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fbf59bc9 TH |
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 | |
e0100983 TH |
49 | * regular address to percpu pointer and back if they need to be |
50 | * different from the default | |
fbf59bc9 | 51 | * |
8d408b4b TH |
52 | * - use pcpu_setup_first_chunk() during percpu area initialization to |
53 | * setup the first chunk containing the kernel static percpu area | |
fbf59bc9 TH |
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> | |
ccea34b5 | 66 | #include <linux/spinlock.h> |
fbf59bc9 | 67 | #include <linux/vmalloc.h> |
a56dbddf | 68 | #include <linux/workqueue.h> |
fbf59bc9 TH |
69 | |
70 | #include <asm/cacheflush.h> | |
e0100983 | 71 | #include <asm/sections.h> |
fbf59bc9 TH |
72 | #include <asm/tlbflush.h> |
73 | ||
fbf59bc9 TH |
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 | ||
e0100983 TH |
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 | ||
fbf59bc9 TH |
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 */ | |
8d408b4b | 98 | bool immutable; /* no [de]population allowed */ |
3e24aa58 TH |
99 | struct page **page; /* points to page array */ |
100 | struct page *page_ar[]; /* #cpus * UNIT_PAGES */ | |
fbf59bc9 TH |
101 | }; |
102 | ||
40150d37 TH |
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; | |
fbf59bc9 TH |
108 | |
109 | /* the address of the first chunk which starts with the kernel static area */ | |
40150d37 | 110 | void *pcpu_base_addr __read_mostly; |
fbf59bc9 TH |
111 | EXPORT_SYMBOL_GPL(pcpu_base_addr); |
112 | ||
edcb4639 TH |
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 | ||
fbf59bc9 | 118 | /* |
ccea34b5 TH |
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. | |
fbf59bc9 | 138 | */ |
ccea34b5 TH |
139 | static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */ |
140 | static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */ | |
fbf59bc9 | 141 | |
40150d37 | 142 | static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */ |
fbf59bc9 TH |
143 | static struct rb_root pcpu_addr_root = RB_ROOT; /* chunks by address */ |
144 | ||
a56dbddf TH |
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 | ||
d9b55eeb | 149 | static int __pcpu_size_to_slot(int size) |
fbf59bc9 | 150 | { |
cae3aeb8 | 151 | int highbit = fls(size); /* size is in bytes */ |
fbf59bc9 TH |
152 | return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1); |
153 | } | |
154 | ||
d9b55eeb TH |
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 | ||
fbf59bc9 TH |
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 | { | |
d9b55eeb | 172 | return cpu * pcpu_unit_pages + page_idx; |
fbf59bc9 TH |
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 | /** | |
1880d93b TH |
195 | * pcpu_mem_alloc - allocate memory |
196 | * @size: bytes to allocate | |
fbf59bc9 | 197 | * |
1880d93b TH |
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. | |
fbf59bc9 | 201 | * |
ccea34b5 TH |
202 | * CONTEXT: |
203 | * Does GFP_KERNEL allocation. | |
204 | * | |
fbf59bc9 | 205 | * RETURNS: |
1880d93b | 206 | * Pointer to the allocated area on success, NULL on failure. |
fbf59bc9 | 207 | */ |
1880d93b | 208 | static void *pcpu_mem_alloc(size_t size) |
fbf59bc9 | 209 | { |
1880d93b TH |
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 | } | |
fbf59bc9 | 219 | |
1880d93b TH |
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 | { | |
fbf59bc9 | 229 | if (size <= PAGE_SIZE) |
1880d93b | 230 | kfree(ptr); |
fbf59bc9 | 231 | else |
1880d93b | 232 | vfree(ptr); |
fbf59bc9 TH |
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 | |
edcb4639 TH |
242 | * moved to the slot. Note that the reserved chunk is never put on |
243 | * chunk slots. | |
ccea34b5 TH |
244 | * |
245 | * CONTEXT: | |
246 | * pcpu_lock. | |
fbf59bc9 TH |
247 | */ |
248 | static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot) | |
249 | { | |
250 | int nslot = pcpu_chunk_slot(chunk); | |
251 | ||
edcb4639 | 252 | if (chunk != pcpu_reserved_chunk && oslot != nslot) { |
fbf59bc9 TH |
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 | * | |
ccea34b5 TH |
292 | * CONTEXT: |
293 | * pcpu_lock. | |
294 | * | |
fbf59bc9 TH |
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 | ||
edcb4639 TH |
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 */ | |
fbf59bc9 TH |
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. | |
ccea34b5 TH |
335 | * |
336 | * CONTEXT: | |
337 | * pcpu_lock. | |
fbf59bc9 TH |
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 | ||
9f7dcf22 TH |
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 | * | |
ccea34b5 TH |
357 | * CONTEXT: |
358 | * pcpu_alloc_mutex, pcpu_lock. pcpu_lock is released and reacquired | |
359 | * if area map is extended. | |
360 | * | |
9f7dcf22 TH |
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 | ||
ccea34b5 TH |
374 | spin_unlock_irq(&pcpu_lock); |
375 | ||
9f7dcf22 TH |
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])); | |
ccea34b5 TH |
381 | if (!new) { |
382 | spin_lock_irq(&pcpu_lock); | |
9f7dcf22 | 383 | return -ENOMEM; |
ccea34b5 TH |
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); | |
9f7dcf22 TH |
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 | ||
fbf59bc9 TH |
409 | /** |
410 | * pcpu_split_block - split a map block | |
411 | * @chunk: chunk of interest | |
412 | * @i: index of map block to split | |
cae3aeb8 TH |
413 | * @head: head size in bytes (can be 0) |
414 | * @tail: tail size in bytes (can be 0) | |
fbf59bc9 TH |
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 | * | |
9f7dcf22 | 424 | * @chunk->map must have enough free slots to accomodate the split. |
ccea34b5 TH |
425 | * |
426 | * CONTEXT: | |
427 | * pcpu_lock. | |
fbf59bc9 | 428 | */ |
9f7dcf22 TH |
429 | static void pcpu_split_block(struct pcpu_chunk *chunk, int i, |
430 | int head, int tail) | |
fbf59bc9 TH |
431 | { |
432 | int nr_extra = !!head + !!tail; | |
1880d93b | 433 | |
9f7dcf22 | 434 | BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra); |
fbf59bc9 | 435 | |
9f7dcf22 | 436 | /* insert new subblocks */ |
fbf59bc9 TH |
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 | } | |
fbf59bc9 TH |
449 | } |
450 | ||
451 | /** | |
452 | * pcpu_alloc_area - allocate area from a pcpu_chunk | |
453 | * @chunk: chunk of interest | |
cae3aeb8 | 454 | * @size: wanted size in bytes |
fbf59bc9 TH |
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 | * | |
9f7dcf22 TH |
461 | * @chunk->map must have at least two free slots. |
462 | * | |
ccea34b5 TH |
463 | * CONTEXT: |
464 | * pcpu_lock. | |
465 | * | |
fbf59bc9 | 466 | * RETURNS: |
9f7dcf22 TH |
467 | * Allocated offset in @chunk on success, -1 if no matching area is |
468 | * found. | |
fbf59bc9 TH |
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 | ||
fbf59bc9 TH |
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) { | |
9f7dcf22 | 516 | pcpu_split_block(chunk, i, head, tail); |
fbf59bc9 TH |
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 | ||
9f7dcf22 TH |
543 | /* tell the upper layer that this chunk has no matching area */ |
544 | return -1; | |
fbf59bc9 TH |
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. | |
ccea34b5 TH |
555 | * |
556 | * CONTEXT: | |
557 | * pcpu_lock. | |
fbf59bc9 TH |
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 | ||
8d408b4b TH |
610 | /* unmap must not be done on immutable chunk */ |
611 | WARN_ON(chunk->immutable); | |
612 | ||
fbf59bc9 TH |
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 | |
cae3aeb8 | 637 | * @size: size of the area to depopulate in bytes |
fbf59bc9 TH |
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. | |
ccea34b5 TH |
643 | * |
644 | * CONTEXT: | |
645 | * pcpu_alloc_mutex. | |
fbf59bc9 | 646 | */ |
cae3aeb8 TH |
647 | static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size, |
648 | bool flush) | |
fbf59bc9 TH |
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 | ||
8d408b4b TH |
697 | /* map must not be done on immutable chunk */ |
698 | WARN_ON(chunk->immutable); | |
699 | ||
fbf59bc9 TH |
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 | |
cae3aeb8 | 720 | * @size: size of the area to populate in bytes |
fbf59bc9 TH |
721 | * |
722 | * For each cpu, populate and map pages [@page_start,@page_end) into | |
723 | * @chunk. The area is cleared on return. | |
ccea34b5 TH |
724 | * |
725 | * CONTEXT: | |
726 | * pcpu_alloc_mutex, does GFP_KERNEL allocation. | |
fbf59bc9 TH |
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; | |
02d51fdf | 734 | int uninitialized_var(map_end); |
fbf59bc9 TH |
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) | |
d9b55eeb | 765 | memset(chunk->vm->addr + cpu * pcpu_unit_size + off, 0, |
fbf59bc9 TH |
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); | |
1880d93b | 781 | pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0])); |
fbf59bc9 TH |
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 | ||
1880d93b | 793 | chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0])); |
fbf59bc9 TH |
794 | chunk->map_alloc = PCPU_DFL_MAP_ALLOC; |
795 | chunk->map[chunk->map_used++] = pcpu_unit_size; | |
3e24aa58 | 796 | chunk->page = chunk->page_ar; |
fbf59bc9 TH |
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 | /** | |
edcb4639 | 812 | * pcpu_alloc - the percpu allocator |
cae3aeb8 | 813 | * @size: size of area to allocate in bytes |
fbf59bc9 | 814 | * @align: alignment of area (max PAGE_SIZE) |
edcb4639 | 815 | * @reserved: allocate from the reserved chunk if available |
fbf59bc9 | 816 | * |
ccea34b5 TH |
817 | * Allocate percpu area of @size bytes aligned at @align. |
818 | * | |
819 | * CONTEXT: | |
820 | * Does GFP_KERNEL allocation. | |
fbf59bc9 TH |
821 | * |
822 | * RETURNS: | |
823 | * Percpu pointer to the allocated area on success, NULL on failure. | |
824 | */ | |
edcb4639 | 825 | static void *pcpu_alloc(size_t size, size_t align, bool reserved) |
fbf59bc9 | 826 | { |
fbf59bc9 TH |
827 | struct pcpu_chunk *chunk; |
828 | int slot, off; | |
829 | ||
8d408b4b | 830 | if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { |
fbf59bc9 TH |
831 | WARN(true, "illegal size (%zu) or align (%zu) for " |
832 | "percpu allocation\n", size, align); | |
833 | return NULL; | |
834 | } | |
835 | ||
ccea34b5 TH |
836 | mutex_lock(&pcpu_alloc_mutex); |
837 | spin_lock_irq(&pcpu_lock); | |
fbf59bc9 | 838 | |
edcb4639 TH |
839 | /* serve reserved allocations from the reserved chunk if available */ |
840 | if (reserved && pcpu_reserved_chunk) { | |
841 | chunk = pcpu_reserved_chunk; | |
9f7dcf22 TH |
842 | if (size > chunk->contig_hint || |
843 | pcpu_extend_area_map(chunk) < 0) | |
ccea34b5 | 844 | goto fail_unlock; |
edcb4639 TH |
845 | off = pcpu_alloc_area(chunk, size, align); |
846 | if (off >= 0) | |
847 | goto area_found; | |
ccea34b5 | 848 | goto fail_unlock; |
edcb4639 TH |
849 | } |
850 | ||
ccea34b5 | 851 | restart: |
edcb4639 | 852 | /* search through normal chunks */ |
fbf59bc9 TH |
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; | |
ccea34b5 TH |
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 | ||
fbf59bc9 TH |
867 | off = pcpu_alloc_area(chunk, size, align); |
868 | if (off >= 0) | |
869 | goto area_found; | |
fbf59bc9 TH |
870 | } |
871 | } | |
872 | ||
873 | /* hmmm... no space left, create a new chunk */ | |
ccea34b5 TH |
874 | spin_unlock_irq(&pcpu_lock); |
875 | ||
fbf59bc9 TH |
876 | chunk = alloc_pcpu_chunk(); |
877 | if (!chunk) | |
ccea34b5 TH |
878 | goto fail_unlock_mutex; |
879 | ||
880 | spin_lock_irq(&pcpu_lock); | |
fbf59bc9 TH |
881 | pcpu_chunk_relocate(chunk, -1); |
882 | pcpu_chunk_addr_insert(chunk); | |
ccea34b5 | 883 | goto restart; |
fbf59bc9 TH |
884 | |
885 | area_found: | |
ccea34b5 TH |
886 | spin_unlock_irq(&pcpu_lock); |
887 | ||
fbf59bc9 TH |
888 | /* populate, map and clear the area */ |
889 | if (pcpu_populate_chunk(chunk, off, size)) { | |
ccea34b5 | 890 | spin_lock_irq(&pcpu_lock); |
fbf59bc9 | 891 | pcpu_free_area(chunk, off); |
ccea34b5 | 892 | goto fail_unlock; |
fbf59bc9 TH |
893 | } |
894 | ||
ccea34b5 TH |
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; | |
fbf59bc9 | 904 | } |
edcb4639 TH |
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 | * | |
ccea34b5 TH |
914 | * CONTEXT: |
915 | * Does GFP_KERNEL allocation. | |
916 | * | |
edcb4639 TH |
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 | } | |
fbf59bc9 TH |
924 | EXPORT_SYMBOL_GPL(__alloc_percpu); |
925 | ||
edcb4639 TH |
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 | * | |
ccea34b5 TH |
935 | * CONTEXT: |
936 | * Does GFP_KERNEL allocation. | |
937 | * | |
edcb4639 TH |
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 | ||
a56dbddf TH |
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. | |
ccea34b5 TH |
951 | * |
952 | * CONTEXT: | |
953 | * workqueue context. | |
a56dbddf TH |
954 | */ |
955 | static void pcpu_reclaim(struct work_struct *work) | |
fbf59bc9 | 956 | { |
a56dbddf TH |
957 | LIST_HEAD(todo); |
958 | struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1]; | |
959 | struct pcpu_chunk *chunk, *next; | |
960 | ||
ccea34b5 TH |
961 | mutex_lock(&pcpu_alloc_mutex); |
962 | spin_lock_irq(&pcpu_lock); | |
a56dbddf TH |
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 | ||
ccea34b5 TH |
975 | spin_unlock_irq(&pcpu_lock); |
976 | mutex_unlock(&pcpu_alloc_mutex); | |
a56dbddf TH |
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 | } | |
fbf59bc9 TH |
982 | } |
983 | ||
984 | /** | |
985 | * free_percpu - free percpu area | |
986 | * @ptr: pointer to area to free | |
987 | * | |
ccea34b5 TH |
988 | * Free percpu area @ptr. |
989 | * | |
990 | * CONTEXT: | |
991 | * Can be called from atomic context. | |
fbf59bc9 TH |
992 | */ |
993 | void free_percpu(void *ptr) | |
994 | { | |
995 | void *addr = __pcpu_ptr_to_addr(ptr); | |
996 | struct pcpu_chunk *chunk; | |
ccea34b5 | 997 | unsigned long flags; |
fbf59bc9 TH |
998 | int off; |
999 | ||
1000 | if (!ptr) | |
1001 | return; | |
1002 | ||
ccea34b5 | 1003 | spin_lock_irqsave(&pcpu_lock, flags); |
fbf59bc9 TH |
1004 | |
1005 | chunk = pcpu_chunk_addr_search(addr); | |
1006 | off = addr - chunk->vm->addr; | |
1007 | ||
1008 | pcpu_free_area(chunk, off); | |
1009 | ||
a56dbddf | 1010 | /* if there are more than one fully free chunks, wake up grim reaper */ |
fbf59bc9 TH |
1011 | if (chunk->free_size == pcpu_unit_size) { |
1012 | struct pcpu_chunk *pos; | |
1013 | ||
a56dbddf | 1014 | list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list) |
fbf59bc9 | 1015 | if (pos != chunk) { |
a56dbddf | 1016 | schedule_work(&pcpu_reclaim_work); |
fbf59bc9 TH |
1017 | break; |
1018 | } | |
1019 | } | |
1020 | ||
ccea34b5 | 1021 | spin_unlock_irqrestore(&pcpu_lock, flags); |
fbf59bc9 TH |
1022 | } |
1023 | EXPORT_SYMBOL_GPL(free_percpu); | |
1024 | ||
1025 | /** | |
8d408b4b TH |
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 | |
edcb4639 | 1029 | * @reserved_size: the size of reserved percpu area in bytes |
cafe8816 | 1030 | * @dyn_size: free size for dynamic allocation in bytes, -1 for auto |
6074d5b0 | 1031 | * @unit_size: unit size in bytes, must be multiple of PAGE_SIZE, -1 for auto |
8d408b4b TH |
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 | * | |
edcb4639 TH |
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 | * | |
6074d5b0 TH |
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 | * | |
cafe8816 TH |
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 + | |
6074d5b0 | 1063 | * @reserved_size + if non-negative, @dyn_size. |
8d408b4b TH |
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. | |
fbf59bc9 | 1072 | * |
edcb4639 TH |
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 | * | |
fbf59bc9 TH |
1080 | * RETURNS: |
1081 | * The determined pcpu_unit_size which can be used to initialize | |
1082 | * percpu access. | |
1083 | */ | |
8d408b4b | 1084 | size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, |
edcb4639 | 1085 | size_t static_size, size_t reserved_size, |
6074d5b0 | 1086 | ssize_t dyn_size, ssize_t unit_size, |
cafe8816 | 1087 | void *base_addr, |
8d408b4b | 1088 | pcpu_populate_pte_fn_t populate_pte_fn) |
fbf59bc9 | 1089 | { |
2441d15c | 1090 | static struct vm_struct first_vm; |
edcb4639 | 1091 | static int smap[2], dmap[2]; |
6074d5b0 TH |
1092 | size_t size_sum = static_size + reserved_size + |
1093 | (dyn_size >= 0 ? dyn_size : 0); | |
edcb4639 | 1094 | struct pcpu_chunk *schunk, *dchunk = NULL; |
fbf59bc9 | 1095 | unsigned int cpu; |
8d408b4b | 1096 | int nr_pages; |
fbf59bc9 TH |
1097 | int err, i; |
1098 | ||
8d408b4b | 1099 | /* santiy checks */ |
edcb4639 TH |
1100 | BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC || |
1101 | ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC); | |
8d408b4b | 1102 | BUG_ON(!static_size); |
cafe8816 | 1103 | if (unit_size >= 0) { |
6074d5b0 | 1104 | BUG_ON(unit_size < size_sum); |
cafe8816 | 1105 | BUG_ON(unit_size & ~PAGE_MASK); |
6074d5b0 TH |
1106 | BUG_ON(unit_size < PCPU_MIN_UNIT_SIZE); |
1107 | } else | |
cafe8816 | 1108 | BUG_ON(base_addr); |
8d408b4b | 1109 | BUG_ON(base_addr && populate_pte_fn); |
fbf59bc9 | 1110 | |
cafe8816 | 1111 | if (unit_size >= 0) |
8d408b4b TH |
1112 | pcpu_unit_pages = unit_size >> PAGE_SHIFT; |
1113 | else | |
1114 | pcpu_unit_pages = max_t(int, PCPU_MIN_UNIT_SIZE >> PAGE_SHIFT, | |
6074d5b0 | 1115 | PFN_UP(size_sum)); |
8d408b4b | 1116 | |
d9b55eeb | 1117 | pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; |
fbf59bc9 | 1118 | pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size; |
fbf59bc9 | 1119 | pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) |
cb83b42e | 1120 | + num_possible_cpus() * pcpu_unit_pages * sizeof(struct page *); |
fbf59bc9 | 1121 | |
cafe8816 | 1122 | if (dyn_size < 0) |
edcb4639 | 1123 | dyn_size = pcpu_unit_size - static_size - reserved_size; |
cafe8816 | 1124 | |
d9b55eeb TH |
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; | |
fbf59bc9 TH |
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 | ||
edcb4639 TH |
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 | */ | |
2441d15c TH |
1141 | schunk = alloc_bootmem(pcpu_chunk_struct_size); |
1142 | INIT_LIST_HEAD(&schunk->list); | |
1143 | schunk->vm = &first_vm; | |
61ace7fa TH |
1144 | schunk->map = smap; |
1145 | schunk->map_alloc = ARRAY_SIZE(smap); | |
3e24aa58 | 1146 | schunk->page = schunk->page_ar; |
edcb4639 TH |
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 | } | |
2441d15c | 1155 | schunk->contig_hint = schunk->free_size; |
fbf59bc9 | 1156 | |
61ace7fa TH |
1157 | schunk->map[schunk->map_used++] = -static_size; |
1158 | if (schunk->free_size) | |
1159 | schunk->map[schunk->map_used++] = schunk->free_size; | |
1160 | ||
edcb4639 TH |
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 | ||
8d408b4b | 1177 | /* allocate vm address */ |
2441d15c TH |
1178 | first_vm.flags = VM_ALLOC; |
1179 | first_vm.size = pcpu_chunk_size; | |
8d408b4b TH |
1180 | |
1181 | if (!base_addr) | |
2441d15c | 1182 | vm_area_register_early(&first_vm, PAGE_SIZE); |
8d408b4b TH |
1183 | else { |
1184 | /* | |
1185 | * Pages already mapped. No need to remap into | |
edcb4639 TH |
1186 | * vmalloc area. In this case the first chunks can't |
1187 | * be mapped or unmapped by percpu and are marked | |
8d408b4b TH |
1188 | * immutable. |
1189 | */ | |
2441d15c TH |
1190 | first_vm.addr = base_addr; |
1191 | schunk->immutable = true; | |
edcb4639 TH |
1192 | if (dchunk) |
1193 | dchunk->immutable = true; | |
8d408b4b TH |
1194 | } |
1195 | ||
1196 | /* assign pages */ | |
1197 | nr_pages = -1; | |
fbf59bc9 | 1198 | for_each_possible_cpu(cpu) { |
8d408b4b TH |
1199 | for (i = 0; i < pcpu_unit_pages; i++) { |
1200 | struct page *page = get_page_fn(cpu, i); | |
1201 | ||
1202 | if (!page) | |
1203 | break; | |
2441d15c | 1204 | *pcpu_chunk_pagep(schunk, cpu, i) = page; |
fbf59bc9 | 1205 | } |
8d408b4b | 1206 | |
61ace7fa | 1207 | BUG_ON(i < PFN_UP(static_size)); |
8d408b4b TH |
1208 | |
1209 | if (nr_pages < 0) | |
1210 | nr_pages = i; | |
1211 | else | |
1212 | BUG_ON(nr_pages != i); | |
fbf59bc9 TH |
1213 | } |
1214 | ||
8d408b4b TH |
1215 | /* map them */ |
1216 | if (populate_pte_fn) { | |
1217 | for_each_possible_cpu(cpu) | |
1218 | for (i = 0; i < nr_pages; i++) | |
2441d15c | 1219 | populate_pte_fn(pcpu_chunk_addr(schunk, |
8d408b4b TH |
1220 | cpu, i)); |
1221 | ||
2441d15c | 1222 | err = pcpu_map(schunk, 0, nr_pages); |
8d408b4b TH |
1223 | if (err) |
1224 | panic("failed to setup static percpu area, err=%d\n", | |
1225 | err); | |
1226 | } | |
fbf59bc9 | 1227 | |
2441d15c | 1228 | /* link the first chunk in */ |
edcb4639 TH |
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 | } | |
fbf59bc9 TH |
1236 | |
1237 | /* we're done */ | |
2441d15c | 1238 | pcpu_base_addr = (void *)pcpu_chunk_addr(schunk, 0, 0); |
fbf59bc9 TH |
1239 | return pcpu_unit_size; |
1240 | } | |
66c3a757 TH |
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 | } |