viafb: clean up virtual memory handling
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / percpu.c
blob43d8cacfdaa5e4f0e1e3ba0b5e8275570e948292
1 /*
2 * linux/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 in vmalloc area. Each
11 * chunk is consisted of boot-time determined number of units and the
12 * first 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. ie. in
17 * vmalloc area
19 * c0 c1 c2
20 * ------------------- ------------------- ------------
21 * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
22 * ------------------- ...... ------------------- .... ------------
24 * Allocation is done in offset-size areas of single unit space. Ie,
25 * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
26 * c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to
27 * cpus. On NUMA, the mapping can be non-linear and even sparse.
28 * Percpu access can be done by configuring percpu base registers
29 * according to cpu to unit mapping and pcpu_unit_size.
31 * There are usually many small percpu allocations many of them being
32 * as small as 4 bytes. The allocator organizes chunks into lists
33 * according to free size and tries to allocate from the fullest one.
34 * Each chunk keeps the maximum contiguous area size hint which is
35 * guaranteed to be eqaul to or larger than the maximum contiguous
36 * area in the chunk. This helps the allocator not to iterate the
37 * chunk maps unnecessarily.
39 * Allocation state in each chunk is kept using an array of integers
40 * on chunk->map. A positive value in the map represents a free
41 * region and negative allocated. Allocation inside a chunk is done
42 * by scanning this map sequentially and serving the first matching
43 * entry. This is mostly copied from the percpu_modalloc() allocator.
44 * Chunks can be determined from the address using the index field
45 * in the page struct. The index field contains a pointer to the chunk.
47 * To use this allocator, arch code should do the followings.
49 * - drop CONFIG_HAVE_LEGACY_PER_CPU_AREA
51 * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
52 * regular address to percpu pointer and back if they need to be
53 * different from the default
55 * - use pcpu_setup_first_chunk() during percpu area initialization to
56 * setup the first chunk containing the kernel static percpu area
59 #include <linux/bitmap.h>
60 #include <linux/bootmem.h>
61 #include <linux/err.h>
62 #include <linux/list.h>
63 #include <linux/log2.h>
64 #include <linux/mm.h>
65 #include <linux/module.h>
66 #include <linux/mutex.h>
67 #include <linux/percpu.h>
68 #include <linux/pfn.h>
69 #include <linux/slab.h>
70 #include <linux/spinlock.h>
71 #include <linux/vmalloc.h>
72 #include <linux/workqueue.h>
74 #include <asm/cacheflush.h>
75 #include <asm/sections.h>
76 #include <asm/tlbflush.h>
78 #define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
79 #define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
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 *)((unsigned long)(addr) - (unsigned long)pcpu_base_addr \
85 + (unsigned long)__per_cpu_start)
86 #endif
87 #ifndef __pcpu_ptr_to_addr
88 #define __pcpu_ptr_to_addr(ptr) \
89 (void *)((unsigned long)(ptr) + (unsigned long)pcpu_base_addr \
90 - (unsigned long)__per_cpu_start)
91 #endif
93 struct pcpu_chunk {
94 struct list_head list; /* linked to pcpu_slot lists */
95 int free_size; /* free bytes in the chunk */
96 int contig_hint; /* max contiguous size hint */
97 void *base_addr; /* base address of this chunk */
98 int map_used; /* # of map entries used */
99 int map_alloc; /* # of map entries allocated */
100 int *map; /* allocation map */
101 struct vm_struct **vms; /* mapped vmalloc regions */
102 bool immutable; /* no [de]population allowed */
103 unsigned long populated[]; /* populated bitmap */
106 static int pcpu_unit_pages __read_mostly;
107 static int pcpu_unit_size __read_mostly;
108 static int pcpu_nr_units __read_mostly;
109 static int pcpu_atom_size __read_mostly;
110 static int pcpu_nr_slots __read_mostly;
111 static size_t pcpu_chunk_struct_size __read_mostly;
113 /* cpus with the lowest and highest unit numbers */
114 static unsigned int pcpu_first_unit_cpu __read_mostly;
115 static unsigned int pcpu_last_unit_cpu __read_mostly;
117 /* the address of the first chunk which starts with the kernel static area */
118 void *pcpu_base_addr __read_mostly;
119 EXPORT_SYMBOL_GPL(pcpu_base_addr);
121 static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
122 const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */
124 /* group information, used for vm allocation */
125 static int pcpu_nr_groups __read_mostly;
126 static const unsigned long *pcpu_group_offsets __read_mostly;
127 static const size_t *pcpu_group_sizes __read_mostly;
130 * The first chunk which always exists. Note that unlike other
131 * chunks, this one can be allocated and mapped in several different
132 * ways and thus often doesn't live in the vmalloc area.
134 static struct pcpu_chunk *pcpu_first_chunk;
137 * Optional reserved chunk. This chunk reserves part of the first
138 * chunk and serves it for reserved allocations. The amount of
139 * reserved offset is in pcpu_reserved_chunk_limit. When reserved
140 * area doesn't exist, the following variables contain NULL and 0
141 * respectively.
143 static struct pcpu_chunk *pcpu_reserved_chunk;
144 static int pcpu_reserved_chunk_limit;
147 * Synchronization rules.
149 * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former
150 * protects allocation/reclaim paths, chunks, populated bitmap and
151 * vmalloc mapping. The latter is a spinlock and protects the index
152 * data structures - chunk slots, chunks and area maps in chunks.
154 * During allocation, pcpu_alloc_mutex is kept locked all the time and
155 * pcpu_lock is grabbed and released as necessary. All actual memory
156 * allocations are done using GFP_KERNEL with pcpu_lock released.
158 * Free path accesses and alters only the index data structures, so it
159 * can be safely called from atomic context. When memory needs to be
160 * returned to the system, free path schedules reclaim_work which
161 * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be
162 * reclaimed, release both locks and frees the chunks. Note that it's
163 * necessary to grab both locks to remove a chunk from circulation as
164 * allocation path might be referencing the chunk with only
165 * pcpu_alloc_mutex locked.
167 static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */
168 static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */
170 static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
172 /* reclaim work to release fully free chunks, scheduled from free path */
173 static void pcpu_reclaim(struct work_struct *work);
174 static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim);
176 static int __pcpu_size_to_slot(int size)
178 int highbit = fls(size); /* size is in bytes */
179 return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
182 static int pcpu_size_to_slot(int size)
184 if (size == pcpu_unit_size)
185 return pcpu_nr_slots - 1;
186 return __pcpu_size_to_slot(size);
189 static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
191 if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
192 return 0;
194 return pcpu_size_to_slot(chunk->free_size);
197 static int pcpu_page_idx(unsigned int cpu, int page_idx)
199 return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
202 static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
203 unsigned int cpu, int page_idx)
205 return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
206 (page_idx << PAGE_SHIFT);
209 static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
210 unsigned int cpu, int page_idx)
212 /* must not be used on pre-mapped chunk */
213 WARN_ON(chunk->immutable);
215 return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
218 /* set the pointer to a chunk in a page struct */
219 static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
221 page->index = (unsigned long)pcpu;
224 /* obtain pointer to a chunk from a page struct */
225 static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
227 return (struct pcpu_chunk *)page->index;
230 static void pcpu_next_unpop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
232 *rs = find_next_zero_bit(chunk->populated, end, *rs);
233 *re = find_next_bit(chunk->populated, end, *rs + 1);
236 static void pcpu_next_pop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
238 *rs = find_next_bit(chunk->populated, end, *rs);
239 *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
243 * (Un)populated page region iterators. Iterate over (un)populated
244 * page regions betwen @start and @end in @chunk. @rs and @re should
245 * be integer variables and will be set to start and end page index of
246 * the current region.
248 #define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
249 for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
250 (rs) < (re); \
251 (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
253 #define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
254 for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
255 (rs) < (re); \
256 (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
259 * pcpu_mem_alloc - allocate memory
260 * @size: bytes to allocate
262 * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
263 * kzalloc() is used; otherwise, vmalloc() is used. The returned
264 * memory is always zeroed.
266 * CONTEXT:
267 * Does GFP_KERNEL allocation.
269 * RETURNS:
270 * Pointer to the allocated area on success, NULL on failure.
272 static void *pcpu_mem_alloc(size_t size)
274 if (size <= PAGE_SIZE)
275 return kzalloc(size, GFP_KERNEL);
276 else {
277 void *ptr = vmalloc(size);
278 if (ptr)
279 memset(ptr, 0, size);
280 return ptr;
285 * pcpu_mem_free - free memory
286 * @ptr: memory to free
287 * @size: size of the area
289 * Free @ptr. @ptr should have been allocated using pcpu_mem_alloc().
291 static void pcpu_mem_free(void *ptr, size_t size)
293 if (size <= PAGE_SIZE)
294 kfree(ptr);
295 else
296 vfree(ptr);
300 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
301 * @chunk: chunk of interest
302 * @oslot: the previous slot it was on
304 * This function is called after an allocation or free changed @chunk.
305 * New slot according to the changed state is determined and @chunk is
306 * moved to the slot. Note that the reserved chunk is never put on
307 * chunk slots.
309 * CONTEXT:
310 * pcpu_lock.
312 static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
314 int nslot = pcpu_chunk_slot(chunk);
316 if (chunk != pcpu_reserved_chunk && oslot != nslot) {
317 if (oslot < nslot)
318 list_move(&chunk->list, &pcpu_slot[nslot]);
319 else
320 list_move_tail(&chunk->list, &pcpu_slot[nslot]);
325 * pcpu_chunk_addr_search - determine chunk containing specified address
326 * @addr: address for which the chunk needs to be determined.
328 * RETURNS:
329 * The address of the found chunk.
331 static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
333 void *first_start = pcpu_first_chunk->base_addr;
335 /* is it in the first chunk? */
336 if (addr >= first_start && addr < first_start + pcpu_unit_size) {
337 /* is it in the reserved area? */
338 if (addr < first_start + pcpu_reserved_chunk_limit)
339 return pcpu_reserved_chunk;
340 return pcpu_first_chunk;
344 * The address is relative to unit0 which might be unused and
345 * thus unmapped. Offset the address to the unit space of the
346 * current processor before looking it up in the vmalloc
347 * space. Note that any possible cpu id can be used here, so
348 * there's no need to worry about preemption or cpu hotplug.
350 addr += pcpu_unit_offsets[raw_smp_processor_id()];
351 return pcpu_get_page_chunk(vmalloc_to_page(addr));
355 * pcpu_extend_area_map - extend area map for allocation
356 * @chunk: target chunk
358 * Extend area map of @chunk so that it can accomodate an allocation.
359 * A single allocation can split an area into three areas, so this
360 * function makes sure that @chunk->map has at least two extra slots.
362 * CONTEXT:
363 * pcpu_alloc_mutex, pcpu_lock. pcpu_lock is released and reacquired
364 * if area map is extended.
366 * RETURNS:
367 * 0 if noop, 1 if successfully extended, -errno on failure.
369 static int pcpu_extend_area_map(struct pcpu_chunk *chunk)
371 int new_alloc;
372 int *new;
373 size_t size;
375 /* has enough? */
376 if (chunk->map_alloc >= chunk->map_used + 2)
377 return 0;
379 spin_unlock_irq(&pcpu_lock);
381 new_alloc = PCPU_DFL_MAP_ALLOC;
382 while (new_alloc < chunk->map_used + 2)
383 new_alloc *= 2;
385 new = pcpu_mem_alloc(new_alloc * sizeof(new[0]));
386 if (!new) {
387 spin_lock_irq(&pcpu_lock);
388 return -ENOMEM;
392 * Acquire pcpu_lock and switch to new area map. Only free
393 * could have happened inbetween, so map_used couldn't have
394 * grown.
396 spin_lock_irq(&pcpu_lock);
397 BUG_ON(new_alloc < chunk->map_used + 2);
399 size = chunk->map_alloc * sizeof(chunk->map[0]);
400 memcpy(new, chunk->map, size);
403 * map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is
404 * one of the first chunks and still using static map.
406 if (chunk->map_alloc >= PCPU_DFL_MAP_ALLOC)
407 pcpu_mem_free(chunk->map, size);
409 chunk->map_alloc = new_alloc;
410 chunk->map = new;
411 return 0;
415 * pcpu_split_block - split a map block
416 * @chunk: chunk of interest
417 * @i: index of map block to split
418 * @head: head size in bytes (can be 0)
419 * @tail: tail size in bytes (can be 0)
421 * Split the @i'th map block into two or three blocks. If @head is
422 * non-zero, @head bytes block is inserted before block @i moving it
423 * to @i+1 and reducing its size by @head bytes.
425 * If @tail is non-zero, the target block, which can be @i or @i+1
426 * depending on @head, is reduced by @tail bytes and @tail byte block
427 * is inserted after the target block.
429 * @chunk->map must have enough free slots to accomodate the split.
431 * CONTEXT:
432 * pcpu_lock.
434 static void pcpu_split_block(struct pcpu_chunk *chunk, int i,
435 int head, int tail)
437 int nr_extra = !!head + !!tail;
439 BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra);
441 /* insert new subblocks */
442 memmove(&chunk->map[i + nr_extra], &chunk->map[i],
443 sizeof(chunk->map[0]) * (chunk->map_used - i));
444 chunk->map_used += nr_extra;
446 if (head) {
447 chunk->map[i + 1] = chunk->map[i] - head;
448 chunk->map[i++] = head;
450 if (tail) {
451 chunk->map[i++] -= tail;
452 chunk->map[i] = tail;
457 * pcpu_alloc_area - allocate area from a pcpu_chunk
458 * @chunk: chunk of interest
459 * @size: wanted size in bytes
460 * @align: wanted align
462 * Try to allocate @size bytes area aligned at @align from @chunk.
463 * Note that this function only allocates the offset. It doesn't
464 * populate or map the area.
466 * @chunk->map must have at least two free slots.
468 * CONTEXT:
469 * pcpu_lock.
471 * RETURNS:
472 * Allocated offset in @chunk on success, -1 if no matching area is
473 * found.
475 static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
477 int oslot = pcpu_chunk_slot(chunk);
478 int max_contig = 0;
479 int i, off;
481 for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) {
482 bool is_last = i + 1 == chunk->map_used;
483 int head, tail;
485 /* extra for alignment requirement */
486 head = ALIGN(off, align) - off;
487 BUG_ON(i == 0 && head != 0);
489 if (chunk->map[i] < 0)
490 continue;
491 if (chunk->map[i] < head + size) {
492 max_contig = max(chunk->map[i], max_contig);
493 continue;
497 * If head is small or the previous block is free,
498 * merge'em. Note that 'small' is defined as smaller
499 * than sizeof(int), which is very small but isn't too
500 * uncommon for percpu allocations.
502 if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) {
503 if (chunk->map[i - 1] > 0)
504 chunk->map[i - 1] += head;
505 else {
506 chunk->map[i - 1] -= head;
507 chunk->free_size -= head;
509 chunk->map[i] -= head;
510 off += head;
511 head = 0;
514 /* if tail is small, just keep it around */
515 tail = chunk->map[i] - head - size;
516 if (tail < sizeof(int))
517 tail = 0;
519 /* split if warranted */
520 if (head || tail) {
521 pcpu_split_block(chunk, i, head, tail);
522 if (head) {
523 i++;
524 off += head;
525 max_contig = max(chunk->map[i - 1], max_contig);
527 if (tail)
528 max_contig = max(chunk->map[i + 1], max_contig);
531 /* update hint and mark allocated */
532 if (is_last)
533 chunk->contig_hint = max_contig; /* fully scanned */
534 else
535 chunk->contig_hint = max(chunk->contig_hint,
536 max_contig);
538 chunk->free_size -= chunk->map[i];
539 chunk->map[i] = -chunk->map[i];
541 pcpu_chunk_relocate(chunk, oslot);
542 return off;
545 chunk->contig_hint = max_contig; /* fully scanned */
546 pcpu_chunk_relocate(chunk, oslot);
548 /* tell the upper layer that this chunk has no matching area */
549 return -1;
553 * pcpu_free_area - free area to a pcpu_chunk
554 * @chunk: chunk of interest
555 * @freeme: offset of area to free
557 * Free area starting from @freeme to @chunk. Note that this function
558 * only modifies the allocation map. It doesn't depopulate or unmap
559 * the area.
561 * CONTEXT:
562 * pcpu_lock.
564 static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
566 int oslot = pcpu_chunk_slot(chunk);
567 int i, off;
569 for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++]))
570 if (off == freeme)
571 break;
572 BUG_ON(off != freeme);
573 BUG_ON(chunk->map[i] > 0);
575 chunk->map[i] = -chunk->map[i];
576 chunk->free_size += chunk->map[i];
578 /* merge with previous? */
579 if (i > 0 && chunk->map[i - 1] >= 0) {
580 chunk->map[i - 1] += chunk->map[i];
581 chunk->map_used--;
582 memmove(&chunk->map[i], &chunk->map[i + 1],
583 (chunk->map_used - i) * sizeof(chunk->map[0]));
584 i--;
586 /* merge with next? */
587 if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) {
588 chunk->map[i] += chunk->map[i + 1];
589 chunk->map_used--;
590 memmove(&chunk->map[i + 1], &chunk->map[i + 2],
591 (chunk->map_used - (i + 1)) * sizeof(chunk->map[0]));
594 chunk->contig_hint = max(chunk->map[i], chunk->contig_hint);
595 pcpu_chunk_relocate(chunk, oslot);
599 * pcpu_get_pages_and_bitmap - get temp pages array and bitmap
600 * @chunk: chunk of interest
601 * @bitmapp: output parameter for bitmap
602 * @may_alloc: may allocate the array
604 * Returns pointer to array of pointers to struct page and bitmap,
605 * both of which can be indexed with pcpu_page_idx(). The returned
606 * array is cleared to zero and *@bitmapp is copied from
607 * @chunk->populated. Note that there is only one array and bitmap
608 * and access exclusion is the caller's responsibility.
610 * CONTEXT:
611 * pcpu_alloc_mutex and does GFP_KERNEL allocation if @may_alloc.
612 * Otherwise, don't care.
614 * RETURNS:
615 * Pointer to temp pages array on success, NULL on failure.
617 static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
618 unsigned long **bitmapp,
619 bool may_alloc)
621 static struct page **pages;
622 static unsigned long *bitmap;
623 size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
624 size_t bitmap_size = BITS_TO_LONGS(pcpu_unit_pages) *
625 sizeof(unsigned long);
627 if (!pages || !bitmap) {
628 if (may_alloc && !pages)
629 pages = pcpu_mem_alloc(pages_size);
630 if (may_alloc && !bitmap)
631 bitmap = pcpu_mem_alloc(bitmap_size);
632 if (!pages || !bitmap)
633 return NULL;
636 memset(pages, 0, pages_size);
637 bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages);
639 *bitmapp = bitmap;
640 return pages;
644 * pcpu_free_pages - free pages which were allocated for @chunk
645 * @chunk: chunk pages were allocated for
646 * @pages: array of pages to be freed, indexed by pcpu_page_idx()
647 * @populated: populated bitmap
648 * @page_start: page index of the first page to be freed
649 * @page_end: page index of the last page to be freed + 1
651 * Free pages [@page_start and @page_end) in @pages for all units.
652 * The pages were allocated for @chunk.
654 static void pcpu_free_pages(struct pcpu_chunk *chunk,
655 struct page **pages, unsigned long *populated,
656 int page_start, int page_end)
658 unsigned int cpu;
659 int i;
661 for_each_possible_cpu(cpu) {
662 for (i = page_start; i < page_end; i++) {
663 struct page *page = pages[pcpu_page_idx(cpu, i)];
665 if (page)
666 __free_page(page);
672 * pcpu_alloc_pages - allocates pages for @chunk
673 * @chunk: target chunk
674 * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
675 * @populated: populated bitmap
676 * @page_start: page index of the first page to be allocated
677 * @page_end: page index of the last page to be allocated + 1
679 * Allocate pages [@page_start,@page_end) into @pages for all units.
680 * The allocation is for @chunk. Percpu core doesn't care about the
681 * content of @pages and will pass it verbatim to pcpu_map_pages().
683 static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
684 struct page **pages, unsigned long *populated,
685 int page_start, int page_end)
687 const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
688 unsigned int cpu;
689 int i;
691 for_each_possible_cpu(cpu) {
692 for (i = page_start; i < page_end; i++) {
693 struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
695 *pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
696 if (!*pagep) {
697 pcpu_free_pages(chunk, pages, populated,
698 page_start, page_end);
699 return -ENOMEM;
703 return 0;
707 * pcpu_pre_unmap_flush - flush cache prior to unmapping
708 * @chunk: chunk the regions to be flushed belongs to
709 * @page_start: page index of the first page to be flushed
710 * @page_end: page index of the last page to be flushed + 1
712 * Pages in [@page_start,@page_end) of @chunk are about to be
713 * unmapped. Flush cache. As each flushing trial can be very
714 * expensive, issue flush on the whole region at once rather than
715 * doing it for each cpu. This could be an overkill but is more
716 * scalable.
718 static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
719 int page_start, int page_end)
721 flush_cache_vunmap(
722 pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
723 pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
726 static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
728 unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
732 * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
733 * @chunk: chunk of interest
734 * @pages: pages array which can be used to pass information to free
735 * @populated: populated bitmap
736 * @page_start: page index of the first page to unmap
737 * @page_end: page index of the last page to unmap + 1
739 * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
740 * Corresponding elements in @pages were cleared by the caller and can
741 * be used to carry information to pcpu_free_pages() which will be
742 * called after all unmaps are finished. The caller should call
743 * proper pre/post flush functions.
745 static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
746 struct page **pages, unsigned long *populated,
747 int page_start, int page_end)
749 unsigned int cpu;
750 int i;
752 for_each_possible_cpu(cpu) {
753 for (i = page_start; i < page_end; i++) {
754 struct page *page;
756 page = pcpu_chunk_page(chunk, cpu, i);
757 WARN_ON(!page);
758 pages[pcpu_page_idx(cpu, i)] = page;
760 __pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
761 page_end - page_start);
764 for (i = page_start; i < page_end; i++)
765 __clear_bit(i, populated);
769 * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
770 * @chunk: pcpu_chunk the regions to be flushed belong to
771 * @page_start: page index of the first page to be flushed
772 * @page_end: page index of the last page to be flushed + 1
774 * Pages [@page_start,@page_end) of @chunk have been unmapped. Flush
775 * TLB for the regions. This can be skipped if the area is to be
776 * returned to vmalloc as vmalloc will handle TLB flushing lazily.
778 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
779 * for the whole region.
781 static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
782 int page_start, int page_end)
784 flush_tlb_kernel_range(
785 pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
786 pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
789 static int __pcpu_map_pages(unsigned long addr, struct page **pages,
790 int nr_pages)
792 return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
793 PAGE_KERNEL, pages);
797 * pcpu_map_pages - map pages into a pcpu_chunk
798 * @chunk: chunk of interest
799 * @pages: pages array containing pages to be mapped
800 * @populated: populated bitmap
801 * @page_start: page index of the first page to map
802 * @page_end: page index of the last page to map + 1
804 * For each cpu, map pages [@page_start,@page_end) into @chunk. The
805 * caller is responsible for calling pcpu_post_map_flush() after all
806 * mappings are complete.
808 * This function is responsible for setting corresponding bits in
809 * @chunk->populated bitmap and whatever is necessary for reverse
810 * lookup (addr -> chunk).
812 static int pcpu_map_pages(struct pcpu_chunk *chunk,
813 struct page **pages, unsigned long *populated,
814 int page_start, int page_end)
816 unsigned int cpu, tcpu;
817 int i, err;
819 for_each_possible_cpu(cpu) {
820 err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
821 &pages[pcpu_page_idx(cpu, page_start)],
822 page_end - page_start);
823 if (err < 0)
824 goto err;
827 /* mapping successful, link chunk and mark populated */
828 for (i = page_start; i < page_end; i++) {
829 for_each_possible_cpu(cpu)
830 pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
831 chunk);
832 __set_bit(i, populated);
835 return 0;
837 err:
838 for_each_possible_cpu(tcpu) {
839 if (tcpu == cpu)
840 break;
841 __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
842 page_end - page_start);
844 return err;
848 * pcpu_post_map_flush - flush cache after mapping
849 * @chunk: pcpu_chunk the regions to be flushed belong to
850 * @page_start: page index of the first page to be flushed
851 * @page_end: page index of the last page to be flushed + 1
853 * Pages [@page_start,@page_end) of @chunk have been mapped. Flush
854 * cache.
856 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
857 * for the whole region.
859 static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
860 int page_start, int page_end)
862 flush_cache_vmap(
863 pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
864 pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
868 * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
869 * @chunk: chunk to depopulate
870 * @off: offset to the area to depopulate
871 * @size: size of the area to depopulate in bytes
872 * @flush: whether to flush cache and tlb or not
874 * For each cpu, depopulate and unmap pages [@page_start,@page_end)
875 * from @chunk. If @flush is true, vcache is flushed before unmapping
876 * and tlb after.
878 * CONTEXT:
879 * pcpu_alloc_mutex.
881 static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
883 int page_start = PFN_DOWN(off);
884 int page_end = PFN_UP(off + size);
885 struct page **pages;
886 unsigned long *populated;
887 int rs, re;
889 /* quick path, check whether it's empty already */
890 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
891 if (rs == page_start && re == page_end)
892 return;
893 break;
896 /* immutable chunks can't be depopulated */
897 WARN_ON(chunk->immutable);
900 * If control reaches here, there must have been at least one
901 * successful population attempt so the temp pages array must
902 * be available now.
904 pages = pcpu_get_pages_and_bitmap(chunk, &populated, false);
905 BUG_ON(!pages);
907 /* unmap and free */
908 pcpu_pre_unmap_flush(chunk, page_start, page_end);
910 pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
911 pcpu_unmap_pages(chunk, pages, populated, rs, re);
913 /* no need to flush tlb, vmalloc will handle it lazily */
915 pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
916 pcpu_free_pages(chunk, pages, populated, rs, re);
918 /* commit new bitmap */
919 bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
923 * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
924 * @chunk: chunk of interest
925 * @off: offset to the area to populate
926 * @size: size of the area to populate in bytes
928 * For each cpu, populate and map pages [@page_start,@page_end) into
929 * @chunk. The area is cleared on return.
931 * CONTEXT:
932 * pcpu_alloc_mutex, does GFP_KERNEL allocation.
934 static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
936 int page_start = PFN_DOWN(off);
937 int page_end = PFN_UP(off + size);
938 int free_end = page_start, unmap_end = page_start;
939 struct page **pages;
940 unsigned long *populated;
941 unsigned int cpu;
942 int rs, re, rc;
944 /* quick path, check whether all pages are already there */
945 pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end) {
946 if (rs == page_start && re == page_end)
947 goto clear;
948 break;
951 /* need to allocate and map pages, this chunk can't be immutable */
952 WARN_ON(chunk->immutable);
954 pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
955 if (!pages)
956 return -ENOMEM;
958 /* alloc and map */
959 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
960 rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
961 if (rc)
962 goto err_free;
963 free_end = re;
966 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
967 rc = pcpu_map_pages(chunk, pages, populated, rs, re);
968 if (rc)
969 goto err_unmap;
970 unmap_end = re;
972 pcpu_post_map_flush(chunk, page_start, page_end);
974 /* commit new bitmap */
975 bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
976 clear:
977 for_each_possible_cpu(cpu)
978 memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
979 return 0;
981 err_unmap:
982 pcpu_pre_unmap_flush(chunk, page_start, unmap_end);
983 pcpu_for_each_unpop_region(chunk, rs, re, page_start, unmap_end)
984 pcpu_unmap_pages(chunk, pages, populated, rs, re);
985 pcpu_post_unmap_tlb_flush(chunk, page_start, unmap_end);
986 err_free:
987 pcpu_for_each_unpop_region(chunk, rs, re, page_start, free_end)
988 pcpu_free_pages(chunk, pages, populated, rs, re);
989 return rc;
992 static void free_pcpu_chunk(struct pcpu_chunk *chunk)
994 if (!chunk)
995 return;
996 if (chunk->vms)
997 pcpu_free_vm_areas(chunk->vms, pcpu_nr_groups);
998 pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
999 kfree(chunk);
1002 static struct pcpu_chunk *alloc_pcpu_chunk(void)
1004 struct pcpu_chunk *chunk;
1006 chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL);
1007 if (!chunk)
1008 return NULL;
1010 chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
1011 chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
1012 chunk->map[chunk->map_used++] = pcpu_unit_size;
1014 chunk->vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
1015 pcpu_nr_groups, pcpu_atom_size,
1016 GFP_KERNEL);
1017 if (!chunk->vms) {
1018 free_pcpu_chunk(chunk);
1019 return NULL;
1022 INIT_LIST_HEAD(&chunk->list);
1023 chunk->free_size = pcpu_unit_size;
1024 chunk->contig_hint = pcpu_unit_size;
1025 chunk->base_addr = chunk->vms[0]->addr - pcpu_group_offsets[0];
1027 return chunk;
1031 * pcpu_alloc - the percpu allocator
1032 * @size: size of area to allocate in bytes
1033 * @align: alignment of area (max PAGE_SIZE)
1034 * @reserved: allocate from the reserved chunk if available
1036 * Allocate percpu area of @size bytes aligned at @align.
1038 * CONTEXT:
1039 * Does GFP_KERNEL allocation.
1041 * RETURNS:
1042 * Percpu pointer to the allocated area on success, NULL on failure.
1044 static void *pcpu_alloc(size_t size, size_t align, bool reserved)
1046 struct pcpu_chunk *chunk;
1047 int slot, off;
1049 if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
1050 WARN(true, "illegal size (%zu) or align (%zu) for "
1051 "percpu allocation\n", size, align);
1052 return NULL;
1055 mutex_lock(&pcpu_alloc_mutex);
1056 spin_lock_irq(&pcpu_lock);
1058 /* serve reserved allocations from the reserved chunk if available */
1059 if (reserved && pcpu_reserved_chunk) {
1060 chunk = pcpu_reserved_chunk;
1061 if (size > chunk->contig_hint ||
1062 pcpu_extend_area_map(chunk) < 0)
1063 goto fail_unlock;
1064 off = pcpu_alloc_area(chunk, size, align);
1065 if (off >= 0)
1066 goto area_found;
1067 goto fail_unlock;
1070 restart:
1071 /* search through normal chunks */
1072 for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
1073 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
1074 if (size > chunk->contig_hint)
1075 continue;
1077 switch (pcpu_extend_area_map(chunk)) {
1078 case 0:
1079 break;
1080 case 1:
1081 goto restart; /* pcpu_lock dropped, restart */
1082 default:
1083 goto fail_unlock;
1086 off = pcpu_alloc_area(chunk, size, align);
1087 if (off >= 0)
1088 goto area_found;
1092 /* hmmm... no space left, create a new chunk */
1093 spin_unlock_irq(&pcpu_lock);
1095 chunk = alloc_pcpu_chunk();
1096 if (!chunk)
1097 goto fail_unlock_mutex;
1099 spin_lock_irq(&pcpu_lock);
1100 pcpu_chunk_relocate(chunk, -1);
1101 goto restart;
1103 area_found:
1104 spin_unlock_irq(&pcpu_lock);
1106 /* populate, map and clear the area */
1107 if (pcpu_populate_chunk(chunk, off, size)) {
1108 spin_lock_irq(&pcpu_lock);
1109 pcpu_free_area(chunk, off);
1110 goto fail_unlock;
1113 mutex_unlock(&pcpu_alloc_mutex);
1115 /* return address relative to base address */
1116 return __addr_to_pcpu_ptr(chunk->base_addr + off);
1118 fail_unlock:
1119 spin_unlock_irq(&pcpu_lock);
1120 fail_unlock_mutex:
1121 mutex_unlock(&pcpu_alloc_mutex);
1122 return NULL;
1126 * __alloc_percpu - allocate dynamic percpu area
1127 * @size: size of area to allocate in bytes
1128 * @align: alignment of area (max PAGE_SIZE)
1130 * Allocate percpu area of @size bytes aligned at @align. Might
1131 * sleep. Might trigger writeouts.
1133 * CONTEXT:
1134 * Does GFP_KERNEL allocation.
1136 * RETURNS:
1137 * Percpu pointer to the allocated area on success, NULL on failure.
1139 void *__alloc_percpu(size_t size, size_t align)
1141 return pcpu_alloc(size, align, false);
1143 EXPORT_SYMBOL_GPL(__alloc_percpu);
1146 * __alloc_reserved_percpu - allocate reserved percpu area
1147 * @size: size of area to allocate in bytes
1148 * @align: alignment of area (max PAGE_SIZE)
1150 * Allocate percpu area of @size bytes aligned at @align from reserved
1151 * percpu area if arch has set it up; otherwise, allocation is served
1152 * from the same dynamic area. Might sleep. Might trigger writeouts.
1154 * CONTEXT:
1155 * Does GFP_KERNEL allocation.
1157 * RETURNS:
1158 * Percpu pointer to the allocated area on success, NULL on failure.
1160 void *__alloc_reserved_percpu(size_t size, size_t align)
1162 return pcpu_alloc(size, align, true);
1166 * pcpu_reclaim - reclaim fully free chunks, workqueue function
1167 * @work: unused
1169 * Reclaim all fully free chunks except for the first one.
1171 * CONTEXT:
1172 * workqueue context.
1174 static void pcpu_reclaim(struct work_struct *work)
1176 LIST_HEAD(todo);
1177 struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1];
1178 struct pcpu_chunk *chunk, *next;
1180 mutex_lock(&pcpu_alloc_mutex);
1181 spin_lock_irq(&pcpu_lock);
1183 list_for_each_entry_safe(chunk, next, head, list) {
1184 WARN_ON(chunk->immutable);
1186 /* spare the first one */
1187 if (chunk == list_first_entry(head, struct pcpu_chunk, list))
1188 continue;
1190 list_move(&chunk->list, &todo);
1193 spin_unlock_irq(&pcpu_lock);
1195 list_for_each_entry_safe(chunk, next, &todo, list) {
1196 pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
1197 free_pcpu_chunk(chunk);
1200 mutex_unlock(&pcpu_alloc_mutex);
1204 * free_percpu - free percpu area
1205 * @ptr: pointer to area to free
1207 * Free percpu area @ptr.
1209 * CONTEXT:
1210 * Can be called from atomic context.
1212 void free_percpu(void *ptr)
1214 void *addr = __pcpu_ptr_to_addr(ptr);
1215 struct pcpu_chunk *chunk;
1216 unsigned long flags;
1217 int off;
1219 if (!ptr)
1220 return;
1222 spin_lock_irqsave(&pcpu_lock, flags);
1224 chunk = pcpu_chunk_addr_search(addr);
1225 off = addr - chunk->base_addr;
1227 pcpu_free_area(chunk, off);
1229 /* if there are more than one fully free chunks, wake up grim reaper */
1230 if (chunk->free_size == pcpu_unit_size) {
1231 struct pcpu_chunk *pos;
1233 list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
1234 if (pos != chunk) {
1235 schedule_work(&pcpu_reclaim_work);
1236 break;
1240 spin_unlock_irqrestore(&pcpu_lock, flags);
1242 EXPORT_SYMBOL_GPL(free_percpu);
1244 static inline size_t pcpu_calc_fc_sizes(size_t static_size,
1245 size_t reserved_size,
1246 ssize_t *dyn_sizep)
1248 size_t size_sum;
1250 size_sum = PFN_ALIGN(static_size + reserved_size +
1251 (*dyn_sizep >= 0 ? *dyn_sizep : 0));
1252 if (*dyn_sizep != 0)
1253 *dyn_sizep = size_sum - static_size - reserved_size;
1255 return size_sum;
1259 * pcpu_alloc_alloc_info - allocate percpu allocation info
1260 * @nr_groups: the number of groups
1261 * @nr_units: the number of units
1263 * Allocate ai which is large enough for @nr_groups groups containing
1264 * @nr_units units. The returned ai's groups[0].cpu_map points to the
1265 * cpu_map array which is long enough for @nr_units and filled with
1266 * NR_CPUS. It's the caller's responsibility to initialize cpu_map
1267 * pointer of other groups.
1269 * RETURNS:
1270 * Pointer to the allocated pcpu_alloc_info on success, NULL on
1271 * failure.
1273 struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
1274 int nr_units)
1276 struct pcpu_alloc_info *ai;
1277 size_t base_size, ai_size;
1278 void *ptr;
1279 int unit;
1281 base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
1282 __alignof__(ai->groups[0].cpu_map[0]));
1283 ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
1285 ptr = alloc_bootmem_nopanic(PFN_ALIGN(ai_size));
1286 if (!ptr)
1287 return NULL;
1288 ai = ptr;
1289 ptr += base_size;
1291 ai->groups[0].cpu_map = ptr;
1293 for (unit = 0; unit < nr_units; unit++)
1294 ai->groups[0].cpu_map[unit] = NR_CPUS;
1296 ai->nr_groups = nr_groups;
1297 ai->__ai_size = PFN_ALIGN(ai_size);
1299 return ai;
1303 * pcpu_free_alloc_info - free percpu allocation info
1304 * @ai: pcpu_alloc_info to free
1306 * Free @ai which was allocated by pcpu_alloc_alloc_info().
1308 void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
1310 free_bootmem(__pa(ai), ai->__ai_size);
1314 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
1315 * @reserved_size: the size of reserved percpu area in bytes
1316 * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
1317 * @atom_size: allocation atom size
1318 * @cpu_distance_fn: callback to determine distance between cpus, optional
1320 * This function determines grouping of units, their mappings to cpus
1321 * and other parameters considering needed percpu size, allocation
1322 * atom size and distances between CPUs.
1324 * Groups are always mutliples of atom size and CPUs which are of
1325 * LOCAL_DISTANCE both ways are grouped together and share space for
1326 * units in the same group. The returned configuration is guaranteed
1327 * to have CPUs on different nodes on different groups and >=75% usage
1328 * of allocated virtual address space.
1330 * RETURNS:
1331 * On success, pointer to the new allocation_info is returned. On
1332 * failure, ERR_PTR value is returned.
1334 struct pcpu_alloc_info * __init pcpu_build_alloc_info(
1335 size_t reserved_size, ssize_t dyn_size,
1336 size_t atom_size,
1337 pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
1339 static int group_map[NR_CPUS] __initdata;
1340 static int group_cnt[NR_CPUS] __initdata;
1341 const size_t static_size = __per_cpu_end - __per_cpu_start;
1342 int group_cnt_max = 0, nr_groups = 1, nr_units = 0;
1343 size_t size_sum, min_unit_size, alloc_size;
1344 int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
1345 int last_allocs, group, unit;
1346 unsigned int cpu, tcpu;
1347 struct pcpu_alloc_info *ai;
1348 unsigned int *cpu_map;
1351 * Determine min_unit_size, alloc_size and max_upa such that
1352 * alloc_size is multiple of atom_size and is the smallest
1353 * which can accomodate 4k aligned segments which are equal to
1354 * or larger than min_unit_size.
1356 size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
1357 min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
1359 alloc_size = roundup(min_unit_size, atom_size);
1360 upa = alloc_size / min_unit_size;
1361 while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1362 upa--;
1363 max_upa = upa;
1365 /* group cpus according to their proximity */
1366 for_each_possible_cpu(cpu) {
1367 group = 0;
1368 next_group:
1369 for_each_possible_cpu(tcpu) {
1370 if (cpu == tcpu)
1371 break;
1372 if (group_map[tcpu] == group && cpu_distance_fn &&
1373 (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
1374 cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
1375 group++;
1376 nr_groups = max(nr_groups, group + 1);
1377 goto next_group;
1380 group_map[cpu] = group;
1381 group_cnt[group]++;
1382 group_cnt_max = max(group_cnt_max, group_cnt[group]);
1386 * Expand unit size until address space usage goes over 75%
1387 * and then as much as possible without using more address
1388 * space.
1390 last_allocs = INT_MAX;
1391 for (upa = max_upa; upa; upa--) {
1392 int allocs = 0, wasted = 0;
1394 if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1395 continue;
1397 for (group = 0; group < nr_groups; group++) {
1398 int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
1399 allocs += this_allocs;
1400 wasted += this_allocs * upa - group_cnt[group];
1404 * Don't accept if wastage is over 25%. The
1405 * greater-than comparison ensures upa==1 always
1406 * passes the following check.
1408 if (wasted > num_possible_cpus() / 3)
1409 continue;
1411 /* and then don't consume more memory */
1412 if (allocs > last_allocs)
1413 break;
1414 last_allocs = allocs;
1415 best_upa = upa;
1417 upa = best_upa;
1419 /* allocate and fill alloc_info */
1420 for (group = 0; group < nr_groups; group++)
1421 nr_units += roundup(group_cnt[group], upa);
1423 ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
1424 if (!ai)
1425 return ERR_PTR(-ENOMEM);
1426 cpu_map = ai->groups[0].cpu_map;
1428 for (group = 0; group < nr_groups; group++) {
1429 ai->groups[group].cpu_map = cpu_map;
1430 cpu_map += roundup(group_cnt[group], upa);
1433 ai->static_size = static_size;
1434 ai->reserved_size = reserved_size;
1435 ai->dyn_size = dyn_size;
1436 ai->unit_size = alloc_size / upa;
1437 ai->atom_size = atom_size;
1438 ai->alloc_size = alloc_size;
1440 for (group = 0, unit = 0; group_cnt[group]; group++) {
1441 struct pcpu_group_info *gi = &ai->groups[group];
1444 * Initialize base_offset as if all groups are located
1445 * back-to-back. The caller should update this to
1446 * reflect actual allocation.
1448 gi->base_offset = unit * ai->unit_size;
1450 for_each_possible_cpu(cpu)
1451 if (group_map[cpu] == group)
1452 gi->cpu_map[gi->nr_units++] = cpu;
1453 gi->nr_units = roundup(gi->nr_units, upa);
1454 unit += gi->nr_units;
1456 BUG_ON(unit != nr_units);
1458 return ai;
1462 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
1463 * @lvl: loglevel
1464 * @ai: allocation info to dump
1466 * Print out information about @ai using loglevel @lvl.
1468 static void pcpu_dump_alloc_info(const char *lvl,
1469 const struct pcpu_alloc_info *ai)
1471 int group_width = 1, cpu_width = 1, width;
1472 char empty_str[] = "--------";
1473 int alloc = 0, alloc_end = 0;
1474 int group, v;
1475 int upa, apl; /* units per alloc, allocs per line */
1477 v = ai->nr_groups;
1478 while (v /= 10)
1479 group_width++;
1481 v = num_possible_cpus();
1482 while (v /= 10)
1483 cpu_width++;
1484 empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
1486 upa = ai->alloc_size / ai->unit_size;
1487 width = upa * (cpu_width + 1) + group_width + 3;
1488 apl = rounddown_pow_of_two(max(60 / width, 1));
1490 printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
1491 lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
1492 ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
1494 for (group = 0; group < ai->nr_groups; group++) {
1495 const struct pcpu_group_info *gi = &ai->groups[group];
1496 int unit = 0, unit_end = 0;
1498 BUG_ON(gi->nr_units % upa);
1499 for (alloc_end += gi->nr_units / upa;
1500 alloc < alloc_end; alloc++) {
1501 if (!(alloc % apl)) {
1502 printk("\n");
1503 printk("%spcpu-alloc: ", lvl);
1505 printk("[%0*d] ", group_width, group);
1507 for (unit_end += upa; unit < unit_end; unit++)
1508 if (gi->cpu_map[unit] != NR_CPUS)
1509 printk("%0*d ", cpu_width,
1510 gi->cpu_map[unit]);
1511 else
1512 printk("%s ", empty_str);
1515 printk("\n");
1519 * pcpu_setup_first_chunk - initialize the first percpu chunk
1520 * @ai: pcpu_alloc_info describing how to percpu area is shaped
1521 * @base_addr: mapped address
1523 * Initialize the first percpu chunk which contains the kernel static
1524 * perpcu area. This function is to be called from arch percpu area
1525 * setup path.
1527 * @ai contains all information necessary to initialize the first
1528 * chunk and prime the dynamic percpu allocator.
1530 * @ai->static_size is the size of static percpu area.
1532 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
1533 * reserve after the static area in the first chunk. This reserves
1534 * the first chunk such that it's available only through reserved
1535 * percpu allocation. This is primarily used to serve module percpu
1536 * static areas on architectures where the addressing model has
1537 * limited offset range for symbol relocations to guarantee module
1538 * percpu symbols fall inside the relocatable range.
1540 * @ai->dyn_size determines the number of bytes available for dynamic
1541 * allocation in the first chunk. The area between @ai->static_size +
1542 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
1544 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
1545 * and equal to or larger than @ai->static_size + @ai->reserved_size +
1546 * @ai->dyn_size.
1548 * @ai->atom_size is the allocation atom size and used as alignment
1549 * for vm areas.
1551 * @ai->alloc_size is the allocation size and always multiple of
1552 * @ai->atom_size. This is larger than @ai->atom_size if
1553 * @ai->unit_size is larger than @ai->atom_size.
1555 * @ai->nr_groups and @ai->groups describe virtual memory layout of
1556 * percpu areas. Units which should be colocated are put into the
1557 * same group. Dynamic VM areas will be allocated according to these
1558 * groupings. If @ai->nr_groups is zero, a single group containing
1559 * all units is assumed.
1561 * The caller should have mapped the first chunk at @base_addr and
1562 * copied static data to each unit.
1564 * If the first chunk ends up with both reserved and dynamic areas, it
1565 * is served by two chunks - one to serve the core static and reserved
1566 * areas and the other for the dynamic area. They share the same vm
1567 * and page map but uses different area allocation map to stay away
1568 * from each other. The latter chunk is circulated in the chunk slots
1569 * and available for dynamic allocation like any other chunks.
1571 * RETURNS:
1572 * 0 on success, -errno on failure.
1574 int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
1575 void *base_addr)
1577 static int smap[2], dmap[2];
1578 size_t dyn_size = ai->dyn_size;
1579 size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
1580 struct pcpu_chunk *schunk, *dchunk = NULL;
1581 unsigned long *group_offsets;
1582 size_t *group_sizes;
1583 unsigned long *unit_off;
1584 unsigned int cpu;
1585 int *unit_map;
1586 int group, unit, i;
1588 /* sanity checks */
1589 BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
1590 ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
1591 BUG_ON(ai->nr_groups <= 0);
1592 BUG_ON(!ai->static_size);
1593 BUG_ON(!base_addr);
1594 BUG_ON(ai->unit_size < size_sum);
1595 BUG_ON(ai->unit_size & ~PAGE_MASK);
1596 BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
1598 pcpu_dump_alloc_info(KERN_DEBUG, ai);
1600 /* process group information and build config tables accordingly */
1601 group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0]));
1602 group_sizes = alloc_bootmem(ai->nr_groups * sizeof(group_sizes[0]));
1603 unit_map = alloc_bootmem(nr_cpu_ids * sizeof(unit_map[0]));
1604 unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0]));
1606 for (cpu = 0; cpu < nr_cpu_ids; cpu++)
1607 unit_map[cpu] = NR_CPUS;
1608 pcpu_first_unit_cpu = NR_CPUS;
1610 for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
1611 const struct pcpu_group_info *gi = &ai->groups[group];
1613 group_offsets[group] = gi->base_offset;
1614 group_sizes[group] = gi->nr_units * ai->unit_size;
1616 for (i = 0; i < gi->nr_units; i++) {
1617 cpu = gi->cpu_map[i];
1618 if (cpu == NR_CPUS)
1619 continue;
1621 BUG_ON(cpu > nr_cpu_ids || !cpu_possible(cpu));
1622 BUG_ON(unit_map[cpu] != NR_CPUS);
1624 unit_map[cpu] = unit + i;
1625 unit_off[cpu] = gi->base_offset + i * ai->unit_size;
1627 if (pcpu_first_unit_cpu == NR_CPUS)
1628 pcpu_first_unit_cpu = cpu;
1631 pcpu_last_unit_cpu = cpu;
1632 pcpu_nr_units = unit;
1634 for_each_possible_cpu(cpu)
1635 BUG_ON(unit_map[cpu] == NR_CPUS);
1637 pcpu_nr_groups = ai->nr_groups;
1638 pcpu_group_offsets = group_offsets;
1639 pcpu_group_sizes = group_sizes;
1640 pcpu_unit_map = unit_map;
1641 pcpu_unit_offsets = unit_off;
1643 /* determine basic parameters */
1644 pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
1645 pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
1646 pcpu_atom_size = ai->atom_size;
1647 pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
1648 BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
1651 * Allocate chunk slots. The additional last slot is for
1652 * empty chunks.
1654 pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
1655 pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0]));
1656 for (i = 0; i < pcpu_nr_slots; i++)
1657 INIT_LIST_HEAD(&pcpu_slot[i]);
1660 * Initialize static chunk. If reserved_size is zero, the
1661 * static chunk covers static area + dynamic allocation area
1662 * in the first chunk. If reserved_size is not zero, it
1663 * covers static area + reserved area (mostly used for module
1664 * static percpu allocation).
1666 schunk = alloc_bootmem(pcpu_chunk_struct_size);
1667 INIT_LIST_HEAD(&schunk->list);
1668 schunk->base_addr = base_addr;
1669 schunk->map = smap;
1670 schunk->map_alloc = ARRAY_SIZE(smap);
1671 schunk->immutable = true;
1672 bitmap_fill(schunk->populated, pcpu_unit_pages);
1674 if (ai->reserved_size) {
1675 schunk->free_size = ai->reserved_size;
1676 pcpu_reserved_chunk = schunk;
1677 pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
1678 } else {
1679 schunk->free_size = dyn_size;
1680 dyn_size = 0; /* dynamic area covered */
1682 schunk->contig_hint = schunk->free_size;
1684 schunk->map[schunk->map_used++] = -ai->static_size;
1685 if (schunk->free_size)
1686 schunk->map[schunk->map_used++] = schunk->free_size;
1688 /* init dynamic chunk if necessary */
1689 if (dyn_size) {
1690 dchunk = alloc_bootmem(pcpu_chunk_struct_size);
1691 INIT_LIST_HEAD(&dchunk->list);
1692 dchunk->base_addr = base_addr;
1693 dchunk->map = dmap;
1694 dchunk->map_alloc = ARRAY_SIZE(dmap);
1695 dchunk->immutable = true;
1696 bitmap_fill(dchunk->populated, pcpu_unit_pages);
1698 dchunk->contig_hint = dchunk->free_size = dyn_size;
1699 dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit;
1700 dchunk->map[dchunk->map_used++] = dchunk->free_size;
1703 /* link the first chunk in */
1704 pcpu_first_chunk = dchunk ?: schunk;
1705 pcpu_chunk_relocate(pcpu_first_chunk, -1);
1707 /* we're done */
1708 pcpu_base_addr = base_addr;
1709 return 0;
1712 const char *pcpu_fc_names[PCPU_FC_NR] __initdata = {
1713 [PCPU_FC_AUTO] = "auto",
1714 [PCPU_FC_EMBED] = "embed",
1715 [PCPU_FC_PAGE] = "page",
1718 enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
1720 static int __init percpu_alloc_setup(char *str)
1722 if (0)
1723 /* nada */;
1724 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
1725 else if (!strcmp(str, "embed"))
1726 pcpu_chosen_fc = PCPU_FC_EMBED;
1727 #endif
1728 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1729 else if (!strcmp(str, "page"))
1730 pcpu_chosen_fc = PCPU_FC_PAGE;
1731 #endif
1732 else
1733 pr_warning("PERCPU: unknown allocator %s specified\n", str);
1735 return 0;
1737 early_param("percpu_alloc", percpu_alloc_setup);
1739 #if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
1740 !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
1742 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
1743 * @reserved_size: the size of reserved percpu area in bytes
1744 * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
1745 * @atom_size: allocation atom size
1746 * @cpu_distance_fn: callback to determine distance between cpus, optional
1747 * @alloc_fn: function to allocate percpu page
1748 * @free_fn: funtion to free percpu page
1750 * This is a helper to ease setting up embedded first percpu chunk and
1751 * can be called where pcpu_setup_first_chunk() is expected.
1753 * If this function is used to setup the first chunk, it is allocated
1754 * by calling @alloc_fn and used as-is without being mapped into
1755 * vmalloc area. Allocations are always whole multiples of @atom_size
1756 * aligned to @atom_size.
1758 * This enables the first chunk to piggy back on the linear physical
1759 * mapping which often uses larger page size. Please note that this
1760 * can result in very sparse cpu->unit mapping on NUMA machines thus
1761 * requiring large vmalloc address space. Don't use this allocator if
1762 * vmalloc space is not orders of magnitude larger than distances
1763 * between node memory addresses (ie. 32bit NUMA machines).
1765 * When @dyn_size is positive, dynamic area might be larger than
1766 * specified to fill page alignment. When @dyn_size is auto,
1767 * @dyn_size is just big enough to fill page alignment after static
1768 * and reserved areas.
1770 * If the needed size is smaller than the minimum or specified unit
1771 * size, the leftover is returned using @free_fn.
1773 * RETURNS:
1774 * 0 on success, -errno on failure.
1776 int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
1777 size_t atom_size,
1778 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
1779 pcpu_fc_alloc_fn_t alloc_fn,
1780 pcpu_fc_free_fn_t free_fn)
1782 void *base = (void *)ULONG_MAX;
1783 void **areas = NULL;
1784 struct pcpu_alloc_info *ai;
1785 size_t size_sum, areas_size;
1786 int group, i, rc;
1788 ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
1789 cpu_distance_fn);
1790 if (IS_ERR(ai))
1791 return PTR_ERR(ai);
1793 size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
1794 areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
1796 areas = alloc_bootmem_nopanic(areas_size);
1797 if (!areas) {
1798 rc = -ENOMEM;
1799 goto out_free;
1802 /* allocate, copy and determine base address */
1803 for (group = 0; group < ai->nr_groups; group++) {
1804 struct pcpu_group_info *gi = &ai->groups[group];
1805 unsigned int cpu = NR_CPUS;
1806 void *ptr;
1808 for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
1809 cpu = gi->cpu_map[i];
1810 BUG_ON(cpu == NR_CPUS);
1812 /* allocate space for the whole group */
1813 ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
1814 if (!ptr) {
1815 rc = -ENOMEM;
1816 goto out_free_areas;
1818 areas[group] = ptr;
1820 base = min(ptr, base);
1822 for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
1823 if (gi->cpu_map[i] == NR_CPUS) {
1824 /* unused unit, free whole */
1825 free_fn(ptr, ai->unit_size);
1826 continue;
1828 /* copy and return the unused part */
1829 memcpy(ptr, __per_cpu_load, ai->static_size);
1830 free_fn(ptr + size_sum, ai->unit_size - size_sum);
1834 /* base address is now known, determine group base offsets */
1835 for (group = 0; group < ai->nr_groups; group++)
1836 ai->groups[group].base_offset = areas[group] - base;
1838 pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
1839 PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
1840 ai->dyn_size, ai->unit_size);
1842 rc = pcpu_setup_first_chunk(ai, base);
1843 goto out_free;
1845 out_free_areas:
1846 for (group = 0; group < ai->nr_groups; group++)
1847 free_fn(areas[group],
1848 ai->groups[group].nr_units * ai->unit_size);
1849 out_free:
1850 pcpu_free_alloc_info(ai);
1851 if (areas)
1852 free_bootmem(__pa(areas), areas_size);
1853 return rc;
1855 #endif /* CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK ||
1856 !CONFIG_HAVE_SETUP_PER_CPU_AREA */
1858 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1860 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
1861 * @reserved_size: the size of reserved percpu area in bytes
1862 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
1863 * @free_fn: funtion to free percpu page, always called with PAGE_SIZE
1864 * @populate_pte_fn: function to populate pte
1866 * This is a helper to ease setting up page-remapped first percpu
1867 * chunk and can be called where pcpu_setup_first_chunk() is expected.
1869 * This is the basic allocator. Static percpu area is allocated
1870 * page-by-page into vmalloc area.
1872 * RETURNS:
1873 * 0 on success, -errno on failure.
1875 int __init pcpu_page_first_chunk(size_t reserved_size,
1876 pcpu_fc_alloc_fn_t alloc_fn,
1877 pcpu_fc_free_fn_t free_fn,
1878 pcpu_fc_populate_pte_fn_t populate_pte_fn)
1880 static struct vm_struct vm;
1881 struct pcpu_alloc_info *ai;
1882 char psize_str[16];
1883 int unit_pages;
1884 size_t pages_size;
1885 struct page **pages;
1886 int unit, i, j, rc;
1888 snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
1890 ai = pcpu_build_alloc_info(reserved_size, -1, PAGE_SIZE, NULL);
1891 if (IS_ERR(ai))
1892 return PTR_ERR(ai);
1893 BUG_ON(ai->nr_groups != 1);
1894 BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
1896 unit_pages = ai->unit_size >> PAGE_SHIFT;
1898 /* unaligned allocations can't be freed, round up to page size */
1899 pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
1900 sizeof(pages[0]));
1901 pages = alloc_bootmem(pages_size);
1903 /* allocate pages */
1904 j = 0;
1905 for (unit = 0; unit < num_possible_cpus(); unit++)
1906 for (i = 0; i < unit_pages; i++) {
1907 unsigned int cpu = ai->groups[0].cpu_map[unit];
1908 void *ptr;
1910 ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
1911 if (!ptr) {
1912 pr_warning("PERCPU: failed to allocate %s page "
1913 "for cpu%u\n", psize_str, cpu);
1914 goto enomem;
1916 pages[j++] = virt_to_page(ptr);
1919 /* allocate vm area, map the pages and copy static data */
1920 vm.flags = VM_ALLOC;
1921 vm.size = num_possible_cpus() * ai->unit_size;
1922 vm_area_register_early(&vm, PAGE_SIZE);
1924 for (unit = 0; unit < num_possible_cpus(); unit++) {
1925 unsigned long unit_addr =
1926 (unsigned long)vm.addr + unit * ai->unit_size;
1928 for (i = 0; i < unit_pages; i++)
1929 populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
1931 /* pte already populated, the following shouldn't fail */
1932 rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
1933 unit_pages);
1934 if (rc < 0)
1935 panic("failed to map percpu area, err=%d\n", rc);
1938 * FIXME: Archs with virtual cache should flush local
1939 * cache for the linear mapping here - something
1940 * equivalent to flush_cache_vmap() on the local cpu.
1941 * flush_cache_vmap() can't be used as most supporting
1942 * data structures are not set up yet.
1945 /* copy static data */
1946 memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
1949 /* we're ready, commit */
1950 pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
1951 unit_pages, psize_str, vm.addr, ai->static_size,
1952 ai->reserved_size, ai->dyn_size);
1954 rc = pcpu_setup_first_chunk(ai, vm.addr);
1955 goto out_free_ar;
1957 enomem:
1958 while (--j >= 0)
1959 free_fn(page_address(pages[j]), PAGE_SIZE);
1960 rc = -ENOMEM;
1961 out_free_ar:
1962 free_bootmem(__pa(pages), pages_size);
1963 pcpu_free_alloc_info(ai);
1964 return rc;
1966 #endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */
1969 * Generic percpu area setup.
1971 * The embedding helper is used because its behavior closely resembles
1972 * the original non-dynamic generic percpu area setup. This is
1973 * important because many archs have addressing restrictions and might
1974 * fail if the percpu area is located far away from the previous
1975 * location. As an added bonus, in non-NUMA cases, embedding is
1976 * generally a good idea TLB-wise because percpu area can piggy back
1977 * on the physical linear memory mapping which uses large page
1978 * mappings on applicable archs.
1980 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
1981 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
1982 EXPORT_SYMBOL(__per_cpu_offset);
1984 static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
1985 size_t align)
1987 return __alloc_bootmem_nopanic(size, align, __pa(MAX_DMA_ADDRESS));
1990 static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
1992 free_bootmem(__pa(ptr), size);
1995 void __init setup_per_cpu_areas(void)
1997 unsigned long delta;
1998 unsigned int cpu;
1999 int rc;
2002 * Always reserve area for module percpu variables. That's
2003 * what the legacy allocator did.
2005 rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
2006 PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
2007 pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
2008 if (rc < 0)
2009 panic("Failed to initialized percpu areas.");
2011 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
2012 for_each_possible_cpu(cpu)
2013 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
2015 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */