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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
58 #include <linux/bitmap.h>
59 #include <linux/bootmem.h>
60 #include <linux/err.h>
61 #include <linux/list.h>
62 #include <linux/log2.h>
64 #include <linux/module.h>
65 #include <linux/mutex.h>
66 #include <linux/percpu.h>
67 #include <linux/pfn.h>
68 #include <linux/slab.h>
69 #include <linux/spinlock.h>
70 #include <linux/vmalloc.h>
71 #include <linux/workqueue.h>
72 #include <linux/kmemleak.h>
74 #include <asm/cacheflush.h>
75 #include <asm/sections.h>
76 #include <asm/tlbflush.h>
79 #define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
80 #define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
81 #define PCPU_ATOMIC_MAP_MARGIN_LOW 32
82 #define PCPU_ATOMIC_MAP_MARGIN_HIGH 64
83 #define PCPU_EMPTY_POP_PAGES_LOW 2
84 #define PCPU_EMPTY_POP_PAGES_HIGH 4
87 /* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
88 #ifndef __addr_to_pcpu_ptr
89 #define __addr_to_pcpu_ptr(addr) \
90 (void __percpu *)((unsigned long)(addr) - \
91 (unsigned long)pcpu_base_addr + \
92 (unsigned long)__per_cpu_start)
94 #ifndef __pcpu_ptr_to_addr
95 #define __pcpu_ptr_to_addr(ptr) \
96 (void __force *)((unsigned long)(ptr) + \
97 (unsigned long)pcpu_base_addr - \
98 (unsigned long)__per_cpu_start)
100 #else /* CONFIG_SMP */
101 /* on UP, it's always identity mapped */
102 #define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
103 #define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
104 #endif /* CONFIG_SMP */
107 struct list_head list
; /* linked to pcpu_slot lists */
108 int free_size
; /* free bytes in the chunk */
109 int contig_hint
; /* max contiguous size hint */
110 void *base_addr
; /* base address of this chunk */
112 int map_used
; /* # of map entries used before the sentry */
113 int map_alloc
; /* # of map entries allocated */
114 int *map
; /* allocation map */
115 struct list_head map_extend_list
;/* on pcpu_map_extend_chunks */
117 void *data
; /* chunk data */
118 int first_free
; /* no free below this */
119 bool immutable
; /* no [de]population allowed */
120 int nr_populated
; /* # of populated pages */
121 unsigned long populated
[]; /* populated bitmap */
124 static int pcpu_unit_pages __read_mostly
;
125 static int pcpu_unit_size __read_mostly
;
126 static int pcpu_nr_units __read_mostly
;
127 static int pcpu_atom_size __read_mostly
;
128 static int pcpu_nr_slots __read_mostly
;
129 static size_t pcpu_chunk_struct_size __read_mostly
;
131 /* cpus with the lowest and highest unit addresses */
132 static unsigned int pcpu_low_unit_cpu __read_mostly
;
133 static unsigned int pcpu_high_unit_cpu __read_mostly
;
135 /* the address of the first chunk which starts with the kernel static area */
136 void *pcpu_base_addr __read_mostly
;
137 EXPORT_SYMBOL_GPL(pcpu_base_addr
);
139 static const int *pcpu_unit_map __read_mostly
; /* cpu -> unit */
140 const unsigned long *pcpu_unit_offsets __read_mostly
; /* cpu -> unit offset */
142 /* group information, used for vm allocation */
143 static int pcpu_nr_groups __read_mostly
;
144 static const unsigned long *pcpu_group_offsets __read_mostly
;
145 static const size_t *pcpu_group_sizes __read_mostly
;
148 * The first chunk which always exists. Note that unlike other
149 * chunks, this one can be allocated and mapped in several different
150 * ways and thus often doesn't live in the vmalloc area.
152 static struct pcpu_chunk
*pcpu_first_chunk
;
155 * Optional reserved chunk. This chunk reserves part of the first
156 * chunk and serves it for reserved allocations. The amount of
157 * reserved offset is in pcpu_reserved_chunk_limit. When reserved
158 * area doesn't exist, the following variables contain NULL and 0
161 static struct pcpu_chunk
*pcpu_reserved_chunk
;
162 static int pcpu_reserved_chunk_limit
;
164 static DEFINE_SPINLOCK(pcpu_lock
); /* all internal data structures */
165 static DEFINE_MUTEX(pcpu_alloc_mutex
); /* chunk create/destroy, [de]pop, map ext */
167 static struct list_head
*pcpu_slot __read_mostly
; /* chunk list slots */
169 /* chunks which need their map areas extended, protected by pcpu_lock */
170 static LIST_HEAD(pcpu_map_extend_chunks
);
173 * The number of empty populated pages, protected by pcpu_lock. The
174 * reserved chunk doesn't contribute to the count.
176 static int pcpu_nr_empty_pop_pages
;
179 * Balance work is used to populate or destroy chunks asynchronously. We
180 * try to keep the number of populated free pages between
181 * PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one
184 static void pcpu_balance_workfn(struct work_struct
*work
);
185 static DECLARE_WORK(pcpu_balance_work
, pcpu_balance_workfn
);
186 static bool pcpu_async_enabled __read_mostly
;
187 static bool pcpu_atomic_alloc_failed
;
189 static void pcpu_schedule_balance_work(void)
191 if (pcpu_async_enabled
)
192 schedule_work(&pcpu_balance_work
);
195 static bool pcpu_addr_in_first_chunk(void *addr
)
197 void *first_start
= pcpu_first_chunk
->base_addr
;
199 return addr
>= first_start
&& addr
< first_start
+ pcpu_unit_size
;
202 static bool pcpu_addr_in_reserved_chunk(void *addr
)
204 void *first_start
= pcpu_first_chunk
->base_addr
;
206 return addr
>= first_start
&&
207 addr
< first_start
+ pcpu_reserved_chunk_limit
;
210 static int __pcpu_size_to_slot(int size
)
212 int highbit
= fls(size
); /* size is in bytes */
213 return max(highbit
- PCPU_SLOT_BASE_SHIFT
+ 2, 1);
216 static int pcpu_size_to_slot(int size
)
218 if (size
== pcpu_unit_size
)
219 return pcpu_nr_slots
- 1;
220 return __pcpu_size_to_slot(size
);
223 static int pcpu_chunk_slot(const struct pcpu_chunk
*chunk
)
225 if (chunk
->free_size
< sizeof(int) || chunk
->contig_hint
< sizeof(int))
228 return pcpu_size_to_slot(chunk
->free_size
);
231 /* set the pointer to a chunk in a page struct */
232 static void pcpu_set_page_chunk(struct page
*page
, struct pcpu_chunk
*pcpu
)
234 page
->index
= (unsigned long)pcpu
;
237 /* obtain pointer to a chunk from a page struct */
238 static struct pcpu_chunk
*pcpu_get_page_chunk(struct page
*page
)
240 return (struct pcpu_chunk
*)page
->index
;
243 static int __maybe_unused
pcpu_page_idx(unsigned int cpu
, int page_idx
)
245 return pcpu_unit_map
[cpu
] * pcpu_unit_pages
+ page_idx
;
248 static unsigned long pcpu_chunk_addr(struct pcpu_chunk
*chunk
,
249 unsigned int cpu
, int page_idx
)
251 return (unsigned long)chunk
->base_addr
+ pcpu_unit_offsets
[cpu
] +
252 (page_idx
<< PAGE_SHIFT
);
255 static void __maybe_unused
pcpu_next_unpop(struct pcpu_chunk
*chunk
,
256 int *rs
, int *re
, int end
)
258 *rs
= find_next_zero_bit(chunk
->populated
, end
, *rs
);
259 *re
= find_next_bit(chunk
->populated
, end
, *rs
+ 1);
262 static void __maybe_unused
pcpu_next_pop(struct pcpu_chunk
*chunk
,
263 int *rs
, int *re
, int end
)
265 *rs
= find_next_bit(chunk
->populated
, end
, *rs
);
266 *re
= find_next_zero_bit(chunk
->populated
, end
, *rs
+ 1);
270 * (Un)populated page region iterators. Iterate over (un)populated
271 * page regions between @start and @end in @chunk. @rs and @re should
272 * be integer variables and will be set to start and end page index of
273 * the current region.
275 #define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
276 for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
278 (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
280 #define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
281 for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
283 (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
286 * pcpu_mem_zalloc - allocate memory
287 * @size: bytes to allocate
289 * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
290 * kzalloc() is used; otherwise, vzalloc() is used. The returned
291 * memory is always zeroed.
294 * Does GFP_KERNEL allocation.
297 * Pointer to the allocated area on success, NULL on failure.
299 static void *pcpu_mem_zalloc(size_t size
)
301 if (WARN_ON_ONCE(!slab_is_available()))
304 if (size
<= PAGE_SIZE
)
305 return kzalloc(size
, GFP_KERNEL
);
307 return vzalloc(size
);
311 * pcpu_mem_free - free memory
312 * @ptr: memory to free
314 * Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc().
316 static void pcpu_mem_free(void *ptr
)
322 * pcpu_count_occupied_pages - count the number of pages an area occupies
323 * @chunk: chunk of interest
324 * @i: index of the area in question
326 * Count the number of pages chunk's @i'th area occupies. When the area's
327 * start and/or end address isn't aligned to page boundary, the straddled
328 * page is included in the count iff the rest of the page is free.
330 static int pcpu_count_occupied_pages(struct pcpu_chunk
*chunk
, int i
)
332 int off
= chunk
->map
[i
] & ~1;
333 int end
= chunk
->map
[i
+ 1] & ~1;
335 if (!PAGE_ALIGNED(off
) && i
> 0) {
336 int prev
= chunk
->map
[i
- 1];
338 if (!(prev
& 1) && prev
<= round_down(off
, PAGE_SIZE
))
339 off
= round_down(off
, PAGE_SIZE
);
342 if (!PAGE_ALIGNED(end
) && i
+ 1 < chunk
->map_used
) {
343 int next
= chunk
->map
[i
+ 1];
344 int nend
= chunk
->map
[i
+ 2] & ~1;
346 if (!(next
& 1) && nend
>= round_up(end
, PAGE_SIZE
))
347 end
= round_up(end
, PAGE_SIZE
);
350 return max_t(int, PFN_DOWN(end
) - PFN_UP(off
), 0);
354 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
355 * @chunk: chunk of interest
356 * @oslot: the previous slot it was on
358 * This function is called after an allocation or free changed @chunk.
359 * New slot according to the changed state is determined and @chunk is
360 * moved to the slot. Note that the reserved chunk is never put on
366 static void pcpu_chunk_relocate(struct pcpu_chunk
*chunk
, int oslot
)
368 int nslot
= pcpu_chunk_slot(chunk
);
370 if (chunk
!= pcpu_reserved_chunk
&& oslot
!= nslot
) {
372 list_move(&chunk
->list
, &pcpu_slot
[nslot
]);
374 list_move_tail(&chunk
->list
, &pcpu_slot
[nslot
]);
379 * pcpu_need_to_extend - determine whether chunk area map needs to be extended
380 * @chunk: chunk of interest
381 * @is_atomic: the allocation context
383 * Determine whether area map of @chunk needs to be extended. If
384 * @is_atomic, only the amount necessary for a new allocation is
385 * considered; however, async extension is scheduled if the left amount is
386 * low. If !@is_atomic, it aims for more empty space. Combined, this
387 * ensures that the map is likely to have enough available space to
388 * accomodate atomic allocations which can't extend maps directly.
394 * New target map allocation length if extension is necessary, 0
397 static int pcpu_need_to_extend(struct pcpu_chunk
*chunk
, bool is_atomic
)
399 int margin
, new_alloc
;
401 lockdep_assert_held(&pcpu_lock
);
406 if (chunk
->map_alloc
<
407 chunk
->map_used
+ PCPU_ATOMIC_MAP_MARGIN_LOW
) {
408 if (list_empty(&chunk
->map_extend_list
)) {
409 list_add_tail(&chunk
->map_extend_list
,
410 &pcpu_map_extend_chunks
);
411 pcpu_schedule_balance_work();
415 margin
= PCPU_ATOMIC_MAP_MARGIN_HIGH
;
418 if (chunk
->map_alloc
>= chunk
->map_used
+ margin
)
421 new_alloc
= PCPU_DFL_MAP_ALLOC
;
422 while (new_alloc
< chunk
->map_used
+ margin
)
429 * pcpu_extend_area_map - extend area map of a chunk
430 * @chunk: chunk of interest
431 * @new_alloc: new target allocation length of the area map
433 * Extend area map of @chunk to have @new_alloc entries.
436 * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock.
439 * 0 on success, -errno on failure.
441 static int pcpu_extend_area_map(struct pcpu_chunk
*chunk
, int new_alloc
)
443 int *old
= NULL
, *new = NULL
;
444 size_t old_size
= 0, new_size
= new_alloc
* sizeof(new[0]);
447 lockdep_assert_held(&pcpu_alloc_mutex
);
449 new = pcpu_mem_zalloc(new_size
);
453 /* acquire pcpu_lock and switch to new area map */
454 spin_lock_irqsave(&pcpu_lock
, flags
);
456 if (new_alloc
<= chunk
->map_alloc
)
459 old_size
= chunk
->map_alloc
* sizeof(chunk
->map
[0]);
462 memcpy(new, old
, old_size
);
464 chunk
->map_alloc
= new_alloc
;
469 spin_unlock_irqrestore(&pcpu_lock
, flags
);
472 * pcpu_mem_free() might end up calling vfree() which uses
473 * IRQ-unsafe lock and thus can't be called under pcpu_lock.
482 * pcpu_fit_in_area - try to fit the requested allocation in a candidate area
483 * @chunk: chunk the candidate area belongs to
484 * @off: the offset to the start of the candidate area
485 * @this_size: the size of the candidate area
486 * @size: the size of the target allocation
487 * @align: the alignment of the target allocation
488 * @pop_only: only allocate from already populated region
490 * We're trying to allocate @size bytes aligned at @align. @chunk's area
491 * at @off sized @this_size is a candidate. This function determines
492 * whether the target allocation fits in the candidate area and returns the
493 * number of bytes to pad after @off. If the target area doesn't fit, -1
496 * If @pop_only is %true, this function only considers the already
497 * populated part of the candidate area.
499 static int pcpu_fit_in_area(struct pcpu_chunk
*chunk
, int off
, int this_size
,
500 int size
, int align
, bool pop_only
)
505 int head
= ALIGN(cand_off
, align
) - off
;
506 int page_start
, page_end
, rs
, re
;
508 if (this_size
< head
+ size
)
515 * If the first unpopulated page is beyond the end of the
516 * allocation, the whole allocation is populated;
517 * otherwise, retry from the end of the unpopulated area.
519 page_start
= PFN_DOWN(head
+ off
);
520 page_end
= PFN_UP(head
+ off
+ size
);
523 pcpu_next_unpop(chunk
, &rs
, &re
, PFN_UP(off
+ this_size
));
526 cand_off
= re
* PAGE_SIZE
;
531 * pcpu_alloc_area - allocate area from a pcpu_chunk
532 * @chunk: chunk of interest
533 * @size: wanted size in bytes
534 * @align: wanted align
535 * @pop_only: allocate only from the populated area
536 * @occ_pages_p: out param for the number of pages the area occupies
538 * Try to allocate @size bytes area aligned at @align from @chunk.
539 * Note that this function only allocates the offset. It doesn't
540 * populate or map the area.
542 * @chunk->map must have at least two free slots.
548 * Allocated offset in @chunk on success, -1 if no matching area is
551 static int pcpu_alloc_area(struct pcpu_chunk
*chunk
, int size
, int align
,
552 bool pop_only
, int *occ_pages_p
)
554 int oslot
= pcpu_chunk_slot(chunk
);
557 bool seen_free
= false;
560 for (i
= chunk
->first_free
, p
= chunk
->map
+ i
; i
< chunk
->map_used
; i
++, p
++) {
568 this_size
= (p
[1] & ~1) - off
;
570 head
= pcpu_fit_in_area(chunk
, off
, this_size
, size
, align
,
574 chunk
->first_free
= i
;
577 max_contig
= max(this_size
, max_contig
);
582 * If head is small or the previous block is free,
583 * merge'em. Note that 'small' is defined as smaller
584 * than sizeof(int), which is very small but isn't too
585 * uncommon for percpu allocations.
587 if (head
&& (head
< sizeof(int) || !(p
[-1] & 1))) {
590 chunk
->free_size
-= head
;
592 max_contig
= max(*p
- p
[-1], max_contig
);
597 /* if tail is small, just keep it around */
598 tail
= this_size
- head
- size
;
599 if (tail
< sizeof(int)) {
601 size
= this_size
- head
;
604 /* split if warranted */
606 int nr_extra
= !!head
+ !!tail
;
608 /* insert new subblocks */
609 memmove(p
+ nr_extra
+ 1, p
+ 1,
610 sizeof(chunk
->map
[0]) * (chunk
->map_used
- i
));
611 chunk
->map_used
+= nr_extra
;
615 chunk
->first_free
= i
;
620 max_contig
= max(head
, max_contig
);
624 max_contig
= max(tail
, max_contig
);
629 chunk
->first_free
= i
+ 1;
631 /* update hint and mark allocated */
632 if (i
+ 1 == chunk
->map_used
)
633 chunk
->contig_hint
= max_contig
; /* fully scanned */
635 chunk
->contig_hint
= max(chunk
->contig_hint
,
638 chunk
->free_size
-= size
;
641 *occ_pages_p
= pcpu_count_occupied_pages(chunk
, i
);
642 pcpu_chunk_relocate(chunk
, oslot
);
646 chunk
->contig_hint
= max_contig
; /* fully scanned */
647 pcpu_chunk_relocate(chunk
, oslot
);
649 /* tell the upper layer that this chunk has no matching area */
654 * pcpu_free_area - free area to a pcpu_chunk
655 * @chunk: chunk of interest
656 * @freeme: offset of area to free
657 * @occ_pages_p: out param for the number of pages the area occupies
659 * Free area starting from @freeme to @chunk. Note that this function
660 * only modifies the allocation map. It doesn't depopulate or unmap
666 static void pcpu_free_area(struct pcpu_chunk
*chunk
, int freeme
,
669 int oslot
= pcpu_chunk_slot(chunk
);
675 freeme
|= 1; /* we are searching for <given offset, in use> pair */
680 unsigned k
= (i
+ j
) / 2;
684 else if (off
> freeme
)
689 BUG_ON(off
!= freeme
);
691 if (i
< chunk
->first_free
)
692 chunk
->first_free
= i
;
696 chunk
->free_size
+= (p
[1] & ~1) - off
;
698 *occ_pages_p
= pcpu_count_occupied_pages(chunk
, i
);
700 /* merge with next? */
703 /* merge with previous? */
704 if (i
> 0 && !(p
[-1] & 1)) {
710 chunk
->map_used
-= to_free
;
711 memmove(p
+ 1, p
+ 1 + to_free
,
712 (chunk
->map_used
- i
) * sizeof(chunk
->map
[0]));
715 chunk
->contig_hint
= max(chunk
->map
[i
+ 1] - chunk
->map
[i
] - 1, chunk
->contig_hint
);
716 pcpu_chunk_relocate(chunk
, oslot
);
719 static struct pcpu_chunk
*pcpu_alloc_chunk(void)
721 struct pcpu_chunk
*chunk
;
723 chunk
= pcpu_mem_zalloc(pcpu_chunk_struct_size
);
727 chunk
->map
= pcpu_mem_zalloc(PCPU_DFL_MAP_ALLOC
*
728 sizeof(chunk
->map
[0]));
730 pcpu_mem_free(chunk
);
734 chunk
->map_alloc
= PCPU_DFL_MAP_ALLOC
;
736 chunk
->map
[1] = pcpu_unit_size
| 1;
739 INIT_LIST_HEAD(&chunk
->list
);
740 INIT_LIST_HEAD(&chunk
->map_extend_list
);
741 chunk
->free_size
= pcpu_unit_size
;
742 chunk
->contig_hint
= pcpu_unit_size
;
747 static void pcpu_free_chunk(struct pcpu_chunk
*chunk
)
751 pcpu_mem_free(chunk
->map
);
752 pcpu_mem_free(chunk
);
756 * pcpu_chunk_populated - post-population bookkeeping
757 * @chunk: pcpu_chunk which got populated
758 * @page_start: the start page
759 * @page_end: the end page
761 * Pages in [@page_start,@page_end) have been populated to @chunk. Update
762 * the bookkeeping information accordingly. Must be called after each
763 * successful population.
765 static void pcpu_chunk_populated(struct pcpu_chunk
*chunk
,
766 int page_start
, int page_end
)
768 int nr
= page_end
- page_start
;
770 lockdep_assert_held(&pcpu_lock
);
772 bitmap_set(chunk
->populated
, page_start
, nr
);
773 chunk
->nr_populated
+= nr
;
774 pcpu_nr_empty_pop_pages
+= nr
;
778 * pcpu_chunk_depopulated - post-depopulation bookkeeping
779 * @chunk: pcpu_chunk which got depopulated
780 * @page_start: the start page
781 * @page_end: the end page
783 * Pages in [@page_start,@page_end) have been depopulated from @chunk.
784 * Update the bookkeeping information accordingly. Must be called after
785 * each successful depopulation.
787 static void pcpu_chunk_depopulated(struct pcpu_chunk
*chunk
,
788 int page_start
, int page_end
)
790 int nr
= page_end
- page_start
;
792 lockdep_assert_held(&pcpu_lock
);
794 bitmap_clear(chunk
->populated
, page_start
, nr
);
795 chunk
->nr_populated
-= nr
;
796 pcpu_nr_empty_pop_pages
-= nr
;
800 * Chunk management implementation.
802 * To allow different implementations, chunk alloc/free and
803 * [de]population are implemented in a separate file which is pulled
804 * into this file and compiled together. The following functions
805 * should be implemented.
807 * pcpu_populate_chunk - populate the specified range of a chunk
808 * pcpu_depopulate_chunk - depopulate the specified range of a chunk
809 * pcpu_create_chunk - create a new chunk
810 * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
811 * pcpu_addr_to_page - translate address to physical address
812 * pcpu_verify_alloc_info - check alloc_info is acceptable during init
814 static int pcpu_populate_chunk(struct pcpu_chunk
*chunk
, int off
, int size
);
815 static void pcpu_depopulate_chunk(struct pcpu_chunk
*chunk
, int off
, int size
);
816 static struct pcpu_chunk
*pcpu_create_chunk(void);
817 static void pcpu_destroy_chunk(struct pcpu_chunk
*chunk
);
818 static struct page
*pcpu_addr_to_page(void *addr
);
819 static int __init
pcpu_verify_alloc_info(const struct pcpu_alloc_info
*ai
);
821 #ifdef CONFIG_NEED_PER_CPU_KM
822 #include "percpu-km.c"
824 #include "percpu-vm.c"
828 * pcpu_chunk_addr_search - determine chunk containing specified address
829 * @addr: address for which the chunk needs to be determined.
832 * The address of the found chunk.
834 static struct pcpu_chunk
*pcpu_chunk_addr_search(void *addr
)
836 /* is it in the first chunk? */
837 if (pcpu_addr_in_first_chunk(addr
)) {
838 /* is it in the reserved area? */
839 if (pcpu_addr_in_reserved_chunk(addr
))
840 return pcpu_reserved_chunk
;
841 return pcpu_first_chunk
;
845 * The address is relative to unit0 which might be unused and
846 * thus unmapped. Offset the address to the unit space of the
847 * current processor before looking it up in the vmalloc
848 * space. Note that any possible cpu id can be used here, so
849 * there's no need to worry about preemption or cpu hotplug.
851 addr
+= pcpu_unit_offsets
[raw_smp_processor_id()];
852 return pcpu_get_page_chunk(pcpu_addr_to_page(addr
));
856 * pcpu_alloc - the percpu allocator
857 * @size: size of area to allocate in bytes
858 * @align: alignment of area (max PAGE_SIZE)
859 * @reserved: allocate from the reserved chunk if available
860 * @gfp: allocation flags
862 * Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't
863 * contain %GFP_KERNEL, the allocation is atomic.
866 * Percpu pointer to the allocated area on success, NULL on failure.
868 static void __percpu
*pcpu_alloc(size_t size
, size_t align
, bool reserved
,
871 static int warn_limit
= 10;
872 struct pcpu_chunk
*chunk
;
874 bool is_atomic
= (gfp
& GFP_KERNEL
) != GFP_KERNEL
;
876 int slot
, off
, new_alloc
, cpu
, ret
;
881 * We want the lowest bit of offset available for in-use/free
882 * indicator, so force >= 16bit alignment and make size even.
884 if (unlikely(align
< 2))
887 size
= ALIGN(size
, 2);
889 if (unlikely(!size
|| size
> PCPU_MIN_UNIT_SIZE
|| align
> PAGE_SIZE
||
890 !is_power_of_2(align
))) {
891 WARN(true, "illegal size (%zu) or align (%zu) for percpu allocation\n",
897 mutex_lock(&pcpu_alloc_mutex
);
899 spin_lock_irqsave(&pcpu_lock
, flags
);
901 /* serve reserved allocations from the reserved chunk if available */
902 if (reserved
&& pcpu_reserved_chunk
) {
903 chunk
= pcpu_reserved_chunk
;
905 if (size
> chunk
->contig_hint
) {
906 err
= "alloc from reserved chunk failed";
910 while ((new_alloc
= pcpu_need_to_extend(chunk
, is_atomic
))) {
911 spin_unlock_irqrestore(&pcpu_lock
, flags
);
913 pcpu_extend_area_map(chunk
, new_alloc
) < 0) {
914 err
= "failed to extend area map of reserved chunk";
917 spin_lock_irqsave(&pcpu_lock
, flags
);
920 off
= pcpu_alloc_area(chunk
, size
, align
, is_atomic
,
925 err
= "alloc from reserved chunk failed";
930 /* search through normal chunks */
931 for (slot
= pcpu_size_to_slot(size
); slot
< pcpu_nr_slots
; slot
++) {
932 list_for_each_entry(chunk
, &pcpu_slot
[slot
], list
) {
933 if (size
> chunk
->contig_hint
)
936 new_alloc
= pcpu_need_to_extend(chunk
, is_atomic
);
940 spin_unlock_irqrestore(&pcpu_lock
, flags
);
941 if (pcpu_extend_area_map(chunk
,
943 err
= "failed to extend area map";
946 spin_lock_irqsave(&pcpu_lock
, flags
);
948 * pcpu_lock has been dropped, need to
949 * restart cpu_slot list walking.
954 off
= pcpu_alloc_area(chunk
, size
, align
, is_atomic
,
961 spin_unlock_irqrestore(&pcpu_lock
, flags
);
964 * No space left. Create a new chunk. We don't want multiple
965 * tasks to create chunks simultaneously. Serialize and create iff
966 * there's still no empty chunk after grabbing the mutex.
971 if (list_empty(&pcpu_slot
[pcpu_nr_slots
- 1])) {
972 chunk
= pcpu_create_chunk();
974 err
= "failed to allocate new chunk";
978 spin_lock_irqsave(&pcpu_lock
, flags
);
979 pcpu_chunk_relocate(chunk
, -1);
981 spin_lock_irqsave(&pcpu_lock
, flags
);
987 spin_unlock_irqrestore(&pcpu_lock
, flags
);
989 /* populate if not all pages are already there */
991 int page_start
, page_end
, rs
, re
;
993 page_start
= PFN_DOWN(off
);
994 page_end
= PFN_UP(off
+ size
);
996 pcpu_for_each_unpop_region(chunk
, rs
, re
, page_start
, page_end
) {
997 WARN_ON(chunk
->immutable
);
999 ret
= pcpu_populate_chunk(chunk
, rs
, re
);
1001 spin_lock_irqsave(&pcpu_lock
, flags
);
1003 pcpu_free_area(chunk
, off
, &occ_pages
);
1004 err
= "failed to populate";
1007 pcpu_chunk_populated(chunk
, rs
, re
);
1008 spin_unlock_irqrestore(&pcpu_lock
, flags
);
1011 mutex_unlock(&pcpu_alloc_mutex
);
1014 if (chunk
!= pcpu_reserved_chunk
)
1015 pcpu_nr_empty_pop_pages
-= occ_pages
;
1017 if (pcpu_nr_empty_pop_pages
< PCPU_EMPTY_POP_PAGES_LOW
)
1018 pcpu_schedule_balance_work();
1020 /* clear the areas and return address relative to base address */
1021 for_each_possible_cpu(cpu
)
1022 memset((void *)pcpu_chunk_addr(chunk
, cpu
, 0) + off
, 0, size
);
1024 ptr
= __addr_to_pcpu_ptr(chunk
->base_addr
+ off
);
1025 kmemleak_alloc_percpu(ptr
, size
, gfp
);
1029 spin_unlock_irqrestore(&pcpu_lock
, flags
);
1031 if (!is_atomic
&& warn_limit
) {
1032 pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n",
1033 size
, align
, is_atomic
, err
);
1036 pr_info("limit reached, disable warning\n");
1039 /* see the flag handling in pcpu_blance_workfn() */
1040 pcpu_atomic_alloc_failed
= true;
1041 pcpu_schedule_balance_work();
1043 mutex_unlock(&pcpu_alloc_mutex
);
1049 * __alloc_percpu_gfp - allocate dynamic percpu area
1050 * @size: size of area to allocate in bytes
1051 * @align: alignment of area (max PAGE_SIZE)
1052 * @gfp: allocation flags
1054 * Allocate zero-filled percpu area of @size bytes aligned at @align. If
1055 * @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can
1056 * be called from any context but is a lot more likely to fail.
1059 * Percpu pointer to the allocated area on success, NULL on failure.
1061 void __percpu
*__alloc_percpu_gfp(size_t size
, size_t align
, gfp_t gfp
)
1063 return pcpu_alloc(size
, align
, false, gfp
);
1065 EXPORT_SYMBOL_GPL(__alloc_percpu_gfp
);
1068 * __alloc_percpu - allocate dynamic percpu area
1069 * @size: size of area to allocate in bytes
1070 * @align: alignment of area (max PAGE_SIZE)
1072 * Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL).
1074 void __percpu
*__alloc_percpu(size_t size
, size_t align
)
1076 return pcpu_alloc(size
, align
, false, GFP_KERNEL
);
1078 EXPORT_SYMBOL_GPL(__alloc_percpu
);
1081 * __alloc_reserved_percpu - allocate reserved percpu area
1082 * @size: size of area to allocate in bytes
1083 * @align: alignment of area (max PAGE_SIZE)
1085 * Allocate zero-filled percpu area of @size bytes aligned at @align
1086 * from reserved percpu area if arch has set it up; otherwise,
1087 * allocation is served from the same dynamic area. Might sleep.
1088 * Might trigger writeouts.
1091 * Does GFP_KERNEL allocation.
1094 * Percpu pointer to the allocated area on success, NULL on failure.
1096 void __percpu
*__alloc_reserved_percpu(size_t size
, size_t align
)
1098 return pcpu_alloc(size
, align
, true, GFP_KERNEL
);
1102 * pcpu_balance_workfn - manage the amount of free chunks and populated pages
1105 * Reclaim all fully free chunks except for the first one.
1107 static void pcpu_balance_workfn(struct work_struct
*work
)
1110 struct list_head
*free_head
= &pcpu_slot
[pcpu_nr_slots
- 1];
1111 struct pcpu_chunk
*chunk
, *next
;
1112 int slot
, nr_to_pop
, ret
;
1115 * There's no reason to keep around multiple unused chunks and VM
1116 * areas can be scarce. Destroy all free chunks except for one.
1118 mutex_lock(&pcpu_alloc_mutex
);
1119 spin_lock_irq(&pcpu_lock
);
1121 list_for_each_entry_safe(chunk
, next
, free_head
, list
) {
1122 WARN_ON(chunk
->immutable
);
1124 /* spare the first one */
1125 if (chunk
== list_first_entry(free_head
, struct pcpu_chunk
, list
))
1128 list_del_init(&chunk
->map_extend_list
);
1129 list_move(&chunk
->list
, &to_free
);
1132 spin_unlock_irq(&pcpu_lock
);
1134 list_for_each_entry_safe(chunk
, next
, &to_free
, list
) {
1137 pcpu_for_each_pop_region(chunk
, rs
, re
, 0, pcpu_unit_pages
) {
1138 pcpu_depopulate_chunk(chunk
, rs
, re
);
1139 spin_lock_irq(&pcpu_lock
);
1140 pcpu_chunk_depopulated(chunk
, rs
, re
);
1141 spin_unlock_irq(&pcpu_lock
);
1143 pcpu_destroy_chunk(chunk
);
1146 /* service chunks which requested async area map extension */
1150 spin_lock_irq(&pcpu_lock
);
1152 chunk
= list_first_entry_or_null(&pcpu_map_extend_chunks
,
1153 struct pcpu_chunk
, map_extend_list
);
1155 list_del_init(&chunk
->map_extend_list
);
1156 new_alloc
= pcpu_need_to_extend(chunk
, false);
1159 spin_unlock_irq(&pcpu_lock
);
1162 pcpu_extend_area_map(chunk
, new_alloc
);
1166 * Ensure there are certain number of free populated pages for
1167 * atomic allocs. Fill up from the most packed so that atomic
1168 * allocs don't increase fragmentation. If atomic allocation
1169 * failed previously, always populate the maximum amount. This
1170 * should prevent atomic allocs larger than PAGE_SIZE from keeping
1171 * failing indefinitely; however, large atomic allocs are not
1172 * something we support properly and can be highly unreliable and
1176 if (pcpu_atomic_alloc_failed
) {
1177 nr_to_pop
= PCPU_EMPTY_POP_PAGES_HIGH
;
1178 /* best effort anyway, don't worry about synchronization */
1179 pcpu_atomic_alloc_failed
= false;
1181 nr_to_pop
= clamp(PCPU_EMPTY_POP_PAGES_HIGH
-
1182 pcpu_nr_empty_pop_pages
,
1183 0, PCPU_EMPTY_POP_PAGES_HIGH
);
1186 for (slot
= pcpu_size_to_slot(PAGE_SIZE
); slot
< pcpu_nr_slots
; slot
++) {
1187 int nr_unpop
= 0, rs
, re
;
1192 spin_lock_irq(&pcpu_lock
);
1193 list_for_each_entry(chunk
, &pcpu_slot
[slot
], list
) {
1194 nr_unpop
= pcpu_unit_pages
- chunk
->nr_populated
;
1198 spin_unlock_irq(&pcpu_lock
);
1203 /* @chunk can't go away while pcpu_alloc_mutex is held */
1204 pcpu_for_each_unpop_region(chunk
, rs
, re
, 0, pcpu_unit_pages
) {
1205 int nr
= min(re
- rs
, nr_to_pop
);
1207 ret
= pcpu_populate_chunk(chunk
, rs
, rs
+ nr
);
1210 spin_lock_irq(&pcpu_lock
);
1211 pcpu_chunk_populated(chunk
, rs
, rs
+ nr
);
1212 spin_unlock_irq(&pcpu_lock
);
1223 /* ran out of chunks to populate, create a new one and retry */
1224 chunk
= pcpu_create_chunk();
1226 spin_lock_irq(&pcpu_lock
);
1227 pcpu_chunk_relocate(chunk
, -1);
1228 spin_unlock_irq(&pcpu_lock
);
1233 mutex_unlock(&pcpu_alloc_mutex
);
1237 * free_percpu - free percpu area
1238 * @ptr: pointer to area to free
1240 * Free percpu area @ptr.
1243 * Can be called from atomic context.
1245 void free_percpu(void __percpu
*ptr
)
1248 struct pcpu_chunk
*chunk
;
1249 unsigned long flags
;
1255 kmemleak_free_percpu(ptr
);
1257 addr
= __pcpu_ptr_to_addr(ptr
);
1259 spin_lock_irqsave(&pcpu_lock
, flags
);
1261 chunk
= pcpu_chunk_addr_search(addr
);
1262 off
= addr
- chunk
->base_addr
;
1264 pcpu_free_area(chunk
, off
, &occ_pages
);
1266 if (chunk
!= pcpu_reserved_chunk
)
1267 pcpu_nr_empty_pop_pages
+= occ_pages
;
1269 /* if there are more than one fully free chunks, wake up grim reaper */
1270 if (chunk
->free_size
== pcpu_unit_size
) {
1271 struct pcpu_chunk
*pos
;
1273 list_for_each_entry(pos
, &pcpu_slot
[pcpu_nr_slots
- 1], list
)
1275 pcpu_schedule_balance_work();
1280 spin_unlock_irqrestore(&pcpu_lock
, flags
);
1282 EXPORT_SYMBOL_GPL(free_percpu
);
1285 * is_kernel_percpu_address - test whether address is from static percpu area
1286 * @addr: address to test
1288 * Test whether @addr belongs to in-kernel static percpu area. Module
1289 * static percpu areas are not considered. For those, use
1290 * is_module_percpu_address().
1293 * %true if @addr is from in-kernel static percpu area, %false otherwise.
1295 bool is_kernel_percpu_address(unsigned long addr
)
1298 const size_t static_size
= __per_cpu_end
- __per_cpu_start
;
1299 void __percpu
*base
= __addr_to_pcpu_ptr(pcpu_base_addr
);
1302 for_each_possible_cpu(cpu
) {
1303 void *start
= per_cpu_ptr(base
, cpu
);
1305 if ((void *)addr
>= start
&& (void *)addr
< start
+ static_size
)
1309 /* on UP, can't distinguish from other static vars, always false */
1314 * per_cpu_ptr_to_phys - convert translated percpu address to physical address
1315 * @addr: the address to be converted to physical address
1317 * Given @addr which is dereferenceable address obtained via one of
1318 * percpu access macros, this function translates it into its physical
1319 * address. The caller is responsible for ensuring @addr stays valid
1320 * until this function finishes.
1322 * percpu allocator has special setup for the first chunk, which currently
1323 * supports either embedding in linear address space or vmalloc mapping,
1324 * and, from the second one, the backing allocator (currently either vm or
1325 * km) provides translation.
1327 * The addr can be translated simply without checking if it falls into the
1328 * first chunk. But the current code reflects better how percpu allocator
1329 * actually works, and the verification can discover both bugs in percpu
1330 * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
1334 * The physical address for @addr.
1336 phys_addr_t
per_cpu_ptr_to_phys(void *addr
)
1338 void __percpu
*base
= __addr_to_pcpu_ptr(pcpu_base_addr
);
1339 bool in_first_chunk
= false;
1340 unsigned long first_low
, first_high
;
1344 * The following test on unit_low/high isn't strictly
1345 * necessary but will speed up lookups of addresses which
1346 * aren't in the first chunk.
1348 first_low
= pcpu_chunk_addr(pcpu_first_chunk
, pcpu_low_unit_cpu
, 0);
1349 first_high
= pcpu_chunk_addr(pcpu_first_chunk
, pcpu_high_unit_cpu
,
1351 if ((unsigned long)addr
>= first_low
&&
1352 (unsigned long)addr
< first_high
) {
1353 for_each_possible_cpu(cpu
) {
1354 void *start
= per_cpu_ptr(base
, cpu
);
1356 if (addr
>= start
&& addr
< start
+ pcpu_unit_size
) {
1357 in_first_chunk
= true;
1363 if (in_first_chunk
) {
1364 if (!is_vmalloc_addr(addr
))
1367 return page_to_phys(vmalloc_to_page(addr
)) +
1368 offset_in_page(addr
);
1370 return page_to_phys(pcpu_addr_to_page(addr
)) +
1371 offset_in_page(addr
);
1375 * pcpu_alloc_alloc_info - allocate percpu allocation info
1376 * @nr_groups: the number of groups
1377 * @nr_units: the number of units
1379 * Allocate ai which is large enough for @nr_groups groups containing
1380 * @nr_units units. The returned ai's groups[0].cpu_map points to the
1381 * cpu_map array which is long enough for @nr_units and filled with
1382 * NR_CPUS. It's the caller's responsibility to initialize cpu_map
1383 * pointer of other groups.
1386 * Pointer to the allocated pcpu_alloc_info on success, NULL on
1389 struct pcpu_alloc_info
* __init
pcpu_alloc_alloc_info(int nr_groups
,
1392 struct pcpu_alloc_info
*ai
;
1393 size_t base_size
, ai_size
;
1397 base_size
= ALIGN(sizeof(*ai
) + nr_groups
* sizeof(ai
->groups
[0]),
1398 __alignof__(ai
->groups
[0].cpu_map
[0]));
1399 ai_size
= base_size
+ nr_units
* sizeof(ai
->groups
[0].cpu_map
[0]);
1401 ptr
= memblock_virt_alloc_nopanic(PFN_ALIGN(ai_size
), 0);
1407 ai
->groups
[0].cpu_map
= ptr
;
1409 for (unit
= 0; unit
< nr_units
; unit
++)
1410 ai
->groups
[0].cpu_map
[unit
] = NR_CPUS
;
1412 ai
->nr_groups
= nr_groups
;
1413 ai
->__ai_size
= PFN_ALIGN(ai_size
);
1419 * pcpu_free_alloc_info - free percpu allocation info
1420 * @ai: pcpu_alloc_info to free
1422 * Free @ai which was allocated by pcpu_alloc_alloc_info().
1424 void __init
pcpu_free_alloc_info(struct pcpu_alloc_info
*ai
)
1426 memblock_free_early(__pa(ai
), ai
->__ai_size
);
1430 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
1432 * @ai: allocation info to dump
1434 * Print out information about @ai using loglevel @lvl.
1436 static void pcpu_dump_alloc_info(const char *lvl
,
1437 const struct pcpu_alloc_info
*ai
)
1439 int group_width
= 1, cpu_width
= 1, width
;
1440 char empty_str
[] = "--------";
1441 int alloc
= 0, alloc_end
= 0;
1443 int upa
, apl
; /* units per alloc, allocs per line */
1449 v
= num_possible_cpus();
1452 empty_str
[min_t(int, cpu_width
, sizeof(empty_str
) - 1)] = '\0';
1454 upa
= ai
->alloc_size
/ ai
->unit_size
;
1455 width
= upa
* (cpu_width
+ 1) + group_width
+ 3;
1456 apl
= rounddown_pow_of_two(max(60 / width
, 1));
1458 printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
1459 lvl
, ai
->static_size
, ai
->reserved_size
, ai
->dyn_size
,
1460 ai
->unit_size
, ai
->alloc_size
/ ai
->atom_size
, ai
->atom_size
);
1462 for (group
= 0; group
< ai
->nr_groups
; group
++) {
1463 const struct pcpu_group_info
*gi
= &ai
->groups
[group
];
1464 int unit
= 0, unit_end
= 0;
1466 BUG_ON(gi
->nr_units
% upa
);
1467 for (alloc_end
+= gi
->nr_units
/ upa
;
1468 alloc
< alloc_end
; alloc
++) {
1469 if (!(alloc
% apl
)) {
1471 printk("%spcpu-alloc: ", lvl
);
1473 pr_cont("[%0*d] ", group_width
, group
);
1475 for (unit_end
+= upa
; unit
< unit_end
; unit
++)
1476 if (gi
->cpu_map
[unit
] != NR_CPUS
)
1478 cpu_width
, gi
->cpu_map
[unit
]);
1480 pr_cont("%s ", empty_str
);
1487 * pcpu_setup_first_chunk - initialize the first percpu chunk
1488 * @ai: pcpu_alloc_info describing how to percpu area is shaped
1489 * @base_addr: mapped address
1491 * Initialize the first percpu chunk which contains the kernel static
1492 * perpcu area. This function is to be called from arch percpu area
1495 * @ai contains all information necessary to initialize the first
1496 * chunk and prime the dynamic percpu allocator.
1498 * @ai->static_size is the size of static percpu area.
1500 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
1501 * reserve after the static area in the first chunk. This reserves
1502 * the first chunk such that it's available only through reserved
1503 * percpu allocation. This is primarily used to serve module percpu
1504 * static areas on architectures where the addressing model has
1505 * limited offset range for symbol relocations to guarantee module
1506 * percpu symbols fall inside the relocatable range.
1508 * @ai->dyn_size determines the number of bytes available for dynamic
1509 * allocation in the first chunk. The area between @ai->static_size +
1510 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
1512 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
1513 * and equal to or larger than @ai->static_size + @ai->reserved_size +
1516 * @ai->atom_size is the allocation atom size and used as alignment
1519 * @ai->alloc_size is the allocation size and always multiple of
1520 * @ai->atom_size. This is larger than @ai->atom_size if
1521 * @ai->unit_size is larger than @ai->atom_size.
1523 * @ai->nr_groups and @ai->groups describe virtual memory layout of
1524 * percpu areas. Units which should be colocated are put into the
1525 * same group. Dynamic VM areas will be allocated according to these
1526 * groupings. If @ai->nr_groups is zero, a single group containing
1527 * all units is assumed.
1529 * The caller should have mapped the first chunk at @base_addr and
1530 * copied static data to each unit.
1532 * If the first chunk ends up with both reserved and dynamic areas, it
1533 * is served by two chunks - one to serve the core static and reserved
1534 * areas and the other for the dynamic area. They share the same vm
1535 * and page map but uses different area allocation map to stay away
1536 * from each other. The latter chunk is circulated in the chunk slots
1537 * and available for dynamic allocation like any other chunks.
1540 * 0 on success, -errno on failure.
1542 int __init
pcpu_setup_first_chunk(const struct pcpu_alloc_info
*ai
,
1545 static int smap
[PERCPU_DYNAMIC_EARLY_SLOTS
] __initdata
;
1546 static int dmap
[PERCPU_DYNAMIC_EARLY_SLOTS
] __initdata
;
1547 size_t dyn_size
= ai
->dyn_size
;
1548 size_t size_sum
= ai
->static_size
+ ai
->reserved_size
+ dyn_size
;
1549 struct pcpu_chunk
*schunk
, *dchunk
= NULL
;
1550 unsigned long *group_offsets
;
1551 size_t *group_sizes
;
1552 unsigned long *unit_off
;
1557 #define PCPU_SETUP_BUG_ON(cond) do { \
1558 if (unlikely(cond)) { \
1559 pr_emerg("failed to initialize, %s\n", #cond); \
1560 pr_emerg("cpu_possible_mask=%*pb\n", \
1561 cpumask_pr_args(cpu_possible_mask)); \
1562 pcpu_dump_alloc_info(KERN_EMERG, ai); \
1568 PCPU_SETUP_BUG_ON(ai
->nr_groups
<= 0);
1570 PCPU_SETUP_BUG_ON(!ai
->static_size
);
1571 PCPU_SETUP_BUG_ON(offset_in_page(__per_cpu_start
));
1573 PCPU_SETUP_BUG_ON(!base_addr
);
1574 PCPU_SETUP_BUG_ON(offset_in_page(base_addr
));
1575 PCPU_SETUP_BUG_ON(ai
->unit_size
< size_sum
);
1576 PCPU_SETUP_BUG_ON(offset_in_page(ai
->unit_size
));
1577 PCPU_SETUP_BUG_ON(ai
->unit_size
< PCPU_MIN_UNIT_SIZE
);
1578 PCPU_SETUP_BUG_ON(ai
->dyn_size
< PERCPU_DYNAMIC_EARLY_SIZE
);
1579 PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai
) < 0);
1581 /* process group information and build config tables accordingly */
1582 group_offsets
= memblock_virt_alloc(ai
->nr_groups
*
1583 sizeof(group_offsets
[0]), 0);
1584 group_sizes
= memblock_virt_alloc(ai
->nr_groups
*
1585 sizeof(group_sizes
[0]), 0);
1586 unit_map
= memblock_virt_alloc(nr_cpu_ids
* sizeof(unit_map
[0]), 0);
1587 unit_off
= memblock_virt_alloc(nr_cpu_ids
* sizeof(unit_off
[0]), 0);
1589 for (cpu
= 0; cpu
< nr_cpu_ids
; cpu
++)
1590 unit_map
[cpu
] = UINT_MAX
;
1592 pcpu_low_unit_cpu
= NR_CPUS
;
1593 pcpu_high_unit_cpu
= NR_CPUS
;
1595 for (group
= 0, unit
= 0; group
< ai
->nr_groups
; group
++, unit
+= i
) {
1596 const struct pcpu_group_info
*gi
= &ai
->groups
[group
];
1598 group_offsets
[group
] = gi
->base_offset
;
1599 group_sizes
[group
] = gi
->nr_units
* ai
->unit_size
;
1601 for (i
= 0; i
< gi
->nr_units
; i
++) {
1602 cpu
= gi
->cpu_map
[i
];
1606 PCPU_SETUP_BUG_ON(cpu
>= nr_cpu_ids
);
1607 PCPU_SETUP_BUG_ON(!cpu_possible(cpu
));
1608 PCPU_SETUP_BUG_ON(unit_map
[cpu
] != UINT_MAX
);
1610 unit_map
[cpu
] = unit
+ i
;
1611 unit_off
[cpu
] = gi
->base_offset
+ i
* ai
->unit_size
;
1613 /* determine low/high unit_cpu */
1614 if (pcpu_low_unit_cpu
== NR_CPUS
||
1615 unit_off
[cpu
] < unit_off
[pcpu_low_unit_cpu
])
1616 pcpu_low_unit_cpu
= cpu
;
1617 if (pcpu_high_unit_cpu
== NR_CPUS
||
1618 unit_off
[cpu
] > unit_off
[pcpu_high_unit_cpu
])
1619 pcpu_high_unit_cpu
= cpu
;
1622 pcpu_nr_units
= unit
;
1624 for_each_possible_cpu(cpu
)
1625 PCPU_SETUP_BUG_ON(unit_map
[cpu
] == UINT_MAX
);
1627 /* we're done parsing the input, undefine BUG macro and dump config */
1628 #undef PCPU_SETUP_BUG_ON
1629 pcpu_dump_alloc_info(KERN_DEBUG
, ai
);
1631 pcpu_nr_groups
= ai
->nr_groups
;
1632 pcpu_group_offsets
= group_offsets
;
1633 pcpu_group_sizes
= group_sizes
;
1634 pcpu_unit_map
= unit_map
;
1635 pcpu_unit_offsets
= unit_off
;
1637 /* determine basic parameters */
1638 pcpu_unit_pages
= ai
->unit_size
>> PAGE_SHIFT
;
1639 pcpu_unit_size
= pcpu_unit_pages
<< PAGE_SHIFT
;
1640 pcpu_atom_size
= ai
->atom_size
;
1641 pcpu_chunk_struct_size
= sizeof(struct pcpu_chunk
) +
1642 BITS_TO_LONGS(pcpu_unit_pages
) * sizeof(unsigned long);
1645 * Allocate chunk slots. The additional last slot is for
1648 pcpu_nr_slots
= __pcpu_size_to_slot(pcpu_unit_size
) + 2;
1649 pcpu_slot
= memblock_virt_alloc(
1650 pcpu_nr_slots
* sizeof(pcpu_slot
[0]), 0);
1651 for (i
= 0; i
< pcpu_nr_slots
; i
++)
1652 INIT_LIST_HEAD(&pcpu_slot
[i
]);
1655 * Initialize static chunk. If reserved_size is zero, the
1656 * static chunk covers static area + dynamic allocation area
1657 * in the first chunk. If reserved_size is not zero, it
1658 * covers static area + reserved area (mostly used for module
1659 * static percpu allocation).
1661 schunk
= memblock_virt_alloc(pcpu_chunk_struct_size
, 0);
1662 INIT_LIST_HEAD(&schunk
->list
);
1663 INIT_LIST_HEAD(&schunk
->map_extend_list
);
1664 schunk
->base_addr
= base_addr
;
1666 schunk
->map_alloc
= ARRAY_SIZE(smap
);
1667 schunk
->immutable
= true;
1668 bitmap_fill(schunk
->populated
, pcpu_unit_pages
);
1669 schunk
->nr_populated
= pcpu_unit_pages
;
1671 if (ai
->reserved_size
) {
1672 schunk
->free_size
= ai
->reserved_size
;
1673 pcpu_reserved_chunk
= schunk
;
1674 pcpu_reserved_chunk_limit
= ai
->static_size
+ ai
->reserved_size
;
1676 schunk
->free_size
= dyn_size
;
1677 dyn_size
= 0; /* dynamic area covered */
1679 schunk
->contig_hint
= schunk
->free_size
;
1682 schunk
->map
[1] = ai
->static_size
;
1683 schunk
->map_used
= 1;
1684 if (schunk
->free_size
)
1685 schunk
->map
[++schunk
->map_used
] = ai
->static_size
+ schunk
->free_size
;
1686 schunk
->map
[schunk
->map_used
] |= 1;
1688 /* init dynamic chunk if necessary */
1690 dchunk
= memblock_virt_alloc(pcpu_chunk_struct_size
, 0);
1691 INIT_LIST_HEAD(&dchunk
->list
);
1692 INIT_LIST_HEAD(&dchunk
->map_extend_list
);
1693 dchunk
->base_addr
= base_addr
;
1695 dchunk
->map_alloc
= ARRAY_SIZE(dmap
);
1696 dchunk
->immutable
= true;
1697 bitmap_fill(dchunk
->populated
, pcpu_unit_pages
);
1698 dchunk
->nr_populated
= pcpu_unit_pages
;
1700 dchunk
->contig_hint
= dchunk
->free_size
= dyn_size
;
1702 dchunk
->map
[1] = pcpu_reserved_chunk_limit
;
1703 dchunk
->map
[2] = (pcpu_reserved_chunk_limit
+ dchunk
->free_size
) | 1;
1704 dchunk
->map_used
= 2;
1707 /* link the first chunk in */
1708 pcpu_first_chunk
= dchunk
?: schunk
;
1709 pcpu_nr_empty_pop_pages
+=
1710 pcpu_count_occupied_pages(pcpu_first_chunk
, 1);
1711 pcpu_chunk_relocate(pcpu_first_chunk
, -1);
1714 pcpu_base_addr
= base_addr
;
1720 const char * const pcpu_fc_names
[PCPU_FC_NR
] __initconst
= {
1721 [PCPU_FC_AUTO
] = "auto",
1722 [PCPU_FC_EMBED
] = "embed",
1723 [PCPU_FC_PAGE
] = "page",
1726 enum pcpu_fc pcpu_chosen_fc __initdata
= PCPU_FC_AUTO
;
1728 static int __init
percpu_alloc_setup(char *str
)
1735 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
1736 else if (!strcmp(str
, "embed"))
1737 pcpu_chosen_fc
= PCPU_FC_EMBED
;
1739 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1740 else if (!strcmp(str
, "page"))
1741 pcpu_chosen_fc
= PCPU_FC_PAGE
;
1744 pr_warn("unknown allocator %s specified\n", str
);
1748 early_param("percpu_alloc", percpu_alloc_setup
);
1751 * pcpu_embed_first_chunk() is used by the generic percpu setup.
1752 * Build it if needed by the arch config or the generic setup is going
1755 #if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
1756 !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
1757 #define BUILD_EMBED_FIRST_CHUNK
1760 /* build pcpu_page_first_chunk() iff needed by the arch config */
1761 #if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
1762 #define BUILD_PAGE_FIRST_CHUNK
1765 /* pcpu_build_alloc_info() is used by both embed and page first chunk */
1766 #if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
1768 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
1769 * @reserved_size: the size of reserved percpu area in bytes
1770 * @dyn_size: minimum free size for dynamic allocation in bytes
1771 * @atom_size: allocation atom size
1772 * @cpu_distance_fn: callback to determine distance between cpus, optional
1774 * This function determines grouping of units, their mappings to cpus
1775 * and other parameters considering needed percpu size, allocation
1776 * atom size and distances between CPUs.
1778 * Groups are always multiples of atom size and CPUs which are of
1779 * LOCAL_DISTANCE both ways are grouped together and share space for
1780 * units in the same group. The returned configuration is guaranteed
1781 * to have CPUs on different nodes on different groups and >=75% usage
1782 * of allocated virtual address space.
1785 * On success, pointer to the new allocation_info is returned. On
1786 * failure, ERR_PTR value is returned.
1788 static struct pcpu_alloc_info
* __init
pcpu_build_alloc_info(
1789 size_t reserved_size
, size_t dyn_size
,
1791 pcpu_fc_cpu_distance_fn_t cpu_distance_fn
)
1793 static int group_map
[NR_CPUS
] __initdata
;
1794 static int group_cnt
[NR_CPUS
] __initdata
;
1795 const size_t static_size
= __per_cpu_end
- __per_cpu_start
;
1796 int nr_groups
= 1, nr_units
= 0;
1797 size_t size_sum
, min_unit_size
, alloc_size
;
1798 int upa
, max_upa
, uninitialized_var(best_upa
); /* units_per_alloc */
1799 int last_allocs
, group
, unit
;
1800 unsigned int cpu
, tcpu
;
1801 struct pcpu_alloc_info
*ai
;
1802 unsigned int *cpu_map
;
1804 /* this function may be called multiple times */
1805 memset(group_map
, 0, sizeof(group_map
));
1806 memset(group_cnt
, 0, sizeof(group_cnt
));
1808 /* calculate size_sum and ensure dyn_size is enough for early alloc */
1809 size_sum
= PFN_ALIGN(static_size
+ reserved_size
+
1810 max_t(size_t, dyn_size
, PERCPU_DYNAMIC_EARLY_SIZE
));
1811 dyn_size
= size_sum
- static_size
- reserved_size
;
1814 * Determine min_unit_size, alloc_size and max_upa such that
1815 * alloc_size is multiple of atom_size and is the smallest
1816 * which can accommodate 4k aligned segments which are equal to
1817 * or larger than min_unit_size.
1819 min_unit_size
= max_t(size_t, size_sum
, PCPU_MIN_UNIT_SIZE
);
1821 alloc_size
= roundup(min_unit_size
, atom_size
);
1822 upa
= alloc_size
/ min_unit_size
;
1823 while (alloc_size
% upa
|| (offset_in_page(alloc_size
/ upa
)))
1827 /* group cpus according to their proximity */
1828 for_each_possible_cpu(cpu
) {
1831 for_each_possible_cpu(tcpu
) {
1834 if (group_map
[tcpu
] == group
&& cpu_distance_fn
&&
1835 (cpu_distance_fn(cpu
, tcpu
) > LOCAL_DISTANCE
||
1836 cpu_distance_fn(tcpu
, cpu
) > LOCAL_DISTANCE
)) {
1838 nr_groups
= max(nr_groups
, group
+ 1);
1842 group_map
[cpu
] = group
;
1847 * Expand unit size until address space usage goes over 75%
1848 * and then as much as possible without using more address
1851 last_allocs
= INT_MAX
;
1852 for (upa
= max_upa
; upa
; upa
--) {
1853 int allocs
= 0, wasted
= 0;
1855 if (alloc_size
% upa
|| (offset_in_page(alloc_size
/ upa
)))
1858 for (group
= 0; group
< nr_groups
; group
++) {
1859 int this_allocs
= DIV_ROUND_UP(group_cnt
[group
], upa
);
1860 allocs
+= this_allocs
;
1861 wasted
+= this_allocs
* upa
- group_cnt
[group
];
1865 * Don't accept if wastage is over 1/3. The
1866 * greater-than comparison ensures upa==1 always
1867 * passes the following check.
1869 if (wasted
> num_possible_cpus() / 3)
1872 /* and then don't consume more memory */
1873 if (allocs
> last_allocs
)
1875 last_allocs
= allocs
;
1880 /* allocate and fill alloc_info */
1881 for (group
= 0; group
< nr_groups
; group
++)
1882 nr_units
+= roundup(group_cnt
[group
], upa
);
1884 ai
= pcpu_alloc_alloc_info(nr_groups
, nr_units
);
1886 return ERR_PTR(-ENOMEM
);
1887 cpu_map
= ai
->groups
[0].cpu_map
;
1889 for (group
= 0; group
< nr_groups
; group
++) {
1890 ai
->groups
[group
].cpu_map
= cpu_map
;
1891 cpu_map
+= roundup(group_cnt
[group
], upa
);
1894 ai
->static_size
= static_size
;
1895 ai
->reserved_size
= reserved_size
;
1896 ai
->dyn_size
= dyn_size
;
1897 ai
->unit_size
= alloc_size
/ upa
;
1898 ai
->atom_size
= atom_size
;
1899 ai
->alloc_size
= alloc_size
;
1901 for (group
= 0, unit
= 0; group_cnt
[group
]; group
++) {
1902 struct pcpu_group_info
*gi
= &ai
->groups
[group
];
1905 * Initialize base_offset as if all groups are located
1906 * back-to-back. The caller should update this to
1907 * reflect actual allocation.
1909 gi
->base_offset
= unit
* ai
->unit_size
;
1911 for_each_possible_cpu(cpu
)
1912 if (group_map
[cpu
] == group
)
1913 gi
->cpu_map
[gi
->nr_units
++] = cpu
;
1914 gi
->nr_units
= roundup(gi
->nr_units
, upa
);
1915 unit
+= gi
->nr_units
;
1917 BUG_ON(unit
!= nr_units
);
1921 #endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
1923 #if defined(BUILD_EMBED_FIRST_CHUNK)
1925 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
1926 * @reserved_size: the size of reserved percpu area in bytes
1927 * @dyn_size: minimum free size for dynamic allocation in bytes
1928 * @atom_size: allocation atom size
1929 * @cpu_distance_fn: callback to determine distance between cpus, optional
1930 * @alloc_fn: function to allocate percpu page
1931 * @free_fn: function to free percpu page
1933 * This is a helper to ease setting up embedded first percpu chunk and
1934 * can be called where pcpu_setup_first_chunk() is expected.
1936 * If this function is used to setup the first chunk, it is allocated
1937 * by calling @alloc_fn and used as-is without being mapped into
1938 * vmalloc area. Allocations are always whole multiples of @atom_size
1939 * aligned to @atom_size.
1941 * This enables the first chunk to piggy back on the linear physical
1942 * mapping which often uses larger page size. Please note that this
1943 * can result in very sparse cpu->unit mapping on NUMA machines thus
1944 * requiring large vmalloc address space. Don't use this allocator if
1945 * vmalloc space is not orders of magnitude larger than distances
1946 * between node memory addresses (ie. 32bit NUMA machines).
1948 * @dyn_size specifies the minimum dynamic area size.
1950 * If the needed size is smaller than the minimum or specified unit
1951 * size, the leftover is returned using @free_fn.
1954 * 0 on success, -errno on failure.
1956 int __init
pcpu_embed_first_chunk(size_t reserved_size
, size_t dyn_size
,
1958 pcpu_fc_cpu_distance_fn_t cpu_distance_fn
,
1959 pcpu_fc_alloc_fn_t alloc_fn
,
1960 pcpu_fc_free_fn_t free_fn
)
1962 void *base
= (void *)ULONG_MAX
;
1963 void **areas
= NULL
;
1964 struct pcpu_alloc_info
*ai
;
1965 size_t size_sum
, areas_size
;
1966 unsigned long max_distance
;
1967 int group
, i
, highest_group
, rc
;
1969 ai
= pcpu_build_alloc_info(reserved_size
, dyn_size
, atom_size
,
1974 size_sum
= ai
->static_size
+ ai
->reserved_size
+ ai
->dyn_size
;
1975 areas_size
= PFN_ALIGN(ai
->nr_groups
* sizeof(void *));
1977 areas
= memblock_virt_alloc_nopanic(areas_size
, 0);
1983 /* allocate, copy and determine base address & max_distance */
1985 for (group
= 0; group
< ai
->nr_groups
; group
++) {
1986 struct pcpu_group_info
*gi
= &ai
->groups
[group
];
1987 unsigned int cpu
= NR_CPUS
;
1990 for (i
= 0; i
< gi
->nr_units
&& cpu
== NR_CPUS
; i
++)
1991 cpu
= gi
->cpu_map
[i
];
1992 BUG_ON(cpu
== NR_CPUS
);
1994 /* allocate space for the whole group */
1995 ptr
= alloc_fn(cpu
, gi
->nr_units
* ai
->unit_size
, atom_size
);
1998 goto out_free_areas
;
2000 /* kmemleak tracks the percpu allocations separately */
2004 base
= min(ptr
, base
);
2005 if (ptr
> areas
[highest_group
])
2006 highest_group
= group
;
2008 max_distance
= areas
[highest_group
] - base
;
2009 max_distance
+= ai
->unit_size
* ai
->groups
[highest_group
].nr_units
;
2011 /* warn if maximum distance is further than 75% of vmalloc space */
2012 if (max_distance
> VMALLOC_TOTAL
* 3 / 4) {
2013 pr_warn("max_distance=0x%lx too large for vmalloc space 0x%lx\n",
2014 max_distance
, VMALLOC_TOTAL
);
2015 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
2016 /* and fail if we have fallback */
2018 goto out_free_areas
;
2023 * Copy data and free unused parts. This should happen after all
2024 * allocations are complete; otherwise, we may end up with
2025 * overlapping groups.
2027 for (group
= 0; group
< ai
->nr_groups
; group
++) {
2028 struct pcpu_group_info
*gi
= &ai
->groups
[group
];
2029 void *ptr
= areas
[group
];
2031 for (i
= 0; i
< gi
->nr_units
; i
++, ptr
+= ai
->unit_size
) {
2032 if (gi
->cpu_map
[i
] == NR_CPUS
) {
2033 /* unused unit, free whole */
2034 free_fn(ptr
, ai
->unit_size
);
2037 /* copy and return the unused part */
2038 memcpy(ptr
, __per_cpu_load
, ai
->static_size
);
2039 free_fn(ptr
+ size_sum
, ai
->unit_size
- size_sum
);
2043 /* base address is now known, determine group base offsets */
2044 for (group
= 0; group
< ai
->nr_groups
; group
++) {
2045 ai
->groups
[group
].base_offset
= areas
[group
] - base
;
2048 pr_info("Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
2049 PFN_DOWN(size_sum
), base
, ai
->static_size
, ai
->reserved_size
,
2050 ai
->dyn_size
, ai
->unit_size
);
2052 rc
= pcpu_setup_first_chunk(ai
, base
);
2056 for (group
= 0; group
< ai
->nr_groups
; group
++)
2058 free_fn(areas
[group
],
2059 ai
->groups
[group
].nr_units
* ai
->unit_size
);
2061 pcpu_free_alloc_info(ai
);
2063 memblock_free_early(__pa(areas
), areas_size
);
2066 #endif /* BUILD_EMBED_FIRST_CHUNK */
2068 #ifdef BUILD_PAGE_FIRST_CHUNK
2070 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
2071 * @reserved_size: the size of reserved percpu area in bytes
2072 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
2073 * @free_fn: function to free percpu page, always called with PAGE_SIZE
2074 * @populate_pte_fn: function to populate pte
2076 * This is a helper to ease setting up page-remapped first percpu
2077 * chunk and can be called where pcpu_setup_first_chunk() is expected.
2079 * This is the basic allocator. Static percpu area is allocated
2080 * page-by-page into vmalloc area.
2083 * 0 on success, -errno on failure.
2085 int __init
pcpu_page_first_chunk(size_t reserved_size
,
2086 pcpu_fc_alloc_fn_t alloc_fn
,
2087 pcpu_fc_free_fn_t free_fn
,
2088 pcpu_fc_populate_pte_fn_t populate_pte_fn
)
2090 static struct vm_struct vm
;
2091 struct pcpu_alloc_info
*ai
;
2095 struct page
**pages
;
2100 snprintf(psize_str
, sizeof(psize_str
), "%luK", PAGE_SIZE
>> 10);
2102 ai
= pcpu_build_alloc_info(reserved_size
, 0, PAGE_SIZE
, NULL
);
2105 BUG_ON(ai
->nr_groups
!= 1);
2106 upa
= ai
->alloc_size
/ai
->unit_size
;
2107 nr_g0_units
= roundup(num_possible_cpus(), upa
);
2108 if (unlikely(WARN_ON(ai
->groups
[0].nr_units
!= nr_g0_units
))) {
2109 pcpu_free_alloc_info(ai
);
2113 unit_pages
= ai
->unit_size
>> PAGE_SHIFT
;
2115 /* unaligned allocations can't be freed, round up to page size */
2116 pages_size
= PFN_ALIGN(unit_pages
* num_possible_cpus() *
2118 pages
= memblock_virt_alloc(pages_size
, 0);
2120 /* allocate pages */
2122 for (unit
= 0; unit
< num_possible_cpus(); unit
++) {
2123 unsigned int cpu
= ai
->groups
[0].cpu_map
[unit
];
2124 for (i
= 0; i
< unit_pages
; i
++) {
2127 ptr
= alloc_fn(cpu
, PAGE_SIZE
, PAGE_SIZE
);
2129 pr_warn("failed to allocate %s page for cpu%u\n",
2133 /* kmemleak tracks the percpu allocations separately */
2135 pages
[j
++] = virt_to_page(ptr
);
2139 /* allocate vm area, map the pages and copy static data */
2140 vm
.flags
= VM_ALLOC
;
2141 vm
.size
= num_possible_cpus() * ai
->unit_size
;
2142 vm_area_register_early(&vm
, PAGE_SIZE
);
2144 for (unit
= 0; unit
< num_possible_cpus(); unit
++) {
2145 unsigned long unit_addr
=
2146 (unsigned long)vm
.addr
+ unit
* ai
->unit_size
;
2148 for (i
= 0; i
< unit_pages
; i
++)
2149 populate_pte_fn(unit_addr
+ (i
<< PAGE_SHIFT
));
2151 /* pte already populated, the following shouldn't fail */
2152 rc
= __pcpu_map_pages(unit_addr
, &pages
[unit
* unit_pages
],
2155 panic("failed to map percpu area, err=%d\n", rc
);
2158 * FIXME: Archs with virtual cache should flush local
2159 * cache for the linear mapping here - something
2160 * equivalent to flush_cache_vmap() on the local cpu.
2161 * flush_cache_vmap() can't be used as most supporting
2162 * data structures are not set up yet.
2165 /* copy static data */
2166 memcpy((void *)unit_addr
, __per_cpu_load
, ai
->static_size
);
2169 /* we're ready, commit */
2170 pr_info("%d %s pages/cpu @%p s%zu r%zu d%zu\n",
2171 unit_pages
, psize_str
, vm
.addr
, ai
->static_size
,
2172 ai
->reserved_size
, ai
->dyn_size
);
2174 rc
= pcpu_setup_first_chunk(ai
, vm
.addr
);
2179 free_fn(page_address(pages
[j
]), PAGE_SIZE
);
2182 memblock_free_early(__pa(pages
), pages_size
);
2183 pcpu_free_alloc_info(ai
);
2186 #endif /* BUILD_PAGE_FIRST_CHUNK */
2188 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
2190 * Generic SMP percpu area setup.
2192 * The embedding helper is used because its behavior closely resembles
2193 * the original non-dynamic generic percpu area setup. This is
2194 * important because many archs have addressing restrictions and might
2195 * fail if the percpu area is located far away from the previous
2196 * location. As an added bonus, in non-NUMA cases, embedding is
2197 * generally a good idea TLB-wise because percpu area can piggy back
2198 * on the physical linear memory mapping which uses large page
2199 * mappings on applicable archs.
2201 unsigned long __per_cpu_offset
[NR_CPUS
] __read_mostly
;
2202 EXPORT_SYMBOL(__per_cpu_offset
);
2204 static void * __init
pcpu_dfl_fc_alloc(unsigned int cpu
, size_t size
,
2207 return memblock_virt_alloc_from_nopanic(
2208 size
, align
, __pa(MAX_DMA_ADDRESS
));
2211 static void __init
pcpu_dfl_fc_free(void *ptr
, size_t size
)
2213 memblock_free_early(__pa(ptr
), size
);
2216 void __init
setup_per_cpu_areas(void)
2218 unsigned long delta
;
2223 * Always reserve area for module percpu variables. That's
2224 * what the legacy allocator did.
2226 rc
= pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE
,
2227 PERCPU_DYNAMIC_RESERVE
, PAGE_SIZE
, NULL
,
2228 pcpu_dfl_fc_alloc
, pcpu_dfl_fc_free
);
2230 panic("Failed to initialize percpu areas.");
2232 delta
= (unsigned long)pcpu_base_addr
- (unsigned long)__per_cpu_start
;
2233 for_each_possible_cpu(cpu
)
2234 __per_cpu_offset
[cpu
] = delta
+ pcpu_unit_offsets
[cpu
];
2236 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
2238 #else /* CONFIG_SMP */
2241 * UP percpu area setup.
2243 * UP always uses km-based percpu allocator with identity mapping.
2244 * Static percpu variables are indistinguishable from the usual static
2245 * variables and don't require any special preparation.
2247 void __init
setup_per_cpu_areas(void)
2249 const size_t unit_size
=
2250 roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE
,
2251 PERCPU_DYNAMIC_RESERVE
));
2252 struct pcpu_alloc_info
*ai
;
2255 ai
= pcpu_alloc_alloc_info(1, 1);
2256 fc
= memblock_virt_alloc_from_nopanic(unit_size
,
2258 __pa(MAX_DMA_ADDRESS
));
2260 panic("Failed to allocate memory for percpu areas.");
2261 /* kmemleak tracks the percpu allocations separately */
2264 ai
->dyn_size
= unit_size
;
2265 ai
->unit_size
= unit_size
;
2266 ai
->atom_size
= unit_size
;
2267 ai
->alloc_size
= unit_size
;
2268 ai
->groups
[0].nr_units
= 1;
2269 ai
->groups
[0].cpu_map
[0] = 0;
2271 if (pcpu_setup_first_chunk(ai
, fc
) < 0)
2272 panic("Failed to initialize percpu areas.");
2275 #endif /* CONFIG_SMP */
2278 * First and reserved chunks are initialized with temporary allocation
2279 * map in initdata so that they can be used before slab is online.
2280 * This function is called after slab is brought up and replaces those
2281 * with properly allocated maps.
2283 void __init
percpu_init_late(void)
2285 struct pcpu_chunk
*target_chunks
[] =
2286 { pcpu_first_chunk
, pcpu_reserved_chunk
, NULL
};
2287 struct pcpu_chunk
*chunk
;
2288 unsigned long flags
;
2291 for (i
= 0; (chunk
= target_chunks
[i
]); i
++) {
2293 const size_t size
= PERCPU_DYNAMIC_EARLY_SLOTS
* sizeof(map
[0]);
2295 BUILD_BUG_ON(size
> PAGE_SIZE
);
2297 map
= pcpu_mem_zalloc(size
);
2300 spin_lock_irqsave(&pcpu_lock
, flags
);
2301 memcpy(map
, chunk
->map
, size
);
2303 spin_unlock_irqrestore(&pcpu_lock
, flags
);
2308 * Percpu allocator is initialized early during boot when neither slab or
2309 * workqueue is available. Plug async management until everything is up
2312 static int __init
percpu_enable_async(void)
2314 pcpu_async_enabled
= true;
2317 subsys_initcall(percpu_enable_async
);