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1 | /* |
2 | * mm/percpu.c - percpu memory allocator |
3 | * |
4 | * Copyright (C) 2009 SUSE Linux Products GmbH |
5 | * Copyright (C) 2009 Tejun Heo <tj@kernel.org> |
6 | * |
7 | * This file is released under the GPLv2. |
8 | * |
9 | * This is percpu allocator which can handle both static and dynamic |
10 | * areas. Percpu areas are allocated in chunks. Each chunk is |
11 | * consisted of boot-time determined number of units and the first |
12 | * chunk is used for static percpu variables in the kernel image |
13 | * (special boot time alloc/init handling necessary as these areas |
14 | * need to be brought up before allocation services are running). |
15 | * Unit grows as necessary and all units grow or shrink in unison. |
16 | * When a chunk is filled up, another chunk is allocated. |
17 | * |
18 | * c0 c1 c2 |
19 | * ------------------- ------------------- ------------ |
20 | * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u |
21 | * ------------------- ...... ------------------- .... ------------ |
22 | * |
23 | * Allocation is done in offset-size areas of single unit space. Ie, |
24 | * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0, |
25 | * c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to |
26 | * cpus. On NUMA, the mapping can be non-linear and even sparse. |
27 | * Percpu access can be done by configuring percpu base registers |
28 | * according to cpu to unit mapping and pcpu_unit_size. |
29 | * |
30 | * There are usually many small percpu allocations many of them being |
31 | * as small as 4 bytes. The allocator organizes chunks into lists |
32 | * according to free size and tries to allocate from the fullest one. |
33 | * Each chunk keeps the maximum contiguous area size hint which is |
34 | * guaranteed to be eqaul to or larger than the maximum contiguous |
35 | * area in the chunk. This helps the allocator not to iterate the |
36 | * chunk maps unnecessarily. |
37 | * |
38 | * Allocation state in each chunk is kept using an array of integers |
39 | * on chunk->map. A positive value in the map represents a free |
40 | * region and negative allocated. Allocation inside a chunk is done |
41 | * by scanning this map sequentially and serving the first matching |
42 | * entry. This is mostly copied from the percpu_modalloc() allocator. |
43 | * Chunks can be determined from the address using the index field |
44 | * in the page struct. The index field contains a pointer to the chunk. |
45 | * |
46 | * To use this allocator, arch code should do the followings. |
47 | * |
48 | * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate |
49 | * regular address to percpu pointer and back if they need to be |
50 | * different from the default |
51 | * |
52 | * - use pcpu_setup_first_chunk() during percpu area initialization to |
53 | * setup the first chunk containing the kernel static percpu area |
54 | */ |
55 | |
56 | #include <linux/bitmap.h> |
57 | #include <linux/bootmem.h> |
58 | #include <linux/err.h> |
59 | #include <linux/list.h> |
60 | #include <linux/log2.h> |
61 | #include <linux/mm.h> |
62 | #include <linux/module.h> |
63 | #include <linux/mutex.h> |
64 | #include <linux/percpu.h> |
65 | #include <linux/pfn.h> |
66 | #include <linux/slab.h> |
67 | #include <linux/spinlock.h> |
68 | #include <linux/vmalloc.h> |
69 | #include <linux/workqueue.h> |
70 | |
71 | #include <asm/cacheflush.h> |
72 | #include <asm/sections.h> |
73 | #include <asm/tlbflush.h> |
74 | #include <asm/io.h> |
75 | |
76 | #define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */ |
77 | #define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */ |
78 | |
79 | /* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */ |
80 | #ifndef __addr_to_pcpu_ptr |
81 | #define __addr_to_pcpu_ptr(addr) \ |
82 | (void __percpu *)((unsigned long)(addr) - \ |
83 | (unsigned long)pcpu_base_addr + \ |
84 | (unsigned long)__per_cpu_start) |
85 | #endif |
86 | #ifndef __pcpu_ptr_to_addr |
87 | #define __pcpu_ptr_to_addr(ptr) \ |
88 | (void __force *)((unsigned long)(ptr) + \ |
89 | (unsigned long)pcpu_base_addr - \ |
90 | (unsigned long)__per_cpu_start) |
91 | #endif |
92 | |
93 | struct pcpu_chunk { |
94 | struct list_head list; /* linked to pcpu_slot lists */ |
95 | int free_size; /* free bytes in the chunk */ |
96 | int contig_hint; /* max contiguous size hint */ |
97 | void *base_addr; /* base address of this chunk */ |
98 | int map_used; /* # of map entries used */ |
99 | int map_alloc; /* # of map entries allocated */ |
100 | int *map; /* allocation map */ |
101 | void *data; /* chunk data */ |
102 | bool immutable; /* no [de]population allowed */ |
103 | unsigned long populated[]; /* populated bitmap */ |
104 | }; |
105 | |
106 | static int pcpu_unit_pages __read_mostly; |
107 | static int pcpu_unit_size __read_mostly; |
108 | static int pcpu_nr_units __read_mostly; |
109 | static int pcpu_atom_size __read_mostly; |
110 | static int pcpu_nr_slots __read_mostly; |
111 | static size_t pcpu_chunk_struct_size __read_mostly; |
112 | |
113 | /* cpus with the lowest and highest unit numbers */ |
114 | static unsigned int pcpu_first_unit_cpu __read_mostly; |
115 | static unsigned int pcpu_last_unit_cpu __read_mostly; |
116 | |
117 | /* the address of the first chunk which starts with the kernel static area */ |
118 | void *pcpu_base_addr __read_mostly; |
119 | EXPORT_SYMBOL_GPL(pcpu_base_addr); |
120 | |
121 | static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */ |
122 | const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */ |
123 | |
124 | /* group information, used for vm allocation */ |
125 | static int pcpu_nr_groups __read_mostly; |
126 | static const unsigned long *pcpu_group_offsets __read_mostly; |
127 | static const size_t *pcpu_group_sizes __read_mostly; |
128 | |
129 | /* |
130 | * The first chunk which always exists. Note that unlike other |
131 | * chunks, this one can be allocated and mapped in several different |
132 | * ways and thus often doesn't live in the vmalloc area. |
133 | */ |
134 | static struct pcpu_chunk *pcpu_first_chunk; |
135 | |
136 | /* |
137 | * Optional reserved chunk. This chunk reserves part of the first |
138 | * chunk and serves it for reserved allocations. The amount of |
139 | * reserved offset is in pcpu_reserved_chunk_limit. When reserved |
140 | * area doesn't exist, the following variables contain NULL and 0 |
141 | * respectively. |
142 | */ |
143 | static struct pcpu_chunk *pcpu_reserved_chunk; |
144 | static int pcpu_reserved_chunk_limit; |
145 | |
146 | /* |
147 | * Synchronization rules. |
148 | * |
149 | * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former |
150 | * protects allocation/reclaim paths, chunks, populated bitmap and |
151 | * vmalloc mapping. The latter is a spinlock and protects the index |
152 | * data structures - chunk slots, chunks and area maps in chunks. |
153 | * |
154 | * During allocation, pcpu_alloc_mutex is kept locked all the time and |
155 | * pcpu_lock is grabbed and released as necessary. All actual memory |
156 | * allocations are done using GFP_KERNEL with pcpu_lock released. In |
157 | * general, percpu memory can't be allocated with irq off but |
158 | * irqsave/restore are still used in alloc path so that it can be used |
159 | * from early init path - sched_init() specifically. |
160 | * |
161 | * Free path accesses and alters only the index data structures, so it |
162 | * can be safely called from atomic context. When memory needs to be |
163 | * returned to the system, free path schedules reclaim_work which |
164 | * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be |
165 | * reclaimed, release both locks and frees the chunks. Note that it's |
166 | * necessary to grab both locks to remove a chunk from circulation as |
167 | * allocation path might be referencing the chunk with only |
168 | * pcpu_alloc_mutex locked. |
169 | */ |
170 | static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */ |
171 | static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */ |
172 | |
173 | static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */ |
174 | |
175 | /* reclaim work to release fully free chunks, scheduled from free path */ |
176 | static void pcpu_reclaim(struct work_struct *work); |
177 | static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim); |
178 | |
179 | static bool pcpu_addr_in_first_chunk(void *addr) |
180 | { |
181 | void *first_start = pcpu_first_chunk->base_addr; |
182 | |
183 | return addr >= first_start && addr < first_start + pcpu_unit_size; |
184 | } |
185 | |
186 | static bool pcpu_addr_in_reserved_chunk(void *addr) |
187 | { |
188 | void *first_start = pcpu_first_chunk->base_addr; |
189 | |
190 | return addr >= first_start && |
191 | addr < first_start + pcpu_reserved_chunk_limit; |
192 | } |
193 | |
194 | static int __pcpu_size_to_slot(int size) |
195 | { |
196 | int highbit = fls(size); /* size is in bytes */ |
197 | return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1); |
198 | } |
199 | |
200 | static int pcpu_size_to_slot(int size) |
201 | { |
202 | if (size == pcpu_unit_size) |
203 | return pcpu_nr_slots - 1; |
204 | return __pcpu_size_to_slot(size); |
205 | } |
206 | |
207 | static int pcpu_chunk_slot(const struct pcpu_chunk *chunk) |
208 | { |
209 | if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int)) |
210 | return 0; |
211 | |
212 | return pcpu_size_to_slot(chunk->free_size); |
213 | } |
214 | |
215 | /* set the pointer to a chunk in a page struct */ |
216 | static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu) |
217 | { |
218 | page->index = (unsigned long)pcpu; |
219 | } |
220 | |
221 | /* obtain pointer to a chunk from a page struct */ |
222 | static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page) |
223 | { |
224 | return (struct pcpu_chunk *)page->index; |
225 | } |
226 | |
227 | static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx) |
228 | { |
229 | return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx; |
230 | } |
231 | |
232 | static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk, |
233 | unsigned int cpu, int page_idx) |
234 | { |
235 | return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] + |
236 | (page_idx << PAGE_SHIFT); |
237 | } |
238 | |
239 | static void __maybe_unused pcpu_next_unpop(struct pcpu_chunk *chunk, |
240 | int *rs, int *re, int end) |
241 | { |
242 | *rs = find_next_zero_bit(chunk->populated, end, *rs); |
243 | *re = find_next_bit(chunk->populated, end, *rs + 1); |
244 | } |
245 | |
246 | static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk, |
247 | int *rs, int *re, int end) |
248 | { |
249 | *rs = find_next_bit(chunk->populated, end, *rs); |
250 | *re = find_next_zero_bit(chunk->populated, end, *rs + 1); |
251 | } |
252 | |
253 | /* |
254 | * (Un)populated page region iterators. Iterate over (un)populated |
255 | * page regions betwen @start and @end in @chunk. @rs and @re should |
256 | * be integer variables and will be set to start and end page index of |
257 | * the current region. |
258 | */ |
259 | #define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \ |
260 | for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \ |
261 | (rs) < (re); \ |
262 | (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end))) |
263 | |
264 | #define pcpu_for_each_pop_region(chunk, rs, re, start, end) \ |
265 | for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \ |
266 | (rs) < (re); \ |
267 | (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end))) |
268 | |
269 | /** |
270 | * pcpu_mem_alloc - allocate memory |
271 | * @size: bytes to allocate |
272 | * |
273 | * Allocate @size bytes. If @size is smaller than PAGE_SIZE, |
274 | * kzalloc() is used; otherwise, vmalloc() is used. The returned |
275 | * memory is always zeroed. |
276 | * |
277 | * CONTEXT: |
278 | * Does GFP_KERNEL allocation. |
279 | * |
280 | * RETURNS: |
281 | * Pointer to the allocated area on success, NULL on failure. |
282 | */ |
283 | static void *pcpu_mem_alloc(size_t size) |
284 | { |
285 | if (size <= PAGE_SIZE) |
286 | return kzalloc(size, GFP_KERNEL); |
287 | else { |
288 | void *ptr = vmalloc(size); |
289 | if (ptr) |
290 | memset(ptr, 0, size); |
291 | return ptr; |
292 | } |
293 | } |
294 | |
295 | /** |
296 | * pcpu_mem_free - free memory |
297 | * @ptr: memory to free |
298 | * @size: size of the area |
299 | * |
300 | * Free @ptr. @ptr should have been allocated using pcpu_mem_alloc(). |
301 | */ |
302 | static void pcpu_mem_free(void *ptr, size_t size) |
303 | { |
304 | if (size <= PAGE_SIZE) |
305 | kfree(ptr); |
306 | else |
307 | vfree(ptr); |
308 | } |
309 | |
310 | /** |
311 | * pcpu_chunk_relocate - put chunk in the appropriate chunk slot |
312 | * @chunk: chunk of interest |
313 | * @oslot: the previous slot it was on |
314 | * |
315 | * This function is called after an allocation or free changed @chunk. |
316 | * New slot according to the changed state is determined and @chunk is |
317 | * moved to the slot. Note that the reserved chunk is never put on |
318 | * chunk slots. |
319 | * |
320 | * CONTEXT: |
321 | * pcpu_lock. |
322 | */ |
323 | static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot) |
324 | { |
325 | int nslot = pcpu_chunk_slot(chunk); |
326 | |
327 | if (chunk != pcpu_reserved_chunk && oslot != nslot) { |
328 | if (oslot < nslot) |
329 | list_move(&chunk->list, &pcpu_slot[nslot]); |
330 | else |
331 | list_move_tail(&chunk->list, &pcpu_slot[nslot]); |
332 | } |
333 | } |
334 | |
335 | /** |
336 | * pcpu_need_to_extend - determine whether chunk area map needs to be extended |
337 | * @chunk: chunk of interest |
338 | * |
339 | * Determine whether area map of @chunk needs to be extended to |
340 | * accomodate a new allocation. |
341 | * |
342 | * CONTEXT: |
343 | * pcpu_lock. |
344 | * |
345 | * RETURNS: |
346 | * New target map allocation length if extension is necessary, 0 |
347 | * otherwise. |
348 | */ |
349 | static int pcpu_need_to_extend(struct pcpu_chunk *chunk) |
350 | { |
351 | int new_alloc; |
352 | |
353 | if (chunk->map_alloc >= chunk->map_used + 2) |
354 | return 0; |
355 | |
356 | new_alloc = PCPU_DFL_MAP_ALLOC; |
357 | while (new_alloc < chunk->map_used + 2) |
358 | new_alloc *= 2; |
359 | |
360 | return new_alloc; |
361 | } |
362 | |
363 | /** |
364 | * pcpu_extend_area_map - extend area map of a chunk |
365 | * @chunk: chunk of interest |
366 | * @new_alloc: new target allocation length of the area map |
367 | * |
368 | * Extend area map of @chunk to have @new_alloc entries. |
369 | * |
370 | * CONTEXT: |
371 | * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock. |
372 | * |
373 | * RETURNS: |
374 | * 0 on success, -errno on failure. |
375 | */ |
376 | static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc) |
377 | { |
378 | int *old = NULL, *new = NULL; |
379 | size_t old_size = 0, new_size = new_alloc * sizeof(new[0]); |
380 | unsigned long flags; |
381 | |
382 | new = pcpu_mem_alloc(new_size); |
383 | if (!new) |
384 | return -ENOMEM; |
385 | |
386 | /* acquire pcpu_lock and switch to new area map */ |
387 | spin_lock_irqsave(&pcpu_lock, flags); |
388 | |
389 | if (new_alloc <= chunk->map_alloc) |
390 | goto out_unlock; |
391 | |
392 | old_size = chunk->map_alloc * sizeof(chunk->map[0]); |
393 | memcpy(new, chunk->map, old_size); |
394 | |
395 | /* |
396 | * map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is |
397 | * one of the first chunks and still using static map. |
398 | */ |
399 | if (chunk->map_alloc >= PCPU_DFL_MAP_ALLOC) |
400 | old = chunk->map; |
401 | |
402 | chunk->map_alloc = new_alloc; |
403 | chunk->map = new; |
404 | new = NULL; |
405 | |
406 | out_unlock: |
407 | spin_unlock_irqrestore(&pcpu_lock, flags); |
408 | |
409 | /* |
410 | * pcpu_mem_free() might end up calling vfree() which uses |
411 | * IRQ-unsafe lock and thus can't be called under pcpu_lock. |
412 | */ |
413 | pcpu_mem_free(old, old_size); |
414 | pcpu_mem_free(new, new_size); |
415 | |
416 | return 0; |
417 | } |
418 | |
419 | /** |
420 | * pcpu_split_block - split a map block |
421 | * @chunk: chunk of interest |
422 | * @i: index of map block to split |
423 | * @head: head size in bytes (can be 0) |
424 | * @tail: tail size in bytes (can be 0) |
425 | * |
426 | * Split the @i'th map block into two or three blocks. If @head is |
427 | * non-zero, @head bytes block is inserted before block @i moving it |
428 | * to @i+1 and reducing its size by @head bytes. |
429 | * |
430 | * If @tail is non-zero, the target block, which can be @i or @i+1 |
431 | * depending on @head, is reduced by @tail bytes and @tail byte block |
432 | * is inserted after the target block. |
433 | * |
434 | * @chunk->map must have enough free slots to accomodate the split. |
435 | * |
436 | * CONTEXT: |
437 | * pcpu_lock. |
438 | */ |
439 | static void pcpu_split_block(struct pcpu_chunk *chunk, int i, |
440 | int head, int tail) |
441 | { |
442 | int nr_extra = !!head + !!tail; |
443 | |
444 | BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra); |
445 | |
446 | /* insert new subblocks */ |
447 | memmove(&chunk->map[i + nr_extra], &chunk->map[i], |
448 | sizeof(chunk->map[0]) * (chunk->map_used - i)); |
449 | chunk->map_used += nr_extra; |
450 | |
451 | if (head) { |
452 | chunk->map[i + 1] = chunk->map[i] - head; |
453 | chunk->map[i++] = head; |
454 | } |
455 | if (tail) { |
456 | chunk->map[i++] -= tail; |
457 | chunk->map[i] = tail; |
458 | } |
459 | } |
460 | |
461 | /** |
462 | * pcpu_alloc_area - allocate area from a pcpu_chunk |
463 | * @chunk: chunk of interest |
464 | * @size: wanted size in bytes |
465 | * @align: wanted align |
466 | * |
467 | * Try to allocate @size bytes area aligned at @align from @chunk. |
468 | * Note that this function only allocates the offset. It doesn't |
469 | * populate or map the area. |
470 | * |
471 | * @chunk->map must have at least two free slots. |
472 | * |
473 | * CONTEXT: |
474 | * pcpu_lock. |
475 | * |
476 | * RETURNS: |
477 | * Allocated offset in @chunk on success, -1 if no matching area is |
478 | * found. |
479 | */ |
480 | static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align) |
481 | { |
482 | int oslot = pcpu_chunk_slot(chunk); |
483 | int max_contig = 0; |
484 | int i, off; |
485 | |
486 | for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) { |
487 | bool is_last = i + 1 == chunk->map_used; |
488 | int head, tail; |
489 | |
490 | /* extra for alignment requirement */ |
491 | head = ALIGN(off, align) - off; |
492 | BUG_ON(i == 0 && head != 0); |
493 | |
494 | if (chunk->map[i] < 0) |
495 | continue; |
496 | if (chunk->map[i] < head + size) { |
497 | max_contig = max(chunk->map[i], max_contig); |
498 | continue; |
499 | } |
500 | |
501 | /* |
502 | * If head is small or the previous block is free, |
503 | * merge'em. Note that 'small' is defined as smaller |
504 | * than sizeof(int), which is very small but isn't too |
505 | * uncommon for percpu allocations. |
506 | */ |
507 | if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) { |
508 | if (chunk->map[i - 1] > 0) |
509 | chunk->map[i - 1] += head; |
510 | else { |
511 | chunk->map[i - 1] -= head; |
512 | chunk->free_size -= head; |
513 | } |
514 | chunk->map[i] -= head; |
515 | off += head; |
516 | head = 0; |
517 | } |
518 | |
519 | /* if tail is small, just keep it around */ |
520 | tail = chunk->map[i] - head - size; |
521 | if (tail < sizeof(int)) |
522 | tail = 0; |
523 | |
524 | /* split if warranted */ |
525 | if (head || tail) { |
526 | pcpu_split_block(chunk, i, head, tail); |
527 | if (head) { |
528 | i++; |
529 | off += head; |
530 | max_contig = max(chunk->map[i - 1], max_contig); |
531 | } |
532 | if (tail) |
533 | max_contig = max(chunk->map[i + 1], max_contig); |
534 | } |
535 | |
536 | /* update hint and mark allocated */ |
537 | if (is_last) |
538 | chunk->contig_hint = max_contig; /* fully scanned */ |
539 | else |
540 | chunk->contig_hint = max(chunk->contig_hint, |
541 | max_contig); |
542 | |
543 | chunk->free_size -= chunk->map[i]; |
544 | chunk->map[i] = -chunk->map[i]; |
545 | |
546 | pcpu_chunk_relocate(chunk, oslot); |
547 | return off; |
548 | } |
549 | |
550 | chunk->contig_hint = max_contig; /* fully scanned */ |
551 | pcpu_chunk_relocate(chunk, oslot); |
552 | |
553 | /* tell the upper layer that this chunk has no matching area */ |
554 | return -1; |
555 | } |
556 | |
557 | /** |
558 | * pcpu_free_area - free area to a pcpu_chunk |
559 | * @chunk: chunk of interest |
560 | * @freeme: offset of area to free |
561 | * |
562 | * Free area starting from @freeme to @chunk. Note that this function |
563 | * only modifies the allocation map. It doesn't depopulate or unmap |
564 | * the area. |
565 | * |
566 | * CONTEXT: |
567 | * pcpu_lock. |
568 | */ |
569 | static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme) |
570 | { |
571 | int oslot = pcpu_chunk_slot(chunk); |
572 | int i, off; |
573 | |
574 | for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) |
575 | if (off == freeme) |
576 | break; |
577 | BUG_ON(off != freeme); |
578 | BUG_ON(chunk->map[i] > 0); |
579 | |
580 | chunk->map[i] = -chunk->map[i]; |
581 | chunk->free_size += chunk->map[i]; |
582 | |
583 | /* merge with previous? */ |
584 | if (i > 0 && chunk->map[i - 1] >= 0) { |
585 | chunk->map[i - 1] += chunk->map[i]; |
586 | chunk->map_used--; |
587 | memmove(&chunk->map[i], &chunk->map[i + 1], |
588 | (chunk->map_used - i) * sizeof(chunk->map[0])); |
589 | i--; |
590 | } |
591 | /* merge with next? */ |
592 | if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) { |
593 | chunk->map[i] += chunk->map[i + 1]; |
594 | chunk->map_used--; |
595 | memmove(&chunk->map[i + 1], &chunk->map[i + 2], |
596 | (chunk->map_used - (i + 1)) * sizeof(chunk->map[0])); |
597 | } |
598 | |
599 | chunk->contig_hint = max(chunk->map[i], chunk->contig_hint); |
600 | pcpu_chunk_relocate(chunk, oslot); |
601 | } |
602 | |
603 | static struct pcpu_chunk *pcpu_alloc_chunk(void) |
604 | { |
605 | struct pcpu_chunk *chunk; |
606 | |
607 | chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL); |
608 | if (!chunk) |
609 | return NULL; |
610 | |
611 | chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0])); |
612 | if (!chunk->map) { |
613 | kfree(chunk); |
614 | return NULL; |
615 | } |
616 | |
617 | chunk->map_alloc = PCPU_DFL_MAP_ALLOC; |
618 | chunk->map[chunk->map_used++] = pcpu_unit_size; |
619 | |
620 | INIT_LIST_HEAD(&chunk->list); |
621 | chunk->free_size = pcpu_unit_size; |
622 | chunk->contig_hint = pcpu_unit_size; |
623 | |
624 | return chunk; |
625 | } |
626 | |
627 | static void pcpu_free_chunk(struct pcpu_chunk *chunk) |
628 | { |
629 | if (!chunk) |
630 | return; |
631 | pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0])); |
632 | kfree(chunk); |
633 | } |
634 | |
635 | /* |
636 | * Chunk management implementation. |
637 | * |
638 | * To allow different implementations, chunk alloc/free and |
639 | * [de]population are implemented in a separate file which is pulled |
640 | * into this file and compiled together. The following functions |
641 | * should be implemented. |
642 | * |
643 | * pcpu_populate_chunk - populate the specified range of a chunk |
644 | * pcpu_depopulate_chunk - depopulate the specified range of a chunk |
645 | * pcpu_create_chunk - create a new chunk |
646 | * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop |
647 | * pcpu_addr_to_page - translate address to physical address |
648 | * pcpu_verify_alloc_info - check alloc_info is acceptable during init |
649 | */ |
650 | static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size); |
651 | static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size); |
652 | static struct pcpu_chunk *pcpu_create_chunk(void); |
653 | static void pcpu_destroy_chunk(struct pcpu_chunk *chunk); |
654 | static struct page *pcpu_addr_to_page(void *addr); |
655 | static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai); |
656 | |
657 | #ifdef CONFIG_NEED_PER_CPU_KM |
658 | #include "percpu-km.c" |
659 | #else |
660 | #include "percpu-vm.c" |
661 | #endif |
662 | |
663 | /** |
664 | * pcpu_chunk_addr_search - determine chunk containing specified address |
665 | * @addr: address for which the chunk needs to be determined. |
666 | * |
667 | * RETURNS: |
668 | * The address of the found chunk. |
669 | */ |
670 | static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) |
671 | { |
672 | /* is it in the first chunk? */ |
673 | if (pcpu_addr_in_first_chunk(addr)) { |
674 | /* is it in the reserved area? */ |
675 | if (pcpu_addr_in_reserved_chunk(addr)) |
676 | return pcpu_reserved_chunk; |
677 | return pcpu_first_chunk; |
678 | } |
679 | |
680 | /* |
681 | * The address is relative to unit0 which might be unused and |
682 | * thus unmapped. Offset the address to the unit space of the |
683 | * current processor before looking it up in the vmalloc |
684 | * space. Note that any possible cpu id can be used here, so |
685 | * there's no need to worry about preemption or cpu hotplug. |
686 | */ |
687 | addr += pcpu_unit_offsets[raw_smp_processor_id()]; |
688 | return pcpu_get_page_chunk(pcpu_addr_to_page(addr)); |
689 | } |
690 | |
691 | /** |
692 | * pcpu_alloc - the percpu allocator |
693 | * @size: size of area to allocate in bytes |
694 | * @align: alignment of area (max PAGE_SIZE) |
695 | * @reserved: allocate from the reserved chunk if available |
696 | * |
697 | * Allocate percpu area of @size bytes aligned at @align. |
698 | * |
699 | * CONTEXT: |
700 | * Does GFP_KERNEL allocation. |
701 | * |
702 | * RETURNS: |
703 | * Percpu pointer to the allocated area on success, NULL on failure. |
704 | */ |
705 | static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) |
706 | { |
707 | static int warn_limit = 10; |
708 | struct pcpu_chunk *chunk; |
709 | const char *err; |
710 | int slot, off, new_alloc; |
711 | unsigned long flags; |
712 | |
713 | if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { |
714 | WARN(true, "illegal size (%zu) or align (%zu) for " |
715 | "percpu allocation\n", size, align); |
716 | return NULL; |
717 | } |
718 | |
719 | mutex_lock(&pcpu_alloc_mutex); |
720 | spin_lock_irqsave(&pcpu_lock, flags); |
721 | |
722 | /* serve reserved allocations from the reserved chunk if available */ |
723 | if (reserved && pcpu_reserved_chunk) { |
724 | chunk = pcpu_reserved_chunk; |
725 | |
726 | if (size > chunk->contig_hint) { |
727 | err = "alloc from reserved chunk failed"; |
728 | goto fail_unlock; |
729 | } |
730 | |
731 | while ((new_alloc = pcpu_need_to_extend(chunk))) { |
732 | spin_unlock_irqrestore(&pcpu_lock, flags); |
733 | if (pcpu_extend_area_map(chunk, new_alloc) < 0) { |
734 | err = "failed to extend area map of reserved chunk"; |
735 | goto fail_unlock_mutex; |
736 | } |
737 | spin_lock_irqsave(&pcpu_lock, flags); |
738 | } |
739 | |
740 | off = pcpu_alloc_area(chunk, size, align); |
741 | if (off >= 0) |
742 | goto area_found; |
743 | |
744 | err = "alloc from reserved chunk failed"; |
745 | goto fail_unlock; |
746 | } |
747 | |
748 | restart: |
749 | /* search through normal chunks */ |
750 | for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) { |
751 | list_for_each_entry(chunk, &pcpu_slot[slot], list) { |
752 | if (size > chunk->contig_hint) |
753 | continue; |
754 | |
755 | new_alloc = pcpu_need_to_extend(chunk); |
756 | if (new_alloc) { |
757 | spin_unlock_irqrestore(&pcpu_lock, flags); |
758 | if (pcpu_extend_area_map(chunk, |
759 | new_alloc) < 0) { |
760 | err = "failed to extend area map"; |
761 | goto fail_unlock_mutex; |
762 | } |
763 | spin_lock_irqsave(&pcpu_lock, flags); |
764 | /* |
765 | * pcpu_lock has been dropped, need to |
766 | * restart cpu_slot list walking. |
767 | */ |
768 | goto restart; |
769 | } |
770 | |
771 | off = pcpu_alloc_area(chunk, size, align); |
772 | if (off >= 0) |
773 | goto area_found; |
774 | } |
775 | } |
776 | |
777 | /* hmmm... no space left, create a new chunk */ |
778 | spin_unlock_irqrestore(&pcpu_lock, flags); |
779 | |
780 | chunk = pcpu_create_chunk(); |
781 | if (!chunk) { |
782 | err = "failed to allocate new chunk"; |
783 | goto fail_unlock_mutex; |
784 | } |
785 | |
786 | spin_lock_irqsave(&pcpu_lock, flags); |
787 | pcpu_chunk_relocate(chunk, -1); |
788 | goto restart; |
789 | |
790 | area_found: |
791 | spin_unlock_irqrestore(&pcpu_lock, flags); |
792 | |
793 | /* populate, map and clear the area */ |
794 | if (pcpu_populate_chunk(chunk, off, size)) { |
795 | spin_lock_irqsave(&pcpu_lock, flags); |
796 | pcpu_free_area(chunk, off); |
797 | err = "failed to populate"; |
798 | goto fail_unlock; |
799 | } |
800 | |
801 | mutex_unlock(&pcpu_alloc_mutex); |
802 | |
803 | /* return address relative to base address */ |
804 | return __addr_to_pcpu_ptr(chunk->base_addr + off); |
805 | |
806 | fail_unlock: |
807 | spin_unlock_irqrestore(&pcpu_lock, flags); |
808 | fail_unlock_mutex: |
809 | mutex_unlock(&pcpu_alloc_mutex); |
810 | if (warn_limit) { |
811 | pr_warning("PERCPU: allocation failed, size=%zu align=%zu, " |
812 | "%s\n", size, align, err); |
813 | dump_stack(); |
814 | if (!--warn_limit) |
815 | pr_info("PERCPU: limit reached, disable warning\n"); |
816 | } |
817 | return NULL; |
818 | } |
819 | |
820 | /** |
821 | * __alloc_percpu - allocate dynamic percpu area |
822 | * @size: size of area to allocate in bytes |
823 | * @align: alignment of area (max PAGE_SIZE) |
824 | * |
825 | * Allocate percpu area of @size bytes aligned at @align. Might |
826 | * sleep. Might trigger writeouts. |
827 | * |
828 | * CONTEXT: |
829 | * Does GFP_KERNEL allocation. |
830 | * |
831 | * RETURNS: |
832 | * Percpu pointer to the allocated area on success, NULL on failure. |
833 | */ |
834 | void __percpu *__alloc_percpu(size_t size, size_t align) |
835 | { |
836 | return pcpu_alloc(size, align, false); |
837 | } |
838 | EXPORT_SYMBOL_GPL(__alloc_percpu); |
839 | |
840 | /** |
841 | * __alloc_reserved_percpu - allocate reserved percpu area |
842 | * @size: size of area to allocate in bytes |
843 | * @align: alignment of area (max PAGE_SIZE) |
844 | * |
845 | * Allocate percpu area of @size bytes aligned at @align from reserved |
846 | * percpu area if arch has set it up; otherwise, allocation is served |
847 | * from the same dynamic area. Might sleep. Might trigger writeouts. |
848 | * |
849 | * CONTEXT: |
850 | * Does GFP_KERNEL allocation. |
851 | * |
852 | * RETURNS: |
853 | * Percpu pointer to the allocated area on success, NULL on failure. |
854 | */ |
855 | void __percpu *__alloc_reserved_percpu(size_t size, size_t align) |
856 | { |
857 | return pcpu_alloc(size, align, true); |
858 | } |
859 | |
860 | /** |
861 | * pcpu_reclaim - reclaim fully free chunks, workqueue function |
862 | * @work: unused |
863 | * |
864 | * Reclaim all fully free chunks except for the first one. |
865 | * |
866 | * CONTEXT: |
867 | * workqueue context. |
868 | */ |
869 | static void pcpu_reclaim(struct work_struct *work) |
870 | { |
871 | LIST_HEAD(todo); |
872 | struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1]; |
873 | struct pcpu_chunk *chunk, *next; |
874 | |
875 | mutex_lock(&pcpu_alloc_mutex); |
876 | spin_lock_irq(&pcpu_lock); |
877 | |
878 | list_for_each_entry_safe(chunk, next, head, list) { |
879 | WARN_ON(chunk->immutable); |
880 | |
881 | /* spare the first one */ |
882 | if (chunk == list_first_entry(head, struct pcpu_chunk, list)) |
883 | continue; |
884 | |
885 | list_move(&chunk->list, &todo); |
886 | } |
887 | |
888 | spin_unlock_irq(&pcpu_lock); |
889 | |
890 | list_for_each_entry_safe(chunk, next, &todo, list) { |
891 | pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size); |
892 | pcpu_destroy_chunk(chunk); |
893 | } |
894 | |
895 | mutex_unlock(&pcpu_alloc_mutex); |
896 | } |
897 | |
898 | /** |
899 | * free_percpu - free percpu area |
900 | * @ptr: pointer to area to free |
901 | * |
902 | * Free percpu area @ptr. |
903 | * |
904 | * CONTEXT: |
905 | * Can be called from atomic context. |
906 | */ |
907 | void free_percpu(void __percpu *ptr) |
908 | { |
909 | void *addr; |
910 | struct pcpu_chunk *chunk; |
911 | unsigned long flags; |
912 | int off; |
913 | |
914 | if (!ptr) |
915 | return; |
916 | |
917 | addr = __pcpu_ptr_to_addr(ptr); |
918 | |
919 | spin_lock_irqsave(&pcpu_lock, flags); |
920 | |
921 | chunk = pcpu_chunk_addr_search(addr); |
922 | off = addr - chunk->base_addr; |
923 | |
924 | pcpu_free_area(chunk, off); |
925 | |
926 | /* if there are more than one fully free chunks, wake up grim reaper */ |
927 | if (chunk->free_size == pcpu_unit_size) { |
928 | struct pcpu_chunk *pos; |
929 | |
930 | list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list) |
931 | if (pos != chunk) { |
932 | schedule_work(&pcpu_reclaim_work); |
933 | break; |
934 | } |
935 | } |
936 | |
937 | spin_unlock_irqrestore(&pcpu_lock, flags); |
938 | } |
939 | EXPORT_SYMBOL_GPL(free_percpu); |
940 | |
941 | /** |
942 | * is_kernel_percpu_address - test whether address is from static percpu area |
943 | * @addr: address to test |
944 | * |
945 | * Test whether @addr belongs to in-kernel static percpu area. Module |
946 | * static percpu areas are not considered. For those, use |
947 | * is_module_percpu_address(). |
948 | * |
949 | * RETURNS: |
950 | * %true if @addr is from in-kernel static percpu area, %false otherwise. |
951 | */ |
952 | bool is_kernel_percpu_address(unsigned long addr) |
953 | { |
954 | const size_t static_size = __per_cpu_end - __per_cpu_start; |
955 | void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); |
956 | unsigned int cpu; |
957 | |
958 | for_each_possible_cpu(cpu) { |
959 | void *start = per_cpu_ptr(base, cpu); |
960 | |
961 | if ((void *)addr >= start && (void *)addr < start + static_size) |
962 | return true; |
963 | } |
964 | return false; |
965 | } |
966 | |
967 | /** |
968 | * per_cpu_ptr_to_phys - convert translated percpu address to physical address |
969 | * @addr: the address to be converted to physical address |
970 | * |
971 | * Given @addr which is dereferenceable address obtained via one of |
972 | * percpu access macros, this function translates it into its physical |
973 | * address. The caller is responsible for ensuring @addr stays valid |
974 | * until this function finishes. |
975 | * |
976 | * RETURNS: |
977 | * The physical address for @addr. |
978 | */ |
979 | phys_addr_t per_cpu_ptr_to_phys(void *addr) |
980 | { |
981 | void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); |
982 | bool in_first_chunk = false; |
983 | unsigned long first_start, first_end; |
984 | unsigned int cpu; |
985 | |
986 | /* |
987 | * The following test on first_start/end isn't strictly |
988 | * necessary but will speed up lookups of addresses which |
989 | * aren't in the first chunk. |
990 | */ |
991 | first_start = pcpu_chunk_addr(pcpu_first_chunk, pcpu_first_unit_cpu, 0); |
992 | first_end = pcpu_chunk_addr(pcpu_first_chunk, pcpu_last_unit_cpu, |
993 | pcpu_unit_pages); |
994 | if ((unsigned long)addr >= first_start && |
995 | (unsigned long)addr < first_end) { |
996 | for_each_possible_cpu(cpu) { |
997 | void *start = per_cpu_ptr(base, cpu); |
998 | |
999 | if (addr >= start && addr < start + pcpu_unit_size) { |
1000 | in_first_chunk = true; |
1001 | break; |
1002 | } |
1003 | } |
1004 | } |
1005 | |
1006 | if (in_first_chunk) { |
1007 | if ((unsigned long)addr < VMALLOC_START || |
1008 | (unsigned long)addr >= VMALLOC_END) |
1009 | return __pa(addr); |
1010 | else |
1011 | return page_to_phys(vmalloc_to_page(addr)); |
1012 | } else |
1013 | return page_to_phys(pcpu_addr_to_page(addr)); |
1014 | } |
1015 | |
1016 | static inline size_t pcpu_calc_fc_sizes(size_t static_size, |
1017 | size_t reserved_size, |
1018 | ssize_t *dyn_sizep) |
1019 | { |
1020 | size_t size_sum; |
1021 | |
1022 | size_sum = PFN_ALIGN(static_size + reserved_size + |
1023 | (*dyn_sizep >= 0 ? *dyn_sizep : 0)); |
1024 | if (*dyn_sizep != 0) |
1025 | *dyn_sizep = size_sum - static_size - reserved_size; |
1026 | |
1027 | return size_sum; |
1028 | } |
1029 | |
1030 | /** |
1031 | * pcpu_alloc_alloc_info - allocate percpu allocation info |
1032 | * @nr_groups: the number of groups |
1033 | * @nr_units: the number of units |
1034 | * |
1035 | * Allocate ai which is large enough for @nr_groups groups containing |
1036 | * @nr_units units. The returned ai's groups[0].cpu_map points to the |
1037 | * cpu_map array which is long enough for @nr_units and filled with |
1038 | * NR_CPUS. It's the caller's responsibility to initialize cpu_map |
1039 | * pointer of other groups. |
1040 | * |
1041 | * RETURNS: |
1042 | * Pointer to the allocated pcpu_alloc_info on success, NULL on |
1043 | * failure. |
1044 | */ |
1045 | struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups, |
1046 | int nr_units) |
1047 | { |
1048 | struct pcpu_alloc_info *ai; |
1049 | size_t base_size, ai_size; |
1050 | void *ptr; |
1051 | int unit; |
1052 | |
1053 | base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]), |
1054 | __alignof__(ai->groups[0].cpu_map[0])); |
1055 | ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]); |
1056 | |
1057 | ptr = alloc_bootmem_nopanic(PFN_ALIGN(ai_size)); |
1058 | if (!ptr) |
1059 | return NULL; |
1060 | ai = ptr; |
1061 | ptr += base_size; |
1062 | |
1063 | ai->groups[0].cpu_map = ptr; |
1064 | |
1065 | for (unit = 0; unit < nr_units; unit++) |
1066 | ai->groups[0].cpu_map[unit] = NR_CPUS; |
1067 | |
1068 | ai->nr_groups = nr_groups; |
1069 | ai->__ai_size = PFN_ALIGN(ai_size); |
1070 | |
1071 | return ai; |
1072 | } |
1073 | |
1074 | /** |
1075 | * pcpu_free_alloc_info - free percpu allocation info |
1076 | * @ai: pcpu_alloc_info to free |
1077 | * |
1078 | * Free @ai which was allocated by pcpu_alloc_alloc_info(). |
1079 | */ |
1080 | void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai) |
1081 | { |
1082 | free_bootmem(__pa(ai), ai->__ai_size); |
1083 | } |
1084 | |
1085 | /** |
1086 | * pcpu_build_alloc_info - build alloc_info considering distances between CPUs |
1087 | * @reserved_size: the size of reserved percpu area in bytes |
1088 | * @dyn_size: free size for dynamic allocation in bytes, -1 for auto |
1089 | * @atom_size: allocation atom size |
1090 | * @cpu_distance_fn: callback to determine distance between cpus, optional |
1091 | * |
1092 | * This function determines grouping of units, their mappings to cpus |
1093 | * and other parameters considering needed percpu size, allocation |
1094 | * atom size and distances between CPUs. |
1095 | * |
1096 | * Groups are always mutliples of atom size and CPUs which are of |
1097 | * LOCAL_DISTANCE both ways are grouped together and share space for |
1098 | * units in the same group. The returned configuration is guaranteed |
1099 | * to have CPUs on different nodes on different groups and >=75% usage |
1100 | * of allocated virtual address space. |
1101 | * |
1102 | * RETURNS: |
1103 | * On success, pointer to the new allocation_info is returned. On |
1104 | * failure, ERR_PTR value is returned. |
1105 | */ |
1106 | struct pcpu_alloc_info * __init pcpu_build_alloc_info( |
1107 | size_t reserved_size, ssize_t dyn_size, |
1108 | size_t atom_size, |
1109 | pcpu_fc_cpu_distance_fn_t cpu_distance_fn) |
1110 | { |
1111 | static int group_map[NR_CPUS] __initdata; |
1112 | static int group_cnt[NR_CPUS] __initdata; |
1113 | const size_t static_size = __per_cpu_end - __per_cpu_start; |
1114 | int nr_groups = 1, nr_units = 0; |
1115 | size_t size_sum, min_unit_size, alloc_size; |
1116 | int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */ |
1117 | int last_allocs, group, unit; |
1118 | unsigned int cpu, tcpu; |
1119 | struct pcpu_alloc_info *ai; |
1120 | unsigned int *cpu_map; |
1121 | |
1122 | /* this function may be called multiple times */ |
1123 | memset(group_map, 0, sizeof(group_map)); |
1124 | memset(group_cnt, 0, sizeof(group_cnt)); |
1125 | |
1126 | /* |
1127 | * Determine min_unit_size, alloc_size and max_upa such that |
1128 | * alloc_size is multiple of atom_size and is the smallest |
1129 | * which can accomodate 4k aligned segments which are equal to |
1130 | * or larger than min_unit_size. |
1131 | */ |
1132 | size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size); |
1133 | min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); |
1134 | |
1135 | alloc_size = roundup(min_unit_size, atom_size); |
1136 | upa = alloc_size / min_unit_size; |
1137 | while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK)) |
1138 | upa--; |
1139 | max_upa = upa; |
1140 | |
1141 | /* group cpus according to their proximity */ |
1142 | for_each_possible_cpu(cpu) { |
1143 | group = 0; |
1144 | next_group: |
1145 | for_each_possible_cpu(tcpu) { |
1146 | if (cpu == tcpu) |
1147 | break; |
1148 | if (group_map[tcpu] == group && cpu_distance_fn && |
1149 | (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE || |
1150 | cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) { |
1151 | group++; |
1152 | nr_groups = max(nr_groups, group + 1); |
1153 | goto next_group; |
1154 | } |
1155 | } |
1156 | group_map[cpu] = group; |
1157 | group_cnt[group]++; |
1158 | } |
1159 | |
1160 | /* |
1161 | * Expand unit size until address space usage goes over 75% |
1162 | * and then as much as possible without using more address |
1163 | * space. |
1164 | */ |
1165 | last_allocs = INT_MAX; |
1166 | for (upa = max_upa; upa; upa--) { |
1167 | int allocs = 0, wasted = 0; |
1168 | |
1169 | if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK)) |
1170 | continue; |
1171 | |
1172 | for (group = 0; group < nr_groups; group++) { |
1173 | int this_allocs = DIV_ROUND_UP(group_cnt[group], upa); |
1174 | allocs += this_allocs; |
1175 | wasted += this_allocs * upa - group_cnt[group]; |
1176 | } |
1177 | |
1178 | /* |
1179 | * Don't accept if wastage is over 25%. The |
1180 | * greater-than comparison ensures upa==1 always |
1181 | * passes the following check. |
1182 | */ |
1183 | if (wasted > num_possible_cpus() / 3) |
1184 | continue; |
1185 | |
1186 | /* and then don't consume more memory */ |
1187 | if (allocs > last_allocs) |
1188 | break; |
1189 | last_allocs = allocs; |
1190 | best_upa = upa; |
1191 | } |
1192 | upa = best_upa; |
1193 | |
1194 | /* allocate and fill alloc_info */ |
1195 | for (group = 0; group < nr_groups; group++) |
1196 | nr_units += roundup(group_cnt[group], upa); |
1197 | |
1198 | ai = pcpu_alloc_alloc_info(nr_groups, nr_units); |
1199 | if (!ai) |
1200 | return ERR_PTR(-ENOMEM); |
1201 | cpu_map = ai->groups[0].cpu_map; |
1202 | |
1203 | for (group = 0; group < nr_groups; group++) { |
1204 | ai->groups[group].cpu_map = cpu_map; |
1205 | cpu_map += roundup(group_cnt[group], upa); |
1206 | } |
1207 | |
1208 | ai->static_size = static_size; |
1209 | ai->reserved_size = reserved_size; |
1210 | ai->dyn_size = dyn_size; |
1211 | ai->unit_size = alloc_size / upa; |
1212 | ai->atom_size = atom_size; |
1213 | ai->alloc_size = alloc_size; |
1214 | |
1215 | for (group = 0, unit = 0; group_cnt[group]; group++) { |
1216 | struct pcpu_group_info *gi = &ai->groups[group]; |
1217 | |
1218 | /* |
1219 | * Initialize base_offset as if all groups are located |
1220 | * back-to-back. The caller should update this to |
1221 | * reflect actual allocation. |
1222 | */ |
1223 | gi->base_offset = unit * ai->unit_size; |
1224 | |
1225 | for_each_possible_cpu(cpu) |
1226 | if (group_map[cpu] == group) |
1227 | gi->cpu_map[gi->nr_units++] = cpu; |
1228 | gi->nr_units = roundup(gi->nr_units, upa); |
1229 | unit += gi->nr_units; |
1230 | } |
1231 | BUG_ON(unit != nr_units); |
1232 | |
1233 | return ai; |
1234 | } |
1235 | |
1236 | /** |
1237 | * pcpu_dump_alloc_info - print out information about pcpu_alloc_info |
1238 | * @lvl: loglevel |
1239 | * @ai: allocation info to dump |
1240 | * |
1241 | * Print out information about @ai using loglevel @lvl. |
1242 | */ |
1243 | static void pcpu_dump_alloc_info(const char *lvl, |
1244 | const struct pcpu_alloc_info *ai) |
1245 | { |
1246 | int group_width = 1, cpu_width = 1, width; |
1247 | char empty_str[] = "--------"; |
1248 | int alloc = 0, alloc_end = 0; |
1249 | int group, v; |
1250 | int upa, apl; /* units per alloc, allocs per line */ |
1251 | |
1252 | v = ai->nr_groups; |
1253 | while (v /= 10) |
1254 | group_width++; |
1255 | |
1256 | v = num_possible_cpus(); |
1257 | while (v /= 10) |
1258 | cpu_width++; |
1259 | empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0'; |
1260 | |
1261 | upa = ai->alloc_size / ai->unit_size; |
1262 | width = upa * (cpu_width + 1) + group_width + 3; |
1263 | apl = rounddown_pow_of_two(max(60 / width, 1)); |
1264 | |
1265 | printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu", |
1266 | lvl, ai->static_size, ai->reserved_size, ai->dyn_size, |
1267 | ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size); |
1268 | |
1269 | for (group = 0; group < ai->nr_groups; group++) { |
1270 | const struct pcpu_group_info *gi = &ai->groups[group]; |
1271 | int unit = 0, unit_end = 0; |
1272 | |
1273 | BUG_ON(gi->nr_units % upa); |
1274 | for (alloc_end += gi->nr_units / upa; |
1275 | alloc < alloc_end; alloc++) { |
1276 | if (!(alloc % apl)) { |
1277 | printk("\n"); |
1278 | printk("%spcpu-alloc: ", lvl); |
1279 | } |
1280 | printk("[%0*d] ", group_width, group); |
1281 | |
1282 | for (unit_end += upa; unit < unit_end; unit++) |
1283 | if (gi->cpu_map[unit] != NR_CPUS) |
1284 | printk("%0*d ", cpu_width, |
1285 | gi->cpu_map[unit]); |
1286 | else |
1287 | printk("%s ", empty_str); |
1288 | } |
1289 | } |
1290 | printk("\n"); |
1291 | } |
1292 | |
1293 | /** |
1294 | * pcpu_setup_first_chunk - initialize the first percpu chunk |
1295 | * @ai: pcpu_alloc_info describing how to percpu area is shaped |
1296 | * @base_addr: mapped address |
1297 | * |
1298 | * Initialize the first percpu chunk which contains the kernel static |
1299 | * perpcu area. This function is to be called from arch percpu area |
1300 | * setup path. |
1301 | * |
1302 | * @ai contains all information necessary to initialize the first |
1303 | * chunk and prime the dynamic percpu allocator. |
1304 | * |
1305 | * @ai->static_size is the size of static percpu area. |
1306 | * |
1307 | * @ai->reserved_size, if non-zero, specifies the amount of bytes to |
1308 | * reserve after the static area in the first chunk. This reserves |
1309 | * the first chunk such that it's available only through reserved |
1310 | * percpu allocation. This is primarily used to serve module percpu |
1311 | * static areas on architectures where the addressing model has |
1312 | * limited offset range for symbol relocations to guarantee module |
1313 | * percpu symbols fall inside the relocatable range. |
1314 | * |
1315 | * @ai->dyn_size determines the number of bytes available for dynamic |
1316 | * allocation in the first chunk. The area between @ai->static_size + |
1317 | * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused. |
1318 | * |
1319 | * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE |
1320 | * and equal to or larger than @ai->static_size + @ai->reserved_size + |
1321 | * @ai->dyn_size. |
1322 | * |
1323 | * @ai->atom_size is the allocation atom size and used as alignment |
1324 | * for vm areas. |
1325 | * |
1326 | * @ai->alloc_size is the allocation size and always multiple of |
1327 | * @ai->atom_size. This is larger than @ai->atom_size if |
1328 | * @ai->unit_size is larger than @ai->atom_size. |
1329 | * |
1330 | * @ai->nr_groups and @ai->groups describe virtual memory layout of |
1331 | * percpu areas. Units which should be colocated are put into the |
1332 | * same group. Dynamic VM areas will be allocated according to these |
1333 | * groupings. If @ai->nr_groups is zero, a single group containing |
1334 | * all units is assumed. |
1335 | * |
1336 | * The caller should have mapped the first chunk at @base_addr and |
1337 | * copied static data to each unit. |
1338 | * |
1339 | * If the first chunk ends up with both reserved and dynamic areas, it |
1340 | * is served by two chunks - one to serve the core static and reserved |
1341 | * areas and the other for the dynamic area. They share the same vm |
1342 | * and page map but uses different area allocation map to stay away |
1343 | * from each other. The latter chunk is circulated in the chunk slots |
1344 | * and available for dynamic allocation like any other chunks. |
1345 | * |
1346 | * RETURNS: |
1347 | * 0 on success, -errno on failure. |
1348 | */ |
1349 | int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, |
1350 | void *base_addr) |
1351 | { |
1352 | static char cpus_buf[4096] __initdata; |
1353 | static int smap[2], dmap[2]; |
1354 | size_t dyn_size = ai->dyn_size; |
1355 | size_t size_sum = ai->static_size + ai->reserved_size + dyn_size; |
1356 | struct pcpu_chunk *schunk, *dchunk = NULL; |
1357 | unsigned long *group_offsets; |
1358 | size_t *group_sizes; |
1359 | unsigned long *unit_off; |
1360 | unsigned int cpu; |
1361 | int *unit_map; |
1362 | int group, unit, i; |
1363 | |
1364 | cpumask_scnprintf(cpus_buf, sizeof(cpus_buf), cpu_possible_mask); |
1365 | |
1366 | #define PCPU_SETUP_BUG_ON(cond) do { \ |
1367 | if (unlikely(cond)) { \ |
1368 | pr_emerg("PERCPU: failed to initialize, %s", #cond); \ |
1369 | pr_emerg("PERCPU: cpu_possible_mask=%s\n", cpus_buf); \ |
1370 | pcpu_dump_alloc_info(KERN_EMERG, ai); \ |
1371 | BUG(); \ |
1372 | } \ |
1373 | } while (0) |
1374 | |
1375 | /* sanity checks */ |
1376 | BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC || |
1377 | ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC); |
1378 | PCPU_SETUP_BUG_ON(ai->nr_groups <= 0); |
1379 | PCPU_SETUP_BUG_ON(!ai->static_size); |
1380 | PCPU_SETUP_BUG_ON(!base_addr); |
1381 | PCPU_SETUP_BUG_ON(ai->unit_size < size_sum); |
1382 | PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK); |
1383 | PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE); |
1384 | PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0); |
1385 | |
1386 | /* process group information and build config tables accordingly */ |
1387 | group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0])); |
1388 | group_sizes = alloc_bootmem(ai->nr_groups * sizeof(group_sizes[0])); |
1389 | unit_map = alloc_bootmem(nr_cpu_ids * sizeof(unit_map[0])); |
1390 | unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0])); |
1391 | |
1392 | for (cpu = 0; cpu < nr_cpu_ids; cpu++) |
1393 | unit_map[cpu] = UINT_MAX; |
1394 | pcpu_first_unit_cpu = NR_CPUS; |
1395 | |
1396 | for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) { |
1397 | const struct pcpu_group_info *gi = &ai->groups[group]; |
1398 | |
1399 | group_offsets[group] = gi->base_offset; |
1400 | group_sizes[group] = gi->nr_units * ai->unit_size; |
1401 | |
1402 | for (i = 0; i < gi->nr_units; i++) { |
1403 | cpu = gi->cpu_map[i]; |
1404 | if (cpu == NR_CPUS) |
1405 | continue; |
1406 | |
1407 | PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids); |
1408 | PCPU_SETUP_BUG_ON(!cpu_possible(cpu)); |
1409 | PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX); |
1410 | |
1411 | unit_map[cpu] = unit + i; |
1412 | unit_off[cpu] = gi->base_offset + i * ai->unit_size; |
1413 | |
1414 | if (pcpu_first_unit_cpu == NR_CPUS) |
1415 | pcpu_first_unit_cpu = cpu; |
1416 | } |
1417 | } |
1418 | pcpu_last_unit_cpu = cpu; |
1419 | pcpu_nr_units = unit; |
1420 | |
1421 | for_each_possible_cpu(cpu) |
1422 | PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX); |
1423 | |
1424 | /* we're done parsing the input, undefine BUG macro and dump config */ |
1425 | #undef PCPU_SETUP_BUG_ON |
1426 | pcpu_dump_alloc_info(KERN_INFO, ai); |
1427 | |
1428 | pcpu_nr_groups = ai->nr_groups; |
1429 | pcpu_group_offsets = group_offsets; |
1430 | pcpu_group_sizes = group_sizes; |
1431 | pcpu_unit_map = unit_map; |
1432 | pcpu_unit_offsets = unit_off; |
1433 | |
1434 | /* determine basic parameters */ |
1435 | pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT; |
1436 | pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; |
1437 | pcpu_atom_size = ai->atom_size; |
1438 | pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) + |
1439 | BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long); |
1440 | |
1441 | /* |
1442 | * Allocate chunk slots. The additional last slot is for |
1443 | * empty chunks. |
1444 | */ |
1445 | pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2; |
1446 | pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0])); |
1447 | for (i = 0; i < pcpu_nr_slots; i++) |
1448 | INIT_LIST_HEAD(&pcpu_slot[i]); |
1449 | |
1450 | /* |
1451 | * Initialize static chunk. If reserved_size is zero, the |
1452 | * static chunk covers static area + dynamic allocation area |
1453 | * in the first chunk. If reserved_size is not zero, it |
1454 | * covers static area + reserved area (mostly used for module |
1455 | * static percpu allocation). |
1456 | */ |
1457 | schunk = alloc_bootmem(pcpu_chunk_struct_size); |
1458 | INIT_LIST_HEAD(&schunk->list); |
1459 | schunk->base_addr = base_addr; |
1460 | schunk->map = smap; |
1461 | schunk->map_alloc = ARRAY_SIZE(smap); |
1462 | schunk->immutable = true; |
1463 | bitmap_fill(schunk->populated, pcpu_unit_pages); |
1464 | |
1465 | if (ai->reserved_size) { |
1466 | schunk->free_size = ai->reserved_size; |
1467 | pcpu_reserved_chunk = schunk; |
1468 | pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size; |
1469 | } else { |
1470 | schunk->free_size = dyn_size; |
1471 | dyn_size = 0; /* dynamic area covered */ |
1472 | } |
1473 | schunk->contig_hint = schunk->free_size; |
1474 | |
1475 | schunk->map[schunk->map_used++] = -ai->static_size; |
1476 | if (schunk->free_size) |
1477 | schunk->map[schunk->map_used++] = schunk->free_size; |
1478 | |
1479 | /* init dynamic chunk if necessary */ |
1480 | if (dyn_size) { |
1481 | dchunk = alloc_bootmem(pcpu_chunk_struct_size); |
1482 | INIT_LIST_HEAD(&dchunk->list); |
1483 | dchunk->base_addr = base_addr; |
1484 | dchunk->map = dmap; |
1485 | dchunk->map_alloc = ARRAY_SIZE(dmap); |
1486 | dchunk->immutable = true; |
1487 | bitmap_fill(dchunk->populated, pcpu_unit_pages); |
1488 | |
1489 | dchunk->contig_hint = dchunk->free_size = dyn_size; |
1490 | dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit; |
1491 | dchunk->map[dchunk->map_used++] = dchunk->free_size; |
1492 | } |
1493 | |
1494 | /* link the first chunk in */ |
1495 | pcpu_first_chunk = dchunk ?: schunk; |
1496 | pcpu_chunk_relocate(pcpu_first_chunk, -1); |
1497 | |
1498 | /* we're done */ |
1499 | pcpu_base_addr = base_addr; |
1500 | return 0; |
1501 | } |
1502 | |
1503 | const char *pcpu_fc_names[PCPU_FC_NR] __initdata = { |
1504 | [PCPU_FC_AUTO] = "auto", |
1505 | [PCPU_FC_EMBED] = "embed", |
1506 | [PCPU_FC_PAGE] = "page", |
1507 | }; |
1508 | |
1509 | enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO; |
1510 | |
1511 | static int __init percpu_alloc_setup(char *str) |
1512 | { |
1513 | if (0) |
1514 | /* nada */; |
1515 | #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK |
1516 | else if (!strcmp(str, "embed")) |
1517 | pcpu_chosen_fc = PCPU_FC_EMBED; |
1518 | #endif |
1519 | #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK |
1520 | else if (!strcmp(str, "page")) |
1521 | pcpu_chosen_fc = PCPU_FC_PAGE; |
1522 | #endif |
1523 | else |
1524 | pr_warning("PERCPU: unknown allocator %s specified\n", str); |
1525 | |
1526 | return 0; |
1527 | } |
1528 | early_param("percpu_alloc", percpu_alloc_setup); |
1529 | |
1530 | #if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \ |
1531 | !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) |
1532 | /** |
1533 | * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem |
1534 | * @reserved_size: the size of reserved percpu area in bytes |
1535 | * @dyn_size: free size for dynamic allocation in bytes, -1 for auto |
1536 | * @atom_size: allocation atom size |
1537 | * @cpu_distance_fn: callback to determine distance between cpus, optional |
1538 | * @alloc_fn: function to allocate percpu page |
1539 | * @free_fn: funtion to free percpu page |
1540 | * |
1541 | * This is a helper to ease setting up embedded first percpu chunk and |
1542 | * can be called where pcpu_setup_first_chunk() is expected. |
1543 | * |
1544 | * If this function is used to setup the first chunk, it is allocated |
1545 | * by calling @alloc_fn and used as-is without being mapped into |
1546 | * vmalloc area. Allocations are always whole multiples of @atom_size |
1547 | * aligned to @atom_size. |
1548 | * |
1549 | * This enables the first chunk to piggy back on the linear physical |
1550 | * mapping which often uses larger page size. Please note that this |
1551 | * can result in very sparse cpu->unit mapping on NUMA machines thus |
1552 | * requiring large vmalloc address space. Don't use this allocator if |
1553 | * vmalloc space is not orders of magnitude larger than distances |
1554 | * between node memory addresses (ie. 32bit NUMA machines). |
1555 | * |
1556 | * When @dyn_size is positive, dynamic area might be larger than |
1557 | * specified to fill page alignment. When @dyn_size is auto, |
1558 | * @dyn_size is just big enough to fill page alignment after static |
1559 | * and reserved areas. |
1560 | * |
1561 | * If the needed size is smaller than the minimum or specified unit |
1562 | * size, the leftover is returned using @free_fn. |
1563 | * |
1564 | * RETURNS: |
1565 | * 0 on success, -errno on failure. |
1566 | */ |
1567 | int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size, |
1568 | size_t atom_size, |
1569 | pcpu_fc_cpu_distance_fn_t cpu_distance_fn, |
1570 | pcpu_fc_alloc_fn_t alloc_fn, |
1571 | pcpu_fc_free_fn_t free_fn) |
1572 | { |
1573 | void *base = (void *)ULONG_MAX; |
1574 | void **areas = NULL; |
1575 | struct pcpu_alloc_info *ai; |
1576 | size_t size_sum, areas_size, max_distance; |
1577 | int group, i, rc; |
1578 | |
1579 | ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size, |
1580 | cpu_distance_fn); |
1581 | if (IS_ERR(ai)) |
1582 | return PTR_ERR(ai); |
1583 | |
1584 | size_sum = ai->static_size + ai->reserved_size + ai->dyn_size; |
1585 | areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *)); |
1586 | |
1587 | areas = alloc_bootmem_nopanic(areas_size); |
1588 | if (!areas) { |
1589 | rc = -ENOMEM; |
1590 | goto out_free; |
1591 | } |
1592 | |
1593 | /* allocate, copy and determine base address */ |
1594 | for (group = 0; group < ai->nr_groups; group++) { |
1595 | struct pcpu_group_info *gi = &ai->groups[group]; |
1596 | unsigned int cpu = NR_CPUS; |
1597 | void *ptr; |
1598 | |
1599 | for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++) |
1600 | cpu = gi->cpu_map[i]; |
1601 | BUG_ON(cpu == NR_CPUS); |
1602 | |
1603 | /* allocate space for the whole group */ |
1604 | ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size); |
1605 | if (!ptr) { |
1606 | rc = -ENOMEM; |
1607 | goto out_free_areas; |
1608 | } |
1609 | areas[group] = ptr; |
1610 | |
1611 | base = min(ptr, base); |
1612 | |
1613 | for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) { |
1614 | if (gi->cpu_map[i] == NR_CPUS) { |
1615 | /* unused unit, free whole */ |
1616 | free_fn(ptr, ai->unit_size); |
1617 | continue; |
1618 | } |
1619 | /* copy and return the unused part */ |
1620 | memcpy(ptr, __per_cpu_load, ai->static_size); |
1621 | free_fn(ptr + size_sum, ai->unit_size - size_sum); |
1622 | } |
1623 | } |
1624 | |
1625 | /* base address is now known, determine group base offsets */ |
1626 | max_distance = 0; |
1627 | for (group = 0; group < ai->nr_groups; group++) { |
1628 | ai->groups[group].base_offset = areas[group] - base; |
1629 | max_distance = max_t(size_t, max_distance, |
1630 | ai->groups[group].base_offset); |
1631 | } |
1632 | max_distance += ai->unit_size; |
1633 | |
1634 | /* warn if maximum distance is further than 75% of vmalloc space */ |
1635 | if (max_distance > (VMALLOC_END - VMALLOC_START) * 3 / 4) { |
1636 | pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc " |
1637 | "space 0x%lx\n", |
1638 | max_distance, VMALLOC_END - VMALLOC_START); |
1639 | #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK |
1640 | /* and fail if we have fallback */ |
1641 | rc = -EINVAL; |
1642 | goto out_free; |
1643 | #endif |
1644 | } |
1645 | |
1646 | pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n", |
1647 | PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size, |
1648 | ai->dyn_size, ai->unit_size); |
1649 | |
1650 | rc = pcpu_setup_first_chunk(ai, base); |
1651 | goto out_free; |
1652 | |
1653 | out_free_areas: |
1654 | for (group = 0; group < ai->nr_groups; group++) |
1655 | free_fn(areas[group], |
1656 | ai->groups[group].nr_units * ai->unit_size); |
1657 | out_free: |
1658 | pcpu_free_alloc_info(ai); |
1659 | if (areas) |
1660 | free_bootmem(__pa(areas), areas_size); |
1661 | return rc; |
1662 | } |
1663 | #endif /* CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK || |
1664 | !CONFIG_HAVE_SETUP_PER_CPU_AREA */ |
1665 | |
1666 | #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK |
1667 | /** |
1668 | * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages |
1669 | * @reserved_size: the size of reserved percpu area in bytes |
1670 | * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE |
1671 | * @free_fn: funtion to free percpu page, always called with PAGE_SIZE |
1672 | * @populate_pte_fn: function to populate pte |
1673 | * |
1674 | * This is a helper to ease setting up page-remapped first percpu |
1675 | * chunk and can be called where pcpu_setup_first_chunk() is expected. |
1676 | * |
1677 | * This is the basic allocator. Static percpu area is allocated |
1678 | * page-by-page into vmalloc area. |
1679 | * |
1680 | * RETURNS: |
1681 | * 0 on success, -errno on failure. |
1682 | */ |
1683 | int __init pcpu_page_first_chunk(size_t reserved_size, |
1684 | pcpu_fc_alloc_fn_t alloc_fn, |
1685 | pcpu_fc_free_fn_t free_fn, |
1686 | pcpu_fc_populate_pte_fn_t populate_pte_fn) |
1687 | { |
1688 | static struct vm_struct vm; |
1689 | struct pcpu_alloc_info *ai; |
1690 | char psize_str[16]; |
1691 | int unit_pages; |
1692 | size_t pages_size; |
1693 | struct page **pages; |
1694 | int unit, i, j, rc; |
1695 | |
1696 | snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10); |
1697 | |
1698 | ai = pcpu_build_alloc_info(reserved_size, -1, PAGE_SIZE, NULL); |
1699 | if (IS_ERR(ai)) |
1700 | return PTR_ERR(ai); |
1701 | BUG_ON(ai->nr_groups != 1); |
1702 | BUG_ON(ai->groups[0].nr_units != num_possible_cpus()); |
1703 | |
1704 | unit_pages = ai->unit_size >> PAGE_SHIFT; |
1705 | |
1706 | /* unaligned allocations can't be freed, round up to page size */ |
1707 | pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() * |
1708 | sizeof(pages[0])); |
1709 | pages = alloc_bootmem(pages_size); |
1710 | |
1711 | /* allocate pages */ |
1712 | j = 0; |
1713 | for (unit = 0; unit < num_possible_cpus(); unit++) |
1714 | for (i = 0; i < unit_pages; i++) { |
1715 | unsigned int cpu = ai->groups[0].cpu_map[unit]; |
1716 | void *ptr; |
1717 | |
1718 | ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE); |
1719 | if (!ptr) { |
1720 | pr_warning("PERCPU: failed to allocate %s page " |
1721 | "for cpu%u\n", psize_str, cpu); |
1722 | goto enomem; |
1723 | } |
1724 | pages[j++] = virt_to_page(ptr); |
1725 | } |
1726 | |
1727 | /* allocate vm area, map the pages and copy static data */ |
1728 | vm.flags = VM_ALLOC; |
1729 | vm.size = num_possible_cpus() * ai->unit_size; |
1730 | vm_area_register_early(&vm, PAGE_SIZE); |
1731 | |
1732 | for (unit = 0; unit < num_possible_cpus(); unit++) { |
1733 | unsigned long unit_addr = |
1734 | (unsigned long)vm.addr + unit * ai->unit_size; |
1735 | |
1736 | for (i = 0; i < unit_pages; i++) |
1737 | populate_pte_fn(unit_addr + (i << PAGE_SHIFT)); |
1738 | |
1739 | /* pte already populated, the following shouldn't fail */ |
1740 | rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages], |
1741 | unit_pages); |
1742 | if (rc < 0) |
1743 | panic("failed to map percpu area, err=%d\n", rc); |
1744 | |
1745 | /* |
1746 | * FIXME: Archs with virtual cache should flush local |
1747 | * cache for the linear mapping here - something |
1748 | * equivalent to flush_cache_vmap() on the local cpu. |
1749 | * flush_cache_vmap() can't be used as most supporting |
1750 | * data structures are not set up yet. |
1751 | */ |
1752 | |
1753 | /* copy static data */ |
1754 | memcpy((void *)unit_addr, __per_cpu_load, ai->static_size); |
1755 | } |
1756 | |
1757 | /* we're ready, commit */ |
1758 | pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n", |
1759 | unit_pages, psize_str, vm.addr, ai->static_size, |
1760 | ai->reserved_size, ai->dyn_size); |
1761 | |
1762 | rc = pcpu_setup_first_chunk(ai, vm.addr); |
1763 | goto out_free_ar; |
1764 | |
1765 | enomem: |
1766 | while (--j >= 0) |
1767 | free_fn(page_address(pages[j]), PAGE_SIZE); |
1768 | rc = -ENOMEM; |
1769 | out_free_ar: |
1770 | free_bootmem(__pa(pages), pages_size); |
1771 | pcpu_free_alloc_info(ai); |
1772 | return rc; |
1773 | } |
1774 | #endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */ |
1775 | |
1776 | /* |
1777 | * Generic percpu area setup. |
1778 | * |
1779 | * The embedding helper is used because its behavior closely resembles |
1780 | * the original non-dynamic generic percpu area setup. This is |
1781 | * important because many archs have addressing restrictions and might |
1782 | * fail if the percpu area is located far away from the previous |
1783 | * location. As an added bonus, in non-NUMA cases, embedding is |
1784 | * generally a good idea TLB-wise because percpu area can piggy back |
1785 | * on the physical linear memory mapping which uses large page |
1786 | * mappings on applicable archs. |
1787 | */ |
1788 | #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA |
1789 | unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; |
1790 | EXPORT_SYMBOL(__per_cpu_offset); |
1791 | |
1792 | static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size, |
1793 | size_t align) |
1794 | { |
1795 | return __alloc_bootmem_nopanic(size, align, __pa(MAX_DMA_ADDRESS)); |
1796 | } |
1797 | |
1798 | static void __init pcpu_dfl_fc_free(void *ptr, size_t size) |
1799 | { |
1800 | free_bootmem(__pa(ptr), size); |
1801 | } |
1802 | |
1803 | void __init setup_per_cpu_areas(void) |
1804 | { |
1805 | unsigned long delta; |
1806 | unsigned int cpu; |
1807 | int rc; |
1808 | |
1809 | /* |
1810 | * Always reserve area for module percpu variables. That's |
1811 | * what the legacy allocator did. |
1812 | */ |
1813 | rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE, |
1814 | PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL, |
1815 | pcpu_dfl_fc_alloc, pcpu_dfl_fc_free); |
1816 | if (rc < 0) |
1817 | panic("Failed to initialized percpu areas."); |
1818 | |
1819 | delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; |
1820 | for_each_possible_cpu(cpu) |
1821 | __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu]; |
1822 | } |
1823 | #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */ |
1824 |
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