diff options
author | Dave Airlie <airlied@redhat.com> | 2009-03-28 20:22:18 -0400 |
---|---|---|
committer | Dave Airlie <airlied@redhat.com> | 2009-03-28 20:22:18 -0400 |
commit | 90f959bcb386da2c71613dcefc6a285e054a539e (patch) | |
tree | ee3e9dd4111d4aad12e579cb0c2c159114dff263 /mm/percpu.c | |
parent | 41f13fe81dd1b08723ab9f3fc3c7f29cfa81f1a5 (diff) | |
parent | 07d43ba98621f08e252a48c96b258b4d572b0257 (diff) |
drm: merge Linux master into HEAD
Conflicts:
drivers/gpu/drm/drm_info.c
drivers/gpu/drm/drm_proc.c
drivers/gpu/drm/i915/i915_gem_debugfs.c
Diffstat (limited to 'mm/percpu.c')
-rw-r--r-- | mm/percpu.c | 1326 |
1 files changed, 1326 insertions, 0 deletions
diff --git a/mm/percpu.c b/mm/percpu.c new file mode 100644 index 000000000000..1aa5d8fbca12 --- /dev/null +++ b/mm/percpu.c | |||
@@ -0,0 +1,1326 @@ | |||
1 | /* | ||
2 | * linux/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 in vmalloc area. Each | ||
11 | * chunk is consisted of num_possible_cpus() units and the first chunk | ||
12 | * is used for static percpu variables in the kernel image (special | ||
13 | * boot time alloc/init handling necessary as these areas need to be | ||
14 | * brought up before allocation services are running). Unit grows as | ||
15 | * necessary and all units grow or shrink in unison. When a chunk is | ||
16 | * filled up, another chunk is allocated. ie. in vmalloc area | ||
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. Percpu access can be done by configuring | ||
26 | * percpu base registers UNIT_SIZE apart. | ||
27 | * | ||
28 | * There are usually many small percpu allocations many of them as | ||
29 | * small as 4 bytes. The allocator organizes chunks into lists | ||
30 | * according to free size and tries to allocate from the fullest one. | ||
31 | * Each chunk keeps the maximum contiguous area size hint which is | ||
32 | * guaranteed to be eqaul to or larger than the maximum contiguous | ||
33 | * area in the chunk. This helps the allocator not to iterate the | ||
34 | * chunk maps unnecessarily. | ||
35 | * | ||
36 | * Allocation state in each chunk is kept using an array of integers | ||
37 | * on chunk->map. A positive value in the map represents a free | ||
38 | * region and negative allocated. Allocation inside a chunk is done | ||
39 | * by scanning this map sequentially and serving the first matching | ||
40 | * entry. This is mostly copied from the percpu_modalloc() allocator. | ||
41 | * Chunks are also linked into a rb tree to ease address to chunk | ||
42 | * mapping during free. | ||
43 | * | ||
44 | * To use this allocator, arch code should do the followings. | ||
45 | * | ||
46 | * - define CONFIG_HAVE_DYNAMIC_PER_CPU_AREA | ||
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/list.h> | ||
59 | #include <linux/mm.h> | ||
60 | #include <linux/module.h> | ||
61 | #include <linux/mutex.h> | ||
62 | #include <linux/percpu.h> | ||
63 | #include <linux/pfn.h> | ||
64 | #include <linux/rbtree.h> | ||
65 | #include <linux/slab.h> | ||
66 | #include <linux/spinlock.h> | ||
67 | #include <linux/vmalloc.h> | ||
68 | #include <linux/workqueue.h> | ||
69 | |||
70 | #include <asm/cacheflush.h> | ||
71 | #include <asm/sections.h> | ||
72 | #include <asm/tlbflush.h> | ||
73 | |||
74 | #define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */ | ||
75 | #define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */ | ||
76 | |||
77 | /* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */ | ||
78 | #ifndef __addr_to_pcpu_ptr | ||
79 | #define __addr_to_pcpu_ptr(addr) \ | ||
80 | (void *)((unsigned long)(addr) - (unsigned long)pcpu_base_addr \ | ||
81 | + (unsigned long)__per_cpu_start) | ||
82 | #endif | ||
83 | #ifndef __pcpu_ptr_to_addr | ||
84 | #define __pcpu_ptr_to_addr(ptr) \ | ||
85 | (void *)((unsigned long)(ptr) + (unsigned long)pcpu_base_addr \ | ||
86 | - (unsigned long)__per_cpu_start) | ||
87 | #endif | ||
88 | |||
89 | struct pcpu_chunk { | ||
90 | struct list_head list; /* linked to pcpu_slot lists */ | ||
91 | struct rb_node rb_node; /* key is chunk->vm->addr */ | ||
92 | int free_size; /* free bytes in the chunk */ | ||
93 | int contig_hint; /* max contiguous size hint */ | ||
94 | struct vm_struct *vm; /* mapped vmalloc region */ | ||
95 | int map_used; /* # of map entries used */ | ||
96 | int map_alloc; /* # of map entries allocated */ | ||
97 | int *map; /* allocation map */ | ||
98 | bool immutable; /* no [de]population allowed */ | ||
99 | struct page **page; /* points to page array */ | ||
100 | struct page *page_ar[]; /* #cpus * UNIT_PAGES */ | ||
101 | }; | ||
102 | |||
103 | static int pcpu_unit_pages __read_mostly; | ||
104 | static int pcpu_unit_size __read_mostly; | ||
105 | static int pcpu_chunk_size __read_mostly; | ||
106 | static int pcpu_nr_slots __read_mostly; | ||
107 | static size_t pcpu_chunk_struct_size __read_mostly; | ||
108 | |||
109 | /* the address of the first chunk which starts with the kernel static area */ | ||
110 | void *pcpu_base_addr __read_mostly; | ||
111 | EXPORT_SYMBOL_GPL(pcpu_base_addr); | ||
112 | |||
113 | /* optional reserved chunk, only accessible for reserved allocations */ | ||
114 | static struct pcpu_chunk *pcpu_reserved_chunk; | ||
115 | /* offset limit of the reserved chunk */ | ||
116 | static int pcpu_reserved_chunk_limit; | ||
117 | |||
118 | /* | ||
119 | * Synchronization rules. | ||
120 | * | ||
121 | * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former | ||
122 | * protects allocation/reclaim paths, chunks and chunk->page arrays. | ||
123 | * The latter is a spinlock and protects the index data structures - | ||
124 | * chunk slots, rbtree, chunks and area maps in chunks. | ||
125 | * | ||
126 | * During allocation, pcpu_alloc_mutex is kept locked all the time and | ||
127 | * pcpu_lock is grabbed and released as necessary. All actual memory | ||
128 | * allocations are done using GFP_KERNEL with pcpu_lock released. | ||
129 | * | ||
130 | * Free path accesses and alters only the index data structures, so it | ||
131 | * can be safely called from atomic context. When memory needs to be | ||
132 | * returned to the system, free path schedules reclaim_work which | ||
133 | * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be | ||
134 | * reclaimed, release both locks and frees the chunks. Note that it's | ||
135 | * necessary to grab both locks to remove a chunk from circulation as | ||
136 | * allocation path might be referencing the chunk with only | ||
137 | * pcpu_alloc_mutex locked. | ||
138 | */ | ||
139 | static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */ | ||
140 | static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */ | ||
141 | |||
142 | static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */ | ||
143 | static struct rb_root pcpu_addr_root = RB_ROOT; /* chunks by address */ | ||
144 | |||
145 | /* reclaim work to release fully free chunks, scheduled from free path */ | ||
146 | static void pcpu_reclaim(struct work_struct *work); | ||
147 | static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim); | ||
148 | |||
149 | static int __pcpu_size_to_slot(int size) | ||
150 | { | ||
151 | int highbit = fls(size); /* size is in bytes */ | ||
152 | return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1); | ||
153 | } | ||
154 | |||
155 | static int pcpu_size_to_slot(int size) | ||
156 | { | ||
157 | if (size == pcpu_unit_size) | ||
158 | return pcpu_nr_slots - 1; | ||
159 | return __pcpu_size_to_slot(size); | ||
160 | } | ||
161 | |||
162 | static int pcpu_chunk_slot(const struct pcpu_chunk *chunk) | ||
163 | { | ||
164 | if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int)) | ||
165 | return 0; | ||
166 | |||
167 | return pcpu_size_to_slot(chunk->free_size); | ||
168 | } | ||
169 | |||
170 | static int pcpu_page_idx(unsigned int cpu, int page_idx) | ||
171 | { | ||
172 | return cpu * pcpu_unit_pages + page_idx; | ||
173 | } | ||
174 | |||
175 | static struct page **pcpu_chunk_pagep(struct pcpu_chunk *chunk, | ||
176 | unsigned int cpu, int page_idx) | ||
177 | { | ||
178 | return &chunk->page[pcpu_page_idx(cpu, page_idx)]; | ||
179 | } | ||
180 | |||
181 | static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk, | ||
182 | unsigned int cpu, int page_idx) | ||
183 | { | ||
184 | return (unsigned long)chunk->vm->addr + | ||
185 | (pcpu_page_idx(cpu, page_idx) << PAGE_SHIFT); | ||
186 | } | ||
187 | |||
188 | static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk, | ||
189 | int page_idx) | ||
190 | { | ||
191 | return *pcpu_chunk_pagep(chunk, 0, page_idx) != NULL; | ||
192 | } | ||
193 | |||
194 | /** | ||
195 | * pcpu_mem_alloc - allocate memory | ||
196 | * @size: bytes to allocate | ||
197 | * | ||
198 | * Allocate @size bytes. If @size is smaller than PAGE_SIZE, | ||
199 | * kzalloc() is used; otherwise, vmalloc() is used. The returned | ||
200 | * memory is always zeroed. | ||
201 | * | ||
202 | * CONTEXT: | ||
203 | * Does GFP_KERNEL allocation. | ||
204 | * | ||
205 | * RETURNS: | ||
206 | * Pointer to the allocated area on success, NULL on failure. | ||
207 | */ | ||
208 | static void *pcpu_mem_alloc(size_t size) | ||
209 | { | ||
210 | if (size <= PAGE_SIZE) | ||
211 | return kzalloc(size, GFP_KERNEL); | ||
212 | else { | ||
213 | void *ptr = vmalloc(size); | ||
214 | if (ptr) | ||
215 | memset(ptr, 0, size); | ||
216 | return ptr; | ||
217 | } | ||
218 | } | ||
219 | |||
220 | /** | ||
221 | * pcpu_mem_free - free memory | ||
222 | * @ptr: memory to free | ||
223 | * @size: size of the area | ||
224 | * | ||
225 | * Free @ptr. @ptr should have been allocated using pcpu_mem_alloc(). | ||
226 | */ | ||
227 | static void pcpu_mem_free(void *ptr, size_t size) | ||
228 | { | ||
229 | if (size <= PAGE_SIZE) | ||
230 | kfree(ptr); | ||
231 | else | ||
232 | vfree(ptr); | ||
233 | } | ||
234 | |||
235 | /** | ||
236 | * pcpu_chunk_relocate - put chunk in the appropriate chunk slot | ||
237 | * @chunk: chunk of interest | ||
238 | * @oslot: the previous slot it was on | ||
239 | * | ||
240 | * This function is called after an allocation or free changed @chunk. | ||
241 | * New slot according to the changed state is determined and @chunk is | ||
242 | * moved to the slot. Note that the reserved chunk is never put on | ||
243 | * chunk slots. | ||
244 | * | ||
245 | * CONTEXT: | ||
246 | * pcpu_lock. | ||
247 | */ | ||
248 | static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot) | ||
249 | { | ||
250 | int nslot = pcpu_chunk_slot(chunk); | ||
251 | |||
252 | if (chunk != pcpu_reserved_chunk && oslot != nslot) { | ||
253 | if (oslot < nslot) | ||
254 | list_move(&chunk->list, &pcpu_slot[nslot]); | ||
255 | else | ||
256 | list_move_tail(&chunk->list, &pcpu_slot[nslot]); | ||
257 | } | ||
258 | } | ||
259 | |||
260 | static struct rb_node **pcpu_chunk_rb_search(void *addr, | ||
261 | struct rb_node **parentp) | ||
262 | { | ||
263 | struct rb_node **p = &pcpu_addr_root.rb_node; | ||
264 | struct rb_node *parent = NULL; | ||
265 | struct pcpu_chunk *chunk; | ||
266 | |||
267 | while (*p) { | ||
268 | parent = *p; | ||
269 | chunk = rb_entry(parent, struct pcpu_chunk, rb_node); | ||
270 | |||
271 | if (addr < chunk->vm->addr) | ||
272 | p = &(*p)->rb_left; | ||
273 | else if (addr > chunk->vm->addr) | ||
274 | p = &(*p)->rb_right; | ||
275 | else | ||
276 | break; | ||
277 | } | ||
278 | |||
279 | if (parentp) | ||
280 | *parentp = parent; | ||
281 | return p; | ||
282 | } | ||
283 | |||
284 | /** | ||
285 | * pcpu_chunk_addr_search - search for chunk containing specified address | ||
286 | * @addr: address to search for | ||
287 | * | ||
288 | * Look for chunk which might contain @addr. More specifically, it | ||
289 | * searchs for the chunk with the highest start address which isn't | ||
290 | * beyond @addr. | ||
291 | * | ||
292 | * CONTEXT: | ||
293 | * pcpu_lock. | ||
294 | * | ||
295 | * RETURNS: | ||
296 | * The address of the found chunk. | ||
297 | */ | ||
298 | static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) | ||
299 | { | ||
300 | struct rb_node *n, *parent; | ||
301 | struct pcpu_chunk *chunk; | ||
302 | |||
303 | /* is it in the reserved chunk? */ | ||
304 | if (pcpu_reserved_chunk) { | ||
305 | void *start = pcpu_reserved_chunk->vm->addr; | ||
306 | |||
307 | if (addr >= start && addr < start + pcpu_reserved_chunk_limit) | ||
308 | return pcpu_reserved_chunk; | ||
309 | } | ||
310 | |||
311 | /* nah... search the regular ones */ | ||
312 | n = *pcpu_chunk_rb_search(addr, &parent); | ||
313 | if (!n) { | ||
314 | /* no exactly matching chunk, the parent is the closest */ | ||
315 | n = parent; | ||
316 | BUG_ON(!n); | ||
317 | } | ||
318 | chunk = rb_entry(n, struct pcpu_chunk, rb_node); | ||
319 | |||
320 | if (addr < chunk->vm->addr) { | ||
321 | /* the parent was the next one, look for the previous one */ | ||
322 | n = rb_prev(n); | ||
323 | BUG_ON(!n); | ||
324 | chunk = rb_entry(n, struct pcpu_chunk, rb_node); | ||
325 | } | ||
326 | |||
327 | return chunk; | ||
328 | } | ||
329 | |||
330 | /** | ||
331 | * pcpu_chunk_addr_insert - insert chunk into address rb tree | ||
332 | * @new: chunk to insert | ||
333 | * | ||
334 | * Insert @new into address rb tree. | ||
335 | * | ||
336 | * CONTEXT: | ||
337 | * pcpu_lock. | ||
338 | */ | ||
339 | static void pcpu_chunk_addr_insert(struct pcpu_chunk *new) | ||
340 | { | ||
341 | struct rb_node **p, *parent; | ||
342 | |||
343 | p = pcpu_chunk_rb_search(new->vm->addr, &parent); | ||
344 | BUG_ON(*p); | ||
345 | rb_link_node(&new->rb_node, parent, p); | ||
346 | rb_insert_color(&new->rb_node, &pcpu_addr_root); | ||
347 | } | ||
348 | |||
349 | /** | ||
350 | * pcpu_extend_area_map - extend area map for allocation | ||
351 | * @chunk: target chunk | ||
352 | * | ||
353 | * Extend area map of @chunk so that it can accomodate an allocation. | ||
354 | * A single allocation can split an area into three areas, so this | ||
355 | * function makes sure that @chunk->map has at least two extra slots. | ||
356 | * | ||
357 | * CONTEXT: | ||
358 | * pcpu_alloc_mutex, pcpu_lock. pcpu_lock is released and reacquired | ||
359 | * if area map is extended. | ||
360 | * | ||
361 | * RETURNS: | ||
362 | * 0 if noop, 1 if successfully extended, -errno on failure. | ||
363 | */ | ||
364 | static int pcpu_extend_area_map(struct pcpu_chunk *chunk) | ||
365 | { | ||
366 | int new_alloc; | ||
367 | int *new; | ||
368 | size_t size; | ||
369 | |||
370 | /* has enough? */ | ||
371 | if (chunk->map_alloc >= chunk->map_used + 2) | ||
372 | return 0; | ||
373 | |||
374 | spin_unlock_irq(&pcpu_lock); | ||
375 | |||
376 | new_alloc = PCPU_DFL_MAP_ALLOC; | ||
377 | while (new_alloc < chunk->map_used + 2) | ||
378 | new_alloc *= 2; | ||
379 | |||
380 | new = pcpu_mem_alloc(new_alloc * sizeof(new[0])); | ||
381 | if (!new) { | ||
382 | spin_lock_irq(&pcpu_lock); | ||
383 | return -ENOMEM; | ||
384 | } | ||
385 | |||
386 | /* | ||
387 | * Acquire pcpu_lock and switch to new area map. Only free | ||
388 | * could have happened inbetween, so map_used couldn't have | ||
389 | * grown. | ||
390 | */ | ||
391 | spin_lock_irq(&pcpu_lock); | ||
392 | BUG_ON(new_alloc < chunk->map_used + 2); | ||
393 | |||
394 | size = chunk->map_alloc * sizeof(chunk->map[0]); | ||
395 | memcpy(new, chunk->map, size); | ||
396 | |||
397 | /* | ||
398 | * map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is | ||
399 | * one of the first chunks and still using static map. | ||
400 | */ | ||
401 | if (chunk->map_alloc >= PCPU_DFL_MAP_ALLOC) | ||
402 | pcpu_mem_free(chunk->map, size); | ||
403 | |||
404 | chunk->map_alloc = new_alloc; | ||
405 | chunk->map = new; | ||
406 | return 0; | ||
407 | } | ||
408 | |||
409 | /** | ||
410 | * pcpu_split_block - split a map block | ||
411 | * @chunk: chunk of interest | ||
412 | * @i: index of map block to split | ||
413 | * @head: head size in bytes (can be 0) | ||
414 | * @tail: tail size in bytes (can be 0) | ||
415 | * | ||
416 | * Split the @i'th map block into two or three blocks. If @head is | ||
417 | * non-zero, @head bytes block is inserted before block @i moving it | ||
418 | * to @i+1 and reducing its size by @head bytes. | ||
419 | * | ||
420 | * If @tail is non-zero, the target block, which can be @i or @i+1 | ||
421 | * depending on @head, is reduced by @tail bytes and @tail byte block | ||
422 | * is inserted after the target block. | ||
423 | * | ||
424 | * @chunk->map must have enough free slots to accomodate the split. | ||
425 | * | ||
426 | * CONTEXT: | ||
427 | * pcpu_lock. | ||
428 | */ | ||
429 | static void pcpu_split_block(struct pcpu_chunk *chunk, int i, | ||
430 | int head, int tail) | ||
431 | { | ||
432 | int nr_extra = !!head + !!tail; | ||
433 | |||
434 | BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra); | ||
435 | |||
436 | /* insert new subblocks */ | ||
437 | memmove(&chunk->map[i + nr_extra], &chunk->map[i], | ||
438 | sizeof(chunk->map[0]) * (chunk->map_used - i)); | ||
439 | chunk->map_used += nr_extra; | ||
440 | |||
441 | if (head) { | ||
442 | chunk->map[i + 1] = chunk->map[i] - head; | ||
443 | chunk->map[i++] = head; | ||
444 | } | ||
445 | if (tail) { | ||
446 | chunk->map[i++] -= tail; | ||
447 | chunk->map[i] = tail; | ||
448 | } | ||
449 | } | ||
450 | |||
451 | /** | ||
452 | * pcpu_alloc_area - allocate area from a pcpu_chunk | ||
453 | * @chunk: chunk of interest | ||
454 | * @size: wanted size in bytes | ||
455 | * @align: wanted align | ||
456 | * | ||
457 | * Try to allocate @size bytes area aligned at @align from @chunk. | ||
458 | * Note that this function only allocates the offset. It doesn't | ||
459 | * populate or map the area. | ||
460 | * | ||
461 | * @chunk->map must have at least two free slots. | ||
462 | * | ||
463 | * CONTEXT: | ||
464 | * pcpu_lock. | ||
465 | * | ||
466 | * RETURNS: | ||
467 | * Allocated offset in @chunk on success, -1 if no matching area is | ||
468 | * found. | ||
469 | */ | ||
470 | static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align) | ||
471 | { | ||
472 | int oslot = pcpu_chunk_slot(chunk); | ||
473 | int max_contig = 0; | ||
474 | int i, off; | ||
475 | |||
476 | for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) { | ||
477 | bool is_last = i + 1 == chunk->map_used; | ||
478 | int head, tail; | ||
479 | |||
480 | /* extra for alignment requirement */ | ||
481 | head = ALIGN(off, align) - off; | ||
482 | BUG_ON(i == 0 && head != 0); | ||
483 | |||
484 | if (chunk->map[i] < 0) | ||
485 | continue; | ||
486 | if (chunk->map[i] < head + size) { | ||
487 | max_contig = max(chunk->map[i], max_contig); | ||
488 | continue; | ||
489 | } | ||
490 | |||
491 | /* | ||
492 | * If head is small or the previous block is free, | ||
493 | * merge'em. Note that 'small' is defined as smaller | ||
494 | * than sizeof(int), which is very small but isn't too | ||
495 | * uncommon for percpu allocations. | ||
496 | */ | ||
497 | if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) { | ||
498 | if (chunk->map[i - 1] > 0) | ||
499 | chunk->map[i - 1] += head; | ||
500 | else { | ||
501 | chunk->map[i - 1] -= head; | ||
502 | chunk->free_size -= head; | ||
503 | } | ||
504 | chunk->map[i] -= head; | ||
505 | off += head; | ||
506 | head = 0; | ||
507 | } | ||
508 | |||
509 | /* if tail is small, just keep it around */ | ||
510 | tail = chunk->map[i] - head - size; | ||
511 | if (tail < sizeof(int)) | ||
512 | tail = 0; | ||
513 | |||
514 | /* split if warranted */ | ||
515 | if (head || tail) { | ||
516 | pcpu_split_block(chunk, i, head, tail); | ||
517 | if (head) { | ||
518 | i++; | ||
519 | off += head; | ||
520 | max_contig = max(chunk->map[i - 1], max_contig); | ||
521 | } | ||
522 | if (tail) | ||
523 | max_contig = max(chunk->map[i + 1], max_contig); | ||
524 | } | ||
525 | |||
526 | /* update hint and mark allocated */ | ||
527 | if (is_last) | ||
528 | chunk->contig_hint = max_contig; /* fully scanned */ | ||
529 | else | ||
530 | chunk->contig_hint = max(chunk->contig_hint, | ||
531 | max_contig); | ||
532 | |||
533 | chunk->free_size -= chunk->map[i]; | ||
534 | chunk->map[i] = -chunk->map[i]; | ||
535 | |||
536 | pcpu_chunk_relocate(chunk, oslot); | ||
537 | return off; | ||
538 | } | ||
539 | |||
540 | chunk->contig_hint = max_contig; /* fully scanned */ | ||
541 | pcpu_chunk_relocate(chunk, oslot); | ||
542 | |||
543 | /* tell the upper layer that this chunk has no matching area */ | ||
544 | return -1; | ||
545 | } | ||
546 | |||
547 | /** | ||
548 | * pcpu_free_area - free area to a pcpu_chunk | ||
549 | * @chunk: chunk of interest | ||
550 | * @freeme: offset of area to free | ||
551 | * | ||
552 | * Free area starting from @freeme to @chunk. Note that this function | ||
553 | * only modifies the allocation map. It doesn't depopulate or unmap | ||
554 | * the area. | ||
555 | * | ||
556 | * CONTEXT: | ||
557 | * pcpu_lock. | ||
558 | */ | ||
559 | static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme) | ||
560 | { | ||
561 | int oslot = pcpu_chunk_slot(chunk); | ||
562 | int i, off; | ||
563 | |||
564 | for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) | ||
565 | if (off == freeme) | ||
566 | break; | ||
567 | BUG_ON(off != freeme); | ||
568 | BUG_ON(chunk->map[i] > 0); | ||
569 | |||
570 | chunk->map[i] = -chunk->map[i]; | ||
571 | chunk->free_size += chunk->map[i]; | ||
572 | |||
573 | /* merge with previous? */ | ||
574 | if (i > 0 && chunk->map[i - 1] >= 0) { | ||
575 | chunk->map[i - 1] += chunk->map[i]; | ||
576 | chunk->map_used--; | ||
577 | memmove(&chunk->map[i], &chunk->map[i + 1], | ||
578 | (chunk->map_used - i) * sizeof(chunk->map[0])); | ||
579 | i--; | ||
580 | } | ||
581 | /* merge with next? */ | ||
582 | if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) { | ||
583 | chunk->map[i] += chunk->map[i + 1]; | ||
584 | chunk->map_used--; | ||
585 | memmove(&chunk->map[i + 1], &chunk->map[i + 2], | ||
586 | (chunk->map_used - (i + 1)) * sizeof(chunk->map[0])); | ||
587 | } | ||
588 | |||
589 | chunk->contig_hint = max(chunk->map[i], chunk->contig_hint); | ||
590 | pcpu_chunk_relocate(chunk, oslot); | ||
591 | } | ||
592 | |||
593 | /** | ||
594 | * pcpu_unmap - unmap pages out of a pcpu_chunk | ||
595 | * @chunk: chunk of interest | ||
596 | * @page_start: page index of the first page to unmap | ||
597 | * @page_end: page index of the last page to unmap + 1 | ||
598 | * @flush: whether to flush cache and tlb or not | ||
599 | * | ||
600 | * For each cpu, unmap pages [@page_start,@page_end) out of @chunk. | ||
601 | * If @flush is true, vcache is flushed before unmapping and tlb | ||
602 | * after. | ||
603 | */ | ||
604 | static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end, | ||
605 | bool flush) | ||
606 | { | ||
607 | unsigned int last = num_possible_cpus() - 1; | ||
608 | unsigned int cpu; | ||
609 | |||
610 | /* unmap must not be done on immutable chunk */ | ||
611 | WARN_ON(chunk->immutable); | ||
612 | |||
613 | /* | ||
614 | * Each flushing trial can be very expensive, issue flush on | ||
615 | * the whole region at once rather than doing it for each cpu. | ||
616 | * This could be an overkill but is more scalable. | ||
617 | */ | ||
618 | if (flush) | ||
619 | flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start), | ||
620 | pcpu_chunk_addr(chunk, last, page_end)); | ||
621 | |||
622 | for_each_possible_cpu(cpu) | ||
623 | unmap_kernel_range_noflush( | ||
624 | pcpu_chunk_addr(chunk, cpu, page_start), | ||
625 | (page_end - page_start) << PAGE_SHIFT); | ||
626 | |||
627 | /* ditto as flush_cache_vunmap() */ | ||
628 | if (flush) | ||
629 | flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start), | ||
630 | pcpu_chunk_addr(chunk, last, page_end)); | ||
631 | } | ||
632 | |||
633 | /** | ||
634 | * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk | ||
635 | * @chunk: chunk to depopulate | ||
636 | * @off: offset to the area to depopulate | ||
637 | * @size: size of the area to depopulate in bytes | ||
638 | * @flush: whether to flush cache and tlb or not | ||
639 | * | ||
640 | * For each cpu, depopulate and unmap pages [@page_start,@page_end) | ||
641 | * from @chunk. If @flush is true, vcache is flushed before unmapping | ||
642 | * and tlb after. | ||
643 | * | ||
644 | * CONTEXT: | ||
645 | * pcpu_alloc_mutex. | ||
646 | */ | ||
647 | static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size, | ||
648 | bool flush) | ||
649 | { | ||
650 | int page_start = PFN_DOWN(off); | ||
651 | int page_end = PFN_UP(off + size); | ||
652 | int unmap_start = -1; | ||
653 | int uninitialized_var(unmap_end); | ||
654 | unsigned int cpu; | ||
655 | int i; | ||
656 | |||
657 | for (i = page_start; i < page_end; i++) { | ||
658 | for_each_possible_cpu(cpu) { | ||
659 | struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i); | ||
660 | |||
661 | if (!*pagep) | ||
662 | continue; | ||
663 | |||
664 | __free_page(*pagep); | ||
665 | |||
666 | /* | ||
667 | * If it's partial depopulation, it might get | ||
668 | * populated or depopulated again. Mark the | ||
669 | * page gone. | ||
670 | */ | ||
671 | *pagep = NULL; | ||
672 | |||
673 | unmap_start = unmap_start < 0 ? i : unmap_start; | ||
674 | unmap_end = i + 1; | ||
675 | } | ||
676 | } | ||
677 | |||
678 | if (unmap_start >= 0) | ||
679 | pcpu_unmap(chunk, unmap_start, unmap_end, flush); | ||
680 | } | ||
681 | |||
682 | /** | ||
683 | * pcpu_map - map pages into a pcpu_chunk | ||
684 | * @chunk: chunk of interest | ||
685 | * @page_start: page index of the first page to map | ||
686 | * @page_end: page index of the last page to map + 1 | ||
687 | * | ||
688 | * For each cpu, map pages [@page_start,@page_end) into @chunk. | ||
689 | * vcache is flushed afterwards. | ||
690 | */ | ||
691 | static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end) | ||
692 | { | ||
693 | unsigned int last = num_possible_cpus() - 1; | ||
694 | unsigned int cpu; | ||
695 | int err; | ||
696 | |||
697 | /* map must not be done on immutable chunk */ | ||
698 | WARN_ON(chunk->immutable); | ||
699 | |||
700 | for_each_possible_cpu(cpu) { | ||
701 | err = map_kernel_range_noflush( | ||
702 | pcpu_chunk_addr(chunk, cpu, page_start), | ||
703 | (page_end - page_start) << PAGE_SHIFT, | ||
704 | PAGE_KERNEL, | ||
705 | pcpu_chunk_pagep(chunk, cpu, page_start)); | ||
706 | if (err < 0) | ||
707 | return err; | ||
708 | } | ||
709 | |||
710 | /* flush at once, please read comments in pcpu_unmap() */ | ||
711 | flush_cache_vmap(pcpu_chunk_addr(chunk, 0, page_start), | ||
712 | pcpu_chunk_addr(chunk, last, page_end)); | ||
713 | return 0; | ||
714 | } | ||
715 | |||
716 | /** | ||
717 | * pcpu_populate_chunk - populate and map an area of a pcpu_chunk | ||
718 | * @chunk: chunk of interest | ||
719 | * @off: offset to the area to populate | ||
720 | * @size: size of the area to populate in bytes | ||
721 | * | ||
722 | * For each cpu, populate and map pages [@page_start,@page_end) into | ||
723 | * @chunk. The area is cleared on return. | ||
724 | * | ||
725 | * CONTEXT: | ||
726 | * pcpu_alloc_mutex, does GFP_KERNEL allocation. | ||
727 | */ | ||
728 | static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size) | ||
729 | { | ||
730 | const gfp_t alloc_mask = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD; | ||
731 | int page_start = PFN_DOWN(off); | ||
732 | int page_end = PFN_UP(off + size); | ||
733 | int map_start = -1; | ||
734 | int uninitialized_var(map_end); | ||
735 | unsigned int cpu; | ||
736 | int i; | ||
737 | |||
738 | for (i = page_start; i < page_end; i++) { | ||
739 | if (pcpu_chunk_page_occupied(chunk, i)) { | ||
740 | if (map_start >= 0) { | ||
741 | if (pcpu_map(chunk, map_start, map_end)) | ||
742 | goto err; | ||
743 | map_start = -1; | ||
744 | } | ||
745 | continue; | ||
746 | } | ||
747 | |||
748 | map_start = map_start < 0 ? i : map_start; | ||
749 | map_end = i + 1; | ||
750 | |||
751 | for_each_possible_cpu(cpu) { | ||
752 | struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i); | ||
753 | |||
754 | *pagep = alloc_pages_node(cpu_to_node(cpu), | ||
755 | alloc_mask, 0); | ||
756 | if (!*pagep) | ||
757 | goto err; | ||
758 | } | ||
759 | } | ||
760 | |||
761 | if (map_start >= 0 && pcpu_map(chunk, map_start, map_end)) | ||
762 | goto err; | ||
763 | |||
764 | for_each_possible_cpu(cpu) | ||
765 | memset(chunk->vm->addr + cpu * pcpu_unit_size + off, 0, | ||
766 | size); | ||
767 | |||
768 | return 0; | ||
769 | err: | ||
770 | /* likely under heavy memory pressure, give memory back */ | ||
771 | pcpu_depopulate_chunk(chunk, off, size, true); | ||
772 | return -ENOMEM; | ||
773 | } | ||
774 | |||
775 | static void free_pcpu_chunk(struct pcpu_chunk *chunk) | ||
776 | { | ||
777 | if (!chunk) | ||
778 | return; | ||
779 | if (chunk->vm) | ||
780 | free_vm_area(chunk->vm); | ||
781 | pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0])); | ||
782 | kfree(chunk); | ||
783 | } | ||
784 | |||
785 | static struct pcpu_chunk *alloc_pcpu_chunk(void) | ||
786 | { | ||
787 | struct pcpu_chunk *chunk; | ||
788 | |||
789 | chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL); | ||
790 | if (!chunk) | ||
791 | return NULL; | ||
792 | |||
793 | chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0])); | ||
794 | chunk->map_alloc = PCPU_DFL_MAP_ALLOC; | ||
795 | chunk->map[chunk->map_used++] = pcpu_unit_size; | ||
796 | chunk->page = chunk->page_ar; | ||
797 | |||
798 | chunk->vm = get_vm_area(pcpu_chunk_size, GFP_KERNEL); | ||
799 | if (!chunk->vm) { | ||
800 | free_pcpu_chunk(chunk); | ||
801 | return NULL; | ||
802 | } | ||
803 | |||
804 | INIT_LIST_HEAD(&chunk->list); | ||
805 | chunk->free_size = pcpu_unit_size; | ||
806 | chunk->contig_hint = pcpu_unit_size; | ||
807 | |||
808 | return chunk; | ||
809 | } | ||
810 | |||
811 | /** | ||
812 | * pcpu_alloc - the percpu allocator | ||
813 | * @size: size of area to allocate in bytes | ||
814 | * @align: alignment of area (max PAGE_SIZE) | ||
815 | * @reserved: allocate from the reserved chunk if available | ||
816 | * | ||
817 | * Allocate percpu area of @size bytes aligned at @align. | ||
818 | * | ||
819 | * CONTEXT: | ||
820 | * Does GFP_KERNEL allocation. | ||
821 | * | ||
822 | * RETURNS: | ||
823 | * Percpu pointer to the allocated area on success, NULL on failure. | ||
824 | */ | ||
825 | static void *pcpu_alloc(size_t size, size_t align, bool reserved) | ||
826 | { | ||
827 | struct pcpu_chunk *chunk; | ||
828 | int slot, off; | ||
829 | |||
830 | if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { | ||
831 | WARN(true, "illegal size (%zu) or align (%zu) for " | ||
832 | "percpu allocation\n", size, align); | ||
833 | return NULL; | ||
834 | } | ||
835 | |||
836 | mutex_lock(&pcpu_alloc_mutex); | ||
837 | spin_lock_irq(&pcpu_lock); | ||
838 | |||
839 | /* serve reserved allocations from the reserved chunk if available */ | ||
840 | if (reserved && pcpu_reserved_chunk) { | ||
841 | chunk = pcpu_reserved_chunk; | ||
842 | if (size > chunk->contig_hint || | ||
843 | pcpu_extend_area_map(chunk) < 0) | ||
844 | goto fail_unlock; | ||
845 | off = pcpu_alloc_area(chunk, size, align); | ||
846 | if (off >= 0) | ||
847 | goto area_found; | ||
848 | goto fail_unlock; | ||
849 | } | ||
850 | |||
851 | restart: | ||
852 | /* search through normal chunks */ | ||
853 | for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) { | ||
854 | list_for_each_entry(chunk, &pcpu_slot[slot], list) { | ||
855 | if (size > chunk->contig_hint) | ||
856 | continue; | ||
857 | |||
858 | switch (pcpu_extend_area_map(chunk)) { | ||
859 | case 0: | ||
860 | break; | ||
861 | case 1: | ||
862 | goto restart; /* pcpu_lock dropped, restart */ | ||
863 | default: | ||
864 | goto fail_unlock; | ||
865 | } | ||
866 | |||
867 | off = pcpu_alloc_area(chunk, size, align); | ||
868 | if (off >= 0) | ||
869 | goto area_found; | ||
870 | } | ||
871 | } | ||
872 | |||
873 | /* hmmm... no space left, create a new chunk */ | ||
874 | spin_unlock_irq(&pcpu_lock); | ||
875 | |||
876 | chunk = alloc_pcpu_chunk(); | ||
877 | if (!chunk) | ||
878 | goto fail_unlock_mutex; | ||
879 | |||
880 | spin_lock_irq(&pcpu_lock); | ||
881 | pcpu_chunk_relocate(chunk, -1); | ||
882 | pcpu_chunk_addr_insert(chunk); | ||
883 | goto restart; | ||
884 | |||
885 | area_found: | ||
886 | spin_unlock_irq(&pcpu_lock); | ||
887 | |||
888 | /* populate, map and clear the area */ | ||
889 | if (pcpu_populate_chunk(chunk, off, size)) { | ||
890 | spin_lock_irq(&pcpu_lock); | ||
891 | pcpu_free_area(chunk, off); | ||
892 | goto fail_unlock; | ||
893 | } | ||
894 | |||
895 | mutex_unlock(&pcpu_alloc_mutex); | ||
896 | |||
897 | return __addr_to_pcpu_ptr(chunk->vm->addr + off); | ||
898 | |||
899 | fail_unlock: | ||
900 | spin_unlock_irq(&pcpu_lock); | ||
901 | fail_unlock_mutex: | ||
902 | mutex_unlock(&pcpu_alloc_mutex); | ||
903 | return NULL; | ||
904 | } | ||
905 | |||
906 | /** | ||
907 | * __alloc_percpu - allocate dynamic percpu area | ||
908 | * @size: size of area to allocate in bytes | ||
909 | * @align: alignment of area (max PAGE_SIZE) | ||
910 | * | ||
911 | * Allocate percpu area of @size bytes aligned at @align. Might | ||
912 | * sleep. Might trigger writeouts. | ||
913 | * | ||
914 | * CONTEXT: | ||
915 | * Does GFP_KERNEL allocation. | ||
916 | * | ||
917 | * RETURNS: | ||
918 | * Percpu pointer to the allocated area on success, NULL on failure. | ||
919 | */ | ||
920 | void *__alloc_percpu(size_t size, size_t align) | ||
921 | { | ||
922 | return pcpu_alloc(size, align, false); | ||
923 | } | ||
924 | EXPORT_SYMBOL_GPL(__alloc_percpu); | ||
925 | |||
926 | /** | ||
927 | * __alloc_reserved_percpu - allocate reserved percpu area | ||
928 | * @size: size of area to allocate in bytes | ||
929 | * @align: alignment of area (max PAGE_SIZE) | ||
930 | * | ||
931 | * Allocate percpu area of @size bytes aligned at @align from reserved | ||
932 | * percpu area if arch has set it up; otherwise, allocation is served | ||
933 | * from the same dynamic area. Might sleep. Might trigger writeouts. | ||
934 | * | ||
935 | * CONTEXT: | ||
936 | * Does GFP_KERNEL allocation. | ||
937 | * | ||
938 | * RETURNS: | ||
939 | * Percpu pointer to the allocated area on success, NULL on failure. | ||
940 | */ | ||
941 | void *__alloc_reserved_percpu(size_t size, size_t align) | ||
942 | { | ||
943 | return pcpu_alloc(size, align, true); | ||
944 | } | ||
945 | |||
946 | /** | ||
947 | * pcpu_reclaim - reclaim fully free chunks, workqueue function | ||
948 | * @work: unused | ||
949 | * | ||
950 | * Reclaim all fully free chunks except for the first one. | ||
951 | * | ||
952 | * CONTEXT: | ||
953 | * workqueue context. | ||
954 | */ | ||
955 | static void pcpu_reclaim(struct work_struct *work) | ||
956 | { | ||
957 | LIST_HEAD(todo); | ||
958 | struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1]; | ||
959 | struct pcpu_chunk *chunk, *next; | ||
960 | |||
961 | mutex_lock(&pcpu_alloc_mutex); | ||
962 | spin_lock_irq(&pcpu_lock); | ||
963 | |||
964 | list_for_each_entry_safe(chunk, next, head, list) { | ||
965 | WARN_ON(chunk->immutable); | ||
966 | |||
967 | /* spare the first one */ | ||
968 | if (chunk == list_first_entry(head, struct pcpu_chunk, list)) | ||
969 | continue; | ||
970 | |||
971 | rb_erase(&chunk->rb_node, &pcpu_addr_root); | ||
972 | list_move(&chunk->list, &todo); | ||
973 | } | ||
974 | |||
975 | spin_unlock_irq(&pcpu_lock); | ||
976 | mutex_unlock(&pcpu_alloc_mutex); | ||
977 | |||
978 | list_for_each_entry_safe(chunk, next, &todo, list) { | ||
979 | pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size, false); | ||
980 | free_pcpu_chunk(chunk); | ||
981 | } | ||
982 | } | ||
983 | |||
984 | /** | ||
985 | * free_percpu - free percpu area | ||
986 | * @ptr: pointer to area to free | ||
987 | * | ||
988 | * Free percpu area @ptr. | ||
989 | * | ||
990 | * CONTEXT: | ||
991 | * Can be called from atomic context. | ||
992 | */ | ||
993 | void free_percpu(void *ptr) | ||
994 | { | ||
995 | void *addr = __pcpu_ptr_to_addr(ptr); | ||
996 | struct pcpu_chunk *chunk; | ||
997 | unsigned long flags; | ||
998 | int off; | ||
999 | |||
1000 | if (!ptr) | ||
1001 | return; | ||
1002 | |||
1003 | spin_lock_irqsave(&pcpu_lock, flags); | ||
1004 | |||
1005 | chunk = pcpu_chunk_addr_search(addr); | ||
1006 | off = addr - chunk->vm->addr; | ||
1007 | |||
1008 | pcpu_free_area(chunk, off); | ||
1009 | |||
1010 | /* if there are more than one fully free chunks, wake up grim reaper */ | ||
1011 | if (chunk->free_size == pcpu_unit_size) { | ||
1012 | struct pcpu_chunk *pos; | ||
1013 | |||
1014 | list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list) | ||
1015 | if (pos != chunk) { | ||
1016 | schedule_work(&pcpu_reclaim_work); | ||
1017 | break; | ||
1018 | } | ||
1019 | } | ||
1020 | |||
1021 | spin_unlock_irqrestore(&pcpu_lock, flags); | ||
1022 | } | ||
1023 | EXPORT_SYMBOL_GPL(free_percpu); | ||
1024 | |||
1025 | /** | ||
1026 | * pcpu_setup_first_chunk - initialize the first percpu chunk | ||
1027 | * @get_page_fn: callback to fetch page pointer | ||
1028 | * @static_size: the size of static percpu area in bytes | ||
1029 | * @reserved_size: the size of reserved percpu area in bytes | ||
1030 | * @dyn_size: free size for dynamic allocation in bytes, -1 for auto | ||
1031 | * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, -1 for auto | ||
1032 | * @base_addr: mapped address, NULL for auto | ||
1033 | * @populate_pte_fn: callback to allocate pagetable, NULL if unnecessary | ||
1034 | * | ||
1035 | * Initialize the first percpu chunk which contains the kernel static | ||
1036 | * perpcu area. This function is to be called from arch percpu area | ||
1037 | * setup path. The first two parameters are mandatory. The rest are | ||
1038 | * optional. | ||
1039 | * | ||
1040 | * @get_page_fn() should return pointer to percpu page given cpu | ||
1041 | * number and page number. It should at least return enough pages to | ||
1042 | * cover the static area. The returned pages for static area should | ||
1043 | * have been initialized with valid data. If @unit_size is specified, | ||
1044 | * it can also return pages after the static area. NULL return | ||
1045 | * indicates end of pages for the cpu. Note that @get_page_fn() must | ||
1046 | * return the same number of pages for all cpus. | ||
1047 | * | ||
1048 | * @reserved_size, if non-zero, specifies the amount of bytes to | ||
1049 | * reserve after the static area in the first chunk. This reserves | ||
1050 | * the first chunk such that it's available only through reserved | ||
1051 | * percpu allocation. This is primarily used to serve module percpu | ||
1052 | * static areas on architectures where the addressing model has | ||
1053 | * limited offset range for symbol relocations to guarantee module | ||
1054 | * percpu symbols fall inside the relocatable range. | ||
1055 | * | ||
1056 | * @dyn_size, if non-negative, determines the number of bytes | ||
1057 | * available for dynamic allocation in the first chunk. Specifying | ||
1058 | * non-negative value makes percpu leave alone the area beyond | ||
1059 | * @static_size + @reserved_size + @dyn_size. | ||
1060 | * | ||
1061 | * @unit_size, if non-negative, specifies unit size and must be | ||
1062 | * aligned to PAGE_SIZE and equal to or larger than @static_size + | ||
1063 | * @reserved_size + if non-negative, @dyn_size. | ||
1064 | * | ||
1065 | * Non-null @base_addr means that the caller already allocated virtual | ||
1066 | * region for the first chunk and mapped it. percpu must not mess | ||
1067 | * with the chunk. Note that @base_addr with 0 @unit_size or non-NULL | ||
1068 | * @populate_pte_fn doesn't make any sense. | ||
1069 | * | ||
1070 | * @populate_pte_fn is used to populate the pagetable. NULL means the | ||
1071 | * caller already populated the pagetable. | ||
1072 | * | ||
1073 | * If the first chunk ends up with both reserved and dynamic areas, it | ||
1074 | * is served by two chunks - one to serve the core static and reserved | ||
1075 | * areas and the other for the dynamic area. They share the same vm | ||
1076 | * and page map but uses different area allocation map to stay away | ||
1077 | * from each other. The latter chunk is circulated in the chunk slots | ||
1078 | * and available for dynamic allocation like any other chunks. | ||
1079 | * | ||
1080 | * RETURNS: | ||
1081 | * The determined pcpu_unit_size which can be used to initialize | ||
1082 | * percpu access. | ||
1083 | */ | ||
1084 | size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, | ||
1085 | size_t static_size, size_t reserved_size, | ||
1086 | ssize_t dyn_size, ssize_t unit_size, | ||
1087 | void *base_addr, | ||
1088 | pcpu_populate_pte_fn_t populate_pte_fn) | ||
1089 | { | ||
1090 | static struct vm_struct first_vm; | ||
1091 | static int smap[2], dmap[2]; | ||
1092 | size_t size_sum = static_size + reserved_size + | ||
1093 | (dyn_size >= 0 ? dyn_size : 0); | ||
1094 | struct pcpu_chunk *schunk, *dchunk = NULL; | ||
1095 | unsigned int cpu; | ||
1096 | int nr_pages; | ||
1097 | int err, i; | ||
1098 | |||
1099 | /* santiy checks */ | ||
1100 | BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC || | ||
1101 | ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC); | ||
1102 | BUG_ON(!static_size); | ||
1103 | if (unit_size >= 0) { | ||
1104 | BUG_ON(unit_size < size_sum); | ||
1105 | BUG_ON(unit_size & ~PAGE_MASK); | ||
1106 | BUG_ON(unit_size < PCPU_MIN_UNIT_SIZE); | ||
1107 | } else | ||
1108 | BUG_ON(base_addr); | ||
1109 | BUG_ON(base_addr && populate_pte_fn); | ||
1110 | |||
1111 | if (unit_size >= 0) | ||
1112 | pcpu_unit_pages = unit_size >> PAGE_SHIFT; | ||
1113 | else | ||
1114 | pcpu_unit_pages = max_t(int, PCPU_MIN_UNIT_SIZE >> PAGE_SHIFT, | ||
1115 | PFN_UP(size_sum)); | ||
1116 | |||
1117 | pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; | ||
1118 | pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size; | ||
1119 | pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) | ||
1120 | + num_possible_cpus() * pcpu_unit_pages * sizeof(struct page *); | ||
1121 | |||
1122 | if (dyn_size < 0) | ||
1123 | dyn_size = pcpu_unit_size - static_size - reserved_size; | ||
1124 | |||
1125 | /* | ||
1126 | * Allocate chunk slots. The additional last slot is for | ||
1127 | * empty chunks. | ||
1128 | */ | ||
1129 | pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2; | ||
1130 | pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0])); | ||
1131 | for (i = 0; i < pcpu_nr_slots; i++) | ||
1132 | INIT_LIST_HEAD(&pcpu_slot[i]); | ||
1133 | |||
1134 | /* | ||
1135 | * Initialize static chunk. If reserved_size is zero, the | ||
1136 | * static chunk covers static area + dynamic allocation area | ||
1137 | * in the first chunk. If reserved_size is not zero, it | ||
1138 | * covers static area + reserved area (mostly used for module | ||
1139 | * static percpu allocation). | ||
1140 | */ | ||
1141 | schunk = alloc_bootmem(pcpu_chunk_struct_size); | ||
1142 | INIT_LIST_HEAD(&schunk->list); | ||
1143 | schunk->vm = &first_vm; | ||
1144 | schunk->map = smap; | ||
1145 | schunk->map_alloc = ARRAY_SIZE(smap); | ||
1146 | schunk->page = schunk->page_ar; | ||
1147 | |||
1148 | if (reserved_size) { | ||
1149 | schunk->free_size = reserved_size; | ||
1150 | pcpu_reserved_chunk = schunk; /* not for dynamic alloc */ | ||
1151 | } else { | ||
1152 | schunk->free_size = dyn_size; | ||
1153 | dyn_size = 0; /* dynamic area covered */ | ||
1154 | } | ||
1155 | schunk->contig_hint = schunk->free_size; | ||
1156 | |||
1157 | schunk->map[schunk->map_used++] = -static_size; | ||
1158 | if (schunk->free_size) | ||
1159 | schunk->map[schunk->map_used++] = schunk->free_size; | ||
1160 | |||
1161 | pcpu_reserved_chunk_limit = static_size + schunk->free_size; | ||
1162 | |||
1163 | /* init dynamic chunk if necessary */ | ||
1164 | if (dyn_size) { | ||
1165 | dchunk = alloc_bootmem(sizeof(struct pcpu_chunk)); | ||
1166 | INIT_LIST_HEAD(&dchunk->list); | ||
1167 | dchunk->vm = &first_vm; | ||
1168 | dchunk->map = dmap; | ||
1169 | dchunk->map_alloc = ARRAY_SIZE(dmap); | ||
1170 | dchunk->page = schunk->page_ar; /* share page map with schunk */ | ||
1171 | |||
1172 | dchunk->contig_hint = dchunk->free_size = dyn_size; | ||
1173 | dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit; | ||
1174 | dchunk->map[dchunk->map_used++] = dchunk->free_size; | ||
1175 | } | ||
1176 | |||
1177 | /* allocate vm address */ | ||
1178 | first_vm.flags = VM_ALLOC; | ||
1179 | first_vm.size = pcpu_chunk_size; | ||
1180 | |||
1181 | if (!base_addr) | ||
1182 | vm_area_register_early(&first_vm, PAGE_SIZE); | ||
1183 | else { | ||
1184 | /* | ||
1185 | * Pages already mapped. No need to remap into | ||
1186 | * vmalloc area. In this case the first chunks can't | ||
1187 | * be mapped or unmapped by percpu and are marked | ||
1188 | * immutable. | ||
1189 | */ | ||
1190 | first_vm.addr = base_addr; | ||
1191 | schunk->immutable = true; | ||
1192 | if (dchunk) | ||
1193 | dchunk->immutable = true; | ||
1194 | } | ||
1195 | |||
1196 | /* assign pages */ | ||
1197 | nr_pages = -1; | ||
1198 | for_each_possible_cpu(cpu) { | ||
1199 | for (i = 0; i < pcpu_unit_pages; i++) { | ||
1200 | struct page *page = get_page_fn(cpu, i); | ||
1201 | |||
1202 | if (!page) | ||
1203 | break; | ||
1204 | *pcpu_chunk_pagep(schunk, cpu, i) = page; | ||
1205 | } | ||
1206 | |||
1207 | BUG_ON(i < PFN_UP(static_size)); | ||
1208 | |||
1209 | if (nr_pages < 0) | ||
1210 | nr_pages = i; | ||
1211 | else | ||
1212 | BUG_ON(nr_pages != i); | ||
1213 | } | ||
1214 | |||
1215 | /* map them */ | ||
1216 | if (populate_pte_fn) { | ||
1217 | for_each_possible_cpu(cpu) | ||
1218 | for (i = 0; i < nr_pages; i++) | ||
1219 | populate_pte_fn(pcpu_chunk_addr(schunk, | ||
1220 | cpu, i)); | ||
1221 | |||
1222 | err = pcpu_map(schunk, 0, nr_pages); | ||
1223 | if (err) | ||
1224 | panic("failed to setup static percpu area, err=%d\n", | ||
1225 | err); | ||
1226 | } | ||
1227 | |||
1228 | /* link the first chunk in */ | ||
1229 | if (!dchunk) { | ||
1230 | pcpu_chunk_relocate(schunk, -1); | ||
1231 | pcpu_chunk_addr_insert(schunk); | ||
1232 | } else { | ||
1233 | pcpu_chunk_relocate(dchunk, -1); | ||
1234 | pcpu_chunk_addr_insert(dchunk); | ||
1235 | } | ||
1236 | |||
1237 | /* we're done */ | ||
1238 | pcpu_base_addr = (void *)pcpu_chunk_addr(schunk, 0, 0); | ||
1239 | return pcpu_unit_size; | ||
1240 | } | ||
1241 | |||
1242 | /* | ||
1243 | * Embedding first chunk setup helper. | ||
1244 | */ | ||
1245 | static void *pcpue_ptr __initdata; | ||
1246 | static size_t pcpue_size __initdata; | ||
1247 | static size_t pcpue_unit_size __initdata; | ||
1248 | |||
1249 | static struct page * __init pcpue_get_page(unsigned int cpu, int pageno) | ||
1250 | { | ||
1251 | size_t off = (size_t)pageno << PAGE_SHIFT; | ||
1252 | |||
1253 | if (off >= pcpue_size) | ||
1254 | return NULL; | ||
1255 | |||
1256 | return virt_to_page(pcpue_ptr + cpu * pcpue_unit_size + off); | ||
1257 | } | ||
1258 | |||
1259 | /** | ||
1260 | * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem | ||
1261 | * @static_size: the size of static percpu area in bytes | ||
1262 | * @reserved_size: the size of reserved percpu area in bytes | ||
1263 | * @dyn_size: free size for dynamic allocation in bytes, -1 for auto | ||
1264 | * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, -1 for auto | ||
1265 | * | ||
1266 | * This is a helper to ease setting up embedded first percpu chunk and | ||
1267 | * can be called where pcpu_setup_first_chunk() is expected. | ||
1268 | * | ||
1269 | * If this function is used to setup the first chunk, it is allocated | ||
1270 | * as a contiguous area using bootmem allocator and used as-is without | ||
1271 | * being mapped into vmalloc area. This enables the first chunk to | ||
1272 | * piggy back on the linear physical mapping which often uses larger | ||
1273 | * page size. | ||
1274 | * | ||
1275 | * When @dyn_size is positive, dynamic area might be larger than | ||
1276 | * specified to fill page alignment. Also, when @dyn_size is auto, | ||
1277 | * @dyn_size does not fill the whole first chunk but only what's | ||
1278 | * necessary for page alignment after static and reserved areas. | ||
1279 | * | ||
1280 | * If the needed size is smaller than the minimum or specified unit | ||
1281 | * size, the leftover is returned to the bootmem allocator. | ||
1282 | * | ||
1283 | * RETURNS: | ||
1284 | * The determined pcpu_unit_size which can be used to initialize | ||
1285 | * percpu access on success, -errno on failure. | ||
1286 | */ | ||
1287 | ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size, | ||
1288 | ssize_t dyn_size, ssize_t unit_size) | ||
1289 | { | ||
1290 | unsigned int cpu; | ||
1291 | |||
1292 | /* determine parameters and allocate */ | ||
1293 | pcpue_size = PFN_ALIGN(static_size + reserved_size + | ||
1294 | (dyn_size >= 0 ? dyn_size : 0)); | ||
1295 | if (dyn_size != 0) | ||
1296 | dyn_size = pcpue_size - static_size - reserved_size; | ||
1297 | |||
1298 | if (unit_size >= 0) { | ||
1299 | BUG_ON(unit_size < pcpue_size); | ||
1300 | pcpue_unit_size = unit_size; | ||
1301 | } else | ||
1302 | pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE); | ||
1303 | |||
1304 | pcpue_ptr = __alloc_bootmem_nopanic( | ||
1305 | num_possible_cpus() * pcpue_unit_size, | ||
1306 | PAGE_SIZE, __pa(MAX_DMA_ADDRESS)); | ||
1307 | if (!pcpue_ptr) | ||
1308 | return -ENOMEM; | ||
1309 | |||
1310 | /* return the leftover and copy */ | ||
1311 | for_each_possible_cpu(cpu) { | ||
1312 | void *ptr = pcpue_ptr + cpu * pcpue_unit_size; | ||
1313 | |||
1314 | free_bootmem(__pa(ptr + pcpue_size), | ||
1315 | pcpue_unit_size - pcpue_size); | ||
1316 | memcpy(ptr, __per_cpu_load, static_size); | ||
1317 | } | ||
1318 | |||
1319 | /* we're ready, commit */ | ||
1320 | pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n", | ||
1321 | pcpue_size >> PAGE_SHIFT, pcpue_ptr, static_size); | ||
1322 | |||
1323 | return pcpu_setup_first_chunk(pcpue_get_page, static_size, | ||
1324 | reserved_size, dyn_size, | ||
1325 | pcpue_unit_size, pcpue_ptr, NULL); | ||
1326 | } | ||