Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-only
2 : /*
3 : * mm/percpu.c - percpu memory allocator
4 : *
5 : * Copyright (C) 2009 SUSE Linux Products GmbH
6 : * Copyright (C) 2009 Tejun Heo <tj@kernel.org>
7 : *
8 : * Copyright (C) 2017 Facebook Inc.
9 : * Copyright (C) 2017 Dennis Zhou <dennis@kernel.org>
10 : *
11 : * The percpu allocator handles both static and dynamic areas. Percpu
12 : * areas are allocated in chunks which are divided into units. There is
13 : * a 1-to-1 mapping for units to possible cpus. These units are grouped
14 : * based on NUMA properties of the machine.
15 : *
16 : * c0 c1 c2
17 : * ------------------- ------------------- ------------
18 : * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
19 : * ------------------- ...... ------------------- .... ------------
20 : *
21 : * Allocation is done by offsets into a unit's address space. Ie., an
22 : * area of 512 bytes at 6k in c1 occupies 512 bytes at 6k in c1:u0,
23 : * c1:u1, c1:u2, etc. On NUMA machines, the mapping may be non-linear
24 : * and even sparse. Access is handled by configuring percpu base
25 : * registers according to the cpu to unit mappings and offsetting the
26 : * base address using pcpu_unit_size.
27 : *
28 : * There is special consideration for the first chunk which must handle
29 : * the static percpu variables in the kernel image as allocation services
30 : * are not online yet. In short, the first chunk is structured like so:
31 : *
32 : * <Static | [Reserved] | Dynamic>
33 : *
34 : * The static data is copied from the original section managed by the
35 : * linker. The reserved section, if non-zero, primarily manages static
36 : * percpu variables from kernel modules. Finally, the dynamic section
37 : * takes care of normal allocations.
38 : *
39 : * The allocator organizes chunks into lists according to free size and
40 : * memcg-awareness. To make a percpu allocation memcg-aware the __GFP_ACCOUNT
41 : * flag should be passed. All memcg-aware allocations are sharing one set
42 : * of chunks and all unaccounted allocations and allocations performed
43 : * by processes belonging to the root memory cgroup are using the second set.
44 : *
45 : * The allocator tries to allocate from the fullest chunk first. Each chunk
46 : * is managed by a bitmap with metadata blocks. The allocation map is updated
47 : * on every allocation and free to reflect the current state while the boundary
48 : * map is only updated on allocation. Each metadata block contains
49 : * information to help mitigate the need to iterate over large portions
50 : * of the bitmap. The reverse mapping from page to chunk is stored in
51 : * the page's index. Lastly, units are lazily backed and grow in unison.
52 : *
53 : * There is a unique conversion that goes on here between bytes and bits.
54 : * Each bit represents a fragment of size PCPU_MIN_ALLOC_SIZE. The chunk
55 : * tracks the number of pages it is responsible for in nr_pages. Helper
56 : * functions are used to convert from between the bytes, bits, and blocks.
57 : * All hints are managed in bits unless explicitly stated.
58 : *
59 : * To use this allocator, arch code should do the following:
60 : *
61 : * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
62 : * regular address to percpu pointer and back if they need to be
63 : * different from the default
64 : *
65 : * - use pcpu_setup_first_chunk() during percpu area initialization to
66 : * setup the first chunk containing the kernel static percpu area
67 : */
68 :
69 : #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
70 :
71 : #include <linux/bitmap.h>
72 : #include <linux/cpumask.h>
73 : #include <linux/memblock.h>
74 : #include <linux/err.h>
75 : #include <linux/lcm.h>
76 : #include <linux/list.h>
77 : #include <linux/log2.h>
78 : #include <linux/mm.h>
79 : #include <linux/module.h>
80 : #include <linux/mutex.h>
81 : #include <linux/percpu.h>
82 : #include <linux/pfn.h>
83 : #include <linux/slab.h>
84 : #include <linux/spinlock.h>
85 : #include <linux/vmalloc.h>
86 : #include <linux/workqueue.h>
87 : #include <linux/kmemleak.h>
88 : #include <linux/sched.h>
89 : #include <linux/sched/mm.h>
90 : #include <linux/memcontrol.h>
91 :
92 : #include <asm/cacheflush.h>
93 : #include <asm/sections.h>
94 : #include <asm/tlbflush.h>
95 : #include <asm/io.h>
96 :
97 : #define CREATE_TRACE_POINTS
98 : #include <trace/events/percpu.h>
99 :
100 : #include "percpu-internal.h"
101 :
102 : /*
103 : * The slots are sorted by the size of the biggest continuous free area.
104 : * 1-31 bytes share the same slot.
105 : */
106 : #define PCPU_SLOT_BASE_SHIFT 5
107 : /* chunks in slots below this are subject to being sidelined on failed alloc */
108 : #define PCPU_SLOT_FAIL_THRESHOLD 3
109 :
110 : #define PCPU_EMPTY_POP_PAGES_LOW 2
111 : #define PCPU_EMPTY_POP_PAGES_HIGH 4
112 :
113 : #ifdef CONFIG_SMP
114 : /* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
115 : #ifndef __addr_to_pcpu_ptr
116 : #define __addr_to_pcpu_ptr(addr) \
117 : (void __percpu *)((unsigned long)(addr) - \
118 : (unsigned long)pcpu_base_addr + \
119 : (unsigned long)__per_cpu_start)
120 : #endif
121 : #ifndef __pcpu_ptr_to_addr
122 : #define __pcpu_ptr_to_addr(ptr) \
123 : (void __force *)((unsigned long)(ptr) + \
124 : (unsigned long)pcpu_base_addr - \
125 : (unsigned long)__per_cpu_start)
126 : #endif
127 : #else /* CONFIG_SMP */
128 : /* on UP, it's always identity mapped */
129 : #define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
130 : #define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
131 : #endif /* CONFIG_SMP */
132 :
133 : static int pcpu_unit_pages __ro_after_init;
134 : static int pcpu_unit_size __ro_after_init;
135 : static int pcpu_nr_units __ro_after_init;
136 : static int pcpu_atom_size __ro_after_init;
137 : int pcpu_nr_slots __ro_after_init;
138 : static int pcpu_free_slot __ro_after_init;
139 : int pcpu_sidelined_slot __ro_after_init;
140 : int pcpu_to_depopulate_slot __ro_after_init;
141 : static size_t pcpu_chunk_struct_size __ro_after_init;
142 :
143 : /* cpus with the lowest and highest unit addresses */
144 : static unsigned int pcpu_low_unit_cpu __ro_after_init;
145 : static unsigned int pcpu_high_unit_cpu __ro_after_init;
146 :
147 : /* the address of the first chunk which starts with the kernel static area */
148 : void *pcpu_base_addr __ro_after_init;
149 :
150 : static const int *pcpu_unit_map __ro_after_init; /* cpu -> unit */
151 : const unsigned long *pcpu_unit_offsets __ro_after_init; /* cpu -> unit offset */
152 :
153 : /* group information, used for vm allocation */
154 : static int pcpu_nr_groups __ro_after_init;
155 : static const unsigned long *pcpu_group_offsets __ro_after_init;
156 : static const size_t *pcpu_group_sizes __ro_after_init;
157 :
158 : /*
159 : * The first chunk which always exists. Note that unlike other
160 : * chunks, this one can be allocated and mapped in several different
161 : * ways and thus often doesn't live in the vmalloc area.
162 : */
163 : struct pcpu_chunk *pcpu_first_chunk __ro_after_init;
164 :
165 : /*
166 : * Optional reserved chunk. This chunk reserves part of the first
167 : * chunk and serves it for reserved allocations. When the reserved
168 : * region doesn't exist, the following variable is NULL.
169 : */
170 : struct pcpu_chunk *pcpu_reserved_chunk __ro_after_init;
171 :
172 : DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
173 : static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop, map ext */
174 :
175 : struct list_head *pcpu_chunk_lists __ro_after_init; /* chunk list slots */
176 :
177 : /* chunks which need their map areas extended, protected by pcpu_lock */
178 : static LIST_HEAD(pcpu_map_extend_chunks);
179 :
180 : /*
181 : * The number of empty populated pages, protected by pcpu_lock.
182 : * The reserved chunk doesn't contribute to the count.
183 : */
184 : int pcpu_nr_empty_pop_pages;
185 :
186 : /*
187 : * The number of populated pages in use by the allocator, protected by
188 : * pcpu_lock. This number is kept per a unit per chunk (i.e. when a page gets
189 : * allocated/deallocated, it is allocated/deallocated in all units of a chunk
190 : * and increments/decrements this count by 1).
191 : */
192 : static unsigned long pcpu_nr_populated;
193 :
194 : /*
195 : * Balance work is used to populate or destroy chunks asynchronously. We
196 : * try to keep the number of populated free pages between
197 : * PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one
198 : * empty chunk.
199 : */
200 : static void pcpu_balance_workfn(struct work_struct *work);
201 : static DECLARE_WORK(pcpu_balance_work, pcpu_balance_workfn);
202 : static bool pcpu_async_enabled __read_mostly;
203 : static bool pcpu_atomic_alloc_failed;
204 :
205 : static void pcpu_schedule_balance_work(void)
206 : {
207 0 : if (pcpu_async_enabled)
208 : schedule_work(&pcpu_balance_work);
209 : }
210 :
211 : /**
212 : * pcpu_addr_in_chunk - check if the address is served from this chunk
213 : * @chunk: chunk of interest
214 : * @addr: percpu address
215 : *
216 : * RETURNS:
217 : * True if the address is served from this chunk.
218 : */
219 : static bool pcpu_addr_in_chunk(struct pcpu_chunk *chunk, void *addr)
220 : {
221 : void *start_addr, *end_addr;
222 :
223 0 : if (!chunk)
224 : return false;
225 :
226 0 : start_addr = chunk->base_addr + chunk->start_offset;
227 0 : end_addr = chunk->base_addr + chunk->nr_pages * PAGE_SIZE -
228 0 : chunk->end_offset;
229 :
230 0 : return addr >= start_addr && addr < end_addr;
231 : }
232 :
233 : static int __pcpu_size_to_slot(int size)
234 : {
235 1428 : int highbit = fls(size); /* size is in bytes */
236 714 : return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
237 : }
238 :
239 : static int pcpu_size_to_slot(int size)
240 : {
241 715 : if (size == pcpu_unit_size)
242 2 : return pcpu_free_slot;
243 713 : return __pcpu_size_to_slot(size);
244 : }
245 :
246 : static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
247 : {
248 477 : const struct pcpu_block_md *chunk_md = &chunk->chunk_md;
249 :
250 954 : if (chunk->free_bytes < PCPU_MIN_ALLOC_SIZE ||
251 477 : chunk_md->contig_hint == 0)
252 : return 0;
253 :
254 477 : return pcpu_size_to_slot(chunk_md->contig_hint * PCPU_MIN_ALLOC_SIZE);
255 : }
256 :
257 : /* set the pointer to a chunk in a page struct */
258 : static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
259 : {
260 0 : page->index = (unsigned long)pcpu;
261 : }
262 :
263 : /* obtain pointer to a chunk from a page struct */
264 : static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
265 : {
266 0 : return (struct pcpu_chunk *)page->index;
267 : }
268 :
269 : static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
270 : {
271 : return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
272 : }
273 :
274 : static unsigned long pcpu_unit_page_offset(unsigned int cpu, int page_idx)
275 : {
276 238 : return pcpu_unit_offsets[cpu] + (page_idx << PAGE_SHIFT);
277 : }
278 :
279 : static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
280 : unsigned int cpu, int page_idx)
281 : {
282 476 : return (unsigned long)chunk->base_addr +
283 238 : pcpu_unit_page_offset(cpu, page_idx);
284 : }
285 :
286 : /*
287 : * The following are helper functions to help access bitmaps and convert
288 : * between bitmap offsets to address offsets.
289 : */
290 : static unsigned long *pcpu_index_alloc_map(struct pcpu_chunk *chunk, int index)
291 : {
292 598 : return chunk->alloc_map +
293 299 : (index * PCPU_BITMAP_BLOCK_BITS / BITS_PER_LONG);
294 : }
295 :
296 : static unsigned long pcpu_off_to_block_index(int off)
297 : {
298 979 : return off / PCPU_BITMAP_BLOCK_BITS;
299 : }
300 :
301 : static unsigned long pcpu_off_to_block_off(int off)
302 : {
303 238 : return off & (PCPU_BITMAP_BLOCK_BITS - 1);
304 : }
305 :
306 : static unsigned long pcpu_block_off_to_off(int index, int off)
307 : {
308 255 : return index * PCPU_BITMAP_BLOCK_BITS + off;
309 : }
310 :
311 : /**
312 : * pcpu_check_block_hint - check against the contig hint
313 : * @block: block of interest
314 : * @bits: size of allocation
315 : * @align: alignment of area (max PAGE_SIZE)
316 : *
317 : * Check to see if the allocation can fit in the block's contig hint.
318 : * Note, a chunk uses the same hints as a block so this can also check against
319 : * the chunk's contig hint.
320 : */
321 : static bool pcpu_check_block_hint(struct pcpu_block_md *block, int bits,
322 : size_t align)
323 : {
324 238 : int bit_off = ALIGN(block->contig_hint_start, align) -
325 : block->contig_hint_start;
326 :
327 238 : return bit_off + bits <= block->contig_hint;
328 : }
329 :
330 : /*
331 : * pcpu_next_hint - determine which hint to use
332 : * @block: block of interest
333 : * @alloc_bits: size of allocation
334 : *
335 : * This determines if we should scan based on the scan_hint or first_free.
336 : * In general, we want to scan from first_free to fulfill allocations by
337 : * first fit. However, if we know a scan_hint at position scan_hint_start
338 : * cannot fulfill an allocation, we can begin scanning from there knowing
339 : * the contig_hint will be our fallback.
340 : */
341 : static int pcpu_next_hint(struct pcpu_block_md *block, int alloc_bits)
342 : {
343 : /*
344 : * The three conditions below determine if we can skip past the
345 : * scan_hint. First, does the scan hint exist. Second, is the
346 : * contig_hint after the scan_hint (possibly not true iff
347 : * contig_hint == scan_hint). Third, is the allocation request
348 : * larger than the scan_hint.
349 : */
350 663 : if (block->scan_hint &&
351 374 : block->contig_hint_start > block->scan_hint_start &&
352 : alloc_bits > block->scan_hint)
353 68 : return block->scan_hint_start + block->scan_hint;
354 :
355 408 : return block->first_free;
356 : }
357 :
358 : /**
359 : * pcpu_next_md_free_region - finds the next hint free area
360 : * @chunk: chunk of interest
361 : * @bit_off: chunk offset
362 : * @bits: size of free area
363 : *
364 : * Helper function for pcpu_for_each_md_free_region. It checks
365 : * block->contig_hint and performs aggregation across blocks to find the
366 : * next hint. It modifies bit_off and bits in-place to be consumed in the
367 : * loop.
368 : */
369 265 : static void pcpu_next_md_free_region(struct pcpu_chunk *chunk, int *bit_off,
370 : int *bits)
371 : {
372 530 : int i = pcpu_off_to_block_index(*bit_off);
373 265 : int block_off = pcpu_off_to_block_off(*bit_off);
374 : struct pcpu_block_md *block;
375 :
376 265 : *bits = 0;
377 1578 : for (block = chunk->md_blocks + i; i < pcpu_chunk_nr_blocks(chunk);
378 1048 : block++, i++) {
379 : /* handles contig area across blocks */
380 1051 : if (*bits) {
381 904 : *bits += block->left_free;
382 904 : if (block->left_free == PCPU_BITMAP_BLOCK_BITS)
383 904 : continue;
384 : return;
385 : }
386 :
387 : /*
388 : * This checks three things. First is there a contig_hint to
389 : * check. Second, have we checked this hint before by
390 : * comparing the block_off. Third, is this the same as the
391 : * right contig hint. In the last case, it spills over into
392 : * the next block and should be handled by the contig area
393 : * across blocks code.
394 : */
395 147 : *bits = block->contig_hint;
396 281 : if (*bits && block->contig_hint_start >= block_off &&
397 134 : *bits + block->contig_hint_start < PCPU_BITMAP_BLOCK_BITS) {
398 6 : *bit_off = pcpu_block_off_to_off(i,
399 : block->contig_hint_start);
400 3 : return;
401 : }
402 : /* reset to satisfy the second predicate above */
403 144 : block_off = 0;
404 :
405 144 : *bits = block->right_free;
406 144 : *bit_off = (i + 1) * PCPU_BITMAP_BLOCK_BITS - block->right_free;
407 : }
408 : }
409 :
410 : /**
411 : * pcpu_next_fit_region - finds fit areas for a given allocation request
412 : * @chunk: chunk of interest
413 : * @alloc_bits: size of allocation
414 : * @align: alignment of area (max PAGE_SIZE)
415 : * @bit_off: chunk offset
416 : * @bits: size of free area
417 : *
418 : * Finds the next free region that is viable for use with a given size and
419 : * alignment. This only returns if there is a valid area to be used for this
420 : * allocation. block->first_free is returned if the allocation request fits
421 : * within the block to see if the request can be fulfilled prior to the contig
422 : * hint.
423 : */
424 238 : static void pcpu_next_fit_region(struct pcpu_chunk *chunk, int alloc_bits,
425 : int align, int *bit_off, int *bits)
426 : {
427 476 : int i = pcpu_off_to_block_index(*bit_off);
428 238 : int block_off = pcpu_off_to_block_off(*bit_off);
429 : struct pcpu_block_md *block;
430 :
431 238 : *bits = 0;
432 490 : for (block = chunk->md_blocks + i; i < pcpu_chunk_nr_blocks(chunk);
433 14 : block++, i++) {
434 : /* handles contig area across blocks */
435 252 : if (*bits) {
436 0 : *bits += block->left_free;
437 0 : if (*bits >= alloc_bits)
438 : return;
439 0 : if (block->left_free == PCPU_BITMAP_BLOCK_BITS)
440 0 : continue;
441 : }
442 :
443 : /* check block->contig_hint */
444 252 : *bits = ALIGN(block->contig_hint_start, align) -
445 : block->contig_hint_start;
446 : /*
447 : * This uses the block offset to determine if this has been
448 : * checked in the prior iteration.
449 : */
450 504 : if (block->contig_hint &&
451 503 : block->contig_hint_start >= block_off &&
452 251 : block->contig_hint >= *bits + alloc_bits) {
453 238 : int start = pcpu_next_hint(block, alloc_bits);
454 :
455 238 : *bits += alloc_bits + block->contig_hint_start -
456 : start;
457 238 : *bit_off = pcpu_block_off_to_off(i, start);
458 238 : return;
459 : }
460 : /* reset to satisfy the second predicate above */
461 14 : block_off = 0;
462 :
463 14 : *bit_off = ALIGN(PCPU_BITMAP_BLOCK_BITS - block->right_free,
464 : align);
465 14 : *bits = PCPU_BITMAP_BLOCK_BITS - *bit_off;
466 28 : *bit_off = pcpu_block_off_to_off(i, *bit_off);
467 14 : if (*bits >= alloc_bits)
468 : return;
469 : }
470 :
471 : /* no valid offsets were found - fail condition */
472 0 : *bit_off = pcpu_chunk_map_bits(chunk);
473 : }
474 :
475 : /*
476 : * Metadata free area iterators. These perform aggregation of free areas
477 : * based on the metadata blocks and return the offset @bit_off and size in
478 : * bits of the free area @bits. pcpu_for_each_fit_region only returns when
479 : * a fit is found for the allocation request.
480 : */
481 : #define pcpu_for_each_md_free_region(chunk, bit_off, bits) \
482 : for (pcpu_next_md_free_region((chunk), &(bit_off), &(bits)); \
483 : (bit_off) < pcpu_chunk_map_bits((chunk)); \
484 : (bit_off) += (bits) + 1, \
485 : pcpu_next_md_free_region((chunk), &(bit_off), &(bits)))
486 :
487 : #define pcpu_for_each_fit_region(chunk, alloc_bits, align, bit_off, bits) \
488 : for (pcpu_next_fit_region((chunk), (alloc_bits), (align), &(bit_off), \
489 : &(bits)); \
490 : (bit_off) < pcpu_chunk_map_bits((chunk)); \
491 : (bit_off) += (bits), \
492 : pcpu_next_fit_region((chunk), (alloc_bits), (align), &(bit_off), \
493 : &(bits)))
494 :
495 : /**
496 : * pcpu_mem_zalloc - allocate memory
497 : * @size: bytes to allocate
498 : * @gfp: allocation flags
499 : *
500 : * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
501 : * kzalloc() is used; otherwise, the equivalent of vzalloc() is used.
502 : * This is to facilitate passing through whitelisted flags. The
503 : * returned memory is always zeroed.
504 : *
505 : * RETURNS:
506 : * Pointer to the allocated area on success, NULL on failure.
507 : */
508 0 : static void *pcpu_mem_zalloc(size_t size, gfp_t gfp)
509 : {
510 0 : if (WARN_ON_ONCE(!slab_is_available()))
511 : return NULL;
512 :
513 0 : if (size <= PAGE_SIZE)
514 0 : return kzalloc(size, gfp);
515 : else
516 0 : return __vmalloc(size, gfp | __GFP_ZERO);
517 : }
518 :
519 : /**
520 : * pcpu_mem_free - free memory
521 : * @ptr: memory to free
522 : *
523 : * Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc().
524 : */
525 : static void pcpu_mem_free(void *ptr)
526 : {
527 0 : kvfree(ptr);
528 : }
529 :
530 2 : static void __pcpu_chunk_move(struct pcpu_chunk *chunk, int slot,
531 : bool move_front)
532 : {
533 2 : if (chunk != pcpu_reserved_chunk) {
534 2 : if (move_front)
535 1 : list_move(&chunk->list, &pcpu_chunk_lists[slot]);
536 : else
537 1 : list_move_tail(&chunk->list, &pcpu_chunk_lists[slot]);
538 : }
539 2 : }
540 :
541 : static void pcpu_chunk_move(struct pcpu_chunk *chunk, int slot)
542 : {
543 0 : __pcpu_chunk_move(chunk, slot, true);
544 : }
545 :
546 : /**
547 : * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
548 : * @chunk: chunk of interest
549 : * @oslot: the previous slot it was on
550 : *
551 : * This function is called after an allocation or free changed @chunk.
552 : * New slot according to the changed state is determined and @chunk is
553 : * moved to the slot. Note that the reserved chunk is never put on
554 : * chunk slots.
555 : *
556 : * CONTEXT:
557 : * pcpu_lock.
558 : */
559 239 : static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
560 : {
561 239 : int nslot = pcpu_chunk_slot(chunk);
562 :
563 : /* leave isolated chunks in-place */
564 239 : if (chunk->isolated)
565 : return;
566 :
567 239 : if (oslot != nslot)
568 2 : __pcpu_chunk_move(chunk, nslot, oslot < nslot);
569 : }
570 :
571 : static void pcpu_isolate_chunk(struct pcpu_chunk *chunk)
572 : {
573 : lockdep_assert_held(&pcpu_lock);
574 :
575 : if (!chunk->isolated) {
576 : chunk->isolated = true;
577 : pcpu_nr_empty_pop_pages -= chunk->nr_empty_pop_pages;
578 : }
579 : list_move(&chunk->list, &pcpu_chunk_lists[pcpu_to_depopulate_slot]);
580 : }
581 :
582 238 : static void pcpu_reintegrate_chunk(struct pcpu_chunk *chunk)
583 : {
584 : lockdep_assert_held(&pcpu_lock);
585 :
586 238 : if (chunk->isolated) {
587 0 : chunk->isolated = false;
588 0 : pcpu_nr_empty_pop_pages += chunk->nr_empty_pop_pages;
589 0 : pcpu_chunk_relocate(chunk, -1);
590 : }
591 238 : }
592 :
593 : /*
594 : * pcpu_update_empty_pages - update empty page counters
595 : * @chunk: chunk of interest
596 : * @nr: nr of empty pages
597 : *
598 : * This is used to keep track of the empty pages now based on the premise
599 : * a md_block covers a page. The hint update functions recognize if a block
600 : * is made full or broken to calculate deltas for keeping track of free pages.
601 : */
602 : static inline void pcpu_update_empty_pages(struct pcpu_chunk *chunk, int nr)
603 : {
604 2 : chunk->nr_empty_pop_pages += nr;
605 2 : if (chunk != pcpu_reserved_chunk && !chunk->isolated)
606 2 : pcpu_nr_empty_pop_pages += nr;
607 : }
608 :
609 : /*
610 : * pcpu_region_overlap - determines if two regions overlap
611 : * @a: start of first region, inclusive
612 : * @b: end of first region, exclusive
613 : * @x: start of second region, inclusive
614 : * @y: end of second region, exclusive
615 : *
616 : * This is used to determine if the hint region [a, b) overlaps with the
617 : * allocated region [x, y).
618 : */
619 : static inline bool pcpu_region_overlap(int a, int b, int x, int y)
620 : {
621 952 : return (a < y) && (x < b);
622 : }
623 :
624 : /**
625 : * pcpu_block_update - updates a block given a free area
626 : * @block: block of interest
627 : * @start: start offset in block
628 : * @end: end offset in block
629 : *
630 : * Updates a block given a known free area. The region [start, end) is
631 : * expected to be the entirety of the free area within a block. Chooses
632 : * the best starting offset if the contig hints are equal.
633 : */
634 459 : static void pcpu_block_update(struct pcpu_block_md *block, int start, int end)
635 : {
636 459 : int contig = end - start;
637 :
638 459 : block->first_free = min(block->first_free, start);
639 459 : if (start == 0)
640 0 : block->left_free = contig;
641 :
642 459 : if (end == block->nr_bits)
643 261 : block->right_free = contig;
644 :
645 459 : if (contig > block->contig_hint) {
646 : /* promote the old contig_hint to be the new scan_hint */
647 276 : if (start > block->contig_hint_start) {
648 268 : if (block->contig_hint > block->scan_hint) {
649 42 : block->scan_hint_start =
650 : block->contig_hint_start;
651 42 : block->scan_hint = block->contig_hint;
652 226 : } else if (start < block->scan_hint_start) {
653 : /*
654 : * The old contig_hint == scan_hint. But, the
655 : * new contig is larger so hold the invariant
656 : * scan_hint_start < contig_hint_start.
657 : */
658 0 : block->scan_hint = 0;
659 : }
660 : } else {
661 8 : block->scan_hint = 0;
662 : }
663 276 : block->contig_hint_start = start;
664 276 : block->contig_hint = contig;
665 183 : } else if (contig == block->contig_hint) {
666 63 : if (block->contig_hint_start &&
667 63 : (!start ||
668 189 : __ffs(start) > __ffs(block->contig_hint_start))) {
669 : /* start has a better alignment so use it */
670 0 : block->contig_hint_start = start;
671 0 : if (start < block->scan_hint_start &&
672 0 : block->contig_hint > block->scan_hint)
673 0 : block->scan_hint = 0;
674 64 : } else if (start > block->scan_hint_start ||
675 1 : block->contig_hint > block->scan_hint) {
676 : /*
677 : * Knowing contig == contig_hint, update the scan_hint
678 : * if it is farther than or larger than the current
679 : * scan_hint.
680 : */
681 63 : block->scan_hint_start = start;
682 63 : block->scan_hint = contig;
683 : }
684 : } else {
685 : /*
686 : * The region is smaller than the contig_hint. So only update
687 : * the scan_hint if it is larger than or equal and farther than
688 : * the current scan_hint.
689 : */
690 120 : if ((start < block->contig_hint_start &&
691 0 : (contig > block->scan_hint ||
692 0 : (contig == block->scan_hint &&
693 0 : start > block->scan_hint_start)))) {
694 0 : block->scan_hint_start = start;
695 0 : block->scan_hint = contig;
696 : }
697 : }
698 459 : }
699 :
700 : /*
701 : * pcpu_block_update_scan - update a block given a free area from a scan
702 : * @chunk: chunk of interest
703 : * @bit_off: chunk offset
704 : * @bits: size of free area
705 : *
706 : * Finding the final allocation spot first goes through pcpu_find_block_fit()
707 : * to find a block that can hold the allocation and then pcpu_alloc_area()
708 : * where a scan is used. When allocations require specific alignments,
709 : * we can inadvertently create holes which will not be seen in the alloc
710 : * or free paths.
711 : *
712 : * This takes a given free area hole and updates a block as it may change the
713 : * scan_hint. We need to scan backwards to ensure we don't miss free bits
714 : * from alignment.
715 : */
716 0 : static void pcpu_block_update_scan(struct pcpu_chunk *chunk, int bit_off,
717 : int bits)
718 : {
719 0 : int s_off = pcpu_off_to_block_off(bit_off);
720 0 : int e_off = s_off + bits;
721 : int s_index, l_bit;
722 : struct pcpu_block_md *block;
723 :
724 0 : if (e_off > PCPU_BITMAP_BLOCK_BITS)
725 : return;
726 :
727 0 : s_index = pcpu_off_to_block_index(bit_off);
728 0 : block = chunk->md_blocks + s_index;
729 :
730 : /* scan backwards in case of alignment skipping free bits */
731 0 : l_bit = find_last_bit(pcpu_index_alloc_map(chunk, s_index), s_off);
732 0 : s_off = (s_off == l_bit) ? 0 : l_bit + 1;
733 :
734 0 : pcpu_block_update(block, s_off, e_off);
735 : }
736 :
737 : /**
738 : * pcpu_chunk_refresh_hint - updates metadata about a chunk
739 : * @chunk: chunk of interest
740 : * @full_scan: if we should scan from the beginning
741 : *
742 : * Iterates over the metadata blocks to find the largest contig area.
743 : * A full scan can be avoided on the allocation path as this is triggered
744 : * if we broke the contig_hint. In doing so, the scan_hint will be before
745 : * the contig_hint or after if the scan_hint == contig_hint. This cannot
746 : * be prevented on freeing as we want to find the largest area possibly
747 : * spanning blocks.
748 : */
749 131 : static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk, bool full_scan)
750 : {
751 131 : struct pcpu_block_md *chunk_md = &chunk->chunk_md;
752 : int bit_off, bits;
753 :
754 : /* promote scan_hint to contig_hint */
755 131 : if (!full_scan && chunk_md->scan_hint) {
756 10 : bit_off = chunk_md->scan_hint_start + chunk_md->scan_hint;
757 10 : chunk_md->contig_hint_start = chunk_md->scan_hint_start;
758 10 : chunk_md->contig_hint = chunk_md->scan_hint;
759 10 : chunk_md->scan_hint = 0;
760 : } else {
761 121 : bit_off = chunk_md->first_free;
762 121 : chunk_md->contig_hint = 0;
763 : }
764 :
765 131 : bits = 0;
766 530 : pcpu_for_each_md_free_region(chunk, bit_off, bits)
767 134 : pcpu_block_update(chunk_md, bit_off, bit_off + bits);
768 131 : }
769 :
770 : /**
771 : * pcpu_block_refresh_hint
772 : * @chunk: chunk of interest
773 : * @index: index of the metadata block
774 : *
775 : * Scans over the block beginning at first_free and updates the block
776 : * metadata accordingly.
777 : */
778 135 : static void pcpu_block_refresh_hint(struct pcpu_chunk *chunk, int index)
779 : {
780 135 : struct pcpu_block_md *block = chunk->md_blocks + index;
781 135 : unsigned long *alloc_map = pcpu_index_alloc_map(chunk, index);
782 : unsigned int start, end; /* region start, region end */
783 :
784 : /* promote scan_hint to contig_hint */
785 135 : if (block->scan_hint) {
786 67 : start = block->scan_hint_start + block->scan_hint;
787 67 : block->contig_hint_start = block->scan_hint_start;
788 67 : block->contig_hint = block->scan_hint;
789 67 : block->scan_hint = 0;
790 : } else {
791 68 : start = block->first_free;
792 68 : block->contig_hint = 0;
793 : }
794 :
795 135 : block->right_free = 0;
796 :
797 : /* iterate over free areas and update the contig hints */
798 460 : for_each_clear_bitrange_from(start, end, alloc_map, PCPU_BITMAP_BLOCK_BITS)
799 325 : pcpu_block_update(block, start, end);
800 135 : }
801 :
802 : /**
803 : * pcpu_block_update_hint_alloc - update hint on allocation path
804 : * @chunk: chunk of interest
805 : * @bit_off: chunk offset
806 : * @bits: size of request
807 : *
808 : * Updates metadata for the allocation path. The metadata only has to be
809 : * refreshed by a full scan iff the chunk's contig hint is broken. Block level
810 : * scans are required if the block's contig hint is broken.
811 : */
812 238 : static void pcpu_block_update_hint_alloc(struct pcpu_chunk *chunk, int bit_off,
813 : int bits)
814 : {
815 238 : struct pcpu_block_md *chunk_md = &chunk->chunk_md;
816 238 : int nr_empty_pages = 0;
817 : struct pcpu_block_md *s_block, *e_block, *block;
818 : int s_index, e_index; /* block indexes of the freed allocation */
819 : int s_off, e_off; /* block offsets of the freed allocation */
820 :
821 : /*
822 : * Calculate per block offsets.
823 : * The calculation uses an inclusive range, but the resulting offsets
824 : * are [start, end). e_index always points to the last block in the
825 : * range.
826 : */
827 238 : s_index = pcpu_off_to_block_index(bit_off);
828 476 : e_index = pcpu_off_to_block_index(bit_off + bits - 1);
829 238 : s_off = pcpu_off_to_block_off(bit_off);
830 476 : e_off = pcpu_off_to_block_off(bit_off + bits - 1) + 1;
831 :
832 238 : s_block = chunk->md_blocks + s_index;
833 238 : e_block = chunk->md_blocks + e_index;
834 :
835 : /*
836 : * Update s_block.
837 : * block->first_free must be updated if the allocation takes its place.
838 : * If the allocation breaks the contig_hint, a scan is required to
839 : * restore this hint.
840 : */
841 238 : if (s_block->contig_hint == PCPU_BITMAP_BLOCK_BITS)
842 2 : nr_empty_pages++;
843 :
844 238 : if (s_off == s_block->first_free)
845 328 : s_block->first_free = find_next_zero_bit(
846 164 : pcpu_index_alloc_map(chunk, s_index),
847 : PCPU_BITMAP_BLOCK_BITS,
848 164 : s_off + bits);
849 :
850 714 : if (pcpu_region_overlap(s_block->scan_hint_start,
851 238 : s_block->scan_hint_start + s_block->scan_hint,
852 : s_off,
853 : s_off + bits))
854 3 : s_block->scan_hint = 0;
855 :
856 476 : if (pcpu_region_overlap(s_block->contig_hint_start,
857 238 : s_block->contig_hint_start +
858 238 : s_block->contig_hint,
859 : s_off,
860 : s_off + bits)) {
861 : /* block contig hint is broken - scan to fix it */
862 135 : if (!s_off)
863 2 : s_block->left_free = 0;
864 135 : pcpu_block_refresh_hint(chunk, s_index);
865 : } else {
866 : /* update left and right contig manually */
867 103 : s_block->left_free = min(s_block->left_free, s_off);
868 103 : if (s_index == e_index)
869 103 : s_block->right_free = min_t(int, s_block->right_free,
870 : PCPU_BITMAP_BLOCK_BITS - e_off);
871 : else
872 0 : s_block->right_free = 0;
873 : }
874 :
875 : /*
876 : * Update e_block.
877 : */
878 238 : if (s_index != e_index) {
879 0 : if (e_block->contig_hint == PCPU_BITMAP_BLOCK_BITS)
880 0 : nr_empty_pages++;
881 :
882 : /*
883 : * When the allocation is across blocks, the end is along
884 : * the left part of the e_block.
885 : */
886 0 : e_block->first_free = find_next_zero_bit(
887 0 : pcpu_index_alloc_map(chunk, e_index),
888 : PCPU_BITMAP_BLOCK_BITS, e_off);
889 :
890 0 : if (e_off == PCPU_BITMAP_BLOCK_BITS) {
891 : /* reset the block */
892 0 : e_block++;
893 : } else {
894 0 : if (e_off > e_block->scan_hint_start)
895 0 : e_block->scan_hint = 0;
896 :
897 0 : e_block->left_free = 0;
898 0 : if (e_off > e_block->contig_hint_start) {
899 : /* contig hint is broken - scan to fix it */
900 0 : pcpu_block_refresh_hint(chunk, e_index);
901 : } else {
902 0 : e_block->right_free =
903 0 : min_t(int, e_block->right_free,
904 : PCPU_BITMAP_BLOCK_BITS - e_off);
905 : }
906 : }
907 :
908 : /* update in-between md_blocks */
909 0 : nr_empty_pages += (e_index - s_index - 1);
910 0 : for (block = s_block + 1; block < e_block; block++) {
911 0 : block->scan_hint = 0;
912 0 : block->contig_hint = 0;
913 0 : block->left_free = 0;
914 0 : block->right_free = 0;
915 : }
916 : }
917 :
918 238 : if (nr_empty_pages)
919 2 : pcpu_update_empty_pages(chunk, -nr_empty_pages);
920 :
921 476 : if (pcpu_region_overlap(chunk_md->scan_hint_start,
922 238 : chunk_md->scan_hint_start +
923 238 : chunk_md->scan_hint,
924 : bit_off,
925 : bit_off + bits))
926 3 : chunk_md->scan_hint = 0;
927 :
928 : /*
929 : * The only time a full chunk scan is required is if the chunk
930 : * contig hint is broken. Otherwise, it means a smaller space
931 : * was used and therefore the chunk contig hint is still correct.
932 : */
933 476 : if (pcpu_region_overlap(chunk_md->contig_hint_start,
934 238 : chunk_md->contig_hint_start +
935 238 : chunk_md->contig_hint,
936 : bit_off,
937 : bit_off + bits))
938 131 : pcpu_chunk_refresh_hint(chunk, false);
939 238 : }
940 :
941 : /**
942 : * pcpu_block_update_hint_free - updates the block hints on the free path
943 : * @chunk: chunk of interest
944 : * @bit_off: chunk offset
945 : * @bits: size of request
946 : *
947 : * Updates metadata for the allocation path. This avoids a blind block
948 : * refresh by making use of the block contig hints. If this fails, it scans
949 : * forward and backward to determine the extent of the free area. This is
950 : * capped at the boundary of blocks.
951 : *
952 : * A chunk update is triggered if a page becomes free, a block becomes free,
953 : * or the free spans across blocks. This tradeoff is to minimize iterating
954 : * over the block metadata to update chunk_md->contig_hint.
955 : * chunk_md->contig_hint may be off by up to a page, but it will never be more
956 : * than the available space. If the contig hint is contained in one block, it
957 : * will be accurate.
958 : */
959 0 : static void pcpu_block_update_hint_free(struct pcpu_chunk *chunk, int bit_off,
960 : int bits)
961 : {
962 0 : int nr_empty_pages = 0;
963 : struct pcpu_block_md *s_block, *e_block, *block;
964 : int s_index, e_index; /* block indexes of the freed allocation */
965 : int s_off, e_off; /* block offsets of the freed allocation */
966 : int start, end; /* start and end of the whole free area */
967 :
968 : /*
969 : * Calculate per block offsets.
970 : * The calculation uses an inclusive range, but the resulting offsets
971 : * are [start, end). e_index always points to the last block in the
972 : * range.
973 : */
974 0 : s_index = pcpu_off_to_block_index(bit_off);
975 0 : e_index = pcpu_off_to_block_index(bit_off + bits - 1);
976 0 : s_off = pcpu_off_to_block_off(bit_off);
977 0 : e_off = pcpu_off_to_block_off(bit_off + bits - 1) + 1;
978 :
979 0 : s_block = chunk->md_blocks + s_index;
980 0 : e_block = chunk->md_blocks + e_index;
981 :
982 : /*
983 : * Check if the freed area aligns with the block->contig_hint.
984 : * If it does, then the scan to find the beginning/end of the
985 : * larger free area can be avoided.
986 : *
987 : * start and end refer to beginning and end of the free area
988 : * within each their respective blocks. This is not necessarily
989 : * the entire free area as it may span blocks past the beginning
990 : * or end of the block.
991 : */
992 0 : start = s_off;
993 0 : if (s_off == s_block->contig_hint + s_block->contig_hint_start) {
994 : start = s_block->contig_hint_start;
995 : } else {
996 : /*
997 : * Scan backwards to find the extent of the free area.
998 : * find_last_bit returns the starting bit, so if the start bit
999 : * is returned, that means there was no last bit and the
1000 : * remainder of the chunk is free.
1001 : */
1002 0 : int l_bit = find_last_bit(pcpu_index_alloc_map(chunk, s_index),
1003 : start);
1004 0 : start = (start == l_bit) ? 0 : l_bit + 1;
1005 : }
1006 :
1007 0 : end = e_off;
1008 0 : if (e_off == e_block->contig_hint_start)
1009 0 : end = e_block->contig_hint_start + e_block->contig_hint;
1010 : else
1011 0 : end = find_next_bit(pcpu_index_alloc_map(chunk, e_index),
1012 : PCPU_BITMAP_BLOCK_BITS, end);
1013 :
1014 : /* update s_block */
1015 0 : e_off = (s_index == e_index) ? end : PCPU_BITMAP_BLOCK_BITS;
1016 0 : if (!start && e_off == PCPU_BITMAP_BLOCK_BITS)
1017 0 : nr_empty_pages++;
1018 0 : pcpu_block_update(s_block, start, e_off);
1019 :
1020 : /* freeing in the same block */
1021 0 : if (s_index != e_index) {
1022 : /* update e_block */
1023 0 : if (end == PCPU_BITMAP_BLOCK_BITS)
1024 0 : nr_empty_pages++;
1025 0 : pcpu_block_update(e_block, 0, end);
1026 :
1027 : /* reset md_blocks in the middle */
1028 0 : nr_empty_pages += (e_index - s_index - 1);
1029 0 : for (block = s_block + 1; block < e_block; block++) {
1030 0 : block->first_free = 0;
1031 0 : block->scan_hint = 0;
1032 0 : block->contig_hint_start = 0;
1033 0 : block->contig_hint = PCPU_BITMAP_BLOCK_BITS;
1034 0 : block->left_free = PCPU_BITMAP_BLOCK_BITS;
1035 0 : block->right_free = PCPU_BITMAP_BLOCK_BITS;
1036 : }
1037 : }
1038 :
1039 0 : if (nr_empty_pages)
1040 : pcpu_update_empty_pages(chunk, nr_empty_pages);
1041 :
1042 : /*
1043 : * Refresh chunk metadata when the free makes a block free or spans
1044 : * across blocks. The contig_hint may be off by up to a page, but if
1045 : * the contig_hint is contained in a block, it will be accurate with
1046 : * the else condition below.
1047 : */
1048 0 : if (((end - start) >= PCPU_BITMAP_BLOCK_BITS) || s_index != e_index)
1049 0 : pcpu_chunk_refresh_hint(chunk, true);
1050 : else
1051 0 : pcpu_block_update(&chunk->chunk_md,
1052 0 : pcpu_block_off_to_off(s_index, start),
1053 : end);
1054 0 : }
1055 :
1056 : /**
1057 : * pcpu_is_populated - determines if the region is populated
1058 : * @chunk: chunk of interest
1059 : * @bit_off: chunk offset
1060 : * @bits: size of area
1061 : * @next_off: return value for the next offset to start searching
1062 : *
1063 : * For atomic allocations, check if the backing pages are populated.
1064 : *
1065 : * RETURNS:
1066 : * Bool if the backing pages are populated.
1067 : * next_index is to skip over unpopulated blocks in pcpu_find_block_fit.
1068 : */
1069 0 : static bool pcpu_is_populated(struct pcpu_chunk *chunk, int bit_off, int bits,
1070 : int *next_off)
1071 : {
1072 : unsigned int start, end;
1073 :
1074 0 : start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE);
1075 0 : end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE);
1076 :
1077 0 : start = find_next_zero_bit(chunk->populated, end, start);
1078 0 : if (start >= end)
1079 : return true;
1080 :
1081 0 : end = find_next_bit(chunk->populated, end, start + 1);
1082 :
1083 0 : *next_off = end * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE;
1084 0 : return false;
1085 : }
1086 :
1087 : /**
1088 : * pcpu_find_block_fit - finds the block index to start searching
1089 : * @chunk: chunk of interest
1090 : * @alloc_bits: size of request in allocation units
1091 : * @align: alignment of area (max PAGE_SIZE bytes)
1092 : * @pop_only: use populated regions only
1093 : *
1094 : * Given a chunk and an allocation spec, find the offset to begin searching
1095 : * for a free region. This iterates over the bitmap metadata blocks to
1096 : * find an offset that will be guaranteed to fit the requirements. It is
1097 : * not quite first fit as if the allocation does not fit in the contig hint
1098 : * of a block or chunk, it is skipped. This errs on the side of caution
1099 : * to prevent excess iteration. Poor alignment can cause the allocator to
1100 : * skip over blocks and chunks that have valid free areas.
1101 : *
1102 : * RETURNS:
1103 : * The offset in the bitmap to begin searching.
1104 : * -1 if no offset is found.
1105 : */
1106 238 : static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits,
1107 : size_t align, bool pop_only)
1108 : {
1109 238 : struct pcpu_block_md *chunk_md = &chunk->chunk_md;
1110 : int bit_off, bits, next_off;
1111 :
1112 : /*
1113 : * This is an optimization to prevent scanning by assuming if the
1114 : * allocation cannot fit in the global hint, there is memory pressure
1115 : * and creating a new chunk would happen soon.
1116 : */
1117 476 : if (!pcpu_check_block_hint(chunk_md, alloc_bits, align))
1118 : return -1;
1119 :
1120 238 : bit_off = pcpu_next_hint(chunk_md, alloc_bits);
1121 238 : bits = 0;
1122 476 : pcpu_for_each_fit_region(chunk, alloc_bits, align, bit_off, bits) {
1123 238 : if (!pop_only || pcpu_is_populated(chunk, bit_off, bits,
1124 : &next_off))
1125 : break;
1126 :
1127 0 : bit_off = next_off;
1128 0 : bits = 0;
1129 : }
1130 :
1131 238 : if (bit_off == pcpu_chunk_map_bits(chunk))
1132 : return -1;
1133 :
1134 238 : return bit_off;
1135 : }
1136 :
1137 : /*
1138 : * pcpu_find_zero_area - modified from bitmap_find_next_zero_area_off()
1139 : * @map: the address to base the search on
1140 : * @size: the bitmap size in bits
1141 : * @start: the bitnumber to start searching at
1142 : * @nr: the number of zeroed bits we're looking for
1143 : * @align_mask: alignment mask for zero area
1144 : * @largest_off: offset of the largest area skipped
1145 : * @largest_bits: size of the largest area skipped
1146 : *
1147 : * The @align_mask should be one less than a power of 2.
1148 : *
1149 : * This is a modified version of bitmap_find_next_zero_area_off() to remember
1150 : * the largest area that was skipped. This is imperfect, but in general is
1151 : * good enough. The largest remembered region is the largest failed region
1152 : * seen. This does not include anything we possibly skipped due to alignment.
1153 : * pcpu_block_update_scan() does scan backwards to try and recover what was
1154 : * lost to alignment. While this can cause scanning to miss earlier possible
1155 : * free areas, smaller allocations will eventually fill those holes.
1156 : */
1157 238 : static unsigned long pcpu_find_zero_area(unsigned long *map,
1158 : unsigned long size,
1159 : unsigned long start,
1160 : unsigned long nr,
1161 : unsigned long align_mask,
1162 : unsigned long *largest_off,
1163 : unsigned long *largest_bits)
1164 : {
1165 : unsigned long index, end, i, area_off, area_bits;
1166 : again:
1167 375 : index = find_next_zero_bit(map, size, start);
1168 :
1169 : /* Align allocation */
1170 375 : index = __ALIGN_MASK(index, align_mask);
1171 375 : area_off = index;
1172 :
1173 375 : end = index + nr;
1174 375 : if (end > size)
1175 : return end;
1176 375 : i = find_next_bit(map, end, index);
1177 375 : if (i < end) {
1178 137 : area_bits = i - area_off;
1179 : /* remember largest unused area with best alignment */
1180 137 : if (area_bits > *largest_bits ||
1181 137 : (area_bits == *largest_bits && *largest_off &&
1182 0 : (!area_off || __ffs(area_off) > __ffs(*largest_off)))) {
1183 0 : *largest_off = area_off;
1184 0 : *largest_bits = area_bits;
1185 : }
1186 :
1187 137 : start = i + 1;
1188 137 : goto again;
1189 : }
1190 : return index;
1191 : }
1192 :
1193 : /**
1194 : * pcpu_alloc_area - allocates an area from a pcpu_chunk
1195 : * @chunk: chunk of interest
1196 : * @alloc_bits: size of request in allocation units
1197 : * @align: alignment of area (max PAGE_SIZE)
1198 : * @start: bit_off to start searching
1199 : *
1200 : * This function takes in a @start offset to begin searching to fit an
1201 : * allocation of @alloc_bits with alignment @align. It needs to scan
1202 : * the allocation map because if it fits within the block's contig hint,
1203 : * @start will be block->first_free. This is an attempt to fill the
1204 : * allocation prior to breaking the contig hint. The allocation and
1205 : * boundary maps are updated accordingly if it confirms a valid
1206 : * free area.
1207 : *
1208 : * RETURNS:
1209 : * Allocated addr offset in @chunk on success.
1210 : * -1 if no matching area is found.
1211 : */
1212 238 : static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits,
1213 : size_t align, int start)
1214 : {
1215 238 : struct pcpu_block_md *chunk_md = &chunk->chunk_md;
1216 238 : size_t align_mask = (align) ? (align - 1) : 0;
1217 238 : unsigned long area_off = 0, area_bits = 0;
1218 : int bit_off, end, oslot;
1219 :
1220 : lockdep_assert_held(&pcpu_lock);
1221 :
1222 238 : oslot = pcpu_chunk_slot(chunk);
1223 :
1224 : /*
1225 : * Search to find a fit.
1226 : */
1227 476 : end = min_t(int, start + alloc_bits + PCPU_BITMAP_BLOCK_BITS,
1228 : pcpu_chunk_map_bits(chunk));
1229 238 : bit_off = pcpu_find_zero_area(chunk->alloc_map, end, start, alloc_bits,
1230 : align_mask, &area_off, &area_bits);
1231 238 : if (bit_off >= end)
1232 : return -1;
1233 :
1234 238 : if (area_bits)
1235 0 : pcpu_block_update_scan(chunk, area_off, area_bits);
1236 :
1237 : /* update alloc map */
1238 476 : bitmap_set(chunk->alloc_map, bit_off, alloc_bits);
1239 :
1240 : /* update boundary map */
1241 476 : set_bit(bit_off, chunk->bound_map);
1242 476 : bitmap_clear(chunk->bound_map, bit_off + 1, alloc_bits - 1);
1243 476 : set_bit(bit_off + alloc_bits, chunk->bound_map);
1244 :
1245 238 : chunk->free_bytes -= alloc_bits * PCPU_MIN_ALLOC_SIZE;
1246 :
1247 : /* update first free bit */
1248 238 : if (bit_off == chunk_md->first_free)
1249 486 : chunk_md->first_free = find_next_zero_bit(
1250 162 : chunk->alloc_map,
1251 162 : pcpu_chunk_map_bits(chunk),
1252 : bit_off + alloc_bits);
1253 :
1254 238 : pcpu_block_update_hint_alloc(chunk, bit_off, alloc_bits);
1255 :
1256 238 : pcpu_chunk_relocate(chunk, oslot);
1257 :
1258 238 : return bit_off * PCPU_MIN_ALLOC_SIZE;
1259 : }
1260 :
1261 : /**
1262 : * pcpu_free_area - frees the corresponding offset
1263 : * @chunk: chunk of interest
1264 : * @off: addr offset into chunk
1265 : *
1266 : * This function determines the size of an allocation to free using
1267 : * the boundary bitmap and clears the allocation map.
1268 : *
1269 : * RETURNS:
1270 : * Number of freed bytes.
1271 : */
1272 0 : static int pcpu_free_area(struct pcpu_chunk *chunk, int off)
1273 : {
1274 0 : struct pcpu_block_md *chunk_md = &chunk->chunk_md;
1275 : int bit_off, bits, end, oslot, freed;
1276 :
1277 : lockdep_assert_held(&pcpu_lock);
1278 0 : pcpu_stats_area_dealloc(chunk);
1279 :
1280 0 : oslot = pcpu_chunk_slot(chunk);
1281 :
1282 0 : bit_off = off / PCPU_MIN_ALLOC_SIZE;
1283 :
1284 : /* find end index */
1285 0 : end = find_next_bit(chunk->bound_map, pcpu_chunk_map_bits(chunk),
1286 0 : bit_off + 1);
1287 0 : bits = end - bit_off;
1288 0 : bitmap_clear(chunk->alloc_map, bit_off, bits);
1289 :
1290 0 : freed = bits * PCPU_MIN_ALLOC_SIZE;
1291 :
1292 : /* update metadata */
1293 0 : chunk->free_bytes += freed;
1294 :
1295 : /* update first free bit */
1296 0 : chunk_md->first_free = min(chunk_md->first_free, bit_off);
1297 :
1298 0 : pcpu_block_update_hint_free(chunk, bit_off, bits);
1299 :
1300 0 : pcpu_chunk_relocate(chunk, oslot);
1301 :
1302 0 : return freed;
1303 : }
1304 :
1305 : static void pcpu_init_md_block(struct pcpu_block_md *block, int nr_bits)
1306 : {
1307 9 : block->scan_hint = 0;
1308 9 : block->contig_hint = nr_bits;
1309 9 : block->left_free = nr_bits;
1310 9 : block->right_free = nr_bits;
1311 9 : block->first_free = 0;
1312 9 : block->nr_bits = nr_bits;
1313 : }
1314 :
1315 1 : static void pcpu_init_md_blocks(struct pcpu_chunk *chunk)
1316 : {
1317 : struct pcpu_block_md *md_block;
1318 :
1319 : /* init the chunk's block */
1320 2 : pcpu_init_md_block(&chunk->chunk_md, pcpu_chunk_map_bits(chunk));
1321 :
1322 10 : for (md_block = chunk->md_blocks;
1323 18 : md_block != chunk->md_blocks + pcpu_chunk_nr_blocks(chunk);
1324 8 : md_block++)
1325 8 : pcpu_init_md_block(md_block, PCPU_BITMAP_BLOCK_BITS);
1326 1 : }
1327 :
1328 : /**
1329 : * pcpu_alloc_first_chunk - creates chunks that serve the first chunk
1330 : * @tmp_addr: the start of the region served
1331 : * @map_size: size of the region served
1332 : *
1333 : * This is responsible for creating the chunks that serve the first chunk. The
1334 : * base_addr is page aligned down of @tmp_addr while the region end is page
1335 : * aligned up. Offsets are kept track of to determine the region served. All
1336 : * this is done to appease the bitmap allocator in avoiding partial blocks.
1337 : *
1338 : * RETURNS:
1339 : * Chunk serving the region at @tmp_addr of @map_size.
1340 : */
1341 1 : static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr,
1342 : int map_size)
1343 : {
1344 : struct pcpu_chunk *chunk;
1345 : unsigned long aligned_addr, lcm_align;
1346 : int start_offset, offset_bits, region_size, region_bits;
1347 : size_t alloc_size;
1348 :
1349 : /* region calculations */
1350 1 : aligned_addr = tmp_addr & PAGE_MASK;
1351 :
1352 1 : start_offset = tmp_addr - aligned_addr;
1353 :
1354 : /*
1355 : * Align the end of the region with the LCM of PAGE_SIZE and
1356 : * PCPU_BITMAP_BLOCK_SIZE. One of these constants is a multiple of
1357 : * the other.
1358 : */
1359 1 : lcm_align = lcm(PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE);
1360 1 : region_size = ALIGN(start_offset + map_size, lcm_align);
1361 :
1362 : /* allocate chunk */
1363 3 : alloc_size = struct_size(chunk, populated,
1364 : BITS_TO_LONGS(region_size >> PAGE_SHIFT));
1365 1 : chunk = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
1366 1 : if (!chunk)
1367 0 : panic("%s: Failed to allocate %zu bytes\n", __func__,
1368 : alloc_size);
1369 :
1370 2 : INIT_LIST_HEAD(&chunk->list);
1371 :
1372 1 : chunk->base_addr = (void *)aligned_addr;
1373 1 : chunk->start_offset = start_offset;
1374 1 : chunk->end_offset = region_size - chunk->start_offset - map_size;
1375 :
1376 1 : chunk->nr_pages = region_size >> PAGE_SHIFT;
1377 1 : region_bits = pcpu_chunk_map_bits(chunk);
1378 :
1379 1 : alloc_size = BITS_TO_LONGS(region_bits) * sizeof(chunk->alloc_map[0]);
1380 1 : chunk->alloc_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
1381 1 : if (!chunk->alloc_map)
1382 0 : panic("%s: Failed to allocate %zu bytes\n", __func__,
1383 : alloc_size);
1384 :
1385 1 : alloc_size =
1386 1 : BITS_TO_LONGS(region_bits + 1) * sizeof(chunk->bound_map[0]);
1387 1 : chunk->bound_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
1388 1 : if (!chunk->bound_map)
1389 0 : panic("%s: Failed to allocate %zu bytes\n", __func__,
1390 : alloc_size);
1391 :
1392 1 : alloc_size = pcpu_chunk_nr_blocks(chunk) * sizeof(chunk->md_blocks[0]);
1393 1 : chunk->md_blocks = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
1394 1 : if (!chunk->md_blocks)
1395 0 : panic("%s: Failed to allocate %zu bytes\n", __func__,
1396 : alloc_size);
1397 :
1398 : #ifdef CONFIG_MEMCG_KMEM
1399 : /* first chunk is free to use */
1400 : chunk->obj_cgroups = NULL;
1401 : #endif
1402 1 : pcpu_init_md_blocks(chunk);
1403 :
1404 : /* manage populated page bitmap */
1405 1 : chunk->immutable = true;
1406 2 : bitmap_fill(chunk->populated, chunk->nr_pages);
1407 1 : chunk->nr_populated = chunk->nr_pages;
1408 1 : chunk->nr_empty_pop_pages = chunk->nr_pages;
1409 :
1410 1 : chunk->free_bytes = map_size;
1411 :
1412 1 : if (chunk->start_offset) {
1413 : /* hide the beginning of the bitmap */
1414 0 : offset_bits = chunk->start_offset / PCPU_MIN_ALLOC_SIZE;
1415 0 : bitmap_set(chunk->alloc_map, 0, offset_bits);
1416 0 : set_bit(0, chunk->bound_map);
1417 0 : set_bit(offset_bits, chunk->bound_map);
1418 :
1419 0 : chunk->chunk_md.first_free = offset_bits;
1420 :
1421 0 : pcpu_block_update_hint_alloc(chunk, 0, offset_bits);
1422 : }
1423 :
1424 1 : if (chunk->end_offset) {
1425 : /* hide the end of the bitmap */
1426 0 : offset_bits = chunk->end_offset / PCPU_MIN_ALLOC_SIZE;
1427 0 : bitmap_set(chunk->alloc_map,
1428 0 : pcpu_chunk_map_bits(chunk) - offset_bits,
1429 : offset_bits);
1430 0 : set_bit((start_offset + map_size) / PCPU_MIN_ALLOC_SIZE,
1431 0 : chunk->bound_map);
1432 0 : set_bit(region_bits, chunk->bound_map);
1433 :
1434 0 : pcpu_block_update_hint_alloc(chunk, pcpu_chunk_map_bits(chunk)
1435 : - offset_bits, offset_bits);
1436 : }
1437 :
1438 1 : return chunk;
1439 : }
1440 :
1441 0 : static struct pcpu_chunk *pcpu_alloc_chunk(gfp_t gfp)
1442 : {
1443 : struct pcpu_chunk *chunk;
1444 : int region_bits;
1445 :
1446 0 : chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size, gfp);
1447 0 : if (!chunk)
1448 : return NULL;
1449 :
1450 0 : INIT_LIST_HEAD(&chunk->list);
1451 0 : chunk->nr_pages = pcpu_unit_pages;
1452 0 : region_bits = pcpu_chunk_map_bits(chunk);
1453 :
1454 0 : chunk->alloc_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits) *
1455 : sizeof(chunk->alloc_map[0]), gfp);
1456 0 : if (!chunk->alloc_map)
1457 : goto alloc_map_fail;
1458 :
1459 0 : chunk->bound_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits + 1) *
1460 : sizeof(chunk->bound_map[0]), gfp);
1461 0 : if (!chunk->bound_map)
1462 : goto bound_map_fail;
1463 :
1464 0 : chunk->md_blocks = pcpu_mem_zalloc(pcpu_chunk_nr_blocks(chunk) *
1465 : sizeof(chunk->md_blocks[0]), gfp);
1466 0 : if (!chunk->md_blocks)
1467 : goto md_blocks_fail;
1468 :
1469 : #ifdef CONFIG_MEMCG_KMEM
1470 : if (!mem_cgroup_kmem_disabled()) {
1471 : chunk->obj_cgroups =
1472 : pcpu_mem_zalloc(pcpu_chunk_map_bits(chunk) *
1473 : sizeof(struct obj_cgroup *), gfp);
1474 : if (!chunk->obj_cgroups)
1475 : goto objcg_fail;
1476 : }
1477 : #endif
1478 :
1479 0 : pcpu_init_md_blocks(chunk);
1480 :
1481 : /* init metadata */
1482 0 : chunk->free_bytes = chunk->nr_pages * PAGE_SIZE;
1483 :
1484 0 : return chunk;
1485 :
1486 : #ifdef CONFIG_MEMCG_KMEM
1487 : objcg_fail:
1488 : pcpu_mem_free(chunk->md_blocks);
1489 : #endif
1490 : md_blocks_fail:
1491 0 : pcpu_mem_free(chunk->bound_map);
1492 : bound_map_fail:
1493 0 : pcpu_mem_free(chunk->alloc_map);
1494 : alloc_map_fail:
1495 0 : pcpu_mem_free(chunk);
1496 :
1497 0 : return NULL;
1498 : }
1499 :
1500 0 : static void pcpu_free_chunk(struct pcpu_chunk *chunk)
1501 : {
1502 0 : if (!chunk)
1503 : return;
1504 : #ifdef CONFIG_MEMCG_KMEM
1505 : pcpu_mem_free(chunk->obj_cgroups);
1506 : #endif
1507 0 : pcpu_mem_free(chunk->md_blocks);
1508 0 : pcpu_mem_free(chunk->bound_map);
1509 0 : pcpu_mem_free(chunk->alloc_map);
1510 : pcpu_mem_free(chunk);
1511 : }
1512 :
1513 : /**
1514 : * pcpu_chunk_populated - post-population bookkeeping
1515 : * @chunk: pcpu_chunk which got populated
1516 : * @page_start: the start page
1517 : * @page_end: the end page
1518 : *
1519 : * Pages in [@page_start,@page_end) have been populated to @chunk. Update
1520 : * the bookkeeping information accordingly. Must be called after each
1521 : * successful population.
1522 : */
1523 0 : static void pcpu_chunk_populated(struct pcpu_chunk *chunk, int page_start,
1524 : int page_end)
1525 : {
1526 0 : int nr = page_end - page_start;
1527 :
1528 : lockdep_assert_held(&pcpu_lock);
1529 :
1530 0 : bitmap_set(chunk->populated, page_start, nr);
1531 0 : chunk->nr_populated += nr;
1532 0 : pcpu_nr_populated += nr;
1533 :
1534 0 : pcpu_update_empty_pages(chunk, nr);
1535 0 : }
1536 :
1537 : /**
1538 : * pcpu_chunk_depopulated - post-depopulation bookkeeping
1539 : * @chunk: pcpu_chunk which got depopulated
1540 : * @page_start: the start page
1541 : * @page_end: the end page
1542 : *
1543 : * Pages in [@page_start,@page_end) have been depopulated from @chunk.
1544 : * Update the bookkeeping information accordingly. Must be called after
1545 : * each successful depopulation.
1546 : */
1547 0 : static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk,
1548 : int page_start, int page_end)
1549 : {
1550 0 : int nr = page_end - page_start;
1551 :
1552 : lockdep_assert_held(&pcpu_lock);
1553 :
1554 0 : bitmap_clear(chunk->populated, page_start, nr);
1555 0 : chunk->nr_populated -= nr;
1556 0 : pcpu_nr_populated -= nr;
1557 :
1558 0 : pcpu_update_empty_pages(chunk, -nr);
1559 0 : }
1560 :
1561 : /*
1562 : * Chunk management implementation.
1563 : *
1564 : * To allow different implementations, chunk alloc/free and
1565 : * [de]population are implemented in a separate file which is pulled
1566 : * into this file and compiled together. The following functions
1567 : * should be implemented.
1568 : *
1569 : * pcpu_populate_chunk - populate the specified range of a chunk
1570 : * pcpu_depopulate_chunk - depopulate the specified range of a chunk
1571 : * pcpu_post_unmap_tlb_flush - flush tlb for the specified range of a chunk
1572 : * pcpu_create_chunk - create a new chunk
1573 : * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
1574 : * pcpu_addr_to_page - translate address to physical address
1575 : * pcpu_verify_alloc_info - check alloc_info is acceptable during init
1576 : */
1577 : static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
1578 : int page_start, int page_end, gfp_t gfp);
1579 : static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
1580 : int page_start, int page_end);
1581 : static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
1582 : int page_start, int page_end);
1583 : static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp);
1584 : static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
1585 : static struct page *pcpu_addr_to_page(void *addr);
1586 : static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
1587 :
1588 : #ifdef CONFIG_NEED_PER_CPU_KM
1589 : #include "percpu-km.c"
1590 : #else
1591 : #include "percpu-vm.c"
1592 : #endif
1593 :
1594 : /**
1595 : * pcpu_chunk_addr_search - determine chunk containing specified address
1596 : * @addr: address for which the chunk needs to be determined.
1597 : *
1598 : * This is an internal function that handles all but static allocations.
1599 : * Static percpu address values should never be passed into the allocator.
1600 : *
1601 : * RETURNS:
1602 : * The address of the found chunk.
1603 : */
1604 0 : static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
1605 : {
1606 : /* is it in the dynamic region (first chunk)? */
1607 0 : if (pcpu_addr_in_chunk(pcpu_first_chunk, addr))
1608 : return pcpu_first_chunk;
1609 :
1610 : /* is it in the reserved region? */
1611 0 : if (pcpu_addr_in_chunk(pcpu_reserved_chunk, addr))
1612 : return pcpu_reserved_chunk;
1613 :
1614 : /*
1615 : * The address is relative to unit0 which might be unused and
1616 : * thus unmapped. Offset the address to the unit space of the
1617 : * current processor before looking it up in the vmalloc
1618 : * space. Note that any possible cpu id can be used here, so
1619 : * there's no need to worry about preemption or cpu hotplug.
1620 : */
1621 0 : addr += pcpu_unit_offsets[raw_smp_processor_id()];
1622 0 : return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
1623 : }
1624 :
1625 : #ifdef CONFIG_MEMCG_KMEM
1626 : static bool pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp,
1627 : struct obj_cgroup **objcgp)
1628 : {
1629 : struct obj_cgroup *objcg;
1630 :
1631 : if (!memcg_kmem_enabled() || !(gfp & __GFP_ACCOUNT))
1632 : return true;
1633 :
1634 : objcg = get_obj_cgroup_from_current();
1635 : if (!objcg)
1636 : return true;
1637 :
1638 : if (obj_cgroup_charge(objcg, gfp, pcpu_obj_full_size(size))) {
1639 : obj_cgroup_put(objcg);
1640 : return false;
1641 : }
1642 :
1643 : *objcgp = objcg;
1644 : return true;
1645 : }
1646 :
1647 : static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg,
1648 : struct pcpu_chunk *chunk, int off,
1649 : size_t size)
1650 : {
1651 : if (!objcg)
1652 : return;
1653 :
1654 : if (likely(chunk && chunk->obj_cgroups)) {
1655 : chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = objcg;
1656 :
1657 : rcu_read_lock();
1658 : mod_memcg_state(obj_cgroup_memcg(objcg), MEMCG_PERCPU_B,
1659 : pcpu_obj_full_size(size));
1660 : rcu_read_unlock();
1661 : } else {
1662 : obj_cgroup_uncharge(objcg, pcpu_obj_full_size(size));
1663 : obj_cgroup_put(objcg);
1664 : }
1665 : }
1666 :
1667 : static void pcpu_memcg_free_hook(struct pcpu_chunk *chunk, int off, size_t size)
1668 : {
1669 : struct obj_cgroup *objcg;
1670 :
1671 : if (unlikely(!chunk->obj_cgroups))
1672 : return;
1673 :
1674 : objcg = chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT];
1675 : if (!objcg)
1676 : return;
1677 : chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = NULL;
1678 :
1679 : obj_cgroup_uncharge(objcg, pcpu_obj_full_size(size));
1680 :
1681 : rcu_read_lock();
1682 : mod_memcg_state(obj_cgroup_memcg(objcg), MEMCG_PERCPU_B,
1683 : -pcpu_obj_full_size(size));
1684 : rcu_read_unlock();
1685 :
1686 : obj_cgroup_put(objcg);
1687 : }
1688 :
1689 : #else /* CONFIG_MEMCG_KMEM */
1690 : static bool
1691 : pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp, struct obj_cgroup **objcgp)
1692 : {
1693 : return true;
1694 : }
1695 :
1696 : static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg,
1697 : struct pcpu_chunk *chunk, int off,
1698 : size_t size)
1699 : {
1700 : }
1701 :
1702 : static void pcpu_memcg_free_hook(struct pcpu_chunk *chunk, int off, size_t size)
1703 : {
1704 : }
1705 : #endif /* CONFIG_MEMCG_KMEM */
1706 :
1707 : /**
1708 : * pcpu_alloc - the percpu allocator
1709 : * @size: size of area to allocate in bytes
1710 : * @align: alignment of area (max PAGE_SIZE)
1711 : * @reserved: allocate from the reserved chunk if available
1712 : * @gfp: allocation flags
1713 : *
1714 : * Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't
1715 : * contain %GFP_KERNEL, the allocation is atomic. If @gfp has __GFP_NOWARN
1716 : * then no warning will be triggered on invalid or failed allocation
1717 : * requests.
1718 : *
1719 : * RETURNS:
1720 : * Percpu pointer to the allocated area on success, NULL on failure.
1721 : */
1722 238 : static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
1723 : gfp_t gfp)
1724 : {
1725 : gfp_t pcpu_gfp;
1726 : bool is_atomic;
1727 : bool do_warn;
1728 238 : struct obj_cgroup *objcg = NULL;
1729 : static int warn_limit = 10;
1730 : struct pcpu_chunk *chunk, *next;
1731 : const char *err;
1732 : int slot, off, cpu, ret;
1733 : unsigned long flags;
1734 : void __percpu *ptr;
1735 : size_t bits, bit_align;
1736 :
1737 238 : gfp = current_gfp_context(gfp);
1738 : /* whitelisted flags that can be passed to the backing allocators */
1739 238 : pcpu_gfp = gfp & (GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
1740 238 : is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;
1741 238 : do_warn = !(gfp & __GFP_NOWARN);
1742 :
1743 : /*
1744 : * There is now a minimum allocation size of PCPU_MIN_ALLOC_SIZE,
1745 : * therefore alignment must be a minimum of that many bytes.
1746 : * An allocation may have internal fragmentation from rounding up
1747 : * of up to PCPU_MIN_ALLOC_SIZE - 1 bytes.
1748 : */
1749 238 : if (unlikely(align < PCPU_MIN_ALLOC_SIZE))
1750 1 : align = PCPU_MIN_ALLOC_SIZE;
1751 :
1752 238 : size = ALIGN(size, PCPU_MIN_ALLOC_SIZE);
1753 238 : bits = size >> PCPU_MIN_ALLOC_SHIFT;
1754 238 : bit_align = align >> PCPU_MIN_ALLOC_SHIFT;
1755 :
1756 476 : if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE ||
1757 : !is_power_of_2(align))) {
1758 0 : WARN(do_warn, "illegal size (%zu) or align (%zu) for percpu allocation\n",
1759 : size, align);
1760 : return NULL;
1761 : }
1762 :
1763 238 : if (unlikely(!pcpu_memcg_pre_alloc_hook(size, gfp, &objcg)))
1764 : return NULL;
1765 :
1766 238 : if (!is_atomic) {
1767 : /*
1768 : * pcpu_balance_workfn() allocates memory under this mutex,
1769 : * and it may wait for memory reclaim. Allow current task
1770 : * to become OOM victim, in case of memory pressure.
1771 : */
1772 238 : if (gfp & __GFP_NOFAIL) {
1773 0 : mutex_lock(&pcpu_alloc_mutex);
1774 238 : } else if (mutex_lock_killable(&pcpu_alloc_mutex)) {
1775 : pcpu_memcg_post_alloc_hook(objcg, NULL, 0, size);
1776 : return NULL;
1777 : }
1778 : }
1779 :
1780 238 : spin_lock_irqsave(&pcpu_lock, flags);
1781 :
1782 : /* serve reserved allocations from the reserved chunk if available */
1783 238 : if (reserved && pcpu_reserved_chunk) {
1784 0 : chunk = pcpu_reserved_chunk;
1785 :
1786 0 : off = pcpu_find_block_fit(chunk, bits, bit_align, is_atomic);
1787 0 : if (off < 0) {
1788 : err = "alloc from reserved chunk failed";
1789 : goto fail_unlock;
1790 : }
1791 :
1792 0 : off = pcpu_alloc_area(chunk, bits, bit_align, off);
1793 0 : if (off >= 0)
1794 : goto area_found;
1795 :
1796 : err = "alloc from reserved chunk failed";
1797 : goto fail_unlock;
1798 : }
1799 :
1800 : restart:
1801 : /* search through normal chunks */
1802 2740 : for (slot = pcpu_size_to_slot(size); slot <= pcpu_free_slot; slot++) {
1803 2740 : list_for_each_entry_safe(chunk, next, &pcpu_chunk_lists[slot],
1804 : list) {
1805 238 : off = pcpu_find_block_fit(chunk, bits, bit_align,
1806 : is_atomic);
1807 238 : if (off < 0) {
1808 0 : if (slot < PCPU_SLOT_FAIL_THRESHOLD)
1809 : pcpu_chunk_move(chunk, 0);
1810 0 : continue;
1811 : }
1812 :
1813 238 : off = pcpu_alloc_area(chunk, bits, bit_align, off);
1814 238 : if (off >= 0) {
1815 238 : pcpu_reintegrate_chunk(chunk);
1816 238 : goto area_found;
1817 : }
1818 : }
1819 : }
1820 :
1821 0 : spin_unlock_irqrestore(&pcpu_lock, flags);
1822 :
1823 : /*
1824 : * No space left. Create a new chunk. We don't want multiple
1825 : * tasks to create chunks simultaneously. Serialize and create iff
1826 : * there's still no empty chunk after grabbing the mutex.
1827 : */
1828 0 : if (is_atomic) {
1829 : err = "atomic alloc failed, no space left";
1830 : goto fail;
1831 : }
1832 :
1833 0 : if (list_empty(&pcpu_chunk_lists[pcpu_free_slot])) {
1834 0 : chunk = pcpu_create_chunk(pcpu_gfp);
1835 0 : if (!chunk) {
1836 : err = "failed to allocate new chunk";
1837 : goto fail;
1838 : }
1839 :
1840 0 : spin_lock_irqsave(&pcpu_lock, flags);
1841 0 : pcpu_chunk_relocate(chunk, -1);
1842 : } else {
1843 0 : spin_lock_irqsave(&pcpu_lock, flags);
1844 : }
1845 :
1846 : goto restart;
1847 :
1848 : area_found:
1849 238 : pcpu_stats_area_alloc(chunk, size);
1850 238 : spin_unlock_irqrestore(&pcpu_lock, flags);
1851 :
1852 : /* populate if not all pages are already there */
1853 238 : if (!is_atomic) {
1854 : unsigned int page_end, rs, re;
1855 :
1856 238 : rs = PFN_DOWN(off);
1857 238 : page_end = PFN_UP(off + size);
1858 :
1859 238 : for_each_clear_bitrange_from(rs, re, chunk->populated, page_end) {
1860 0 : WARN_ON(chunk->immutable);
1861 :
1862 0 : ret = pcpu_populate_chunk(chunk, rs, re, pcpu_gfp);
1863 :
1864 0 : spin_lock_irqsave(&pcpu_lock, flags);
1865 : if (ret) {
1866 : pcpu_free_area(chunk, off);
1867 : err = "failed to populate";
1868 : goto fail_unlock;
1869 : }
1870 0 : pcpu_chunk_populated(chunk, rs, re);
1871 0 : spin_unlock_irqrestore(&pcpu_lock, flags);
1872 : }
1873 :
1874 238 : mutex_unlock(&pcpu_alloc_mutex);
1875 : }
1876 :
1877 238 : if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
1878 : pcpu_schedule_balance_work();
1879 :
1880 : /* clear the areas and return address relative to base address */
1881 238 : for_each_possible_cpu(cpu)
1882 476 : memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
1883 :
1884 238 : ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
1885 238 : kmemleak_alloc_percpu(ptr, size, gfp);
1886 :
1887 238 : trace_percpu_alloc_percpu(reserved, is_atomic, size, align,
1888 : chunk->base_addr, off, ptr);
1889 :
1890 238 : pcpu_memcg_post_alloc_hook(objcg, chunk, off, size);
1891 :
1892 238 : return ptr;
1893 :
1894 : fail_unlock:
1895 : spin_unlock_irqrestore(&pcpu_lock, flags);
1896 : fail:
1897 0 : trace_percpu_alloc_percpu_fail(reserved, is_atomic, size, align);
1898 :
1899 0 : if (!is_atomic && do_warn && warn_limit) {
1900 0 : pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n",
1901 : size, align, is_atomic, err);
1902 0 : dump_stack();
1903 0 : if (!--warn_limit)
1904 0 : pr_info("limit reached, disable warning\n");
1905 : }
1906 0 : if (is_atomic) {
1907 : /* see the flag handling in pcpu_balance_workfn() */
1908 0 : pcpu_atomic_alloc_failed = true;
1909 : pcpu_schedule_balance_work();
1910 : } else {
1911 0 : mutex_unlock(&pcpu_alloc_mutex);
1912 : }
1913 :
1914 : pcpu_memcg_post_alloc_hook(objcg, NULL, 0, size);
1915 :
1916 : return NULL;
1917 : }
1918 :
1919 : /**
1920 : * __alloc_percpu_gfp - allocate dynamic percpu area
1921 : * @size: size of area to allocate in bytes
1922 : * @align: alignment of area (max PAGE_SIZE)
1923 : * @gfp: allocation flags
1924 : *
1925 : * Allocate zero-filled percpu area of @size bytes aligned at @align. If
1926 : * @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can
1927 : * be called from any context but is a lot more likely to fail. If @gfp
1928 : * has __GFP_NOWARN then no warning will be triggered on invalid or failed
1929 : * allocation requests.
1930 : *
1931 : * RETURNS:
1932 : * Percpu pointer to the allocated area on success, NULL on failure.
1933 : */
1934 0 : void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp)
1935 : {
1936 0 : return pcpu_alloc(size, align, false, gfp);
1937 : }
1938 : EXPORT_SYMBOL_GPL(__alloc_percpu_gfp);
1939 :
1940 : /**
1941 : * __alloc_percpu - allocate dynamic percpu area
1942 : * @size: size of area to allocate in bytes
1943 : * @align: alignment of area (max PAGE_SIZE)
1944 : *
1945 : * Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL).
1946 : */
1947 238 : void __percpu *__alloc_percpu(size_t size, size_t align)
1948 : {
1949 238 : return pcpu_alloc(size, align, false, GFP_KERNEL);
1950 : }
1951 : EXPORT_SYMBOL_GPL(__alloc_percpu);
1952 :
1953 : /**
1954 : * __alloc_reserved_percpu - allocate reserved percpu area
1955 : * @size: size of area to allocate in bytes
1956 : * @align: alignment of area (max PAGE_SIZE)
1957 : *
1958 : * Allocate zero-filled percpu area of @size bytes aligned at @align
1959 : * from reserved percpu area if arch has set it up; otherwise,
1960 : * allocation is served from the same dynamic area. Might sleep.
1961 : * Might trigger writeouts.
1962 : *
1963 : * CONTEXT:
1964 : * Does GFP_KERNEL allocation.
1965 : *
1966 : * RETURNS:
1967 : * Percpu pointer to the allocated area on success, NULL on failure.
1968 : */
1969 0 : void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
1970 : {
1971 0 : return pcpu_alloc(size, align, true, GFP_KERNEL);
1972 : }
1973 :
1974 : /**
1975 : * pcpu_balance_free - manage the amount of free chunks
1976 : * @empty_only: free chunks only if there are no populated pages
1977 : *
1978 : * If empty_only is %false, reclaim all fully free chunks regardless of the
1979 : * number of populated pages. Otherwise, only reclaim chunks that have no
1980 : * populated pages.
1981 : *
1982 : * CONTEXT:
1983 : * pcpu_lock (can be dropped temporarily)
1984 : */
1985 0 : static void pcpu_balance_free(bool empty_only)
1986 : {
1987 0 : LIST_HEAD(to_free);
1988 0 : struct list_head *free_head = &pcpu_chunk_lists[pcpu_free_slot];
1989 : struct pcpu_chunk *chunk, *next;
1990 :
1991 : lockdep_assert_held(&pcpu_lock);
1992 :
1993 : /*
1994 : * There's no reason to keep around multiple unused chunks and VM
1995 : * areas can be scarce. Destroy all free chunks except for one.
1996 : */
1997 0 : list_for_each_entry_safe(chunk, next, free_head, list) {
1998 0 : WARN_ON(chunk->immutable);
1999 :
2000 : /* spare the first one */
2001 0 : if (chunk == list_first_entry(free_head, struct pcpu_chunk, list))
2002 0 : continue;
2003 :
2004 0 : if (!empty_only || chunk->nr_empty_pop_pages == 0)
2005 0 : list_move(&chunk->list, &to_free);
2006 : }
2007 :
2008 0 : if (list_empty(&to_free))
2009 0 : return;
2010 :
2011 0 : spin_unlock_irq(&pcpu_lock);
2012 0 : list_for_each_entry_safe(chunk, next, &to_free, list) {
2013 : unsigned int rs, re;
2014 :
2015 0 : for_each_set_bitrange(rs, re, chunk->populated, chunk->nr_pages) {
2016 0 : pcpu_depopulate_chunk(chunk, rs, re);
2017 0 : spin_lock_irq(&pcpu_lock);
2018 0 : pcpu_chunk_depopulated(chunk, rs, re);
2019 0 : spin_unlock_irq(&pcpu_lock);
2020 : }
2021 0 : pcpu_destroy_chunk(chunk);
2022 0 : cond_resched();
2023 : }
2024 0 : spin_lock_irq(&pcpu_lock);
2025 : }
2026 :
2027 : /**
2028 : * pcpu_balance_populated - manage the amount of populated pages
2029 : *
2030 : * Maintain a certain amount of populated pages to satisfy atomic allocations.
2031 : * It is possible that this is called when physical memory is scarce causing
2032 : * OOM killer to be triggered. We should avoid doing so until an actual
2033 : * allocation causes the failure as it is possible that requests can be
2034 : * serviced from already backed regions.
2035 : *
2036 : * CONTEXT:
2037 : * pcpu_lock (can be dropped temporarily)
2038 : */
2039 0 : static void pcpu_balance_populated(void)
2040 : {
2041 : /* gfp flags passed to underlying allocators */
2042 0 : const gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
2043 : struct pcpu_chunk *chunk;
2044 : int slot, nr_to_pop, ret;
2045 :
2046 : lockdep_assert_held(&pcpu_lock);
2047 :
2048 : /*
2049 : * Ensure there are certain number of free populated pages for
2050 : * atomic allocs. Fill up from the most packed so that atomic
2051 : * allocs don't increase fragmentation. If atomic allocation
2052 : * failed previously, always populate the maximum amount. This
2053 : * should prevent atomic allocs larger than PAGE_SIZE from keeping
2054 : * failing indefinitely; however, large atomic allocs are not
2055 : * something we support properly and can be highly unreliable and
2056 : * inefficient.
2057 : */
2058 : retry_pop:
2059 0 : if (pcpu_atomic_alloc_failed) {
2060 0 : nr_to_pop = PCPU_EMPTY_POP_PAGES_HIGH;
2061 : /* best effort anyway, don't worry about synchronization */
2062 0 : pcpu_atomic_alloc_failed = false;
2063 : } else {
2064 0 : nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH -
2065 : pcpu_nr_empty_pop_pages,
2066 : 0, PCPU_EMPTY_POP_PAGES_HIGH);
2067 : }
2068 :
2069 0 : for (slot = pcpu_size_to_slot(PAGE_SIZE); slot <= pcpu_free_slot; slot++) {
2070 0 : unsigned int nr_unpop = 0, rs, re;
2071 :
2072 0 : if (!nr_to_pop)
2073 : break;
2074 :
2075 0 : list_for_each_entry(chunk, &pcpu_chunk_lists[slot], list) {
2076 0 : nr_unpop = chunk->nr_pages - chunk->nr_populated;
2077 0 : if (nr_unpop)
2078 : break;
2079 : }
2080 :
2081 0 : if (!nr_unpop)
2082 0 : continue;
2083 :
2084 : /* @chunk can't go away while pcpu_alloc_mutex is held */
2085 0 : for_each_clear_bitrange(rs, re, chunk->populated, chunk->nr_pages) {
2086 0 : int nr = min_t(int, re - rs, nr_to_pop);
2087 :
2088 0 : spin_unlock_irq(&pcpu_lock);
2089 0 : ret = pcpu_populate_chunk(chunk, rs, rs + nr, gfp);
2090 0 : cond_resched();
2091 0 : spin_lock_irq(&pcpu_lock);
2092 : if (!ret) {
2093 0 : nr_to_pop -= nr;
2094 0 : pcpu_chunk_populated(chunk, rs, rs + nr);
2095 : } else {
2096 : nr_to_pop = 0;
2097 : }
2098 :
2099 0 : if (!nr_to_pop)
2100 : break;
2101 : }
2102 : }
2103 :
2104 0 : if (nr_to_pop) {
2105 : /* ran out of chunks to populate, create a new one and retry */
2106 0 : spin_unlock_irq(&pcpu_lock);
2107 0 : chunk = pcpu_create_chunk(gfp);
2108 0 : cond_resched();
2109 0 : spin_lock_irq(&pcpu_lock);
2110 0 : if (chunk) {
2111 0 : pcpu_chunk_relocate(chunk, -1);
2112 0 : goto retry_pop;
2113 : }
2114 : }
2115 0 : }
2116 :
2117 : /**
2118 : * pcpu_reclaim_populated - scan over to_depopulate chunks and free empty pages
2119 : *
2120 : * Scan over chunks in the depopulate list and try to release unused populated
2121 : * pages back to the system. Depopulated chunks are sidelined to prevent
2122 : * repopulating these pages unless required. Fully free chunks are reintegrated
2123 : * and freed accordingly (1 is kept around). If we drop below the empty
2124 : * populated pages threshold, reintegrate the chunk if it has empty free pages.
2125 : * Each chunk is scanned in the reverse order to keep populated pages close to
2126 : * the beginning of the chunk.
2127 : *
2128 : * CONTEXT:
2129 : * pcpu_lock (can be dropped temporarily)
2130 : *
2131 : */
2132 0 : static void pcpu_reclaim_populated(void)
2133 : {
2134 : struct pcpu_chunk *chunk;
2135 : struct pcpu_block_md *block;
2136 : int freed_page_start, freed_page_end;
2137 : int i, end;
2138 : bool reintegrate;
2139 :
2140 : lockdep_assert_held(&pcpu_lock);
2141 :
2142 : /*
2143 : * Once a chunk is isolated to the to_depopulate list, the chunk is no
2144 : * longer discoverable to allocations whom may populate pages. The only
2145 : * other accessor is the free path which only returns area back to the
2146 : * allocator not touching the populated bitmap.
2147 : */
2148 0 : while (!list_empty(&pcpu_chunk_lists[pcpu_to_depopulate_slot])) {
2149 0 : chunk = list_first_entry(&pcpu_chunk_lists[pcpu_to_depopulate_slot],
2150 : struct pcpu_chunk, list);
2151 0 : WARN_ON(chunk->immutable);
2152 :
2153 : /*
2154 : * Scan chunk's pages in the reverse order to keep populated
2155 : * pages close to the beginning of the chunk.
2156 : */
2157 0 : freed_page_start = chunk->nr_pages;
2158 0 : freed_page_end = 0;
2159 0 : reintegrate = false;
2160 0 : for (i = chunk->nr_pages - 1, end = -1; i >= 0; i--) {
2161 : /* no more work to do */
2162 0 : if (chunk->nr_empty_pop_pages == 0)
2163 : break;
2164 :
2165 : /* reintegrate chunk to prevent atomic alloc failures */
2166 0 : if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_HIGH) {
2167 : reintegrate = true;
2168 : goto end_chunk;
2169 : }
2170 :
2171 : /*
2172 : * If the page is empty and populated, start or
2173 : * extend the (i, end) range. If i == 0, decrease
2174 : * i and perform the depopulation to cover the last
2175 : * (first) page in the chunk.
2176 : */
2177 0 : block = chunk->md_blocks + i;
2178 0 : if (block->contig_hint == PCPU_BITMAP_BLOCK_BITS &&
2179 0 : test_bit(i, chunk->populated)) {
2180 0 : if (end == -1)
2181 0 : end = i;
2182 0 : if (i > 0)
2183 0 : continue;
2184 0 : i--;
2185 : }
2186 :
2187 : /* depopulate if there is an active range */
2188 0 : if (end == -1)
2189 0 : continue;
2190 :
2191 0 : spin_unlock_irq(&pcpu_lock);
2192 0 : pcpu_depopulate_chunk(chunk, i + 1, end + 1);
2193 0 : cond_resched();
2194 0 : spin_lock_irq(&pcpu_lock);
2195 :
2196 0 : pcpu_chunk_depopulated(chunk, i + 1, end + 1);
2197 0 : freed_page_start = min(freed_page_start, i + 1);
2198 0 : freed_page_end = max(freed_page_end, end + 1);
2199 :
2200 : /* reset the range and continue */
2201 0 : end = -1;
2202 : }
2203 :
2204 : end_chunk:
2205 : /* batch tlb flush per chunk to amortize cost */
2206 0 : if (freed_page_start < freed_page_end) {
2207 0 : spin_unlock_irq(&pcpu_lock);
2208 0 : pcpu_post_unmap_tlb_flush(chunk,
2209 : freed_page_start,
2210 : freed_page_end);
2211 0 : cond_resched();
2212 : spin_lock_irq(&pcpu_lock);
2213 : }
2214 :
2215 0 : if (reintegrate || chunk->free_bytes == pcpu_unit_size)
2216 0 : pcpu_reintegrate_chunk(chunk);
2217 : else
2218 0 : list_move_tail(&chunk->list,
2219 0 : &pcpu_chunk_lists[pcpu_sidelined_slot]);
2220 : }
2221 0 : }
2222 :
2223 : /**
2224 : * pcpu_balance_workfn - manage the amount of free chunks and populated pages
2225 : * @work: unused
2226 : *
2227 : * For each chunk type, manage the number of fully free chunks and the number of
2228 : * populated pages. An important thing to consider is when pages are freed and
2229 : * how they contribute to the global counts.
2230 : */
2231 0 : static void pcpu_balance_workfn(struct work_struct *work)
2232 : {
2233 : /*
2234 : * pcpu_balance_free() is called twice because the first time we may
2235 : * trim pages in the active pcpu_nr_empty_pop_pages which may cause us
2236 : * to grow other chunks. This then gives pcpu_reclaim_populated() time
2237 : * to move fully free chunks to the active list to be freed if
2238 : * appropriate.
2239 : */
2240 0 : mutex_lock(&pcpu_alloc_mutex);
2241 0 : spin_lock_irq(&pcpu_lock);
2242 :
2243 0 : pcpu_balance_free(false);
2244 0 : pcpu_reclaim_populated();
2245 0 : pcpu_balance_populated();
2246 0 : pcpu_balance_free(true);
2247 :
2248 0 : spin_unlock_irq(&pcpu_lock);
2249 0 : mutex_unlock(&pcpu_alloc_mutex);
2250 0 : }
2251 :
2252 : /**
2253 : * free_percpu - free percpu area
2254 : * @ptr: pointer to area to free
2255 : *
2256 : * Free percpu area @ptr.
2257 : *
2258 : * CONTEXT:
2259 : * Can be called from atomic context.
2260 : */
2261 0 : void free_percpu(void __percpu *ptr)
2262 : {
2263 : void *addr;
2264 : struct pcpu_chunk *chunk;
2265 : unsigned long flags;
2266 : int size, off;
2267 0 : bool need_balance = false;
2268 :
2269 0 : if (!ptr)
2270 : return;
2271 :
2272 0 : kmemleak_free_percpu(ptr);
2273 :
2274 0 : addr = __pcpu_ptr_to_addr(ptr);
2275 :
2276 0 : spin_lock_irqsave(&pcpu_lock, flags);
2277 :
2278 0 : chunk = pcpu_chunk_addr_search(addr);
2279 0 : off = addr - chunk->base_addr;
2280 :
2281 0 : size = pcpu_free_area(chunk, off);
2282 :
2283 0 : pcpu_memcg_free_hook(chunk, off, size);
2284 :
2285 : /*
2286 : * If there are more than one fully free chunks, wake up grim reaper.
2287 : * If the chunk is isolated, it may be in the process of being
2288 : * reclaimed. Let reclaim manage cleaning up of that chunk.
2289 : */
2290 0 : if (!chunk->isolated && chunk->free_bytes == pcpu_unit_size) {
2291 : struct pcpu_chunk *pos;
2292 :
2293 0 : list_for_each_entry(pos, &pcpu_chunk_lists[pcpu_free_slot], list)
2294 0 : if (pos != chunk) {
2295 : need_balance = true;
2296 : break;
2297 : }
2298 : } else if (pcpu_should_reclaim_chunk(chunk)) {
2299 : pcpu_isolate_chunk(chunk);
2300 : need_balance = true;
2301 : }
2302 :
2303 0 : trace_percpu_free_percpu(chunk->base_addr, off, ptr);
2304 :
2305 0 : spin_unlock_irqrestore(&pcpu_lock, flags);
2306 :
2307 0 : if (need_balance)
2308 : pcpu_schedule_balance_work();
2309 : }
2310 : EXPORT_SYMBOL_GPL(free_percpu);
2311 :
2312 0 : bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr)
2313 : {
2314 : #ifdef CONFIG_SMP
2315 : const size_t static_size = __per_cpu_end - __per_cpu_start;
2316 : void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
2317 : unsigned int cpu;
2318 :
2319 : for_each_possible_cpu(cpu) {
2320 : void *start = per_cpu_ptr(base, cpu);
2321 : void *va = (void *)addr;
2322 :
2323 : if (va >= start && va < start + static_size) {
2324 : if (can_addr) {
2325 : *can_addr = (unsigned long) (va - start);
2326 : *can_addr += (unsigned long)
2327 : per_cpu_ptr(base, get_boot_cpu_id());
2328 : }
2329 : return true;
2330 : }
2331 : }
2332 : #endif
2333 : /* on UP, can't distinguish from other static vars, always false */
2334 0 : return false;
2335 : }
2336 :
2337 : /**
2338 : * is_kernel_percpu_address - test whether address is from static percpu area
2339 : * @addr: address to test
2340 : *
2341 : * Test whether @addr belongs to in-kernel static percpu area. Module
2342 : * static percpu areas are not considered. For those, use
2343 : * is_module_percpu_address().
2344 : *
2345 : * RETURNS:
2346 : * %true if @addr is from in-kernel static percpu area, %false otherwise.
2347 : */
2348 0 : bool is_kernel_percpu_address(unsigned long addr)
2349 : {
2350 0 : return __is_kernel_percpu_address(addr, NULL);
2351 : }
2352 :
2353 : /**
2354 : * per_cpu_ptr_to_phys - convert translated percpu address to physical address
2355 : * @addr: the address to be converted to physical address
2356 : *
2357 : * Given @addr which is dereferenceable address obtained via one of
2358 : * percpu access macros, this function translates it into its physical
2359 : * address. The caller is responsible for ensuring @addr stays valid
2360 : * until this function finishes.
2361 : *
2362 : * percpu allocator has special setup for the first chunk, which currently
2363 : * supports either embedding in linear address space or vmalloc mapping,
2364 : * and, from the second one, the backing allocator (currently either vm or
2365 : * km) provides translation.
2366 : *
2367 : * The addr can be translated simply without checking if it falls into the
2368 : * first chunk. But the current code reflects better how percpu allocator
2369 : * actually works, and the verification can discover both bugs in percpu
2370 : * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
2371 : * code.
2372 : *
2373 : * RETURNS:
2374 : * The physical address for @addr.
2375 : */
2376 0 : phys_addr_t per_cpu_ptr_to_phys(void *addr)
2377 : {
2378 0 : void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
2379 0 : bool in_first_chunk = false;
2380 : unsigned long first_low, first_high;
2381 : unsigned int cpu;
2382 :
2383 : /*
2384 : * The following test on unit_low/high isn't strictly
2385 : * necessary but will speed up lookups of addresses which
2386 : * aren't in the first chunk.
2387 : *
2388 : * The address check is against full chunk sizes. pcpu_base_addr
2389 : * points to the beginning of the first chunk including the
2390 : * static region. Assumes good intent as the first chunk may
2391 : * not be full (ie. < pcpu_unit_pages in size).
2392 : */
2393 0 : first_low = (unsigned long)pcpu_base_addr +
2394 0 : pcpu_unit_page_offset(pcpu_low_unit_cpu, 0);
2395 0 : first_high = (unsigned long)pcpu_base_addr +
2396 0 : pcpu_unit_page_offset(pcpu_high_unit_cpu, pcpu_unit_pages);
2397 0 : if ((unsigned long)addr >= first_low &&
2398 0 : (unsigned long)addr < first_high) {
2399 0 : for_each_possible_cpu(cpu) {
2400 0 : void *start = per_cpu_ptr(base, cpu);
2401 :
2402 0 : if (addr >= start && addr < start + pcpu_unit_size) {
2403 : in_first_chunk = true;
2404 : break;
2405 : }
2406 : }
2407 : }
2408 :
2409 0 : if (in_first_chunk) {
2410 0 : if (!is_vmalloc_addr(addr))
2411 0 : return __pa(addr);
2412 : else
2413 0 : return page_to_phys(vmalloc_to_page(addr)) +
2414 0 : offset_in_page(addr);
2415 : } else
2416 0 : return page_to_phys(pcpu_addr_to_page(addr)) +
2417 0 : offset_in_page(addr);
2418 : }
2419 :
2420 : /**
2421 : * pcpu_alloc_alloc_info - allocate percpu allocation info
2422 : * @nr_groups: the number of groups
2423 : * @nr_units: the number of units
2424 : *
2425 : * Allocate ai which is large enough for @nr_groups groups containing
2426 : * @nr_units units. The returned ai's groups[0].cpu_map points to the
2427 : * cpu_map array which is long enough for @nr_units and filled with
2428 : * NR_CPUS. It's the caller's responsibility to initialize cpu_map
2429 : * pointer of other groups.
2430 : *
2431 : * RETURNS:
2432 : * Pointer to the allocated pcpu_alloc_info on success, NULL on
2433 : * failure.
2434 : */
2435 1 : struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
2436 : int nr_units)
2437 : {
2438 : struct pcpu_alloc_info *ai;
2439 : size_t base_size, ai_size;
2440 : void *ptr;
2441 : int unit;
2442 :
2443 3 : base_size = ALIGN(struct_size(ai, groups, nr_groups),
2444 : __alignof__(ai->groups[0].cpu_map[0]));
2445 1 : ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
2446 :
2447 2 : ptr = memblock_alloc(PFN_ALIGN(ai_size), PAGE_SIZE);
2448 1 : if (!ptr)
2449 : return NULL;
2450 1 : ai = ptr;
2451 1 : ptr += base_size;
2452 :
2453 1 : ai->groups[0].cpu_map = ptr;
2454 :
2455 2 : for (unit = 0; unit < nr_units; unit++)
2456 1 : ai->groups[0].cpu_map[unit] = NR_CPUS;
2457 :
2458 1 : ai->nr_groups = nr_groups;
2459 1 : ai->__ai_size = PFN_ALIGN(ai_size);
2460 :
2461 1 : return ai;
2462 : }
2463 :
2464 : /**
2465 : * pcpu_free_alloc_info - free percpu allocation info
2466 : * @ai: pcpu_alloc_info to free
2467 : *
2468 : * Free @ai which was allocated by pcpu_alloc_alloc_info().
2469 : */
2470 1 : void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
2471 : {
2472 1 : memblock_free(ai, ai->__ai_size);
2473 1 : }
2474 :
2475 : /**
2476 : * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
2477 : * @lvl: loglevel
2478 : * @ai: allocation info to dump
2479 : *
2480 : * Print out information about @ai using loglevel @lvl.
2481 : */
2482 1 : static void pcpu_dump_alloc_info(const char *lvl,
2483 : const struct pcpu_alloc_info *ai)
2484 : {
2485 1 : int group_width = 1, cpu_width = 1, width;
2486 1 : char empty_str[] = "--------";
2487 1 : int alloc = 0, alloc_end = 0;
2488 : int group, v;
2489 : int upa, apl; /* units per alloc, allocs per line */
2490 :
2491 1 : v = ai->nr_groups;
2492 2 : while (v /= 10)
2493 0 : group_width++;
2494 :
2495 1 : v = num_possible_cpus();
2496 1 : while (v /= 10)
2497 : cpu_width++;
2498 1 : empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
2499 :
2500 1 : upa = ai->alloc_size / ai->unit_size;
2501 1 : width = upa * (cpu_width + 1) + group_width + 3;
2502 2 : apl = rounddown_pow_of_two(max(60 / width, 1));
2503 :
2504 1 : printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
2505 : lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
2506 : ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
2507 :
2508 2 : for (group = 0; group < ai->nr_groups; group++) {
2509 1 : const struct pcpu_group_info *gi = &ai->groups[group];
2510 1 : int unit = 0, unit_end = 0;
2511 :
2512 1 : BUG_ON(gi->nr_units % upa);
2513 3 : for (alloc_end += gi->nr_units / upa;
2514 1 : alloc < alloc_end; alloc++) {
2515 1 : if (!(alloc % apl)) {
2516 1 : pr_cont("\n");
2517 1 : printk("%spcpu-alloc: ", lvl);
2518 : }
2519 1 : pr_cont("[%0*d] ", group_width, group);
2520 :
2521 2 : for (unit_end += upa; unit < unit_end; unit++)
2522 1 : if (gi->cpu_map[unit] != NR_CPUS)
2523 1 : pr_cont("%0*d ",
2524 : cpu_width, gi->cpu_map[unit]);
2525 : else
2526 0 : pr_cont("%s ", empty_str);
2527 : }
2528 : }
2529 1 : pr_cont("\n");
2530 1 : }
2531 :
2532 : /**
2533 : * pcpu_setup_first_chunk - initialize the first percpu chunk
2534 : * @ai: pcpu_alloc_info describing how to percpu area is shaped
2535 : * @base_addr: mapped address
2536 : *
2537 : * Initialize the first percpu chunk which contains the kernel static
2538 : * percpu area. This function is to be called from arch percpu area
2539 : * setup path.
2540 : *
2541 : * @ai contains all information necessary to initialize the first
2542 : * chunk and prime the dynamic percpu allocator.
2543 : *
2544 : * @ai->static_size is the size of static percpu area.
2545 : *
2546 : * @ai->reserved_size, if non-zero, specifies the amount of bytes to
2547 : * reserve after the static area in the first chunk. This reserves
2548 : * the first chunk such that it's available only through reserved
2549 : * percpu allocation. This is primarily used to serve module percpu
2550 : * static areas on architectures where the addressing model has
2551 : * limited offset range for symbol relocations to guarantee module
2552 : * percpu symbols fall inside the relocatable range.
2553 : *
2554 : * @ai->dyn_size determines the number of bytes available for dynamic
2555 : * allocation in the first chunk. The area between @ai->static_size +
2556 : * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
2557 : *
2558 : * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
2559 : * and equal to or larger than @ai->static_size + @ai->reserved_size +
2560 : * @ai->dyn_size.
2561 : *
2562 : * @ai->atom_size is the allocation atom size and used as alignment
2563 : * for vm areas.
2564 : *
2565 : * @ai->alloc_size is the allocation size and always multiple of
2566 : * @ai->atom_size. This is larger than @ai->atom_size if
2567 : * @ai->unit_size is larger than @ai->atom_size.
2568 : *
2569 : * @ai->nr_groups and @ai->groups describe virtual memory layout of
2570 : * percpu areas. Units which should be colocated are put into the
2571 : * same group. Dynamic VM areas will be allocated according to these
2572 : * groupings. If @ai->nr_groups is zero, a single group containing
2573 : * all units is assumed.
2574 : *
2575 : * The caller should have mapped the first chunk at @base_addr and
2576 : * copied static data to each unit.
2577 : *
2578 : * The first chunk will always contain a static and a dynamic region.
2579 : * However, the static region is not managed by any chunk. If the first
2580 : * chunk also contains a reserved region, it is served by two chunks -
2581 : * one for the reserved region and one for the dynamic region. They
2582 : * share the same vm, but use offset regions in the area allocation map.
2583 : * The chunk serving the dynamic region is circulated in the chunk slots
2584 : * and available for dynamic allocation like any other chunk.
2585 : */
2586 1 : void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
2587 : void *base_addr)
2588 : {
2589 1 : size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
2590 : size_t static_size, dyn_size;
2591 : struct pcpu_chunk *chunk;
2592 : unsigned long *group_offsets;
2593 : size_t *group_sizes;
2594 : unsigned long *unit_off;
2595 : unsigned int cpu;
2596 : int *unit_map;
2597 : int group, unit, i;
2598 : int map_size;
2599 : unsigned long tmp_addr;
2600 : size_t alloc_size;
2601 :
2602 : #define PCPU_SETUP_BUG_ON(cond) do { \
2603 : if (unlikely(cond)) { \
2604 : pr_emerg("failed to initialize, %s\n", #cond); \
2605 : pr_emerg("cpu_possible_mask=%*pb\n", \
2606 : cpumask_pr_args(cpu_possible_mask)); \
2607 : pcpu_dump_alloc_info(KERN_EMERG, ai); \
2608 : BUG(); \
2609 : } \
2610 : } while (0)
2611 :
2612 : /* sanity checks */
2613 1 : PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
2614 : #ifdef CONFIG_SMP
2615 : PCPU_SETUP_BUG_ON(!ai->static_size);
2616 : PCPU_SETUP_BUG_ON(offset_in_page(__per_cpu_start));
2617 : #endif
2618 1 : PCPU_SETUP_BUG_ON(!base_addr);
2619 1 : PCPU_SETUP_BUG_ON(offset_in_page(base_addr));
2620 1 : PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
2621 1 : PCPU_SETUP_BUG_ON(offset_in_page(ai->unit_size));
2622 1 : PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
2623 : PCPU_SETUP_BUG_ON(!IS_ALIGNED(ai->unit_size, PCPU_BITMAP_BLOCK_SIZE));
2624 1 : PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
2625 1 : PCPU_SETUP_BUG_ON(!ai->dyn_size);
2626 1 : PCPU_SETUP_BUG_ON(!IS_ALIGNED(ai->reserved_size, PCPU_MIN_ALLOC_SIZE));
2627 : PCPU_SETUP_BUG_ON(!(IS_ALIGNED(PCPU_BITMAP_BLOCK_SIZE, PAGE_SIZE) ||
2628 : IS_ALIGNED(PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE)));
2629 1 : PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
2630 :
2631 : /* process group information and build config tables accordingly */
2632 1 : alloc_size = ai->nr_groups * sizeof(group_offsets[0]);
2633 1 : group_offsets = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
2634 1 : if (!group_offsets)
2635 0 : panic("%s: Failed to allocate %zu bytes\n", __func__,
2636 : alloc_size);
2637 :
2638 1 : alloc_size = ai->nr_groups * sizeof(group_sizes[0]);
2639 1 : group_sizes = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
2640 1 : if (!group_sizes)
2641 0 : panic("%s: Failed to allocate %zu bytes\n", __func__,
2642 : alloc_size);
2643 :
2644 1 : alloc_size = nr_cpu_ids * sizeof(unit_map[0]);
2645 1 : unit_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
2646 1 : if (!unit_map)
2647 0 : panic("%s: Failed to allocate %zu bytes\n", __func__,
2648 : alloc_size);
2649 :
2650 1 : alloc_size = nr_cpu_ids * sizeof(unit_off[0]);
2651 1 : unit_off = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
2652 1 : if (!unit_off)
2653 0 : panic("%s: Failed to allocate %zu bytes\n", __func__,
2654 : alloc_size);
2655 :
2656 1 : for (cpu = 0; cpu < nr_cpu_ids; cpu++)
2657 1 : unit_map[cpu] = UINT_MAX;
2658 :
2659 1 : pcpu_low_unit_cpu = NR_CPUS;
2660 1 : pcpu_high_unit_cpu = NR_CPUS;
2661 :
2662 2 : for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
2663 1 : const struct pcpu_group_info *gi = &ai->groups[group];
2664 :
2665 1 : group_offsets[group] = gi->base_offset;
2666 1 : group_sizes[group] = gi->nr_units * ai->unit_size;
2667 :
2668 2 : for (i = 0; i < gi->nr_units; i++) {
2669 1 : cpu = gi->cpu_map[i];
2670 1 : if (cpu == NR_CPUS)
2671 0 : continue;
2672 :
2673 1 : PCPU_SETUP_BUG_ON(cpu >= nr_cpu_ids);
2674 1 : PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
2675 1 : PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
2676 :
2677 1 : unit_map[cpu] = unit + i;
2678 1 : unit_off[cpu] = gi->base_offset + i * ai->unit_size;
2679 :
2680 : /* determine low/high unit_cpu */
2681 1 : if (pcpu_low_unit_cpu == NR_CPUS ||
2682 0 : unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
2683 1 : pcpu_low_unit_cpu = cpu;
2684 1 : if (pcpu_high_unit_cpu == NR_CPUS ||
2685 0 : unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
2686 1 : pcpu_high_unit_cpu = cpu;
2687 : }
2688 : }
2689 1 : pcpu_nr_units = unit;
2690 :
2691 2 : for_each_possible_cpu(cpu)
2692 1 : PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
2693 :
2694 : /* we're done parsing the input, undefine BUG macro and dump config */
2695 : #undef PCPU_SETUP_BUG_ON
2696 1 : pcpu_dump_alloc_info(KERN_DEBUG, ai);
2697 :
2698 1 : pcpu_nr_groups = ai->nr_groups;
2699 1 : pcpu_group_offsets = group_offsets;
2700 1 : pcpu_group_sizes = group_sizes;
2701 1 : pcpu_unit_map = unit_map;
2702 1 : pcpu_unit_offsets = unit_off;
2703 :
2704 : /* determine basic parameters */
2705 1 : pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
2706 1 : pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
2707 1 : pcpu_atom_size = ai->atom_size;
2708 3 : pcpu_chunk_struct_size = struct_size(chunk, populated,
2709 : BITS_TO_LONGS(pcpu_unit_pages));
2710 :
2711 1 : pcpu_stats_save_ai(ai);
2712 :
2713 : /*
2714 : * Allocate chunk slots. The slots after the active slots are:
2715 : * sidelined_slot - isolated, depopulated chunks
2716 : * free_slot - fully free chunks
2717 : * to_depopulate_slot - isolated, chunks to depopulate
2718 : */
2719 2 : pcpu_sidelined_slot = __pcpu_size_to_slot(pcpu_unit_size) + 1;
2720 1 : pcpu_free_slot = pcpu_sidelined_slot + 1;
2721 1 : pcpu_to_depopulate_slot = pcpu_free_slot + 1;
2722 1 : pcpu_nr_slots = pcpu_to_depopulate_slot + 1;
2723 2 : pcpu_chunk_lists = memblock_alloc(pcpu_nr_slots *
2724 : sizeof(pcpu_chunk_lists[0]),
2725 : SMP_CACHE_BYTES);
2726 1 : if (!pcpu_chunk_lists)
2727 0 : panic("%s: Failed to allocate %zu bytes\n", __func__,
2728 : pcpu_nr_slots * sizeof(pcpu_chunk_lists[0]));
2729 :
2730 17 : for (i = 0; i < pcpu_nr_slots; i++)
2731 34 : INIT_LIST_HEAD(&pcpu_chunk_lists[i]);
2732 :
2733 : /*
2734 : * The end of the static region needs to be aligned with the
2735 : * minimum allocation size as this offsets the reserved and
2736 : * dynamic region. The first chunk ends page aligned by
2737 : * expanding the dynamic region, therefore the dynamic region
2738 : * can be shrunk to compensate while still staying above the
2739 : * configured sizes.
2740 : */
2741 1 : static_size = ALIGN(ai->static_size, PCPU_MIN_ALLOC_SIZE);
2742 1 : dyn_size = ai->dyn_size - (static_size - ai->static_size);
2743 :
2744 : /*
2745 : * Initialize first chunk.
2746 : * If the reserved_size is non-zero, this initializes the reserved
2747 : * chunk. If the reserved_size is zero, the reserved chunk is NULL
2748 : * and the dynamic region is initialized here. The first chunk,
2749 : * pcpu_first_chunk, will always point to the chunk that serves
2750 : * the dynamic region.
2751 : */
2752 1 : tmp_addr = (unsigned long)base_addr + static_size;
2753 1 : map_size = ai->reserved_size ?: dyn_size;
2754 1 : chunk = pcpu_alloc_first_chunk(tmp_addr, map_size);
2755 :
2756 : /* init dynamic chunk if necessary */
2757 1 : if (ai->reserved_size) {
2758 0 : pcpu_reserved_chunk = chunk;
2759 :
2760 0 : tmp_addr = (unsigned long)base_addr + static_size +
2761 : ai->reserved_size;
2762 0 : map_size = dyn_size;
2763 0 : chunk = pcpu_alloc_first_chunk(tmp_addr, map_size);
2764 : }
2765 :
2766 : /* link the first chunk in */
2767 1 : pcpu_first_chunk = chunk;
2768 1 : pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages;
2769 1 : pcpu_chunk_relocate(pcpu_first_chunk, -1);
2770 :
2771 : /* include all regions of the first chunk */
2772 1 : pcpu_nr_populated += PFN_DOWN(size_sum);
2773 :
2774 : pcpu_stats_chunk_alloc();
2775 1 : trace_percpu_create_chunk(base_addr);
2776 :
2777 : /* we're done */
2778 1 : pcpu_base_addr = base_addr;
2779 1 : }
2780 :
2781 : #ifdef CONFIG_SMP
2782 :
2783 : const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = {
2784 : [PCPU_FC_AUTO] = "auto",
2785 : [PCPU_FC_EMBED] = "embed",
2786 : [PCPU_FC_PAGE] = "page",
2787 : };
2788 :
2789 : enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
2790 :
2791 : static int __init percpu_alloc_setup(char *str)
2792 : {
2793 : if (!str)
2794 : return -EINVAL;
2795 :
2796 : if (0)
2797 : /* nada */;
2798 : #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
2799 : else if (!strcmp(str, "embed"))
2800 : pcpu_chosen_fc = PCPU_FC_EMBED;
2801 : #endif
2802 : #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
2803 : else if (!strcmp(str, "page"))
2804 : pcpu_chosen_fc = PCPU_FC_PAGE;
2805 : #endif
2806 : else
2807 : pr_warn("unknown allocator %s specified\n", str);
2808 :
2809 : return 0;
2810 : }
2811 : early_param("percpu_alloc", percpu_alloc_setup);
2812 :
2813 : /*
2814 : * pcpu_embed_first_chunk() is used by the generic percpu setup.
2815 : * Build it if needed by the arch config or the generic setup is going
2816 : * to be used.
2817 : */
2818 : #if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
2819 : !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
2820 : #define BUILD_EMBED_FIRST_CHUNK
2821 : #endif
2822 :
2823 : /* build pcpu_page_first_chunk() iff needed by the arch config */
2824 : #if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
2825 : #define BUILD_PAGE_FIRST_CHUNK
2826 : #endif
2827 :
2828 : /* pcpu_build_alloc_info() is used by both embed and page first chunk */
2829 : #if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
2830 : /**
2831 : * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
2832 : * @reserved_size: the size of reserved percpu area in bytes
2833 : * @dyn_size: minimum free size for dynamic allocation in bytes
2834 : * @atom_size: allocation atom size
2835 : * @cpu_distance_fn: callback to determine distance between cpus, optional
2836 : *
2837 : * This function determines grouping of units, their mappings to cpus
2838 : * and other parameters considering needed percpu size, allocation
2839 : * atom size and distances between CPUs.
2840 : *
2841 : * Groups are always multiples of atom size and CPUs which are of
2842 : * LOCAL_DISTANCE both ways are grouped together and share space for
2843 : * units in the same group. The returned configuration is guaranteed
2844 : * to have CPUs on different nodes on different groups and >=75% usage
2845 : * of allocated virtual address space.
2846 : *
2847 : * RETURNS:
2848 : * On success, pointer to the new allocation_info is returned. On
2849 : * failure, ERR_PTR value is returned.
2850 : */
2851 : static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
2852 : size_t reserved_size, size_t dyn_size,
2853 : size_t atom_size,
2854 : pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
2855 : {
2856 : static int group_map[NR_CPUS] __initdata;
2857 : static int group_cnt[NR_CPUS] __initdata;
2858 : static struct cpumask mask __initdata;
2859 : const size_t static_size = __per_cpu_end - __per_cpu_start;
2860 : int nr_groups = 1, nr_units = 0;
2861 : size_t size_sum, min_unit_size, alloc_size;
2862 : int upa, max_upa, best_upa; /* units_per_alloc */
2863 : int last_allocs, group, unit;
2864 : unsigned int cpu, tcpu;
2865 : struct pcpu_alloc_info *ai;
2866 : unsigned int *cpu_map;
2867 :
2868 : /* this function may be called multiple times */
2869 : memset(group_map, 0, sizeof(group_map));
2870 : memset(group_cnt, 0, sizeof(group_cnt));
2871 : cpumask_clear(&mask);
2872 :
2873 : /* calculate size_sum and ensure dyn_size is enough for early alloc */
2874 : size_sum = PFN_ALIGN(static_size + reserved_size +
2875 : max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
2876 : dyn_size = size_sum - static_size - reserved_size;
2877 :
2878 : /*
2879 : * Determine min_unit_size, alloc_size and max_upa such that
2880 : * alloc_size is multiple of atom_size and is the smallest
2881 : * which can accommodate 4k aligned segments which are equal to
2882 : * or larger than min_unit_size.
2883 : */
2884 : min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
2885 :
2886 : /* determine the maximum # of units that can fit in an allocation */
2887 : alloc_size = roundup(min_unit_size, atom_size);
2888 : upa = alloc_size / min_unit_size;
2889 : while (alloc_size % upa || (offset_in_page(alloc_size / upa)))
2890 : upa--;
2891 : max_upa = upa;
2892 :
2893 : cpumask_copy(&mask, cpu_possible_mask);
2894 :
2895 : /* group cpus according to their proximity */
2896 : for (group = 0; !cpumask_empty(&mask); group++) {
2897 : /* pop the group's first cpu */
2898 : cpu = cpumask_first(&mask);
2899 : group_map[cpu] = group;
2900 : group_cnt[group]++;
2901 : cpumask_clear_cpu(cpu, &mask);
2902 :
2903 : for_each_cpu(tcpu, &mask) {
2904 : if (!cpu_distance_fn ||
2905 : (cpu_distance_fn(cpu, tcpu) == LOCAL_DISTANCE &&
2906 : cpu_distance_fn(tcpu, cpu) == LOCAL_DISTANCE)) {
2907 : group_map[tcpu] = group;
2908 : group_cnt[group]++;
2909 : cpumask_clear_cpu(tcpu, &mask);
2910 : }
2911 : }
2912 : }
2913 : nr_groups = group;
2914 :
2915 : /*
2916 : * Wasted space is caused by a ratio imbalance of upa to group_cnt.
2917 : * Expand the unit_size until we use >= 75% of the units allocated.
2918 : * Related to atom_size, which could be much larger than the unit_size.
2919 : */
2920 : last_allocs = INT_MAX;
2921 : best_upa = 0;
2922 : for (upa = max_upa; upa; upa--) {
2923 : int allocs = 0, wasted = 0;
2924 :
2925 : if (alloc_size % upa || (offset_in_page(alloc_size / upa)))
2926 : continue;
2927 :
2928 : for (group = 0; group < nr_groups; group++) {
2929 : int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
2930 : allocs += this_allocs;
2931 : wasted += this_allocs * upa - group_cnt[group];
2932 : }
2933 :
2934 : /*
2935 : * Don't accept if wastage is over 1/3. The
2936 : * greater-than comparison ensures upa==1 always
2937 : * passes the following check.
2938 : */
2939 : if (wasted > num_possible_cpus() / 3)
2940 : continue;
2941 :
2942 : /* and then don't consume more memory */
2943 : if (allocs > last_allocs)
2944 : break;
2945 : last_allocs = allocs;
2946 : best_upa = upa;
2947 : }
2948 : BUG_ON(!best_upa);
2949 : upa = best_upa;
2950 :
2951 : /* allocate and fill alloc_info */
2952 : for (group = 0; group < nr_groups; group++)
2953 : nr_units += roundup(group_cnt[group], upa);
2954 :
2955 : ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
2956 : if (!ai)
2957 : return ERR_PTR(-ENOMEM);
2958 : cpu_map = ai->groups[0].cpu_map;
2959 :
2960 : for (group = 0; group < nr_groups; group++) {
2961 : ai->groups[group].cpu_map = cpu_map;
2962 : cpu_map += roundup(group_cnt[group], upa);
2963 : }
2964 :
2965 : ai->static_size = static_size;
2966 : ai->reserved_size = reserved_size;
2967 : ai->dyn_size = dyn_size;
2968 : ai->unit_size = alloc_size / upa;
2969 : ai->atom_size = atom_size;
2970 : ai->alloc_size = alloc_size;
2971 :
2972 : for (group = 0, unit = 0; group < nr_groups; group++) {
2973 : struct pcpu_group_info *gi = &ai->groups[group];
2974 :
2975 : /*
2976 : * Initialize base_offset as if all groups are located
2977 : * back-to-back. The caller should update this to
2978 : * reflect actual allocation.
2979 : */
2980 : gi->base_offset = unit * ai->unit_size;
2981 :
2982 : for_each_possible_cpu(cpu)
2983 : if (group_map[cpu] == group)
2984 : gi->cpu_map[gi->nr_units++] = cpu;
2985 : gi->nr_units = roundup(gi->nr_units, upa);
2986 : unit += gi->nr_units;
2987 : }
2988 : BUG_ON(unit != nr_units);
2989 :
2990 : return ai;
2991 : }
2992 :
2993 : static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align,
2994 : pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
2995 : {
2996 : const unsigned long goal = __pa(MAX_DMA_ADDRESS);
2997 : #ifdef CONFIG_NUMA
2998 : int node = NUMA_NO_NODE;
2999 : void *ptr;
3000 :
3001 : if (cpu_to_nd_fn)
3002 : node = cpu_to_nd_fn(cpu);
3003 :
3004 : if (node == NUMA_NO_NODE || !node_online(node) || !NODE_DATA(node)) {
3005 : ptr = memblock_alloc_from(size, align, goal);
3006 : pr_info("cpu %d has no node %d or node-local memory\n",
3007 : cpu, node);
3008 : pr_debug("per cpu data for cpu%d %zu bytes at 0x%llx\n",
3009 : cpu, size, (u64)__pa(ptr));
3010 : } else {
3011 : ptr = memblock_alloc_try_nid(size, align, goal,
3012 : MEMBLOCK_ALLOC_ACCESSIBLE,
3013 : node);
3014 :
3015 : pr_debug("per cpu data for cpu%d %zu bytes on node%d at 0x%llx\n",
3016 : cpu, size, node, (u64)__pa(ptr));
3017 : }
3018 : return ptr;
3019 : #else
3020 : return memblock_alloc_from(size, align, goal);
3021 : #endif
3022 : }
3023 :
3024 : static void __init pcpu_fc_free(void *ptr, size_t size)
3025 : {
3026 : memblock_free(ptr, size);
3027 : }
3028 : #endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
3029 :
3030 : #if defined(BUILD_EMBED_FIRST_CHUNK)
3031 : /**
3032 : * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
3033 : * @reserved_size: the size of reserved percpu area in bytes
3034 : * @dyn_size: minimum free size for dynamic allocation in bytes
3035 : * @atom_size: allocation atom size
3036 : * @cpu_distance_fn: callback to determine distance between cpus, optional
3037 : * @cpu_to_nd_fn: callback to convert cpu to it's node, optional
3038 : *
3039 : * This is a helper to ease setting up embedded first percpu chunk and
3040 : * can be called where pcpu_setup_first_chunk() is expected.
3041 : *
3042 : * If this function is used to setup the first chunk, it is allocated
3043 : * by calling pcpu_fc_alloc and used as-is without being mapped into
3044 : * vmalloc area. Allocations are always whole multiples of @atom_size
3045 : * aligned to @atom_size.
3046 : *
3047 : * This enables the first chunk to piggy back on the linear physical
3048 : * mapping which often uses larger page size. Please note that this
3049 : * can result in very sparse cpu->unit mapping on NUMA machines thus
3050 : * requiring large vmalloc address space. Don't use this allocator if
3051 : * vmalloc space is not orders of magnitude larger than distances
3052 : * between node memory addresses (ie. 32bit NUMA machines).
3053 : *
3054 : * @dyn_size specifies the minimum dynamic area size.
3055 : *
3056 : * If the needed size is smaller than the minimum or specified unit
3057 : * size, the leftover is returned using pcpu_fc_free.
3058 : *
3059 : * RETURNS:
3060 : * 0 on success, -errno on failure.
3061 : */
3062 : int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
3063 : size_t atom_size,
3064 : pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
3065 : pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
3066 : {
3067 : void *base = (void *)ULONG_MAX;
3068 : void **areas = NULL;
3069 : struct pcpu_alloc_info *ai;
3070 : size_t size_sum, areas_size;
3071 : unsigned long max_distance;
3072 : int group, i, highest_group, rc = 0;
3073 :
3074 : ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
3075 : cpu_distance_fn);
3076 : if (IS_ERR(ai))
3077 : return PTR_ERR(ai);
3078 :
3079 : size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
3080 : areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
3081 :
3082 : areas = memblock_alloc(areas_size, SMP_CACHE_BYTES);
3083 : if (!areas) {
3084 : rc = -ENOMEM;
3085 : goto out_free;
3086 : }
3087 :
3088 : /* allocate, copy and determine base address & max_distance */
3089 : highest_group = 0;
3090 : for (group = 0; group < ai->nr_groups; group++) {
3091 : struct pcpu_group_info *gi = &ai->groups[group];
3092 : unsigned int cpu = NR_CPUS;
3093 : void *ptr;
3094 :
3095 : for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
3096 : cpu = gi->cpu_map[i];
3097 : BUG_ON(cpu == NR_CPUS);
3098 :
3099 : /* allocate space for the whole group */
3100 : ptr = pcpu_fc_alloc(cpu, gi->nr_units * ai->unit_size, atom_size, cpu_to_nd_fn);
3101 : if (!ptr) {
3102 : rc = -ENOMEM;
3103 : goto out_free_areas;
3104 : }
3105 : /* kmemleak tracks the percpu allocations separately */
3106 : kmemleak_free(ptr);
3107 : areas[group] = ptr;
3108 :
3109 : base = min(ptr, base);
3110 : if (ptr > areas[highest_group])
3111 : highest_group = group;
3112 : }
3113 : max_distance = areas[highest_group] - base;
3114 : max_distance += ai->unit_size * ai->groups[highest_group].nr_units;
3115 :
3116 : /* warn if maximum distance is further than 75% of vmalloc space */
3117 : if (max_distance > VMALLOC_TOTAL * 3 / 4) {
3118 : pr_warn("max_distance=0x%lx too large for vmalloc space 0x%lx\n",
3119 : max_distance, VMALLOC_TOTAL);
3120 : #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
3121 : /* and fail if we have fallback */
3122 : rc = -EINVAL;
3123 : goto out_free_areas;
3124 : #endif
3125 : }
3126 :
3127 : /*
3128 : * Copy data and free unused parts. This should happen after all
3129 : * allocations are complete; otherwise, we may end up with
3130 : * overlapping groups.
3131 : */
3132 : for (group = 0; group < ai->nr_groups; group++) {
3133 : struct pcpu_group_info *gi = &ai->groups[group];
3134 : void *ptr = areas[group];
3135 :
3136 : for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
3137 : if (gi->cpu_map[i] == NR_CPUS) {
3138 : /* unused unit, free whole */
3139 : pcpu_fc_free(ptr, ai->unit_size);
3140 : continue;
3141 : }
3142 : /* copy and return the unused part */
3143 : memcpy(ptr, __per_cpu_load, ai->static_size);
3144 : pcpu_fc_free(ptr + size_sum, ai->unit_size - size_sum);
3145 : }
3146 : }
3147 :
3148 : /* base address is now known, determine group base offsets */
3149 : for (group = 0; group < ai->nr_groups; group++) {
3150 : ai->groups[group].base_offset = areas[group] - base;
3151 : }
3152 :
3153 : pr_info("Embedded %zu pages/cpu s%zu r%zu d%zu u%zu\n",
3154 : PFN_DOWN(size_sum), ai->static_size, ai->reserved_size,
3155 : ai->dyn_size, ai->unit_size);
3156 :
3157 : pcpu_setup_first_chunk(ai, base);
3158 : goto out_free;
3159 :
3160 : out_free_areas:
3161 : for (group = 0; group < ai->nr_groups; group++)
3162 : if (areas[group])
3163 : pcpu_fc_free(areas[group],
3164 : ai->groups[group].nr_units * ai->unit_size);
3165 : out_free:
3166 : pcpu_free_alloc_info(ai);
3167 : if (areas)
3168 : memblock_free(areas, areas_size);
3169 : return rc;
3170 : }
3171 : #endif /* BUILD_EMBED_FIRST_CHUNK */
3172 :
3173 : #ifdef BUILD_PAGE_FIRST_CHUNK
3174 : #include <asm/pgalloc.h>
3175 :
3176 : #ifndef P4D_TABLE_SIZE
3177 : #define P4D_TABLE_SIZE PAGE_SIZE
3178 : #endif
3179 :
3180 : #ifndef PUD_TABLE_SIZE
3181 : #define PUD_TABLE_SIZE PAGE_SIZE
3182 : #endif
3183 :
3184 : #ifndef PMD_TABLE_SIZE
3185 : #define PMD_TABLE_SIZE PAGE_SIZE
3186 : #endif
3187 :
3188 : #ifndef PTE_TABLE_SIZE
3189 : #define PTE_TABLE_SIZE PAGE_SIZE
3190 : #endif
3191 : void __init __weak pcpu_populate_pte(unsigned long addr)
3192 : {
3193 : pgd_t *pgd = pgd_offset_k(addr);
3194 : p4d_t *p4d;
3195 : pud_t *pud;
3196 : pmd_t *pmd;
3197 :
3198 : if (pgd_none(*pgd)) {
3199 : p4d_t *new;
3200 :
3201 : new = memblock_alloc(P4D_TABLE_SIZE, P4D_TABLE_SIZE);
3202 : if (!new)
3203 : goto err_alloc;
3204 : pgd_populate(&init_mm, pgd, new);
3205 : }
3206 :
3207 : p4d = p4d_offset(pgd, addr);
3208 : if (p4d_none(*p4d)) {
3209 : pud_t *new;
3210 :
3211 : new = memblock_alloc(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
3212 : if (!new)
3213 : goto err_alloc;
3214 : p4d_populate(&init_mm, p4d, new);
3215 : }
3216 :
3217 : pud = pud_offset(p4d, addr);
3218 : if (pud_none(*pud)) {
3219 : pmd_t *new;
3220 :
3221 : new = memblock_alloc(PMD_TABLE_SIZE, PMD_TABLE_SIZE);
3222 : if (!new)
3223 : goto err_alloc;
3224 : pud_populate(&init_mm, pud, new);
3225 : }
3226 :
3227 : pmd = pmd_offset(pud, addr);
3228 : if (!pmd_present(*pmd)) {
3229 : pte_t *new;
3230 :
3231 : new = memblock_alloc(PTE_TABLE_SIZE, PTE_TABLE_SIZE);
3232 : if (!new)
3233 : goto err_alloc;
3234 : pmd_populate_kernel(&init_mm, pmd, new);
3235 : }
3236 :
3237 : return;
3238 :
3239 : err_alloc:
3240 : panic("%s: Failed to allocate memory\n", __func__);
3241 : }
3242 :
3243 : /**
3244 : * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
3245 : * @reserved_size: the size of reserved percpu area in bytes
3246 : * @cpu_to_nd_fn: callback to convert cpu to it's node, optional
3247 : *
3248 : * This is a helper to ease setting up page-remapped first percpu
3249 : * chunk and can be called where pcpu_setup_first_chunk() is expected.
3250 : *
3251 : * This is the basic allocator. Static percpu area is allocated
3252 : * page-by-page into vmalloc area.
3253 : *
3254 : * RETURNS:
3255 : * 0 on success, -errno on failure.
3256 : */
3257 : int __init pcpu_page_first_chunk(size_t reserved_size, pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
3258 : {
3259 : static struct vm_struct vm;
3260 : struct pcpu_alloc_info *ai;
3261 : char psize_str[16];
3262 : int unit_pages;
3263 : size_t pages_size;
3264 : struct page **pages;
3265 : int unit, i, j, rc = 0;
3266 : int upa;
3267 : int nr_g0_units;
3268 :
3269 : snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
3270 :
3271 : ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
3272 : if (IS_ERR(ai))
3273 : return PTR_ERR(ai);
3274 : BUG_ON(ai->nr_groups != 1);
3275 : upa = ai->alloc_size/ai->unit_size;
3276 : nr_g0_units = roundup(num_possible_cpus(), upa);
3277 : if (WARN_ON(ai->groups[0].nr_units != nr_g0_units)) {
3278 : pcpu_free_alloc_info(ai);
3279 : return -EINVAL;
3280 : }
3281 :
3282 : unit_pages = ai->unit_size >> PAGE_SHIFT;
3283 :
3284 : /* unaligned allocations can't be freed, round up to page size */
3285 : pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
3286 : sizeof(pages[0]));
3287 : pages = memblock_alloc(pages_size, SMP_CACHE_BYTES);
3288 : if (!pages)
3289 : panic("%s: Failed to allocate %zu bytes\n", __func__,
3290 : pages_size);
3291 :
3292 : /* allocate pages */
3293 : j = 0;
3294 : for (unit = 0; unit < num_possible_cpus(); unit++) {
3295 : unsigned int cpu = ai->groups[0].cpu_map[unit];
3296 : for (i = 0; i < unit_pages; i++) {
3297 : void *ptr;
3298 :
3299 : ptr = pcpu_fc_alloc(cpu, PAGE_SIZE, PAGE_SIZE, cpu_to_nd_fn);
3300 : if (!ptr) {
3301 : pr_warn("failed to allocate %s page for cpu%u\n",
3302 : psize_str, cpu);
3303 : goto enomem;
3304 : }
3305 : /* kmemleak tracks the percpu allocations separately */
3306 : kmemleak_free(ptr);
3307 : pages[j++] = virt_to_page(ptr);
3308 : }
3309 : }
3310 :
3311 : /* allocate vm area, map the pages and copy static data */
3312 : vm.flags = VM_ALLOC;
3313 : vm.size = num_possible_cpus() * ai->unit_size;
3314 : vm_area_register_early(&vm, PAGE_SIZE);
3315 :
3316 : for (unit = 0; unit < num_possible_cpus(); unit++) {
3317 : unsigned long unit_addr =
3318 : (unsigned long)vm.addr + unit * ai->unit_size;
3319 :
3320 : for (i = 0; i < unit_pages; i++)
3321 : pcpu_populate_pte(unit_addr + (i << PAGE_SHIFT));
3322 :
3323 : /* pte already populated, the following shouldn't fail */
3324 : rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
3325 : unit_pages);
3326 : if (rc < 0)
3327 : panic("failed to map percpu area, err=%d\n", rc);
3328 :
3329 : /*
3330 : * FIXME: Archs with virtual cache should flush local
3331 : * cache for the linear mapping here - something
3332 : * equivalent to flush_cache_vmap() on the local cpu.
3333 : * flush_cache_vmap() can't be used as most supporting
3334 : * data structures are not set up yet.
3335 : */
3336 :
3337 : /* copy static data */
3338 : memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
3339 : }
3340 :
3341 : /* we're ready, commit */
3342 : pr_info("%d %s pages/cpu s%zu r%zu d%zu\n",
3343 : unit_pages, psize_str, ai->static_size,
3344 : ai->reserved_size, ai->dyn_size);
3345 :
3346 : pcpu_setup_first_chunk(ai, vm.addr);
3347 : goto out_free_ar;
3348 :
3349 : enomem:
3350 : while (--j >= 0)
3351 : pcpu_fc_free(page_address(pages[j]), PAGE_SIZE);
3352 : rc = -ENOMEM;
3353 : out_free_ar:
3354 : memblock_free(pages, pages_size);
3355 : pcpu_free_alloc_info(ai);
3356 : return rc;
3357 : }
3358 : #endif /* BUILD_PAGE_FIRST_CHUNK */
3359 :
3360 : #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
3361 : /*
3362 : * Generic SMP percpu area setup.
3363 : *
3364 : * The embedding helper is used because its behavior closely resembles
3365 : * the original non-dynamic generic percpu area setup. This is
3366 : * important because many archs have addressing restrictions and might
3367 : * fail if the percpu area is located far away from the previous
3368 : * location. As an added bonus, in non-NUMA cases, embedding is
3369 : * generally a good idea TLB-wise because percpu area can piggy back
3370 : * on the physical linear memory mapping which uses large page
3371 : * mappings on applicable archs.
3372 : */
3373 : unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
3374 : EXPORT_SYMBOL(__per_cpu_offset);
3375 :
3376 : void __init setup_per_cpu_areas(void)
3377 : {
3378 : unsigned long delta;
3379 : unsigned int cpu;
3380 : int rc;
3381 :
3382 : /*
3383 : * Always reserve area for module percpu variables. That's
3384 : * what the legacy allocator did.
3385 : */
3386 : rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE, PERCPU_DYNAMIC_RESERVE,
3387 : PAGE_SIZE, NULL, NULL);
3388 : if (rc < 0)
3389 : panic("Failed to initialize percpu areas.");
3390 :
3391 : delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
3392 : for_each_possible_cpu(cpu)
3393 : __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
3394 : }
3395 : #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
3396 :
3397 : #else /* CONFIG_SMP */
3398 :
3399 : /*
3400 : * UP percpu area setup.
3401 : *
3402 : * UP always uses km-based percpu allocator with identity mapping.
3403 : * Static percpu variables are indistinguishable from the usual static
3404 : * variables and don't require any special preparation.
3405 : */
3406 1 : void __init setup_per_cpu_areas(void)
3407 : {
3408 1 : const size_t unit_size =
3409 : roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
3410 : PERCPU_DYNAMIC_RESERVE));
3411 : struct pcpu_alloc_info *ai;
3412 : void *fc;
3413 :
3414 1 : ai = pcpu_alloc_alloc_info(1, 1);
3415 2 : fc = memblock_alloc_from(unit_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
3416 1 : if (!ai || !fc)
3417 0 : panic("Failed to allocate memory for percpu areas.");
3418 : /* kmemleak tracks the percpu allocations separately */
3419 : kmemleak_free(fc);
3420 :
3421 1 : ai->dyn_size = unit_size;
3422 1 : ai->unit_size = unit_size;
3423 1 : ai->atom_size = unit_size;
3424 1 : ai->alloc_size = unit_size;
3425 1 : ai->groups[0].nr_units = 1;
3426 1 : ai->groups[0].cpu_map[0] = 0;
3427 :
3428 1 : pcpu_setup_first_chunk(ai, fc);
3429 1 : pcpu_free_alloc_info(ai);
3430 1 : }
3431 :
3432 : #endif /* CONFIG_SMP */
3433 :
3434 : /*
3435 : * pcpu_nr_pages - calculate total number of populated backing pages
3436 : *
3437 : * This reflects the number of pages populated to back chunks. Metadata is
3438 : * excluded in the number exposed in meminfo as the number of backing pages
3439 : * scales with the number of cpus and can quickly outweigh the memory used for
3440 : * metadata. It also keeps this calculation nice and simple.
3441 : *
3442 : * RETURNS:
3443 : * Total number of populated backing pages in use by the allocator.
3444 : */
3445 0 : unsigned long pcpu_nr_pages(void)
3446 : {
3447 0 : return pcpu_nr_populated * pcpu_nr_units;
3448 : }
3449 :
3450 : /*
3451 : * Percpu allocator is initialized early during boot when neither slab or
3452 : * workqueue is available. Plug async management until everything is up
3453 : * and running.
3454 : */
3455 1 : static int __init percpu_enable_async(void)
3456 : {
3457 1 : pcpu_async_enabled = true;
3458 1 : return 0;
3459 : }
3460 : subsys_initcall(percpu_enable_async);
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