308 * @size: size of the area
310 * Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc().
312 static void pcpu_mem_free(void *ptr, size_t size)
314 if (size <= PAGE_SIZE)
321 * pcpu_count_occupied_pages - count the number of pages an area occupies
322 * @chunk: chunk of interest
323 * @i: index of the area in question
325 * Count the number of pages chunk's @i'th area occupies. When the area's
326 * start and/or end address isn't aligned to page boundary, the straddled
327 * page is included in the count iff the rest of the page is free.
329 static int pcpu_count_occupied_pages(struct pcpu_chunk *chunk, int i)
331 int off = chunk->map[i] & ~1;
332 int end = chunk->map[i + 1] & ~1;
334 if (!PAGE_ALIGNED(off) && i > 0) {
335 int prev = chunk->map[i - 1];
337 if (!(prev & 1) && prev <= round_down(off, PAGE_SIZE))
338 off = round_down(off, PAGE_SIZE);
341 if (!PAGE_ALIGNED(end) && i + 1 < chunk->map_used) {
342 int next = chunk->map[i + 1];
343 int nend = chunk->map[i + 2] & ~1;
345 if (!(next & 1) && nend >= round_up(end, PAGE_SIZE))
346 end = round_up(end, PAGE_SIZE);
349 return max_t(int, PFN_DOWN(end) - PFN_UP(off), 0);
353 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
354 * @chunk: chunk of interest
355 * @oslot: the previous slot it was on
357 * This function is called after an allocation or free changed @chunk.
358 * New slot according to the changed state is determined and @chunk is
359 * moved to the slot. Note that the reserved chunk is never put on
365 static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
367 int nslot = pcpu_chunk_slot(chunk);
369 if (chunk != pcpu_reserved_chunk && oslot != nslot) {
371 list_move(&chunk->list, &pcpu_slot[nslot]);
373 list_move_tail(&chunk->list, &pcpu_slot[nslot]);
378 * pcpu_need_to_extend - determine whether chunk area map needs to be extended
379 * @chunk: chunk of interest
380 * @is_atomic: the allocation context
382 * Determine whether area map of @chunk needs to be extended. If
383 * @is_atomic, only the amount necessary for a new allocation is
384 * considered; however, async extension is scheduled if the left amount is
385 * low. If !@is_atomic, it aims for more empty space. Combined, this
386 * ensures that the map is likely to have enough available space to
387 * accomodate atomic allocations which can't extend maps directly.
393 * New target map allocation length if extension is necessary, 0
396 static int pcpu_need_to_extend(struct pcpu_chunk *chunk, bool is_atomic)
398 int margin, new_alloc;
403 if (chunk->map_alloc <
404 chunk->map_used + PCPU_ATOMIC_MAP_MARGIN_LOW &&
406 schedule_work(&chunk->map_extend_work);
408 margin = PCPU_ATOMIC_MAP_MARGIN_HIGH;
411 if (chunk->map_alloc >= chunk->map_used + margin)
414 new_alloc = PCPU_DFL_MAP_ALLOC;
415 while (new_alloc < chunk->map_used + margin)
422 * pcpu_extend_area_map - extend area map of a chunk
423 * @chunk: chunk of interest
424 * @new_alloc: new target allocation length of the area map
426 * Extend area map of @chunk to have @new_alloc entries.
429 * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock.
432 * 0 on success, -errno on failure.
434 static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
436 int *old = NULL, *new = NULL;
437 size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
440 new = pcpu_mem_zalloc(new_size);
444 /* acquire pcpu_lock and switch to new area map */
445 spin_lock_irqsave(&pcpu_lock, flags);
447 if (new_alloc <= chunk->map_alloc)
450 old_size = chunk->map_alloc * sizeof(chunk->map[0]);
453 memcpy(new, old, old_size);
455 chunk->map_alloc = new_alloc;
460 spin_unlock_irqrestore(&pcpu_lock, flags);
463 * pcpu_mem_free() might end up calling vfree() which uses
464 * IRQ-unsafe lock and thus can't be called under pcpu_lock.
466 pcpu_mem_free(old, old_size);
467 pcpu_mem_free(new, new_size);
472 static void pcpu_map_extend_workfn(struct work_struct *work)
474 struct pcpu_chunk *chunk = container_of(work, struct pcpu_chunk,
478 spin_lock_irq(&pcpu_lock);
479 new_alloc = pcpu_need_to_extend(chunk, false);
480 spin_unlock_irq(&pcpu_lock);
483 pcpu_extend_area_map(chunk, new_alloc);
487 * pcpu_fit_in_area - try to fit the requested allocation in a candidate area
488 * @chunk: chunk the candidate area belongs to
489 * @off: the offset to the start of the candidate area
490 * @this_size: the size of the candidate area
491 * @size: the size of the target allocation
492 * @align: the alignment of the target allocation
493 * @pop_only: only allocate from already populated region
495 * We're trying to allocate @size bytes aligned at @align. @chunk's area
496 * at @off sized @this_size is a candidate. This function determines
497 * whether the target allocation fits in the candidate area and returns the
498 * number of bytes to pad after @off. If the target area doesn't fit, -1
501 * If @pop_only is %true, this function only considers the already
502 * populated part of the candidate area.
504 static int pcpu_fit_in_area(struct pcpu_chunk *chunk, int off, int this_size,
505 int size, int align, bool pop_only)
510 int head = ALIGN(cand_off, align) - off;
511 int page_start, page_end, rs, re;
513 if (this_size < head + size)
520 * If the first unpopulated page is beyond the end of the
521 * allocation, the whole allocation is populated;
522 * otherwise, retry from the end of the unpopulated area.
524 page_start = PFN_DOWN(head + off);
525 page_end = PFN_UP(head + off + size);
528 pcpu_next_unpop(chunk, &rs, &re, PFN_UP(off + this_size));
531 cand_off = re * PAGE_SIZE;
536 * pcpu_alloc_area - allocate area from a pcpu_chunk
537 * @chunk: chunk of interest
538 * @size: wanted size in bytes
539 * @align: wanted align
540 * @pop_only: allocate only from the populated area
541 * @occ_pages_p: out param for the number of pages the area occupies
543 * Try to allocate @size bytes area aligned at @align from @chunk.
544 * Note that this function only allocates the offset. It doesn't
545 * populate or map the area.
547 * @chunk->map must have at least two free slots.
553 * Allocated offset in @chunk on success, -1 if no matching area is
556 static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align,
557 bool pop_only, int *occ_pages_p)
559 int oslot = pcpu_chunk_slot(chunk);
562 bool seen_free = false;
565 for (i = chunk->first_free, p = chunk->map + i; i < chunk->map_used; i++, p++) {
573 this_size = (p[1] & ~1) - off;
575 head = pcpu_fit_in_area(chunk, off, this_size, size, align,
579 chunk->first_free = i;
582 max_contig = max(this_size, max_contig);
587 * If head is small or the previous block is free,
588 * merge'em. Note that 'small' is defined as smaller
589 * than sizeof(int), which is very small but isn't too
590 * uncommon for percpu allocations.
592 if (head && (head < sizeof(int) || !(p[-1] & 1))) {
595 chunk->free_size -= head;
597 max_contig = max(*p - p[-1], max_contig);
602 /* if tail is small, just keep it around */
603 tail = this_size - head - size;
604 if (tail < sizeof(int)) {
606 size = this_size - head;
609 /* split if warranted */
611 int nr_extra = !!head + !!tail;
613 /* insert new subblocks */
614 memmove(p + nr_extra + 1, p + 1,
615 sizeof(chunk->map[0]) * (chunk->map_used - i));
616 chunk->map_used += nr_extra;
620 chunk->first_free = i;
625 max_contig = max(head, max_contig);
629 max_contig = max(tail, max_contig);
634 chunk->first_free = i + 1;
636 /* update hint and mark allocated */
637 if (i + 1 == chunk->map_used)
638 chunk->contig_hint = max_contig; /* fully scanned */
640 chunk->contig_hint = max(chunk->contig_hint,
643 chunk->free_size -= size;
646 *occ_pages_p = pcpu_count_occupied_pages(chunk, i);
647 pcpu_chunk_relocate(chunk, oslot);
651 chunk->contig_hint = max_contig; /* fully scanned */
652 pcpu_chunk_relocate(chunk, oslot);
654 /* tell the upper layer that this chunk has no matching area */
659 * pcpu_free_area - free area to a pcpu_chunk
660 * @chunk: chunk of interest
661 * @freeme: offset of area to free
662 * @occ_pages_p: out param for the number of pages the area occupies
664 * Free area starting from @freeme to @chunk. Note that this function
665 * only modifies the allocation map. It doesn't depopulate or unmap
671 static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme,
674 int oslot = pcpu_chunk_slot(chunk);
680 freeme |= 1; /* we are searching for <given offset, in use> pair */
685 unsigned k = (i + j) / 2;
689 else if (off > freeme)
694 BUG_ON(off != freeme);
696 if (i < chunk->first_free)
697 chunk->first_free = i;
701 chunk->free_size += (p[1] & ~1) - off;
703 *occ_pages_p = pcpu_count_occupied_pages(chunk, i);
705 /* merge with next? */
708 /* merge with previous? */
709 if (i > 0 && !(p[-1] & 1)) {
715 chunk->map_used -= to_free;
716 memmove(p + 1, p + 1 + to_free,
717 (chunk->map_used - i) * sizeof(chunk->map[0]));
720 chunk->contig_hint = max(chunk->map[i + 1] - chunk->map[i] - 1, chunk->contig_hint);
721 pcpu_chunk_relocate(chunk, oslot);
724 static struct pcpu_chunk *pcpu_alloc_chunk(void)
726 struct pcpu_chunk *chunk;
728 chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size);
732 chunk->map = pcpu_mem_zalloc(PCPU_DFL_MAP_ALLOC *
733 sizeof(chunk->map[0]));
735 pcpu_mem_free(chunk, pcpu_chunk_struct_size);
739 chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
741 chunk->map[1] = pcpu_unit_size | 1;
744 INIT_LIST_HEAD(&chunk->list);
745 INIT_WORK(&chunk->map_extend_work, pcpu_map_extend_workfn);
746 chunk->free_size = pcpu_unit_size;
747 chunk->contig_hint = pcpu_unit_size;
752 static void pcpu_free_chunk(struct pcpu_chunk *chunk)
756 pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
757 pcpu_mem_free(chunk, pcpu_chunk_struct_size);
761 * pcpu_chunk_populated - post-population bookkeeping
762 * @chunk: pcpu_chunk which got populated
763 * @page_start: the start page
764 * @page_end: the end page
766 * Pages in [@page_start,@page_end) have been populated to @chunk. Update
767 * the bookkeeping information accordingly. Must be called after each
768 * successful population.
770 static void pcpu_chunk_populated(struct pcpu_chunk *chunk,
771 int page_start, int page_end)
773 int nr = page_end - page_start;
775 lockdep_assert_held(&pcpu_lock);
777 bitmap_set(chunk->populated, page_start, nr);
778 chunk->nr_populated += nr;
779 pcpu_nr_empty_pop_pages += nr;
783 * pcpu_chunk_depopulated - post-depopulation bookkeeping
784 * @chunk: pcpu_chunk which got depopulated
785 * @page_start: the start page
786 * @page_end: the end page
788 * Pages in [@page_start,@page_end) have been depopulated from @chunk.
789 * Update the bookkeeping information accordingly. Must be called after
790 * each successful depopulation.
792 static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk,
793 int page_start, int page_end)
795 int nr = page_end - page_start;
797 lockdep_assert_held(&pcpu_lock);
799 bitmap_clear(chunk->populated, page_start, nr);
800 chunk->nr_populated -= nr;
801 pcpu_nr_empty_pop_pages -= nr;
805 * Chunk management implementation.
807 * To allow different implementations, chunk alloc/free and
808 * [de]population are implemented in a separate file which is pulled
809 * into this file and compiled together. The following functions
810 * should be implemented.
812 * pcpu_populate_chunk - populate the specified range of a chunk
813 * pcpu_depopulate_chunk - depopulate the specified range of a chunk
814 * pcpu_create_chunk - create a new chunk
815 * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
816 * pcpu_addr_to_page - translate address to physical address
817 * pcpu_verify_alloc_info - check alloc_info is acceptable during init
819 static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size);
820 static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size);
821 static struct pcpu_chunk *pcpu_create_chunk(void);
822 static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
823 static struct page *pcpu_addr_to_page(void *addr);
824 static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
826 #ifdef CONFIG_NEED_PER_CPU_KM
827 #include "percpu-km.c"
829 #include "percpu-vm.c"
833 * pcpu_chunk_addr_search - determine chunk containing specified address
834 * @addr: address for which the chunk needs to be determined.
837 * The address of the found chunk.
839 static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
841 /* is it in the first chunk? */
842 if (pcpu_addr_in_first_chunk(addr)) {
843 /* is it in the reserved area? */
844 if (pcpu_addr_in_reserved_chunk(addr))
845 return pcpu_reserved_chunk;
846 return pcpu_first_chunk;
850 * The address is relative to unit0 which might be unused and
851 * thus unmapped. Offset the address to the unit space of the
852 * current processor before looking it up in the vmalloc
853 * space. Note that any possible cpu id can be used here, so
854 * there's no need to worry about preemption or cpu hotplug.
856 addr += pcpu_unit_offsets[raw_smp_processor_id()];
857 return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
861 * pcpu_alloc - the percpu allocator
862 * @size: size of area to allocate in bytes
863 * @align: alignment of area (max PAGE_SIZE)
864 * @reserved: allocate from the reserved chunk if available
865 * @gfp: allocation flags
867 * Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't
868 * contain %GFP_KERNEL, the allocation is atomic.
871 * Percpu pointer to the allocated area on success, NULL on failure.
873 static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
876 static int warn_limit = 10;
877 struct pcpu_chunk *chunk;
879 bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;
881 int slot, off, new_alloc, cpu, ret;
886 * We want the lowest bit of offset available for in-use/free
887 * indicator, so force >= 16bit alignment and make size even.
889 if (unlikely(align < 2))
892 size = ALIGN(size, 2);
894 if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
895 WARN(true, "illegal size (%zu) or align (%zu) for "
896 "percpu allocation\n", size, align);
900 spin_lock_irqsave(&pcpu_lock, flags);
902 /* serve reserved allocations from the reserved chunk if available */
903 if (reserved && pcpu_reserved_chunk) {
904 chunk = pcpu_reserved_chunk;
906 if (size > chunk->contig_hint) {
907 err = "alloc from reserved chunk failed";
911 while ((new_alloc = pcpu_need_to_extend(chunk, is_atomic))) {
912 spin_unlock_irqrestore(&pcpu_lock, flags);
914 pcpu_extend_area_map(chunk, new_alloc) < 0) {
915 err = "failed to extend area map of reserved chunk";
918 spin_lock_irqsave(&pcpu_lock, flags);
921 off = pcpu_alloc_area(chunk, size, align, is_atomic,
926 err = "alloc from reserved chunk failed";
931 /* search through normal chunks */
932 for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
933 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
934 if (size > chunk->contig_hint)
937 new_alloc = pcpu_need_to_extend(chunk, is_atomic);
941 spin_unlock_irqrestore(&pcpu_lock, flags);
942 if (pcpu_extend_area_map(chunk,
944 err = "failed to extend area map";
947 spin_lock_irqsave(&pcpu_lock, flags);
949 * pcpu_lock has been dropped, need to
950 * restart cpu_slot list walking.
955 off = pcpu_alloc_area(chunk, size, align, is_atomic,
962 spin_unlock_irqrestore(&pcpu_lock, flags);
965 * No space left. Create a new chunk. We don't want multiple
966 * tasks to create chunks simultaneously. Serialize and create iff
967 * there's still no empty chunk after grabbing the mutex.
972 mutex_lock(&pcpu_alloc_mutex);
974 if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
975 chunk = pcpu_create_chunk();
977 mutex_unlock(&pcpu_alloc_mutex);
978 err = "failed to allocate new chunk";
982 spin_lock_irqsave(&pcpu_lock, flags);
983 pcpu_chunk_relocate(chunk, -1);
985 spin_lock_irqsave(&pcpu_lock, flags);
988 mutex_unlock(&pcpu_alloc_mutex);
992 spin_unlock_irqrestore(&pcpu_lock, flags);
994 /* populate if not all pages are already there */
996 int page_start, page_end, rs, re;
998 mutex_lock(&pcpu_alloc_mutex);
1000 page_start = PFN_DOWN(off);
1001 page_end = PFN_UP(off + size);
1003 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
1004 WARN_ON(chunk->immutable);
1006 ret = pcpu_populate_chunk(chunk, rs, re);
1008 spin_lock_irqsave(&pcpu_lock, flags);
1010 mutex_unlock(&pcpu_alloc_mutex);
1011 pcpu_free_area(chunk, off, &occ_pages);
1012 err = "failed to populate";
1015 pcpu_chunk_populated(chunk, rs, re);
1016 spin_unlock_irqrestore(&pcpu_lock, flags);
1019 mutex_unlock(&pcpu_alloc_mutex);
1022 if (chunk != pcpu_reserved_chunk)
1023 pcpu_nr_empty_pop_pages -= occ_pages;
1025 if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
1026 pcpu_schedule_balance_work();
1028 /* clear the areas and return address relative to base address */
1029 for_each_possible_cpu(cpu)
1030 memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
1032 ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
1033 kmemleak_alloc_percpu(ptr, size);
1037 spin_unlock_irqrestore(&pcpu_lock, flags);
1039 if (!is_atomic && warn_limit) {
1040 pr_warning("PERCPU: allocation failed, size=%zu align=%zu atomic=%d, %s\n",
1041 size, align, is_atomic, err);
1044 pr_info("PERCPU: limit reached, disable warning\n");
1047 /* see the flag handling in pcpu_blance_workfn() */
1048 pcpu_atomic_alloc_failed = true;
1049 pcpu_schedule_balance_work();
1055 * __alloc_percpu_gfp - allocate dynamic percpu area
1056 * @size: size of area to allocate in bytes
1057 * @align: alignment of area (max PAGE_SIZE)
1058 * @gfp: allocation flags
1060 * Allocate zero-filled percpu area of @size bytes aligned at @align. If
1061 * @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can
1062 * be called from any context but is a lot more likely to fail.
1065 * Percpu pointer to the allocated area on success, NULL on failure.
1067 void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp)
1069 return pcpu_alloc(size, align, false, gfp);
1071 EXPORT_SYMBOL_GPL(__alloc_percpu_gfp);
1074 * __alloc_percpu - allocate dynamic percpu area
1075 * @size: size of area to allocate in bytes
1076 * @align: alignment of area (max PAGE_SIZE)
1078 * Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL).
1080 void __percpu *__alloc_percpu(size_t size, size_t align)
1082 return pcpu_alloc(size, align, false, GFP_KERNEL);
1084 EXPORT_SYMBOL_GPL(__alloc_percpu);
1087 * __alloc_reserved_percpu - allocate reserved percpu area
1088 * @size: size of area to allocate in bytes
1089 * @align: alignment of area (max PAGE_SIZE)
1091 * Allocate zero-filled percpu area of @size bytes aligned at @align
1092 * from reserved percpu area if arch has set it up; otherwise,
1093 * allocation is served from the same dynamic area. Might sleep.
1094 * Might trigger writeouts.
1097 * Does GFP_KERNEL allocation.
1100 * Percpu pointer to the allocated area on success, NULL on failure.
1102 void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
1104 return pcpu_alloc(size, align, true, GFP_KERNEL);
1108 * pcpu_balance_workfn - manage the amount of free chunks and populated pages
1111 * Reclaim all fully free chunks except for the first one.
1113 static void pcpu_balance_workfn(struct work_struct *work)
1116 struct list_head *free_head = &pcpu_slot[pcpu_nr_slots - 1];
1117 struct pcpu_chunk *chunk, *next;
1118 int slot, nr_to_pop, ret;
1121 * There's no reason to keep around multiple unused chunks and VM
1122 * areas can be scarce. Destroy all free chunks except for one.
1124 mutex_lock(&pcpu_alloc_mutex);
1125 spin_lock_irq(&pcpu_lock);
1127 list_for_each_entry_safe(chunk, next, free_head, list) {
1128 WARN_ON(chunk->immutable);
1130 /* spare the first one */
1131 if (chunk == list_first_entry(free_head, struct pcpu_chunk, list))
1134 list_move(&chunk->list, &to_free);
1137 spin_unlock_irq(&pcpu_lock);
1139 list_for_each_entry_safe(chunk, next, &to_free, list) {
1142 pcpu_for_each_pop_region(chunk, rs, re, 0, pcpu_unit_pages) {
1143 pcpu_depopulate_chunk(chunk, rs, re);
1144 spin_lock_irq(&pcpu_lock);
1145 pcpu_chunk_depopulated(chunk, rs, re);
1146 spin_unlock_irq(&pcpu_lock);
1148 pcpu_destroy_chunk(chunk);
1152 * Ensure there are certain number of free populated pages for
1153 * atomic allocs. Fill up from the most packed so that atomic
1154 * allocs don't increase fragmentation. If atomic allocation
1155 * failed previously, always populate the maximum amount. This
1156 * should prevent atomic allocs larger than PAGE_SIZE from keeping
1157 * failing indefinitely; however, large atomic allocs are not
1158 * something we support properly and can be highly unreliable and
1162 if (pcpu_atomic_alloc_failed) {
1163 nr_to_pop = PCPU_EMPTY_POP_PAGES_HIGH;
1164 /* best effort anyway, don't worry about synchronization */
1165 pcpu_atomic_alloc_failed = false;
1167 nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH -
1168 pcpu_nr_empty_pop_pages,
1169 0, PCPU_EMPTY_POP_PAGES_HIGH);
1172 for (slot = pcpu_size_to_slot(PAGE_SIZE); slot < pcpu_nr_slots; slot++) {
1173 int nr_unpop = 0, rs, re;
1178 spin_lock_irq(&pcpu_lock);
1179 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
1180 nr_unpop = pcpu_unit_pages - chunk->nr_populated;
1184 spin_unlock_irq(&pcpu_lock);
1189 /* @chunk can't go away while pcpu_alloc_mutex is held */
1190 pcpu_for_each_unpop_region(chunk, rs, re, 0, pcpu_unit_pages) {
1191 int nr = min(re - rs, nr_to_pop);
1193 ret = pcpu_populate_chunk(chunk, rs, rs + nr);
1196 spin_lock_irq(&pcpu_lock);
1197 pcpu_chunk_populated(chunk, rs, rs + nr);
1198 spin_unlock_irq(&pcpu_lock);
1209 /* ran out of chunks to populate, create a new one and retry */
1210 chunk = pcpu_create_chunk();
1212 spin_lock_irq(&pcpu_lock);
1213 pcpu_chunk_relocate(chunk, -1);
1214 spin_unlock_irq(&pcpu_lock);
1219 mutex_unlock(&pcpu_alloc_mutex);
1223 * free_percpu - free percpu area
1224 * @ptr: pointer to area to free
1226 * Free percpu area @ptr.
1229 * Can be called from atomic context.
1231 void free_percpu(void __percpu *ptr)
1234 struct pcpu_chunk *chunk;
1235 unsigned long flags;
1241 kmemleak_free_percpu(ptr);
1243 addr = __pcpu_ptr_to_addr(ptr);
1245 spin_lock_irqsave(&pcpu_lock, flags);
1247 chunk = pcpu_chunk_addr_search(addr);
1248 off = addr - chunk->base_addr;
1250 pcpu_free_area(chunk, off, &occ_pages);
1252 if (chunk != pcpu_reserved_chunk)
1253 pcpu_nr_empty_pop_pages += occ_pages;
1255 /* if there are more than one fully free chunks, wake up grim reaper */
1256 if (chunk->free_size == pcpu_unit_size) {
1257 struct pcpu_chunk *pos;
1259 list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
1261 pcpu_schedule_balance_work();
1266 spin_unlock_irqrestore(&pcpu_lock, flags);
1268 EXPORT_SYMBOL_GPL(free_percpu);
1271 * is_kernel_percpu_address - test whether address is from static percpu area
1272 * @addr: address to test
1274 * Test whether @addr belongs to in-kernel static percpu area. Module
1275 * static percpu areas are not considered. For those, use
1276 * is_module_percpu_address().
1279 * %true if @addr is from in-kernel static percpu area, %false otherwise.
1281 bool is_kernel_percpu_address(unsigned long addr)
1284 const size_t static_size = __per_cpu_end - __per_cpu_start;
1285 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
1288 for_each_possible_cpu(cpu) {
1289 void *start = per_cpu_ptr(base, cpu);
1291 if ((void *)addr >= start && (void *)addr < start + static_size)
1295 /* on UP, can't distinguish from other static vars, always false */
1300 * per_cpu_ptr_to_phys - convert translated percpu address to physical address
1301 * @addr: the address to be converted to physical address
1303 * Given @addr which is dereferenceable address obtained via one of
1304 * percpu access macros, this function translates it into its physical
1305 * address. The caller is responsible for ensuring @addr stays valid
1306 * until this function finishes.
1308 * percpu allocator has special setup for the first chunk, which currently
1309 * supports either embedding in linear address space or vmalloc mapping,
1310 * and, from the second one, the backing allocator (currently either vm or
1311 * km) provides translation.
1313 * The addr can be tranlated simply without checking if it falls into the
1314 * first chunk. But the current code reflects better how percpu allocator
1315 * actually works, and the verification can discover both bugs in percpu
1316 * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
1320 * The physical address for @addr.
1322 phys_addr_t per_cpu_ptr_to_phys(void *addr)
1324 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
1325 bool in_first_chunk = false;
1326 unsigned long first_low, first_high;
1330 * The following test on unit_low/high isn't strictly
1331 * necessary but will speed up lookups of addresses which
1332 * aren't in the first chunk.
1334 first_low = pcpu_chunk_addr(pcpu_first_chunk, pcpu_low_unit_cpu, 0);
1335 first_high = pcpu_chunk_addr(pcpu_first_chunk, pcpu_high_unit_cpu,
1337 if ((unsigned long)addr >= first_low &&
1338 (unsigned long)addr < first_high) {
1339 for_each_possible_cpu(cpu) {
1340 void *start = per_cpu_ptr(base, cpu);
1342 if (addr >= start && addr < start + pcpu_unit_size) {
1343 in_first_chunk = true;
1349 if (in_first_chunk) {
1350 if (!is_vmalloc_addr(addr))
1353 return page_to_phys(vmalloc_to_page(addr)) +
1354 offset_in_page(addr);
1356 return page_to_phys(pcpu_addr_to_page(addr)) +
1357 offset_in_page(addr);
1361 * pcpu_alloc_alloc_info - allocate percpu allocation info
1362 * @nr_groups: the number of groups
1363 * @nr_units: the number of units
1365 * Allocate ai which is large enough for @nr_groups groups containing
1366 * @nr_units units. The returned ai's groups[0].cpu_map points to the
1367 * cpu_map array which is long enough for @nr_units and filled with
1368 * NR_CPUS. It's the caller's responsibility to initialize cpu_map
1369 * pointer of other groups.
1372 * Pointer to the allocated pcpu_alloc_info on success, NULL on
1375 struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
1378 struct pcpu_alloc_info *ai;
1379 size_t base_size, ai_size;
1383 base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
1384 __alignof__(ai->groups[0].cpu_map[0]));
1385 ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
1387 ptr = memblock_virt_alloc_nopanic(PFN_ALIGN(ai_size), 0);
1393 ai->groups[0].cpu_map = ptr;
1395 for (unit = 0; unit < nr_units; unit++)
1396 ai->groups[0].cpu_map[unit] = NR_CPUS;
1398 ai->nr_groups = nr_groups;
1399 ai->__ai_size = PFN_ALIGN(ai_size);
1405 * pcpu_free_alloc_info - free percpu allocation info
1406 * @ai: pcpu_alloc_info to free
1408 * Free @ai which was allocated by pcpu_alloc_alloc_info().
1410 void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
1412 memblock_free_early(__pa(ai), ai->__ai_size);
1416 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
1418 * @ai: allocation info to dump
1420 * Print out information about @ai using loglevel @lvl.
1422 static void pcpu_dump_alloc_info(const char *lvl,
1423 const struct pcpu_alloc_info *ai)
1425 int group_width = 1, cpu_width = 1, width;
1426 char empty_str[] = "--------";
1427 int alloc = 0, alloc_end = 0;
1429 int upa, apl; /* units per alloc, allocs per line */
1435 v = num_possible_cpus();
1438 empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
1440 upa = ai->alloc_size / ai->unit_size;
1441 width = upa * (cpu_width + 1) + group_width + 3;
1442 apl = rounddown_pow_of_two(max(60 / width, 1));
1444 printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
1445 lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
1446 ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
1448 for (group = 0; group < ai->nr_groups; group++) {
1449 const struct pcpu_group_info *gi = &ai->groups[group];
1450 int unit = 0, unit_end = 0;
1452 BUG_ON(gi->nr_units % upa);
1453 for (alloc_end += gi->nr_units / upa;
1454 alloc < alloc_end; alloc++) {
1455 if (!(alloc % apl)) {
1456 printk(KERN_CONT "\n");
1457 printk("%spcpu-alloc: ", lvl);
1459 printk(KERN_CONT "[%0*d] ", group_width, group);
1461 for (unit_end += upa; unit < unit_end; unit++)
1462 if (gi->cpu_map[unit] != NR_CPUS)
1463 printk(KERN_CONT "%0*d ", cpu_width,
1466 printk(KERN_CONT "%s ", empty_str);
1469 printk(KERN_CONT "\n");
1473 * pcpu_setup_first_chunk - initialize the first percpu chunk
1474 * @ai: pcpu_alloc_info describing how to percpu area is shaped
1475 * @base_addr: mapped address
1477 * Initialize the first percpu chunk which contains the kernel static
1478 * perpcu area. This function is to be called from arch percpu area
1481 * @ai contains all information necessary to initialize the first
1482 * chunk and prime the dynamic percpu allocator.
1484 * @ai->static_size is the size of static percpu area.
1486 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
1487 * reserve after the static area in the first chunk. This reserves
1488 * the first chunk such that it's available only through reserved
1489 * percpu allocation. This is primarily used to serve module percpu
1490 * static areas on architectures where the addressing model has
1491 * limited offset range for symbol relocations to guarantee module
1492 * percpu symbols fall inside the relocatable range.
1494 * @ai->dyn_size determines the number of bytes available for dynamic
1495 * allocation in the first chunk. The area between @ai->static_size +
1496 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
1498 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
1499 * and equal to or larger than @ai->static_size + @ai->reserved_size +
1502 * @ai->atom_size is the allocation atom size and used as alignment
1505 * @ai->alloc_size is the allocation size and always multiple of
1506 * @ai->atom_size. This is larger than @ai->atom_size if
1507 * @ai->unit_size is larger than @ai->atom_size.
1509 * @ai->nr_groups and @ai->groups describe virtual memory layout of
1510 * percpu areas. Units which should be colocated are put into the
1511 * same group. Dynamic VM areas will be allocated according to these
1512 * groupings. If @ai->nr_groups is zero, a single group containing
1513 * all units is assumed.
1515 * The caller should have mapped the first chunk at @base_addr and
1516 * copied static data to each unit.
1518 * If the first chunk ends up with both reserved and dynamic areas, it
1519 * is served by two chunks - one to serve the core static and reserved
1520 * areas and the other for the dynamic area. They share the same vm
1521 * and page map but uses different area allocation map to stay away
1522 * from each other. The latter chunk is circulated in the chunk slots
1523 * and available for dynamic allocation like any other chunks.
1526 * 0 on success, -errno on failure.
1528 int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
1531 static int smap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
1532 static int dmap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
1533 size_t dyn_size = ai->dyn_size;
1534 size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
1535 struct pcpu_chunk *schunk, *dchunk = NULL;
1536 unsigned long *group_offsets;
1537 size_t *group_sizes;
1538 unsigned long *unit_off;
1543 #define PCPU_SETUP_BUG_ON(cond) do { \
1544 if (unlikely(cond)) { \
1545 pr_emerg("PERCPU: failed to initialize, %s", #cond); \
1546 pr_emerg("PERCPU: cpu_possible_mask=%*pb\n", \
1547 cpumask_pr_args(cpu_possible_mask)); \
1548 pcpu_dump_alloc_info(KERN_EMERG, ai); \
1554 PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
1556 PCPU_SETUP_BUG_ON(!ai->static_size);
1557 PCPU_SETUP_BUG_ON((unsigned long)__per_cpu_start & ~PAGE_MASK);
1559 PCPU_SETUP_BUG_ON(!base_addr);
1560 PCPU_SETUP_BUG_ON((unsigned long)base_addr & ~PAGE_MASK);
1561 PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
1562 PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
1563 PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
1564 PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
1565 PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
1567 /* process group information and build config tables accordingly */
1568 group_offsets = memblock_virt_alloc(ai->nr_groups *
1569 sizeof(group_offsets[0]), 0);
1570 group_sizes = memblock_virt_alloc(ai->nr_groups *
1571 sizeof(group_sizes[0]), 0);
1572 unit_map = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_map[0]), 0);
1573 unit_off = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_off[0]), 0);
1575 for (cpu = 0; cpu < nr_cpu_ids; cpu++)
1576 unit_map[cpu] = UINT_MAX;
1578 pcpu_low_unit_cpu = NR_CPUS;
1579 pcpu_high_unit_cpu = NR_CPUS;
1581 for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
1582 const struct pcpu_group_info *gi = &ai->groups[group];
1584 group_offsets[group] = gi->base_offset;
1585 group_sizes[group] = gi->nr_units * ai->unit_size;
1587 for (i = 0; i < gi->nr_units; i++) {
1588 cpu = gi->cpu_map[i];
1592 PCPU_SETUP_BUG_ON(cpu >= nr_cpu_ids);
1593 PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
1594 PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
1596 unit_map[cpu] = unit + i;
1597 unit_off[cpu] = gi->base_offset + i * ai->unit_size;
1599 /* determine low/high unit_cpu */
1600 if (pcpu_low_unit_cpu == NR_CPUS ||
1601 unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
1602 pcpu_low_unit_cpu = cpu;
1603 if (pcpu_high_unit_cpu == NR_CPUS ||
1604 unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
1605 pcpu_high_unit_cpu = cpu;
1608 pcpu_nr_units = unit;
1610 for_each_possible_cpu(cpu)
1611 PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
1613 /* we're done parsing the input, undefine BUG macro and dump config */
1614 #undef PCPU_SETUP_BUG_ON
1615 pcpu_dump_alloc_info(KERN_DEBUG, ai);
1617 pcpu_nr_groups = ai->nr_groups;
1618 pcpu_group_offsets = group_offsets;
1619 pcpu_group_sizes = group_sizes;
1620 pcpu_unit_map = unit_map;
1621 pcpu_unit_offsets = unit_off;
1623 /* determine basic parameters */
1624 pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
1625 pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
1626 pcpu_atom_size = ai->atom_size;
1627 pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
1628 BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
1631 * Allocate chunk slots. The additional last slot is for
1634 pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
1635 pcpu_slot = memblock_virt_alloc(
1636 pcpu_nr_slots * sizeof(pcpu_slot[0]), 0);
1637 for (i = 0; i < pcpu_nr_slots; i++)
1638 INIT_LIST_HEAD(&pcpu_slot[i]);
1641 * Initialize static chunk. If reserved_size is zero, the
1642 * static chunk covers static area + dynamic allocation area
1643 * in the first chunk. If reserved_size is not zero, it
1644 * covers static area + reserved area (mostly used for module
1645 * static percpu allocation).
1647 schunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
1648 INIT_LIST_HEAD(&schunk->list);
1649 INIT_WORK(&schunk->map_extend_work, pcpu_map_extend_workfn);
1650 schunk->base_addr = base_addr;
1652 schunk->map_alloc = ARRAY_SIZE(smap);
1653 schunk->immutable = true;
1654 bitmap_fill(schunk->populated, pcpu_unit_pages);
1655 schunk->nr_populated = pcpu_unit_pages;
1657 if (ai->reserved_size) {
1658 schunk->free_size = ai->reserved_size;
1659 pcpu_reserved_chunk = schunk;
1660 pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
1662 schunk->free_size = dyn_size;
1663 dyn_size = 0; /* dynamic area covered */
1665 schunk->contig_hint = schunk->free_size;
1668 schunk->map[1] = ai->static_size;
1669 schunk->map_used = 1;
1670 if (schunk->free_size)
1671 schunk->map[++schunk->map_used] = 1 | (ai->static_size + schunk->free_size);
1673 schunk->map[1] |= 1;
1675 /* init dynamic chunk if necessary */
1677 dchunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
1678 INIT_LIST_HEAD(&dchunk->list);
1679 INIT_WORK(&dchunk->map_extend_work, pcpu_map_extend_workfn);
1680 dchunk->base_addr = base_addr;
1682 dchunk->map_alloc = ARRAY_SIZE(dmap);
1683 dchunk->immutable = true;
1684 bitmap_fill(dchunk->populated, pcpu_unit_pages);
1685 dchunk->nr_populated = pcpu_unit_pages;
1687 dchunk->contig_hint = dchunk->free_size = dyn_size;
1689 dchunk->map[1] = pcpu_reserved_chunk_limit;
1690 dchunk->map[2] = (pcpu_reserved_chunk_limit + dchunk->free_size) | 1;
1691 dchunk->map_used = 2;
1694 /* link the first chunk in */
1695 pcpu_first_chunk = dchunk ?: schunk;
1696 pcpu_nr_empty_pop_pages +=
1697 pcpu_count_occupied_pages(pcpu_first_chunk, 1);
1698 pcpu_chunk_relocate(pcpu_first_chunk, -1);
1701 pcpu_base_addr = base_addr;
1707 const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = {
1708 [PCPU_FC_AUTO] = "auto",
1709 [PCPU_FC_EMBED] = "embed",
1710 [PCPU_FC_PAGE] = "page",
1713 enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
1715 static int __init percpu_alloc_setup(char *str)
1722 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
1723 else if (!strcmp(str, "embed"))
1724 pcpu_chosen_fc = PCPU_FC_EMBED;
1726 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1727 else if (!strcmp(str, "page"))
1728 pcpu_chosen_fc = PCPU_FC_PAGE;
1731 pr_warning("PERCPU: unknown allocator %s specified\n", str);
1735 early_param("percpu_alloc", percpu_alloc_setup);
1738 * pcpu_embed_first_chunk() is used by the generic percpu setup.
1739 * Build it if needed by the arch config or the generic setup is going
1742 #if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
1743 !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
1744 #define BUILD_EMBED_FIRST_CHUNK
1747 /* build pcpu_page_first_chunk() iff needed by the arch config */
1748 #if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
1749 #define BUILD_PAGE_FIRST_CHUNK
1752 /* pcpu_build_alloc_info() is used by both embed and page first chunk */
1753 #if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
1755 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
1756 * @reserved_size: the size of reserved percpu area in bytes
1757 * @dyn_size: minimum free size for dynamic allocation in bytes
1758 * @atom_size: allocation atom size
1759 * @cpu_distance_fn: callback to determine distance between cpus, optional
1761 * This function determines grouping of units, their mappings to cpus
1762 * and other parameters considering needed percpu size, allocation
1763 * atom size and distances between CPUs.
1765 * Groups are always mutliples of atom size and CPUs which are of
1766 * LOCAL_DISTANCE both ways are grouped together and share space for
1767 * units in the same group. The returned configuration is guaranteed
1768 * to have CPUs on different nodes on different groups and >=75% usage
1769 * of allocated virtual address space.
1772 * On success, pointer to the new allocation_info is returned. On
1773 * failure, ERR_PTR value is returned.
1775 static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
1776 size_t reserved_size, size_t dyn_size,
1778 pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
1780 static int group_map[NR_CPUS] __initdata;
1781 static int group_cnt[NR_CPUS] __initdata;
1782 const size_t static_size = __per_cpu_end - __per_cpu_start;
1783 int nr_groups = 1, nr_units = 0;
1784 size_t size_sum, min_unit_size, alloc_size;
1785 int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
1786 int last_allocs, group, unit;
1787 unsigned int cpu, tcpu;
1788 struct pcpu_alloc_info *ai;
1789 unsigned int *cpu_map;
1791 /* this function may be called multiple times */
1792 memset(group_map, 0, sizeof(group_map));
1793 memset(group_cnt, 0, sizeof(group_cnt));
1795 /* calculate size_sum and ensure dyn_size is enough for early alloc */
1796 size_sum = PFN_ALIGN(static_size + reserved_size +
1797 max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
1798 dyn_size = size_sum - static_size - reserved_size;
1801 * Determine min_unit_size, alloc_size and max_upa such that
1802 * alloc_size is multiple of atom_size and is the smallest
1803 * which can accommodate 4k aligned segments which are equal to
1804 * or larger than min_unit_size.
1806 min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
1808 alloc_size = roundup(min_unit_size, atom_size);
1809 upa = alloc_size / min_unit_size;
1810 while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1814 /* group cpus according to their proximity */
1815 for_each_possible_cpu(cpu) {
1818 for_each_possible_cpu(tcpu) {
1821 if (group_map[tcpu] == group && cpu_distance_fn &&
1822 (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
1823 cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
1825 nr_groups = max(nr_groups, group + 1);
1829 group_map[cpu] = group;
1834 * Expand unit size until address space usage goes over 75%
1835 * and then as much as possible without using more address
1838 last_allocs = INT_MAX;
1839 for (upa = max_upa; upa; upa--) {
1840 int allocs = 0, wasted = 0;
1842 if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1845 for (group = 0; group < nr_groups; group++) {
1846 int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
1847 allocs += this_allocs;
1848 wasted += this_allocs * upa - group_cnt[group];
1852 * Don't accept if wastage is over 1/3. The
1853 * greater-than comparison ensures upa==1 always
1854 * passes the following check.
1856 if (wasted > num_possible_cpus() / 3)
1859 /* and then don't consume more memory */
1860 if (allocs > last_allocs)
1862 last_allocs = allocs;
1867 /* allocate and fill alloc_info */
1868 for (group = 0; group < nr_groups; group++)
1869 nr_units += roundup(group_cnt[group], upa);
1871 ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
1873 return ERR_PTR(-ENOMEM);
1874 cpu_map = ai->groups[0].cpu_map;
1876 for (group = 0; group < nr_groups; group++) {
1877 ai->groups[group].cpu_map = cpu_map;
1878 cpu_map += roundup(group_cnt[group], upa);
1881 ai->static_size = static_size;
1882 ai->reserved_size = reserved_size;
1883 ai->dyn_size = dyn_size;
1884 ai->unit_size = alloc_size / upa;
1885 ai->atom_size = atom_size;
1886 ai->alloc_size = alloc_size;
1888 for (group = 0, unit = 0; group_cnt[group]; group++) {
1889 struct pcpu_group_info *gi = &ai->groups[group];
1892 * Initialize base_offset as if all groups are located
1893 * back-to-back. The caller should update this to
1894 * reflect actual allocation.
1896 gi->base_offset = unit * ai->unit_size;
1898 for_each_possible_cpu(cpu)
1899 if (group_map[cpu] == group)
1900 gi->cpu_map[gi->nr_units++] = cpu;
1901 gi->nr_units = roundup(gi->nr_units, upa);
1902 unit += gi->nr_units;
1904 BUG_ON(unit != nr_units);
1908 #endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
1910 #if defined(BUILD_EMBED_FIRST_CHUNK)
1912 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
1913 * @reserved_size: the size of reserved percpu area in bytes
1914 * @dyn_size: minimum free size for dynamic allocation in bytes
1915 * @atom_size: allocation atom size
1916 * @cpu_distance_fn: callback to determine distance between cpus, optional
1917 * @alloc_fn: function to allocate percpu page
1918 * @free_fn: function to free percpu page
1920 * This is a helper to ease setting up embedded first percpu chunk and
1921 * can be called where pcpu_setup_first_chunk() is expected.
1923 * If this function is used to setup the first chunk, it is allocated
1924 * by calling @alloc_fn and used as-is without being mapped into
1925 * vmalloc area. Allocations are always whole multiples of @atom_size
1926 * aligned to @atom_size.
1928 * This enables the first chunk to piggy back on the linear physical
1929 * mapping which often uses larger page size. Please note that this
1930 * can result in very sparse cpu->unit mapping on NUMA machines thus
1931 * requiring large vmalloc address space. Don't use this allocator if
1932 * vmalloc space is not orders of magnitude larger than distances
1933 * between node memory addresses (ie. 32bit NUMA machines).
1935 * @dyn_size specifies the minimum dynamic area size.
1937 * If the needed size is smaller than the minimum or specified unit
1938 * size, the leftover is returned using @free_fn.
1941 * 0 on success, -errno on failure.
1943 int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
1945 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
1946 pcpu_fc_alloc_fn_t alloc_fn,
1947 pcpu_fc_free_fn_t free_fn)
1949 void *base = (void *)ULONG_MAX;
1950 void **areas = NULL;
1951 struct pcpu_alloc_info *ai;
1952 size_t size_sum, areas_size, max_distance;
1955 ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
1960 size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
1961 areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
1963 areas = memblock_virt_alloc_nopanic(areas_size, 0);
1969 /* allocate, copy and determine base address */
1970 for (group = 0; group < ai->nr_groups; group++) {
1971 struct pcpu_group_info *gi = &ai->groups[group];
1972 unsigned int cpu = NR_CPUS;
1975 for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
1976 cpu = gi->cpu_map[i];
1977 BUG_ON(cpu == NR_CPUS);
1979 /* allocate space for the whole group */
1980 ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
1983 goto out_free_areas;
1985 /* kmemleak tracks the percpu allocations separately */
1989 base = min(ptr, base);
1993 * Copy data and free unused parts. This should happen after all
1994 * allocations are complete; otherwise, we may end up with
1995 * overlapping groups.
1997 for (group = 0; group < ai->nr_groups; group++) {
1998 struct pcpu_group_info *gi = &ai->groups[group];
1999 void *ptr = areas[group];
2001 for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
2002 if (gi->cpu_map[i] == NR_CPUS) {
2003 /* unused unit, free whole */
2004 free_fn(ptr, ai->unit_size);
2007 /* copy and return the unused part */
2008 memcpy(ptr, __per_cpu_load, ai->static_size);
2009 free_fn(ptr + size_sum, ai->unit_size - size_sum);
2013 /* base address is now known, determine group base offsets */
2015 for (group = 0; group < ai->nr_groups; group++) {
2016 ai->groups[group].base_offset = areas[group] - base;
2017 max_distance = max_t(size_t, max_distance,
2018 ai->groups[group].base_offset);
2020 max_distance += ai->unit_size;
2022 /* warn if maximum distance is further than 75% of vmalloc space */
2023 if (max_distance > VMALLOC_TOTAL * 3 / 4) {
2024 pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc "
2025 "space 0x%lx\n", max_distance,
2027 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
2028 /* and fail if we have fallback */
2034 pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
2035 PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
2036 ai->dyn_size, ai->unit_size);
2038 rc = pcpu_setup_first_chunk(ai, base);
2042 for (group = 0; group < ai->nr_groups; group++)
2044 free_fn(areas[group],
2045 ai->groups[group].nr_units * ai->unit_size);
2047 pcpu_free_alloc_info(ai);
2049 memblock_free_early(__pa(areas), areas_size);
2052 #endif /* BUILD_EMBED_FIRST_CHUNK */
2054 #ifdef BUILD_PAGE_FIRST_CHUNK
2056 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
2057 * @reserved_size: the size of reserved percpu area in bytes
2058 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
2059 * @free_fn: function to free percpu page, always called with PAGE_SIZE
2060 * @populate_pte_fn: function to populate pte
2062 * This is a helper to ease setting up page-remapped first percpu
2063 * chunk and can be called where pcpu_setup_first_chunk() is expected.
2065 * This is the basic allocator. Static percpu area is allocated
2066 * page-by-page into vmalloc area.
2069 * 0 on success, -errno on failure.
2071 int __init pcpu_page_first_chunk(size_t reserved_size,
2072 pcpu_fc_alloc_fn_t alloc_fn,
2073 pcpu_fc_free_fn_t free_fn,
2074 pcpu_fc_populate_pte_fn_t populate_pte_fn)
2076 static struct vm_struct vm;
2077 struct pcpu_alloc_info *ai;
2081 struct page **pages;
2084 snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
2086 ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
2089 BUG_ON(ai->nr_groups != 1);
2090 BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
2092 unit_pages = ai->unit_size >> PAGE_SHIFT;
2094 /* unaligned allocations can't be freed, round up to page size */
2095 pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
2097 pages = memblock_virt_alloc(pages_size, 0);
2099 /* allocate pages */
2101 for (unit = 0; unit < num_possible_cpus(); unit++)
2102 for (i = 0; i < unit_pages; i++) {
2103 unsigned int cpu = ai->groups[0].cpu_map[unit];
2106 ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
2108 pr_warning("PERCPU: failed to allocate %s page "
2109 "for cpu%u\n", psize_str, cpu);
2112 /* kmemleak tracks the percpu allocations separately */
2114 pages[j++] = virt_to_page(ptr);
2117 /* allocate vm area, map the pages and copy static data */
2118 vm.flags = VM_ALLOC;
2119 vm.size = num_possible_cpus() * ai->unit_size;
2120 vm_area_register_early(&vm, PAGE_SIZE);
2122 for (unit = 0; unit < num_possible_cpus(); unit++) {
2123 unsigned long unit_addr =
2124 (unsigned long)vm.addr + unit * ai->unit_size;
2126 for (i = 0; i < unit_pages; i++)
2127 populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
2129 /* pte already populated, the following shouldn't fail */
2130 rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
2133 panic("failed to map percpu area, err=%d\n", rc);
2136 * FIXME: Archs with virtual cache should flush local
2137 * cache for the linear mapping here - something
2138 * equivalent to flush_cache_vmap() on the local cpu.
2139 * flush_cache_vmap() can't be used as most supporting
2140 * data structures are not set up yet.
2143 /* copy static data */
2144 memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
2147 /* we're ready, commit */
2148 pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
2149 unit_pages, psize_str, vm.addr, ai->static_size,
2150 ai->reserved_size, ai->dyn_size);
2152 rc = pcpu_setup_first_chunk(ai, vm.addr);
2157 free_fn(page_address(pages[j]), PAGE_SIZE);
2160 memblock_free_early(__pa(pages), pages_size);
2161 pcpu_free_alloc_info(ai);
2164 #endif /* BUILD_PAGE_FIRST_CHUNK */
2166 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
2168 * Generic SMP percpu area setup.
2170 * The embedding helper is used because its behavior closely resembles
2171 * the original non-dynamic generic percpu area setup. This is
2172 * important because many archs have addressing restrictions and might
2173 * fail if the percpu area is located far away from the previous
2174 * location. As an added bonus, in non-NUMA cases, embedding is
2175 * generally a good idea TLB-wise because percpu area can piggy back
2176 * on the physical linear memory mapping which uses large page
2177 * mappings on applicable archs.
2179 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
2180 EXPORT_SYMBOL(__per_cpu_offset);
2182 static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
2185 return memblock_virt_alloc_from_nopanic(
2186 size, align, __pa(MAX_DMA_ADDRESS));
2189 static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
2191 memblock_free_early(__pa(ptr), size);
2194 void __init setup_per_cpu_areas(void)
2196 unsigned long delta;
2201 * Always reserve area for module percpu variables. That's
2202 * what the legacy allocator did.
2204 rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
2205 PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
2206 pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
2208 panic("Failed to initialize percpu areas.");
2210 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
2211 for_each_possible_cpu(cpu)
2212 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
2214 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
2216 #else /* CONFIG_SMP */
2219 * UP percpu area setup.
2221 * UP always uses km-based percpu allocator with identity mapping.
2222 * Static percpu variables are indistinguishable from the usual static
2223 * variables and don't require any special preparation.
2225 void __init setup_per_cpu_areas(void)
2227 const size_t unit_size =
2228 roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
2229 PERCPU_DYNAMIC_RESERVE));
2230 struct pcpu_alloc_info *ai;
2233 ai = pcpu_alloc_alloc_info(1, 1);
2234 fc = memblock_virt_alloc_from_nopanic(unit_size,
2236 __pa(MAX_DMA_ADDRESS));
2238 panic("Failed to allocate memory for percpu areas.");
2239 /* kmemleak tracks the percpu allocations separately */
2242 ai->dyn_size = unit_size;
2243 ai->unit_size = unit_size;
2244 ai->atom_size = unit_size;
2245 ai->alloc_size = unit_size;
2246 ai->groups[0].nr_units = 1;
2247 ai->groups[0].cpu_map[0] = 0;
2249 if (pcpu_setup_first_chunk(ai, fc) < 0)
2250 panic("Failed to initialize percpu areas.");
2253 #endif /* CONFIG_SMP */
2256 * First and reserved chunks are initialized with temporary allocation
2257 * map in initdata so that they can be used before slab is online.
2258 * This function is called after slab is brought up and replaces those
2259 * with properly allocated maps.
2261 void __init percpu_init_late(void)
2263 struct pcpu_chunk *target_chunks[] =
2264 { pcpu_first_chunk, pcpu_reserved_chunk, NULL };
2265 struct pcpu_chunk *chunk;
2266 unsigned long flags;
2269 for (i = 0; (chunk = target_chunks[i]); i++) {
2271 const size_t size = PERCPU_DYNAMIC_EARLY_SLOTS * sizeof(map[0]);
2273 BUILD_BUG_ON(size > PAGE_SIZE);
2275 map = pcpu_mem_zalloc(size);
2278 spin_lock_irqsave(&pcpu_lock, flags);
2279 memcpy(map, chunk->map, size);
2281 spin_unlock_irqrestore(&pcpu_lock, flags);
2286 * Percpu allocator is initialized early during boot when neither slab or
2287 * workqueue is available. Plug async management until everything is up
2290 static int __init percpu_enable_async(void)
2292 pcpu_async_enabled = true;
2295 subsys_initcall(percpu_enable_async);