net: ipv6 bind to device issue
[linux-2.6-block.git] / mm / percpu.c
CommitLineData
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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
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11 * chunk is consisted of boot-time determined number of units and the
12 * first chunk is used for static percpu variables in the kernel image
13 * (special boot time alloc/init handling necessary as these areas
14 * need to be brought up before allocation services are running).
15 * Unit grows as necessary and all units grow or shrink in unison.
16 * When a chunk is filled up, another chunk is allocated. ie. in
17 * vmalloc area
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18 *
19 * c0 c1 c2
20 * ------------------- ------------------- ------------
21 * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
22 * ------------------- ...... ------------------- .... ------------
23 *
24 * Allocation is done in offset-size areas of single unit space. Ie,
25 * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
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26 * c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to
27 * cpus. On NUMA, the mapping can be non-linear and even sparse.
28 * Percpu access can be done by configuring percpu base registers
29 * according to cpu to unit mapping and pcpu_unit_size.
fbf59bc9 30 *
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31 * There are usually many small percpu allocations many of them being
32 * as small as 4 bytes. The allocator organizes chunks into lists
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33 * according to free size and tries to allocate from the fullest one.
34 * Each chunk keeps the maximum contiguous area size hint which is
35 * guaranteed to be eqaul to or larger than the maximum contiguous
36 * area in the chunk. This helps the allocator not to iterate the
37 * chunk maps unnecessarily.
38 *
39 * Allocation state in each chunk is kept using an array of integers
40 * on chunk->map. A positive value in the map represents a free
41 * region and negative allocated. Allocation inside a chunk is done
42 * by scanning this map sequentially and serving the first matching
43 * entry. This is mostly copied from the percpu_modalloc() allocator.
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44 * Chunks can be determined from the address using the index field
45 * in the page struct. The index field contains a pointer to the chunk.
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46 *
47 * To use this allocator, arch code should do the followings.
48 *
fbf59bc9 49 * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
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50 * regular address to percpu pointer and back if they need to be
51 * different from the default
fbf59bc9 52 *
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53 * - use pcpu_setup_first_chunk() during percpu area initialization to
54 * setup the first chunk containing the kernel static percpu area
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55 */
56
57#include <linux/bitmap.h>
58#include <linux/bootmem.h>
fd1e8a1f 59#include <linux/err.h>
fbf59bc9 60#include <linux/list.h>
a530b795 61#include <linux/log2.h>
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62#include <linux/mm.h>
63#include <linux/module.h>
64#include <linux/mutex.h>
65#include <linux/percpu.h>
66#include <linux/pfn.h>
fbf59bc9 67#include <linux/slab.h>
ccea34b5 68#include <linux/spinlock.h>
fbf59bc9 69#include <linux/vmalloc.h>
a56dbddf 70#include <linux/workqueue.h>
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71
72#include <asm/cacheflush.h>
e0100983 73#include <asm/sections.h>
fbf59bc9 74#include <asm/tlbflush.h>
3b034b0d 75#include <asm/io.h>
fbf59bc9 76
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77#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
78#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
79
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80/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
81#ifndef __addr_to_pcpu_ptr
82#define __addr_to_pcpu_ptr(addr) \
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83 (void __percpu *)((unsigned long)(addr) - \
84 (unsigned long)pcpu_base_addr + \
85 (unsigned long)__per_cpu_start)
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86#endif
87#ifndef __pcpu_ptr_to_addr
88#define __pcpu_ptr_to_addr(ptr) \
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89 (void __force *)((unsigned long)(ptr) + \
90 (unsigned long)pcpu_base_addr - \
91 (unsigned long)__per_cpu_start)
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92#endif
93
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94struct pcpu_chunk {
95 struct list_head list; /* linked to pcpu_slot lists */
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96 int free_size; /* free bytes in the chunk */
97 int contig_hint; /* max contiguous size hint */
bba174f5 98 void *base_addr; /* base address of this chunk */
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99 int map_used; /* # of map entries used */
100 int map_alloc; /* # of map entries allocated */
101 int *map; /* allocation map */
6563297c 102 struct vm_struct **vms; /* mapped vmalloc regions */
8d408b4b 103 bool immutable; /* no [de]population allowed */
ce3141a2 104 unsigned long populated[]; /* populated bitmap */
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105};
106
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107static int pcpu_unit_pages __read_mostly;
108static int pcpu_unit_size __read_mostly;
2f39e637 109static int pcpu_nr_units __read_mostly;
6563297c 110static int pcpu_atom_size __read_mostly;
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111static int pcpu_nr_slots __read_mostly;
112static size_t pcpu_chunk_struct_size __read_mostly;
fbf59bc9 113
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114/* cpus with the lowest and highest unit numbers */
115static unsigned int pcpu_first_unit_cpu __read_mostly;
116static unsigned int pcpu_last_unit_cpu __read_mostly;
117
fbf59bc9 118/* the address of the first chunk which starts with the kernel static area */
40150d37 119void *pcpu_base_addr __read_mostly;
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120EXPORT_SYMBOL_GPL(pcpu_base_addr);
121
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122static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
123const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */
2f39e637 124
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125/* group information, used for vm allocation */
126static int pcpu_nr_groups __read_mostly;
127static const unsigned long *pcpu_group_offsets __read_mostly;
128static const size_t *pcpu_group_sizes __read_mostly;
129
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130/*
131 * The first chunk which always exists. Note that unlike other
132 * chunks, this one can be allocated and mapped in several different
133 * ways and thus often doesn't live in the vmalloc area.
134 */
135static struct pcpu_chunk *pcpu_first_chunk;
136
137/*
138 * Optional reserved chunk. This chunk reserves part of the first
139 * chunk and serves it for reserved allocations. The amount of
140 * reserved offset is in pcpu_reserved_chunk_limit. When reserved
141 * area doesn't exist, the following variables contain NULL and 0
142 * respectively.
143 */
edcb4639 144static struct pcpu_chunk *pcpu_reserved_chunk;
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145static int pcpu_reserved_chunk_limit;
146
fbf59bc9 147/*
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148 * Synchronization rules.
149 *
150 * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former
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151 * protects allocation/reclaim paths, chunks, populated bitmap and
152 * vmalloc mapping. The latter is a spinlock and protects the index
153 * data structures - chunk slots, chunks and area maps in chunks.
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154 *
155 * During allocation, pcpu_alloc_mutex is kept locked all the time and
156 * pcpu_lock is grabbed and released as necessary. All actual memory
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157 * allocations are done using GFP_KERNEL with pcpu_lock released. In
158 * general, percpu memory can't be allocated with irq off but
159 * irqsave/restore are still used in alloc path so that it can be used
160 * from early init path - sched_init() specifically.
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161 *
162 * Free path accesses and alters only the index data structures, so it
163 * can be safely called from atomic context. When memory needs to be
164 * returned to the system, free path schedules reclaim_work which
165 * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be
166 * reclaimed, release both locks and frees the chunks. Note that it's
167 * necessary to grab both locks to remove a chunk from circulation as
168 * allocation path might be referencing the chunk with only
169 * pcpu_alloc_mutex locked.
fbf59bc9 170 */
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171static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */
172static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */
fbf59bc9 173
40150d37 174static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
fbf59bc9 175
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176/* reclaim work to release fully free chunks, scheduled from free path */
177static void pcpu_reclaim(struct work_struct *work);
178static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim);
179
d9b55eeb 180static int __pcpu_size_to_slot(int size)
fbf59bc9 181{
cae3aeb8 182 int highbit = fls(size); /* size is in bytes */
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183 return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
184}
185
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186static int pcpu_size_to_slot(int size)
187{
188 if (size == pcpu_unit_size)
189 return pcpu_nr_slots - 1;
190 return __pcpu_size_to_slot(size);
191}
192
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193static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
194{
195 if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
196 return 0;
197
198 return pcpu_size_to_slot(chunk->free_size);
199}
200
201static int pcpu_page_idx(unsigned int cpu, int page_idx)
202{
2f39e637 203 return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
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204}
205
206static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
207 unsigned int cpu, int page_idx)
208{
bba174f5 209 return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
fb435d52 210 (page_idx << PAGE_SHIFT);
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211}
212
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213static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
214 unsigned int cpu, int page_idx)
fbf59bc9 215{
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216 /* must not be used on pre-mapped chunk */
217 WARN_ON(chunk->immutable);
c8a51be4 218
ce3141a2 219 return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
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220}
221
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222/* set the pointer to a chunk in a page struct */
223static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
224{
225 page->index = (unsigned long)pcpu;
226}
227
228/* obtain pointer to a chunk from a page struct */
229static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
230{
231 return (struct pcpu_chunk *)page->index;
232}
233
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234static void pcpu_next_unpop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
235{
236 *rs = find_next_zero_bit(chunk->populated, end, *rs);
237 *re = find_next_bit(chunk->populated, end, *rs + 1);
238}
239
240static void pcpu_next_pop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
241{
242 *rs = find_next_bit(chunk->populated, end, *rs);
243 *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
244}
245
246/*
247 * (Un)populated page region iterators. Iterate over (un)populated
248 * page regions betwen @start and @end in @chunk. @rs and @re should
249 * be integer variables and will be set to start and end page index of
250 * the current region.
251 */
252#define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
253 for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
254 (rs) < (re); \
255 (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
256
257#define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
258 for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
259 (rs) < (re); \
260 (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
261
fbf59bc9 262/**
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263 * pcpu_mem_alloc - allocate memory
264 * @size: bytes to allocate
fbf59bc9 265 *
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266 * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
267 * kzalloc() is used; otherwise, vmalloc() is used. The returned
268 * memory is always zeroed.
fbf59bc9 269 *
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270 * CONTEXT:
271 * Does GFP_KERNEL allocation.
272 *
fbf59bc9 273 * RETURNS:
1880d93b 274 * Pointer to the allocated area on success, NULL on failure.
fbf59bc9 275 */
1880d93b 276static void *pcpu_mem_alloc(size_t size)
fbf59bc9 277{
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278 if (size <= PAGE_SIZE)
279 return kzalloc(size, GFP_KERNEL);
280 else {
281 void *ptr = vmalloc(size);
282 if (ptr)
283 memset(ptr, 0, size);
284 return ptr;
285 }
286}
fbf59bc9 287
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288/**
289 * pcpu_mem_free - free memory
290 * @ptr: memory to free
291 * @size: size of the area
292 *
293 * Free @ptr. @ptr should have been allocated using pcpu_mem_alloc().
294 */
295static void pcpu_mem_free(void *ptr, size_t size)
296{
fbf59bc9 297 if (size <= PAGE_SIZE)
1880d93b 298 kfree(ptr);
fbf59bc9 299 else
1880d93b 300 vfree(ptr);
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301}
302
303/**
304 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
305 * @chunk: chunk of interest
306 * @oslot: the previous slot it was on
307 *
308 * This function is called after an allocation or free changed @chunk.
309 * New slot according to the changed state is determined and @chunk is
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310 * moved to the slot. Note that the reserved chunk is never put on
311 * chunk slots.
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312 *
313 * CONTEXT:
314 * pcpu_lock.
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315 */
316static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
317{
318 int nslot = pcpu_chunk_slot(chunk);
319
edcb4639 320 if (chunk != pcpu_reserved_chunk && oslot != nslot) {
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321 if (oslot < nslot)
322 list_move(&chunk->list, &pcpu_slot[nslot]);
323 else
324 list_move_tail(&chunk->list, &pcpu_slot[nslot]);
325 }
326}
327
fbf59bc9 328/**
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329 * pcpu_chunk_addr_search - determine chunk containing specified address
330 * @addr: address for which the chunk needs to be determined.
ccea34b5 331 *
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332 * RETURNS:
333 * The address of the found chunk.
334 */
335static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
336{
bba174f5 337 void *first_start = pcpu_first_chunk->base_addr;
fbf59bc9 338
ae9e6bc9 339 /* is it in the first chunk? */
79ba6ac8 340 if (addr >= first_start && addr < first_start + pcpu_unit_size) {
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341 /* is it in the reserved area? */
342 if (addr < first_start + pcpu_reserved_chunk_limit)
edcb4639 343 return pcpu_reserved_chunk;
ae9e6bc9 344 return pcpu_first_chunk;
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345 }
346
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347 /*
348 * The address is relative to unit0 which might be unused and
349 * thus unmapped. Offset the address to the unit space of the
350 * current processor before looking it up in the vmalloc
351 * space. Note that any possible cpu id can be used here, so
352 * there's no need to worry about preemption or cpu hotplug.
353 */
5579fd7e 354 addr += pcpu_unit_offsets[raw_smp_processor_id()];
e1b9aa3f 355 return pcpu_get_page_chunk(vmalloc_to_page(addr));
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356}
357
9f7dcf22 358/**
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359 * pcpu_need_to_extend - determine whether chunk area map needs to be extended
360 * @chunk: chunk of interest
9f7dcf22 361 *
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362 * Determine whether area map of @chunk needs to be extended to
363 * accomodate a new allocation.
9f7dcf22 364 *
ccea34b5 365 * CONTEXT:
833af842 366 * pcpu_lock.
ccea34b5 367 *
9f7dcf22 368 * RETURNS:
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369 * New target map allocation length if extension is necessary, 0
370 * otherwise.
9f7dcf22 371 */
833af842 372static int pcpu_need_to_extend(struct pcpu_chunk *chunk)
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373{
374 int new_alloc;
9f7dcf22 375
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376 if (chunk->map_alloc >= chunk->map_used + 2)
377 return 0;
378
379 new_alloc = PCPU_DFL_MAP_ALLOC;
380 while (new_alloc < chunk->map_used + 2)
381 new_alloc *= 2;
382
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383 return new_alloc;
384}
385
386/**
387 * pcpu_extend_area_map - extend area map of a chunk
388 * @chunk: chunk of interest
389 * @new_alloc: new target allocation length of the area map
390 *
391 * Extend area map of @chunk to have @new_alloc entries.
392 *
393 * CONTEXT:
394 * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock.
395 *
396 * RETURNS:
397 * 0 on success, -errno on failure.
398 */
399static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
400{
401 int *old = NULL, *new = NULL;
402 size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
403 unsigned long flags;
404
405 new = pcpu_mem_alloc(new_size);
406 if (!new)
9f7dcf22 407 return -ENOMEM;
ccea34b5 408
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409 /* acquire pcpu_lock and switch to new area map */
410 spin_lock_irqsave(&pcpu_lock, flags);
411
412 if (new_alloc <= chunk->map_alloc)
413 goto out_unlock;
9f7dcf22 414
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415 old_size = chunk->map_alloc * sizeof(chunk->map[0]);
416 memcpy(new, chunk->map, old_size);
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417
418 /*
419 * map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is
420 * one of the first chunks and still using static map.
421 */
422 if (chunk->map_alloc >= PCPU_DFL_MAP_ALLOC)
833af842 423 old = chunk->map;
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424
425 chunk->map_alloc = new_alloc;
426 chunk->map = new;
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427 new = NULL;
428
429out_unlock:
430 spin_unlock_irqrestore(&pcpu_lock, flags);
431
432 /*
433 * pcpu_mem_free() might end up calling vfree() which uses
434 * IRQ-unsafe lock and thus can't be called under pcpu_lock.
435 */
436 pcpu_mem_free(old, old_size);
437 pcpu_mem_free(new, new_size);
438
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439 return 0;
440}
441
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442/**
443 * pcpu_split_block - split a map block
444 * @chunk: chunk of interest
445 * @i: index of map block to split
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446 * @head: head size in bytes (can be 0)
447 * @tail: tail size in bytes (can be 0)
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448 *
449 * Split the @i'th map block into two or three blocks. If @head is
450 * non-zero, @head bytes block is inserted before block @i moving it
451 * to @i+1 and reducing its size by @head bytes.
452 *
453 * If @tail is non-zero, the target block, which can be @i or @i+1
454 * depending on @head, is reduced by @tail bytes and @tail byte block
455 * is inserted after the target block.
456 *
9f7dcf22 457 * @chunk->map must have enough free slots to accomodate the split.
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458 *
459 * CONTEXT:
460 * pcpu_lock.
fbf59bc9 461 */
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462static void pcpu_split_block(struct pcpu_chunk *chunk, int i,
463 int head, int tail)
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464{
465 int nr_extra = !!head + !!tail;
1880d93b 466
9f7dcf22 467 BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra);
fbf59bc9 468
9f7dcf22 469 /* insert new subblocks */
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470 memmove(&chunk->map[i + nr_extra], &chunk->map[i],
471 sizeof(chunk->map[0]) * (chunk->map_used - i));
472 chunk->map_used += nr_extra;
473
474 if (head) {
475 chunk->map[i + 1] = chunk->map[i] - head;
476 chunk->map[i++] = head;
477 }
478 if (tail) {
479 chunk->map[i++] -= tail;
480 chunk->map[i] = tail;
481 }
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482}
483
484/**
485 * pcpu_alloc_area - allocate area from a pcpu_chunk
486 * @chunk: chunk of interest
cae3aeb8 487 * @size: wanted size in bytes
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488 * @align: wanted align
489 *
490 * Try to allocate @size bytes area aligned at @align from @chunk.
491 * Note that this function only allocates the offset. It doesn't
492 * populate or map the area.
493 *
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494 * @chunk->map must have at least two free slots.
495 *
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496 * CONTEXT:
497 * pcpu_lock.
498 *
fbf59bc9 499 * RETURNS:
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500 * Allocated offset in @chunk on success, -1 if no matching area is
501 * found.
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502 */
503static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
504{
505 int oslot = pcpu_chunk_slot(chunk);
506 int max_contig = 0;
507 int i, off;
508
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509 for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) {
510 bool is_last = i + 1 == chunk->map_used;
511 int head, tail;
512
513 /* extra for alignment requirement */
514 head = ALIGN(off, align) - off;
515 BUG_ON(i == 0 && head != 0);
516
517 if (chunk->map[i] < 0)
518 continue;
519 if (chunk->map[i] < head + size) {
520 max_contig = max(chunk->map[i], max_contig);
521 continue;
522 }
523
524 /*
525 * If head is small or the previous block is free,
526 * merge'em. Note that 'small' is defined as smaller
527 * than sizeof(int), which is very small but isn't too
528 * uncommon for percpu allocations.
529 */
530 if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) {
531 if (chunk->map[i - 1] > 0)
532 chunk->map[i - 1] += head;
533 else {
534 chunk->map[i - 1] -= head;
535 chunk->free_size -= head;
536 }
537 chunk->map[i] -= head;
538 off += head;
539 head = 0;
540 }
541
542 /* if tail is small, just keep it around */
543 tail = chunk->map[i] - head - size;
544 if (tail < sizeof(int))
545 tail = 0;
546
547 /* split if warranted */
548 if (head || tail) {
9f7dcf22 549 pcpu_split_block(chunk, i, head, tail);
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550 if (head) {
551 i++;
552 off += head;
553 max_contig = max(chunk->map[i - 1], max_contig);
554 }
555 if (tail)
556 max_contig = max(chunk->map[i + 1], max_contig);
557 }
558
559 /* update hint and mark allocated */
560 if (is_last)
561 chunk->contig_hint = max_contig; /* fully scanned */
562 else
563 chunk->contig_hint = max(chunk->contig_hint,
564 max_contig);
565
566 chunk->free_size -= chunk->map[i];
567 chunk->map[i] = -chunk->map[i];
568
569 pcpu_chunk_relocate(chunk, oslot);
570 return off;
571 }
572
573 chunk->contig_hint = max_contig; /* fully scanned */
574 pcpu_chunk_relocate(chunk, oslot);
575
9f7dcf22
TH
576 /* tell the upper layer that this chunk has no matching area */
577 return -1;
fbf59bc9
TH
578}
579
580/**
581 * pcpu_free_area - free area to a pcpu_chunk
582 * @chunk: chunk of interest
583 * @freeme: offset of area to free
584 *
585 * Free area starting from @freeme to @chunk. Note that this function
586 * only modifies the allocation map. It doesn't depopulate or unmap
587 * the area.
ccea34b5
TH
588 *
589 * CONTEXT:
590 * pcpu_lock.
fbf59bc9
TH
591 */
592static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
593{
594 int oslot = pcpu_chunk_slot(chunk);
595 int i, off;
596
597 for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++]))
598 if (off == freeme)
599 break;
600 BUG_ON(off != freeme);
601 BUG_ON(chunk->map[i] > 0);
602
603 chunk->map[i] = -chunk->map[i];
604 chunk->free_size += chunk->map[i];
605
606 /* merge with previous? */
607 if (i > 0 && chunk->map[i - 1] >= 0) {
608 chunk->map[i - 1] += chunk->map[i];
609 chunk->map_used--;
610 memmove(&chunk->map[i], &chunk->map[i + 1],
611 (chunk->map_used - i) * sizeof(chunk->map[0]));
612 i--;
613 }
614 /* merge with next? */
615 if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) {
616 chunk->map[i] += chunk->map[i + 1];
617 chunk->map_used--;
618 memmove(&chunk->map[i + 1], &chunk->map[i + 2],
619 (chunk->map_used - (i + 1)) * sizeof(chunk->map[0]));
620 }
621
622 chunk->contig_hint = max(chunk->map[i], chunk->contig_hint);
623 pcpu_chunk_relocate(chunk, oslot);
624}
625
626/**
ce3141a2 627 * pcpu_get_pages_and_bitmap - get temp pages array and bitmap
fbf59bc9 628 * @chunk: chunk of interest
ce3141a2
TH
629 * @bitmapp: output parameter for bitmap
630 * @may_alloc: may allocate the array
fbf59bc9 631 *
ce3141a2
TH
632 * Returns pointer to array of pointers to struct page and bitmap,
633 * both of which can be indexed with pcpu_page_idx(). The returned
634 * array is cleared to zero and *@bitmapp is copied from
635 * @chunk->populated. Note that there is only one array and bitmap
636 * and access exclusion is the caller's responsibility.
637 *
638 * CONTEXT:
639 * pcpu_alloc_mutex and does GFP_KERNEL allocation if @may_alloc.
640 * Otherwise, don't care.
641 *
642 * RETURNS:
643 * Pointer to temp pages array on success, NULL on failure.
fbf59bc9 644 */
ce3141a2
TH
645static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
646 unsigned long **bitmapp,
647 bool may_alloc)
fbf59bc9 648{
ce3141a2
TH
649 static struct page **pages;
650 static unsigned long *bitmap;
2f39e637 651 size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
ce3141a2
TH
652 size_t bitmap_size = BITS_TO_LONGS(pcpu_unit_pages) *
653 sizeof(unsigned long);
654
655 if (!pages || !bitmap) {
656 if (may_alloc && !pages)
657 pages = pcpu_mem_alloc(pages_size);
658 if (may_alloc && !bitmap)
659 bitmap = pcpu_mem_alloc(bitmap_size);
660 if (!pages || !bitmap)
661 return NULL;
662 }
fbf59bc9 663
ce3141a2
TH
664 memset(pages, 0, pages_size);
665 bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages);
8d408b4b 666
ce3141a2
TH
667 *bitmapp = bitmap;
668 return pages;
669}
fbf59bc9 670
ce3141a2
TH
671/**
672 * pcpu_free_pages - free pages which were allocated for @chunk
673 * @chunk: chunk pages were allocated for
674 * @pages: array of pages to be freed, indexed by pcpu_page_idx()
675 * @populated: populated bitmap
676 * @page_start: page index of the first page to be freed
677 * @page_end: page index of the last page to be freed + 1
678 *
679 * Free pages [@page_start and @page_end) in @pages for all units.
680 * The pages were allocated for @chunk.
681 */
682static void pcpu_free_pages(struct pcpu_chunk *chunk,
683 struct page **pages, unsigned long *populated,
684 int page_start, int page_end)
685{
686 unsigned int cpu;
687 int i;
688
689 for_each_possible_cpu(cpu) {
690 for (i = page_start; i < page_end; i++) {
691 struct page *page = pages[pcpu_page_idx(cpu, i)];
692
693 if (page)
694 __free_page(page);
695 }
696 }
fbf59bc9
TH
697}
698
699/**
ce3141a2
TH
700 * pcpu_alloc_pages - allocates pages for @chunk
701 * @chunk: target chunk
702 * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
703 * @populated: populated bitmap
704 * @page_start: page index of the first page to be allocated
705 * @page_end: page index of the last page to be allocated + 1
706 *
707 * Allocate pages [@page_start,@page_end) into @pages for all units.
708 * The allocation is for @chunk. Percpu core doesn't care about the
709 * content of @pages and will pass it verbatim to pcpu_map_pages().
fbf59bc9 710 */
ce3141a2
TH
711static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
712 struct page **pages, unsigned long *populated,
713 int page_start, int page_end)
fbf59bc9 714{
ce3141a2 715 const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
fbf59bc9
TH
716 unsigned int cpu;
717 int i;
718
ce3141a2
TH
719 for_each_possible_cpu(cpu) {
720 for (i = page_start; i < page_end; i++) {
721 struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
722
723 *pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
724 if (!*pagep) {
725 pcpu_free_pages(chunk, pages, populated,
726 page_start, page_end);
727 return -ENOMEM;
728 }
729 }
730 }
731 return 0;
732}
fbf59bc9 733
ce3141a2
TH
734/**
735 * pcpu_pre_unmap_flush - flush cache prior to unmapping
736 * @chunk: chunk the regions to be flushed belongs to
737 * @page_start: page index of the first page to be flushed
738 * @page_end: page index of the last page to be flushed + 1
739 *
740 * Pages in [@page_start,@page_end) of @chunk are about to be
741 * unmapped. Flush cache. As each flushing trial can be very
742 * expensive, issue flush on the whole region at once rather than
743 * doing it for each cpu. This could be an overkill but is more
744 * scalable.
745 */
746static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
747 int page_start, int page_end)
748{
2f39e637
TH
749 flush_cache_vunmap(
750 pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
751 pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
ce3141a2
TH
752}
753
754static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
755{
756 unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
757}
fbf59bc9 758
ce3141a2
TH
759/**
760 * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
fbf59bc9 761 * @chunk: chunk of interest
ce3141a2
TH
762 * @pages: pages array which can be used to pass information to free
763 * @populated: populated bitmap
fbf59bc9
TH
764 * @page_start: page index of the first page to unmap
765 * @page_end: page index of the last page to unmap + 1
fbf59bc9
TH
766 *
767 * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
ce3141a2
TH
768 * Corresponding elements in @pages were cleared by the caller and can
769 * be used to carry information to pcpu_free_pages() which will be
770 * called after all unmaps are finished. The caller should call
771 * proper pre/post flush functions.
fbf59bc9 772 */
ce3141a2
TH
773static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
774 struct page **pages, unsigned long *populated,
775 int page_start, int page_end)
fbf59bc9 776{
fbf59bc9 777 unsigned int cpu;
ce3141a2 778 int i;
fbf59bc9 779
ce3141a2
TH
780 for_each_possible_cpu(cpu) {
781 for (i = page_start; i < page_end; i++) {
782 struct page *page;
fbf59bc9 783
ce3141a2
TH
784 page = pcpu_chunk_page(chunk, cpu, i);
785 WARN_ON(!page);
786 pages[pcpu_page_idx(cpu, i)] = page;
fbf59bc9 787 }
ce3141a2
TH
788 __pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
789 page_end - page_start);
fbf59bc9
TH
790 }
791
ce3141a2
TH
792 for (i = page_start; i < page_end; i++)
793 __clear_bit(i, populated);
794}
795
796/**
797 * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
798 * @chunk: pcpu_chunk the regions to be flushed belong to
799 * @page_start: page index of the first page to be flushed
800 * @page_end: page index of the last page to be flushed + 1
801 *
802 * Pages [@page_start,@page_end) of @chunk have been unmapped. Flush
803 * TLB for the regions. This can be skipped if the area is to be
804 * returned to vmalloc as vmalloc will handle TLB flushing lazily.
805 *
806 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
807 * for the whole region.
808 */
809static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
810 int page_start, int page_end)
811{
2f39e637
TH
812 flush_tlb_kernel_range(
813 pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
814 pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
fbf59bc9
TH
815}
816
c8a51be4
TH
817static int __pcpu_map_pages(unsigned long addr, struct page **pages,
818 int nr_pages)
819{
820 return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
821 PAGE_KERNEL, pages);
fbf59bc9
TH
822}
823
824/**
ce3141a2 825 * pcpu_map_pages - map pages into a pcpu_chunk
fbf59bc9 826 * @chunk: chunk of interest
ce3141a2
TH
827 * @pages: pages array containing pages to be mapped
828 * @populated: populated bitmap
fbf59bc9
TH
829 * @page_start: page index of the first page to map
830 * @page_end: page index of the last page to map + 1
831 *
ce3141a2
TH
832 * For each cpu, map pages [@page_start,@page_end) into @chunk. The
833 * caller is responsible for calling pcpu_post_map_flush() after all
834 * mappings are complete.
835 *
836 * This function is responsible for setting corresponding bits in
837 * @chunk->populated bitmap and whatever is necessary for reverse
838 * lookup (addr -> chunk).
fbf59bc9 839 */
ce3141a2
TH
840static int pcpu_map_pages(struct pcpu_chunk *chunk,
841 struct page **pages, unsigned long *populated,
842 int page_start, int page_end)
fbf59bc9 843{
ce3141a2
TH
844 unsigned int cpu, tcpu;
845 int i, err;
8d408b4b 846
fbf59bc9 847 for_each_possible_cpu(cpu) {
c8a51be4 848 err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
ce3141a2 849 &pages[pcpu_page_idx(cpu, page_start)],
c8a51be4 850 page_end - page_start);
fbf59bc9 851 if (err < 0)
ce3141a2 852 goto err;
c8a51be4
TH
853 }
854
ce3141a2
TH
855 /* mapping successful, link chunk and mark populated */
856 for (i = page_start; i < page_end; i++) {
857 for_each_possible_cpu(cpu)
858 pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
859 chunk);
860 __set_bit(i, populated);
fbf59bc9
TH
861 }
862
fbf59bc9 863 return 0;
ce3141a2
TH
864
865err:
866 for_each_possible_cpu(tcpu) {
867 if (tcpu == cpu)
868 break;
869 __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
870 page_end - page_start);
871 }
872 return err;
873}
874
875/**
876 * pcpu_post_map_flush - flush cache after mapping
877 * @chunk: pcpu_chunk the regions to be flushed belong to
878 * @page_start: page index of the first page to be flushed
879 * @page_end: page index of the last page to be flushed + 1
880 *
881 * Pages [@page_start,@page_end) of @chunk have been mapped. Flush
882 * cache.
883 *
884 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
885 * for the whole region.
886 */
887static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
888 int page_start, int page_end)
889{
2f39e637
TH
890 flush_cache_vmap(
891 pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
892 pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
c8a51be4
TH
893}
894
fbf59bc9
TH
895/**
896 * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
897 * @chunk: chunk to depopulate
898 * @off: offset to the area to depopulate
cae3aeb8 899 * @size: size of the area to depopulate in bytes
fbf59bc9
TH
900 * @flush: whether to flush cache and tlb or not
901 *
902 * For each cpu, depopulate and unmap pages [@page_start,@page_end)
903 * from @chunk. If @flush is true, vcache is flushed before unmapping
904 * and tlb after.
ccea34b5
TH
905 *
906 * CONTEXT:
907 * pcpu_alloc_mutex.
fbf59bc9 908 */
ce3141a2 909static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
fbf59bc9
TH
910{
911 int page_start = PFN_DOWN(off);
912 int page_end = PFN_UP(off + size);
ce3141a2
TH
913 struct page **pages;
914 unsigned long *populated;
915 int rs, re;
916
917 /* quick path, check whether it's empty already */
22b737f4
WC
918 rs = page_start;
919 pcpu_next_unpop(chunk, &rs, &re, page_end);
920 if (rs == page_start && re == page_end)
921 return;
fbf59bc9 922
ce3141a2
TH
923 /* immutable chunks can't be depopulated */
924 WARN_ON(chunk->immutable);
fbf59bc9 925
ce3141a2
TH
926 /*
927 * If control reaches here, there must have been at least one
928 * successful population attempt so the temp pages array must
929 * be available now.
930 */
931 pages = pcpu_get_pages_and_bitmap(chunk, &populated, false);
932 BUG_ON(!pages);
fbf59bc9 933
ce3141a2
TH
934 /* unmap and free */
935 pcpu_pre_unmap_flush(chunk, page_start, page_end);
fbf59bc9 936
ce3141a2
TH
937 pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
938 pcpu_unmap_pages(chunk, pages, populated, rs, re);
fbf59bc9 939
ce3141a2
TH
940 /* no need to flush tlb, vmalloc will handle it lazily */
941
942 pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
943 pcpu_free_pages(chunk, pages, populated, rs, re);
fbf59bc9 944
ce3141a2
TH
945 /* commit new bitmap */
946 bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
fbf59bc9
TH
947}
948
949/**
950 * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
951 * @chunk: chunk of interest
952 * @off: offset to the area to populate
cae3aeb8 953 * @size: size of the area to populate in bytes
fbf59bc9
TH
954 *
955 * For each cpu, populate and map pages [@page_start,@page_end) into
956 * @chunk. The area is cleared on return.
ccea34b5
TH
957 *
958 * CONTEXT:
959 * pcpu_alloc_mutex, does GFP_KERNEL allocation.
fbf59bc9
TH
960 */
961static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
962{
fbf59bc9
TH
963 int page_start = PFN_DOWN(off);
964 int page_end = PFN_UP(off + size);
ce3141a2
TH
965 int free_end = page_start, unmap_end = page_start;
966 struct page **pages;
967 unsigned long *populated;
fbf59bc9 968 unsigned int cpu;
ce3141a2 969 int rs, re, rc;
fbf59bc9 970
ce3141a2 971 /* quick path, check whether all pages are already there */
22b737f4
WC
972 rs = page_start;
973 pcpu_next_pop(chunk, &rs, &re, page_end);
974 if (rs == page_start && re == page_end)
975 goto clear;
fbf59bc9 976
ce3141a2
TH
977 /* need to allocate and map pages, this chunk can't be immutable */
978 WARN_ON(chunk->immutable);
fbf59bc9 979
ce3141a2
TH
980 pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
981 if (!pages)
982 return -ENOMEM;
fbf59bc9 983
ce3141a2
TH
984 /* alloc and map */
985 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
986 rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
987 if (rc)
988 goto err_free;
989 free_end = re;
fbf59bc9
TH
990 }
991
ce3141a2
TH
992 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
993 rc = pcpu_map_pages(chunk, pages, populated, rs, re);
994 if (rc)
995 goto err_unmap;
996 unmap_end = re;
997 }
998 pcpu_post_map_flush(chunk, page_start, page_end);
fbf59bc9 999
ce3141a2
TH
1000 /* commit new bitmap */
1001 bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
1002clear:
fbf59bc9 1003 for_each_possible_cpu(cpu)
2f39e637 1004 memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
fbf59bc9 1005 return 0;
ce3141a2
TH
1006
1007err_unmap:
1008 pcpu_pre_unmap_flush(chunk, page_start, unmap_end);
1009 pcpu_for_each_unpop_region(chunk, rs, re, page_start, unmap_end)
1010 pcpu_unmap_pages(chunk, pages, populated, rs, re);
1011 pcpu_post_unmap_tlb_flush(chunk, page_start, unmap_end);
1012err_free:
1013 pcpu_for_each_unpop_region(chunk, rs, re, page_start, free_end)
1014 pcpu_free_pages(chunk, pages, populated, rs, re);
1015 return rc;
fbf59bc9
TH
1016}
1017
1018static void free_pcpu_chunk(struct pcpu_chunk *chunk)
1019{
1020 if (!chunk)
1021 return;
6563297c
TH
1022 if (chunk->vms)
1023 pcpu_free_vm_areas(chunk->vms, pcpu_nr_groups);
1880d93b 1024 pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
fbf59bc9
TH
1025 kfree(chunk);
1026}
1027
1028static struct pcpu_chunk *alloc_pcpu_chunk(void)
1029{
1030 struct pcpu_chunk *chunk;
1031
1032 chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL);
1033 if (!chunk)
1034 return NULL;
1035
1880d93b 1036 chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
fbf59bc9
TH
1037 chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
1038 chunk->map[chunk->map_used++] = pcpu_unit_size;
1039
6563297c
TH
1040 chunk->vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
1041 pcpu_nr_groups, pcpu_atom_size,
1042 GFP_KERNEL);
1043 if (!chunk->vms) {
fbf59bc9
TH
1044 free_pcpu_chunk(chunk);
1045 return NULL;
1046 }
1047
1048 INIT_LIST_HEAD(&chunk->list);
1049 chunk->free_size = pcpu_unit_size;
1050 chunk->contig_hint = pcpu_unit_size;
6563297c 1051 chunk->base_addr = chunk->vms[0]->addr - pcpu_group_offsets[0];
fbf59bc9
TH
1052
1053 return chunk;
1054}
1055
1056/**
edcb4639 1057 * pcpu_alloc - the percpu allocator
cae3aeb8 1058 * @size: size of area to allocate in bytes
fbf59bc9 1059 * @align: alignment of area (max PAGE_SIZE)
edcb4639 1060 * @reserved: allocate from the reserved chunk if available
fbf59bc9 1061 *
ccea34b5
TH
1062 * Allocate percpu area of @size bytes aligned at @align.
1063 *
1064 * CONTEXT:
1065 * Does GFP_KERNEL allocation.
fbf59bc9
TH
1066 *
1067 * RETURNS:
1068 * Percpu pointer to the allocated area on success, NULL on failure.
1069 */
43cf38eb 1070static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
fbf59bc9 1071{
f2badb0c 1072 static int warn_limit = 10;
fbf59bc9 1073 struct pcpu_chunk *chunk;
f2badb0c 1074 const char *err;
833af842 1075 int slot, off, new_alloc;
403a91b1 1076 unsigned long flags;
fbf59bc9 1077
8d408b4b 1078 if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
fbf59bc9
TH
1079 WARN(true, "illegal size (%zu) or align (%zu) for "
1080 "percpu allocation\n", size, align);
1081 return NULL;
1082 }
1083
ccea34b5 1084 mutex_lock(&pcpu_alloc_mutex);
403a91b1 1085 spin_lock_irqsave(&pcpu_lock, flags);
fbf59bc9 1086
edcb4639
TH
1087 /* serve reserved allocations from the reserved chunk if available */
1088 if (reserved && pcpu_reserved_chunk) {
1089 chunk = pcpu_reserved_chunk;
833af842
TH
1090
1091 if (size > chunk->contig_hint) {
1092 err = "alloc from reserved chunk failed";
ccea34b5 1093 goto fail_unlock;
f2badb0c 1094 }
833af842
TH
1095
1096 while ((new_alloc = pcpu_need_to_extend(chunk))) {
1097 spin_unlock_irqrestore(&pcpu_lock, flags);
1098 if (pcpu_extend_area_map(chunk, new_alloc) < 0) {
1099 err = "failed to extend area map of reserved chunk";
1100 goto fail_unlock_mutex;
1101 }
1102 spin_lock_irqsave(&pcpu_lock, flags);
1103 }
1104
edcb4639
TH
1105 off = pcpu_alloc_area(chunk, size, align);
1106 if (off >= 0)
1107 goto area_found;
833af842 1108
f2badb0c 1109 err = "alloc from reserved chunk failed";
ccea34b5 1110 goto fail_unlock;
edcb4639
TH
1111 }
1112
ccea34b5 1113restart:
edcb4639 1114 /* search through normal chunks */
fbf59bc9
TH
1115 for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
1116 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
1117 if (size > chunk->contig_hint)
1118 continue;
ccea34b5 1119
833af842
TH
1120 new_alloc = pcpu_need_to_extend(chunk);
1121 if (new_alloc) {
1122 spin_unlock_irqrestore(&pcpu_lock, flags);
1123 if (pcpu_extend_area_map(chunk,
1124 new_alloc) < 0) {
1125 err = "failed to extend area map";
1126 goto fail_unlock_mutex;
1127 }
1128 spin_lock_irqsave(&pcpu_lock, flags);
1129 /*
1130 * pcpu_lock has been dropped, need to
1131 * restart cpu_slot list walking.
1132 */
1133 goto restart;
ccea34b5
TH
1134 }
1135
fbf59bc9
TH
1136 off = pcpu_alloc_area(chunk, size, align);
1137 if (off >= 0)
1138 goto area_found;
fbf59bc9
TH
1139 }
1140 }
1141
1142 /* hmmm... no space left, create a new chunk */
403a91b1 1143 spin_unlock_irqrestore(&pcpu_lock, flags);
ccea34b5 1144
fbf59bc9 1145 chunk = alloc_pcpu_chunk();
f2badb0c
TH
1146 if (!chunk) {
1147 err = "failed to allocate new chunk";
ccea34b5 1148 goto fail_unlock_mutex;
f2badb0c 1149 }
ccea34b5 1150
403a91b1 1151 spin_lock_irqsave(&pcpu_lock, flags);
fbf59bc9 1152 pcpu_chunk_relocate(chunk, -1);
ccea34b5 1153 goto restart;
fbf59bc9
TH
1154
1155area_found:
403a91b1 1156 spin_unlock_irqrestore(&pcpu_lock, flags);
ccea34b5 1157
fbf59bc9
TH
1158 /* populate, map and clear the area */
1159 if (pcpu_populate_chunk(chunk, off, size)) {
403a91b1 1160 spin_lock_irqsave(&pcpu_lock, flags);
fbf59bc9 1161 pcpu_free_area(chunk, off);
f2badb0c 1162 err = "failed to populate";
ccea34b5 1163 goto fail_unlock;
fbf59bc9
TH
1164 }
1165
ccea34b5
TH
1166 mutex_unlock(&pcpu_alloc_mutex);
1167
bba174f5
TH
1168 /* return address relative to base address */
1169 return __addr_to_pcpu_ptr(chunk->base_addr + off);
ccea34b5
TH
1170
1171fail_unlock:
403a91b1 1172 spin_unlock_irqrestore(&pcpu_lock, flags);
ccea34b5
TH
1173fail_unlock_mutex:
1174 mutex_unlock(&pcpu_alloc_mutex);
f2badb0c
TH
1175 if (warn_limit) {
1176 pr_warning("PERCPU: allocation failed, size=%zu align=%zu, "
1177 "%s\n", size, align, err);
1178 dump_stack();
1179 if (!--warn_limit)
1180 pr_info("PERCPU: limit reached, disable warning\n");
1181 }
ccea34b5 1182 return NULL;
fbf59bc9 1183}
edcb4639
TH
1184
1185/**
1186 * __alloc_percpu - allocate dynamic percpu area
1187 * @size: size of area to allocate in bytes
1188 * @align: alignment of area (max PAGE_SIZE)
1189 *
1190 * Allocate percpu area of @size bytes aligned at @align. Might
1191 * sleep. Might trigger writeouts.
1192 *
ccea34b5
TH
1193 * CONTEXT:
1194 * Does GFP_KERNEL allocation.
1195 *
edcb4639
TH
1196 * RETURNS:
1197 * Percpu pointer to the allocated area on success, NULL on failure.
1198 */
43cf38eb 1199void __percpu *__alloc_percpu(size_t size, size_t align)
edcb4639
TH
1200{
1201 return pcpu_alloc(size, align, false);
1202}
fbf59bc9
TH
1203EXPORT_SYMBOL_GPL(__alloc_percpu);
1204
edcb4639
TH
1205/**
1206 * __alloc_reserved_percpu - allocate reserved percpu area
1207 * @size: size of area to allocate in bytes
1208 * @align: alignment of area (max PAGE_SIZE)
1209 *
1210 * Allocate percpu area of @size bytes aligned at @align from reserved
1211 * percpu area if arch has set it up; otherwise, allocation is served
1212 * from the same dynamic area. Might sleep. Might trigger writeouts.
1213 *
ccea34b5
TH
1214 * CONTEXT:
1215 * Does GFP_KERNEL allocation.
1216 *
edcb4639
TH
1217 * RETURNS:
1218 * Percpu pointer to the allocated area on success, NULL on failure.
1219 */
43cf38eb 1220void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
edcb4639
TH
1221{
1222 return pcpu_alloc(size, align, true);
1223}
1224
a56dbddf
TH
1225/**
1226 * pcpu_reclaim - reclaim fully free chunks, workqueue function
1227 * @work: unused
1228 *
1229 * Reclaim all fully free chunks except for the first one.
ccea34b5
TH
1230 *
1231 * CONTEXT:
1232 * workqueue context.
a56dbddf
TH
1233 */
1234static void pcpu_reclaim(struct work_struct *work)
fbf59bc9 1235{
a56dbddf
TH
1236 LIST_HEAD(todo);
1237 struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1];
1238 struct pcpu_chunk *chunk, *next;
1239
ccea34b5
TH
1240 mutex_lock(&pcpu_alloc_mutex);
1241 spin_lock_irq(&pcpu_lock);
a56dbddf
TH
1242
1243 list_for_each_entry_safe(chunk, next, head, list) {
1244 WARN_ON(chunk->immutable);
1245
1246 /* spare the first one */
1247 if (chunk == list_first_entry(head, struct pcpu_chunk, list))
1248 continue;
1249
a56dbddf
TH
1250 list_move(&chunk->list, &todo);
1251 }
1252
ccea34b5 1253 spin_unlock_irq(&pcpu_lock);
a56dbddf
TH
1254
1255 list_for_each_entry_safe(chunk, next, &todo, list) {
ce3141a2 1256 pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
a56dbddf
TH
1257 free_pcpu_chunk(chunk);
1258 }
971f3918
TH
1259
1260 mutex_unlock(&pcpu_alloc_mutex);
fbf59bc9
TH
1261}
1262
1263/**
1264 * free_percpu - free percpu area
1265 * @ptr: pointer to area to free
1266 *
ccea34b5
TH
1267 * Free percpu area @ptr.
1268 *
1269 * CONTEXT:
1270 * Can be called from atomic context.
fbf59bc9 1271 */
43cf38eb 1272void free_percpu(void __percpu *ptr)
fbf59bc9 1273{
129182e5 1274 void *addr;
fbf59bc9 1275 struct pcpu_chunk *chunk;
ccea34b5 1276 unsigned long flags;
fbf59bc9
TH
1277 int off;
1278
1279 if (!ptr)
1280 return;
1281
129182e5
AM
1282 addr = __pcpu_ptr_to_addr(ptr);
1283
ccea34b5 1284 spin_lock_irqsave(&pcpu_lock, flags);
fbf59bc9
TH
1285
1286 chunk = pcpu_chunk_addr_search(addr);
bba174f5 1287 off = addr - chunk->base_addr;
fbf59bc9
TH
1288
1289 pcpu_free_area(chunk, off);
1290
a56dbddf 1291 /* if there are more than one fully free chunks, wake up grim reaper */
fbf59bc9
TH
1292 if (chunk->free_size == pcpu_unit_size) {
1293 struct pcpu_chunk *pos;
1294
a56dbddf 1295 list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
fbf59bc9 1296 if (pos != chunk) {
a56dbddf 1297 schedule_work(&pcpu_reclaim_work);
fbf59bc9
TH
1298 break;
1299 }
1300 }
1301
ccea34b5 1302 spin_unlock_irqrestore(&pcpu_lock, flags);
fbf59bc9
TH
1303}
1304EXPORT_SYMBOL_GPL(free_percpu);
1305
10fad5e4
TH
1306/**
1307 * is_kernel_percpu_address - test whether address is from static percpu area
1308 * @addr: address to test
1309 *
1310 * Test whether @addr belongs to in-kernel static percpu area. Module
1311 * static percpu areas are not considered. For those, use
1312 * is_module_percpu_address().
1313 *
1314 * RETURNS:
1315 * %true if @addr is from in-kernel static percpu area, %false otherwise.
1316 */
1317bool is_kernel_percpu_address(unsigned long addr)
1318{
1319 const size_t static_size = __per_cpu_end - __per_cpu_start;
1320 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
1321 unsigned int cpu;
1322
1323 for_each_possible_cpu(cpu) {
1324 void *start = per_cpu_ptr(base, cpu);
1325
1326 if ((void *)addr >= start && (void *)addr < start + static_size)
1327 return true;
1328 }
1329 return false;
1330}
1331
3b034b0d
VG
1332/**
1333 * per_cpu_ptr_to_phys - convert translated percpu address to physical address
1334 * @addr: the address to be converted to physical address
1335 *
1336 * Given @addr which is dereferenceable address obtained via one of
1337 * percpu access macros, this function translates it into its physical
1338 * address. The caller is responsible for ensuring @addr stays valid
1339 * until this function finishes.
1340 *
1341 * RETURNS:
1342 * The physical address for @addr.
1343 */
1344phys_addr_t per_cpu_ptr_to_phys(void *addr)
1345{
1346 if ((unsigned long)addr < VMALLOC_START ||
1347 (unsigned long)addr >= VMALLOC_END)
1348 return __pa(addr);
1349 else
1350 return page_to_phys(vmalloc_to_page(addr));
1351}
1352
033e48fb
TH
1353static inline size_t pcpu_calc_fc_sizes(size_t static_size,
1354 size_t reserved_size,
1355 ssize_t *dyn_sizep)
1356{
1357 size_t size_sum;
1358
1359 size_sum = PFN_ALIGN(static_size + reserved_size +
1360 (*dyn_sizep >= 0 ? *dyn_sizep : 0));
1361 if (*dyn_sizep != 0)
1362 *dyn_sizep = size_sum - static_size - reserved_size;
1363
1364 return size_sum;
1365}
1366
fbf59bc9 1367/**
fd1e8a1f
TH
1368 * pcpu_alloc_alloc_info - allocate percpu allocation info
1369 * @nr_groups: the number of groups
1370 * @nr_units: the number of units
1371 *
1372 * Allocate ai which is large enough for @nr_groups groups containing
1373 * @nr_units units. The returned ai's groups[0].cpu_map points to the
1374 * cpu_map array which is long enough for @nr_units and filled with
1375 * NR_CPUS. It's the caller's responsibility to initialize cpu_map
1376 * pointer of other groups.
1377 *
1378 * RETURNS:
1379 * Pointer to the allocated pcpu_alloc_info on success, NULL on
1380 * failure.
1381 */
1382struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
1383 int nr_units)
1384{
1385 struct pcpu_alloc_info *ai;
1386 size_t base_size, ai_size;
1387 void *ptr;
1388 int unit;
1389
1390 base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
1391 __alignof__(ai->groups[0].cpu_map[0]));
1392 ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
1393
1394 ptr = alloc_bootmem_nopanic(PFN_ALIGN(ai_size));
1395 if (!ptr)
1396 return NULL;
1397 ai = ptr;
1398 ptr += base_size;
1399
1400 ai->groups[0].cpu_map = ptr;
1401
1402 for (unit = 0; unit < nr_units; unit++)
1403 ai->groups[0].cpu_map[unit] = NR_CPUS;
1404
1405 ai->nr_groups = nr_groups;
1406 ai->__ai_size = PFN_ALIGN(ai_size);
1407
1408 return ai;
1409}
1410
1411/**
1412 * pcpu_free_alloc_info - free percpu allocation info
1413 * @ai: pcpu_alloc_info to free
1414 *
1415 * Free @ai which was allocated by pcpu_alloc_alloc_info().
1416 */
1417void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
1418{
1419 free_bootmem(__pa(ai), ai->__ai_size);
1420}
1421
1422/**
1423 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
edcb4639 1424 * @reserved_size: the size of reserved percpu area in bytes
cafe8816 1425 * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
fd1e8a1f
TH
1426 * @atom_size: allocation atom size
1427 * @cpu_distance_fn: callback to determine distance between cpus, optional
033e48fb 1428 *
fd1e8a1f
TH
1429 * This function determines grouping of units, their mappings to cpus
1430 * and other parameters considering needed percpu size, allocation
1431 * atom size and distances between CPUs.
033e48fb 1432 *
fd1e8a1f
TH
1433 * Groups are always mutliples of atom size and CPUs which are of
1434 * LOCAL_DISTANCE both ways are grouped together and share space for
1435 * units in the same group. The returned configuration is guaranteed
1436 * to have CPUs on different nodes on different groups and >=75% usage
1437 * of allocated virtual address space.
033e48fb
TH
1438 *
1439 * RETURNS:
fd1e8a1f
TH
1440 * On success, pointer to the new allocation_info is returned. On
1441 * failure, ERR_PTR value is returned.
033e48fb 1442 */
fd1e8a1f
TH
1443struct pcpu_alloc_info * __init pcpu_build_alloc_info(
1444 size_t reserved_size, ssize_t dyn_size,
1445 size_t atom_size,
1446 pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
033e48fb
TH
1447{
1448 static int group_map[NR_CPUS] __initdata;
1449 static int group_cnt[NR_CPUS] __initdata;
1450 const size_t static_size = __per_cpu_end - __per_cpu_start;
fd1e8a1f 1451 int group_cnt_max = 0, nr_groups = 1, nr_units = 0;
033e48fb
TH
1452 size_t size_sum, min_unit_size, alloc_size;
1453 int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
fd1e8a1f 1454 int last_allocs, group, unit;
033e48fb 1455 unsigned int cpu, tcpu;
fd1e8a1f
TH
1456 struct pcpu_alloc_info *ai;
1457 unsigned int *cpu_map;
033e48fb 1458
fb59e72e
TH
1459 /* this function may be called multiple times */
1460 memset(group_map, 0, sizeof(group_map));
1461 memset(group_cnt, 0, sizeof(group_map));
1462
033e48fb
TH
1463 /*
1464 * Determine min_unit_size, alloc_size and max_upa such that
fd1e8a1f 1465 * alloc_size is multiple of atom_size and is the smallest
033e48fb
TH
1466 * which can accomodate 4k aligned segments which are equal to
1467 * or larger than min_unit_size.
1468 */
fd1e8a1f 1469 size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
033e48fb
TH
1470 min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
1471
fd1e8a1f 1472 alloc_size = roundup(min_unit_size, atom_size);
033e48fb
TH
1473 upa = alloc_size / min_unit_size;
1474 while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1475 upa--;
1476 max_upa = upa;
1477
1478 /* group cpus according to their proximity */
1479 for_each_possible_cpu(cpu) {
1480 group = 0;
1481 next_group:
1482 for_each_possible_cpu(tcpu) {
1483 if (cpu == tcpu)
1484 break;
fd1e8a1f 1485 if (group_map[tcpu] == group && cpu_distance_fn &&
033e48fb
TH
1486 (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
1487 cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
1488 group++;
fd1e8a1f 1489 nr_groups = max(nr_groups, group + 1);
033e48fb
TH
1490 goto next_group;
1491 }
1492 }
1493 group_map[cpu] = group;
1494 group_cnt[group]++;
1495 group_cnt_max = max(group_cnt_max, group_cnt[group]);
1496 }
1497
1498 /*
1499 * Expand unit size until address space usage goes over 75%
1500 * and then as much as possible without using more address
1501 * space.
1502 */
1503 last_allocs = INT_MAX;
1504 for (upa = max_upa; upa; upa--) {
1505 int allocs = 0, wasted = 0;
1506
1507 if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1508 continue;
1509
fd1e8a1f 1510 for (group = 0; group < nr_groups; group++) {
033e48fb
TH
1511 int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
1512 allocs += this_allocs;
1513 wasted += this_allocs * upa - group_cnt[group];
1514 }
1515
1516 /*
1517 * Don't accept if wastage is over 25%. The
1518 * greater-than comparison ensures upa==1 always
1519 * passes the following check.
1520 */
1521 if (wasted > num_possible_cpus() / 3)
1522 continue;
1523
1524 /* and then don't consume more memory */
1525 if (allocs > last_allocs)
1526 break;
1527 last_allocs = allocs;
1528 best_upa = upa;
1529 }
fd1e8a1f
TH
1530 upa = best_upa;
1531
1532 /* allocate and fill alloc_info */
1533 for (group = 0; group < nr_groups; group++)
1534 nr_units += roundup(group_cnt[group], upa);
1535
1536 ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
1537 if (!ai)
1538 return ERR_PTR(-ENOMEM);
1539 cpu_map = ai->groups[0].cpu_map;
1540
1541 for (group = 0; group < nr_groups; group++) {
1542 ai->groups[group].cpu_map = cpu_map;
1543 cpu_map += roundup(group_cnt[group], upa);
1544 }
1545
1546 ai->static_size = static_size;
1547 ai->reserved_size = reserved_size;
1548 ai->dyn_size = dyn_size;
1549 ai->unit_size = alloc_size / upa;
1550 ai->atom_size = atom_size;
1551 ai->alloc_size = alloc_size;
1552
1553 for (group = 0, unit = 0; group_cnt[group]; group++) {
1554 struct pcpu_group_info *gi = &ai->groups[group];
1555
1556 /*
1557 * Initialize base_offset as if all groups are located
1558 * back-to-back. The caller should update this to
1559 * reflect actual allocation.
1560 */
1561 gi->base_offset = unit * ai->unit_size;
033e48fb 1562
033e48fb
TH
1563 for_each_possible_cpu(cpu)
1564 if (group_map[cpu] == group)
fd1e8a1f
TH
1565 gi->cpu_map[gi->nr_units++] = cpu;
1566 gi->nr_units = roundup(gi->nr_units, upa);
1567 unit += gi->nr_units;
033e48fb 1568 }
fd1e8a1f 1569 BUG_ON(unit != nr_units);
033e48fb 1570
fd1e8a1f 1571 return ai;
033e48fb
TH
1572}
1573
fd1e8a1f
TH
1574/**
1575 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
1576 * @lvl: loglevel
1577 * @ai: allocation info to dump
1578 *
1579 * Print out information about @ai using loglevel @lvl.
1580 */
1581static void pcpu_dump_alloc_info(const char *lvl,
1582 const struct pcpu_alloc_info *ai)
033e48fb 1583{
fd1e8a1f 1584 int group_width = 1, cpu_width = 1, width;
033e48fb 1585 char empty_str[] = "--------";
fd1e8a1f
TH
1586 int alloc = 0, alloc_end = 0;
1587 int group, v;
1588 int upa, apl; /* units per alloc, allocs per line */
1589
1590 v = ai->nr_groups;
1591 while (v /= 10)
1592 group_width++;
033e48fb 1593
fd1e8a1f 1594 v = num_possible_cpus();
033e48fb 1595 while (v /= 10)
fd1e8a1f
TH
1596 cpu_width++;
1597 empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
033e48fb 1598
fd1e8a1f
TH
1599 upa = ai->alloc_size / ai->unit_size;
1600 width = upa * (cpu_width + 1) + group_width + 3;
1601 apl = rounddown_pow_of_two(max(60 / width, 1));
033e48fb 1602
fd1e8a1f
TH
1603 printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
1604 lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
1605 ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
033e48fb 1606
fd1e8a1f
TH
1607 for (group = 0; group < ai->nr_groups; group++) {
1608 const struct pcpu_group_info *gi = &ai->groups[group];
1609 int unit = 0, unit_end = 0;
1610
1611 BUG_ON(gi->nr_units % upa);
1612 for (alloc_end += gi->nr_units / upa;
1613 alloc < alloc_end; alloc++) {
1614 if (!(alloc % apl)) {
033e48fb 1615 printk("\n");
fd1e8a1f
TH
1616 printk("%spcpu-alloc: ", lvl);
1617 }
1618 printk("[%0*d] ", group_width, group);
1619
1620 for (unit_end += upa; unit < unit_end; unit++)
1621 if (gi->cpu_map[unit] != NR_CPUS)
1622 printk("%0*d ", cpu_width,
1623 gi->cpu_map[unit]);
1624 else
1625 printk("%s ", empty_str);
033e48fb 1626 }
033e48fb
TH
1627 }
1628 printk("\n");
1629}
033e48fb 1630
fbf59bc9 1631/**
8d408b4b 1632 * pcpu_setup_first_chunk - initialize the first percpu chunk
fd1e8a1f 1633 * @ai: pcpu_alloc_info describing how to percpu area is shaped
38a6be52 1634 * @base_addr: mapped address
8d408b4b
TH
1635 *
1636 * Initialize the first percpu chunk which contains the kernel static
1637 * perpcu area. This function is to be called from arch percpu area
38a6be52 1638 * setup path.
8d408b4b 1639 *
fd1e8a1f
TH
1640 * @ai contains all information necessary to initialize the first
1641 * chunk and prime the dynamic percpu allocator.
1642 *
1643 * @ai->static_size is the size of static percpu area.
1644 *
1645 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
edcb4639
TH
1646 * reserve after the static area in the first chunk. This reserves
1647 * the first chunk such that it's available only through reserved
1648 * percpu allocation. This is primarily used to serve module percpu
1649 * static areas on architectures where the addressing model has
1650 * limited offset range for symbol relocations to guarantee module
1651 * percpu symbols fall inside the relocatable range.
1652 *
fd1e8a1f
TH
1653 * @ai->dyn_size determines the number of bytes available for dynamic
1654 * allocation in the first chunk. The area between @ai->static_size +
1655 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
6074d5b0 1656 *
fd1e8a1f
TH
1657 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
1658 * and equal to or larger than @ai->static_size + @ai->reserved_size +
1659 * @ai->dyn_size.
8d408b4b 1660 *
fd1e8a1f
TH
1661 * @ai->atom_size is the allocation atom size and used as alignment
1662 * for vm areas.
8d408b4b 1663 *
fd1e8a1f
TH
1664 * @ai->alloc_size is the allocation size and always multiple of
1665 * @ai->atom_size. This is larger than @ai->atom_size if
1666 * @ai->unit_size is larger than @ai->atom_size.
1667 *
1668 * @ai->nr_groups and @ai->groups describe virtual memory layout of
1669 * percpu areas. Units which should be colocated are put into the
1670 * same group. Dynamic VM areas will be allocated according to these
1671 * groupings. If @ai->nr_groups is zero, a single group containing
1672 * all units is assumed.
8d408b4b 1673 *
38a6be52
TH
1674 * The caller should have mapped the first chunk at @base_addr and
1675 * copied static data to each unit.
fbf59bc9 1676 *
edcb4639
TH
1677 * If the first chunk ends up with both reserved and dynamic areas, it
1678 * is served by two chunks - one to serve the core static and reserved
1679 * areas and the other for the dynamic area. They share the same vm
1680 * and page map but uses different area allocation map to stay away
1681 * from each other. The latter chunk is circulated in the chunk slots
1682 * and available for dynamic allocation like any other chunks.
1683 *
fbf59bc9 1684 * RETURNS:
fb435d52 1685 * 0 on success, -errno on failure.
fbf59bc9 1686 */
fb435d52
TH
1687int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
1688 void *base_addr)
fbf59bc9 1689{
635b75fc 1690 static char cpus_buf[4096] __initdata;
edcb4639 1691 static int smap[2], dmap[2];
fd1e8a1f
TH
1692 size_t dyn_size = ai->dyn_size;
1693 size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
edcb4639 1694 struct pcpu_chunk *schunk, *dchunk = NULL;
6563297c
TH
1695 unsigned long *group_offsets;
1696 size_t *group_sizes;
fb435d52 1697 unsigned long *unit_off;
fbf59bc9 1698 unsigned int cpu;
fd1e8a1f
TH
1699 int *unit_map;
1700 int group, unit, i;
fbf59bc9 1701
635b75fc
TH
1702 cpumask_scnprintf(cpus_buf, sizeof(cpus_buf), cpu_possible_mask);
1703
1704#define PCPU_SETUP_BUG_ON(cond) do { \
1705 if (unlikely(cond)) { \
1706 pr_emerg("PERCPU: failed to initialize, %s", #cond); \
1707 pr_emerg("PERCPU: cpu_possible_mask=%s\n", cpus_buf); \
1708 pcpu_dump_alloc_info(KERN_EMERG, ai); \
1709 BUG(); \
1710 } \
1711} while (0)
1712
2f39e637 1713 /* sanity checks */
edcb4639
TH
1714 BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
1715 ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
635b75fc
TH
1716 PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
1717 PCPU_SETUP_BUG_ON(!ai->static_size);
1718 PCPU_SETUP_BUG_ON(!base_addr);
1719 PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
1720 PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
1721 PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
8d408b4b 1722
6563297c
TH
1723 /* process group information and build config tables accordingly */
1724 group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0]));
1725 group_sizes = alloc_bootmem(ai->nr_groups * sizeof(group_sizes[0]));
fd1e8a1f 1726 unit_map = alloc_bootmem(nr_cpu_ids * sizeof(unit_map[0]));
fb435d52 1727 unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0]));
2f39e637 1728
fd1e8a1f 1729 for (cpu = 0; cpu < nr_cpu_ids; cpu++)
ffe0d5a5 1730 unit_map[cpu] = UINT_MAX;
fd1e8a1f 1731 pcpu_first_unit_cpu = NR_CPUS;
2f39e637 1732
fd1e8a1f
TH
1733 for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
1734 const struct pcpu_group_info *gi = &ai->groups[group];
2f39e637 1735
6563297c
TH
1736 group_offsets[group] = gi->base_offset;
1737 group_sizes[group] = gi->nr_units * ai->unit_size;
1738
fd1e8a1f
TH
1739 for (i = 0; i < gi->nr_units; i++) {
1740 cpu = gi->cpu_map[i];
1741 if (cpu == NR_CPUS)
1742 continue;
8d408b4b 1743
635b75fc
TH
1744 PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids);
1745 PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
1746 PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
fbf59bc9 1747
fd1e8a1f 1748 unit_map[cpu] = unit + i;
fb435d52
TH
1749 unit_off[cpu] = gi->base_offset + i * ai->unit_size;
1750
fd1e8a1f
TH
1751 if (pcpu_first_unit_cpu == NR_CPUS)
1752 pcpu_first_unit_cpu = cpu;
1753 }
2f39e637 1754 }
fd1e8a1f
TH
1755 pcpu_last_unit_cpu = cpu;
1756 pcpu_nr_units = unit;
1757
1758 for_each_possible_cpu(cpu)
635b75fc
TH
1759 PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
1760
1761 /* we're done parsing the input, undefine BUG macro and dump config */
1762#undef PCPU_SETUP_BUG_ON
1763 pcpu_dump_alloc_info(KERN_INFO, ai);
fd1e8a1f 1764
6563297c
TH
1765 pcpu_nr_groups = ai->nr_groups;
1766 pcpu_group_offsets = group_offsets;
1767 pcpu_group_sizes = group_sizes;
fd1e8a1f 1768 pcpu_unit_map = unit_map;
fb435d52 1769 pcpu_unit_offsets = unit_off;
2f39e637
TH
1770
1771 /* determine basic parameters */
fd1e8a1f 1772 pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
d9b55eeb 1773 pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
6563297c 1774 pcpu_atom_size = ai->atom_size;
ce3141a2
TH
1775 pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
1776 BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
cafe8816 1777
d9b55eeb
TH
1778 /*
1779 * Allocate chunk slots. The additional last slot is for
1780 * empty chunks.
1781 */
1782 pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
fbf59bc9
TH
1783 pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0]));
1784 for (i = 0; i < pcpu_nr_slots; i++)
1785 INIT_LIST_HEAD(&pcpu_slot[i]);
1786
edcb4639
TH
1787 /*
1788 * Initialize static chunk. If reserved_size is zero, the
1789 * static chunk covers static area + dynamic allocation area
1790 * in the first chunk. If reserved_size is not zero, it
1791 * covers static area + reserved area (mostly used for module
1792 * static percpu allocation).
1793 */
2441d15c
TH
1794 schunk = alloc_bootmem(pcpu_chunk_struct_size);
1795 INIT_LIST_HEAD(&schunk->list);
bba174f5 1796 schunk->base_addr = base_addr;
61ace7fa
TH
1797 schunk->map = smap;
1798 schunk->map_alloc = ARRAY_SIZE(smap);
38a6be52 1799 schunk->immutable = true;
ce3141a2 1800 bitmap_fill(schunk->populated, pcpu_unit_pages);
edcb4639 1801
fd1e8a1f
TH
1802 if (ai->reserved_size) {
1803 schunk->free_size = ai->reserved_size;
ae9e6bc9 1804 pcpu_reserved_chunk = schunk;
fd1e8a1f 1805 pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
edcb4639
TH
1806 } else {
1807 schunk->free_size = dyn_size;
1808 dyn_size = 0; /* dynamic area covered */
1809 }
2441d15c 1810 schunk->contig_hint = schunk->free_size;
fbf59bc9 1811
fd1e8a1f 1812 schunk->map[schunk->map_used++] = -ai->static_size;
61ace7fa
TH
1813 if (schunk->free_size)
1814 schunk->map[schunk->map_used++] = schunk->free_size;
1815
edcb4639
TH
1816 /* init dynamic chunk if necessary */
1817 if (dyn_size) {
ce3141a2 1818 dchunk = alloc_bootmem(pcpu_chunk_struct_size);
edcb4639 1819 INIT_LIST_HEAD(&dchunk->list);
bba174f5 1820 dchunk->base_addr = base_addr;
edcb4639
TH
1821 dchunk->map = dmap;
1822 dchunk->map_alloc = ARRAY_SIZE(dmap);
38a6be52 1823 dchunk->immutable = true;
ce3141a2 1824 bitmap_fill(dchunk->populated, pcpu_unit_pages);
edcb4639
TH
1825
1826 dchunk->contig_hint = dchunk->free_size = dyn_size;
1827 dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit;
1828 dchunk->map[dchunk->map_used++] = dchunk->free_size;
1829 }
1830
2441d15c 1831 /* link the first chunk in */
ae9e6bc9
TH
1832 pcpu_first_chunk = dchunk ?: schunk;
1833 pcpu_chunk_relocate(pcpu_first_chunk, -1);
fbf59bc9
TH
1834
1835 /* we're done */
bba174f5 1836 pcpu_base_addr = base_addr;
fb435d52 1837 return 0;
fbf59bc9 1838}
66c3a757 1839
f58dc01b
TH
1840const char *pcpu_fc_names[PCPU_FC_NR] __initdata = {
1841 [PCPU_FC_AUTO] = "auto",
1842 [PCPU_FC_EMBED] = "embed",
1843 [PCPU_FC_PAGE] = "page",
f58dc01b 1844};
66c3a757 1845
f58dc01b 1846enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
66c3a757 1847
f58dc01b
TH
1848static int __init percpu_alloc_setup(char *str)
1849{
1850 if (0)
1851 /* nada */;
1852#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
1853 else if (!strcmp(str, "embed"))
1854 pcpu_chosen_fc = PCPU_FC_EMBED;
1855#endif
1856#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1857 else if (!strcmp(str, "page"))
1858 pcpu_chosen_fc = PCPU_FC_PAGE;
f58dc01b
TH
1859#endif
1860 else
1861 pr_warning("PERCPU: unknown allocator %s specified\n", str);
66c3a757 1862
f58dc01b 1863 return 0;
66c3a757 1864}
f58dc01b 1865early_param("percpu_alloc", percpu_alloc_setup);
66c3a757 1866
08fc4580
TH
1867#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
1868 !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
66c3a757
TH
1869/**
1870 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
66c3a757
TH
1871 * @reserved_size: the size of reserved percpu area in bytes
1872 * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
c8826dd5
TH
1873 * @atom_size: allocation atom size
1874 * @cpu_distance_fn: callback to determine distance between cpus, optional
1875 * @alloc_fn: function to allocate percpu page
1876 * @free_fn: funtion to free percpu page
66c3a757
TH
1877 *
1878 * This is a helper to ease setting up embedded first percpu chunk and
1879 * can be called where pcpu_setup_first_chunk() is expected.
1880 *
1881 * If this function is used to setup the first chunk, it is allocated
c8826dd5
TH
1882 * by calling @alloc_fn and used as-is without being mapped into
1883 * vmalloc area. Allocations are always whole multiples of @atom_size
1884 * aligned to @atom_size.
1885 *
1886 * This enables the first chunk to piggy back on the linear physical
1887 * mapping which often uses larger page size. Please note that this
1888 * can result in very sparse cpu->unit mapping on NUMA machines thus
1889 * requiring large vmalloc address space. Don't use this allocator if
1890 * vmalloc space is not orders of magnitude larger than distances
1891 * between node memory addresses (ie. 32bit NUMA machines).
66c3a757
TH
1892 *
1893 * When @dyn_size is positive, dynamic area might be larger than
788e5abc
TH
1894 * specified to fill page alignment. When @dyn_size is auto,
1895 * @dyn_size is just big enough to fill page alignment after static
1896 * and reserved areas.
66c3a757
TH
1897 *
1898 * If the needed size is smaller than the minimum or specified unit
c8826dd5 1899 * size, the leftover is returned using @free_fn.
66c3a757
TH
1900 *
1901 * RETURNS:
fb435d52 1902 * 0 on success, -errno on failure.
66c3a757 1903 */
c8826dd5
TH
1904int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
1905 size_t atom_size,
1906 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
1907 pcpu_fc_alloc_fn_t alloc_fn,
1908 pcpu_fc_free_fn_t free_fn)
66c3a757 1909{
c8826dd5
TH
1910 void *base = (void *)ULONG_MAX;
1911 void **areas = NULL;
fd1e8a1f 1912 struct pcpu_alloc_info *ai;
6ea529a2 1913 size_t size_sum, areas_size, max_distance;
c8826dd5 1914 int group, i, rc;
66c3a757 1915
c8826dd5
TH
1916 ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
1917 cpu_distance_fn);
fd1e8a1f
TH
1918 if (IS_ERR(ai))
1919 return PTR_ERR(ai);
66c3a757 1920
fd1e8a1f 1921 size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
c8826dd5 1922 areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
fa8a7094 1923
c8826dd5
TH
1924 areas = alloc_bootmem_nopanic(areas_size);
1925 if (!areas) {
fb435d52 1926 rc = -ENOMEM;
c8826dd5 1927 goto out_free;
fa8a7094 1928 }
66c3a757 1929
c8826dd5
TH
1930 /* allocate, copy and determine base address */
1931 for (group = 0; group < ai->nr_groups; group++) {
1932 struct pcpu_group_info *gi = &ai->groups[group];
1933 unsigned int cpu = NR_CPUS;
1934 void *ptr;
1935
1936 for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
1937 cpu = gi->cpu_map[i];
1938 BUG_ON(cpu == NR_CPUS);
1939
1940 /* allocate space for the whole group */
1941 ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
1942 if (!ptr) {
1943 rc = -ENOMEM;
1944 goto out_free_areas;
1945 }
1946 areas[group] = ptr;
fd1e8a1f 1947
c8826dd5
TH
1948 base = min(ptr, base);
1949
1950 for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
1951 if (gi->cpu_map[i] == NR_CPUS) {
1952 /* unused unit, free whole */
1953 free_fn(ptr, ai->unit_size);
1954 continue;
1955 }
1956 /* copy and return the unused part */
1957 memcpy(ptr, __per_cpu_load, ai->static_size);
1958 free_fn(ptr + size_sum, ai->unit_size - size_sum);
1959 }
fa8a7094 1960 }
66c3a757 1961
c8826dd5 1962 /* base address is now known, determine group base offsets */
6ea529a2
TH
1963 max_distance = 0;
1964 for (group = 0; group < ai->nr_groups; group++) {
c8826dd5 1965 ai->groups[group].base_offset = areas[group] - base;
1a0c3298
TH
1966 max_distance = max_t(size_t, max_distance,
1967 ai->groups[group].base_offset);
6ea529a2
TH
1968 }
1969 max_distance += ai->unit_size;
1970
1971 /* warn if maximum distance is further than 75% of vmalloc space */
1972 if (max_distance > (VMALLOC_END - VMALLOC_START) * 3 / 4) {
1a0c3298 1973 pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc "
6ea529a2
TH
1974 "space 0x%lx\n",
1975 max_distance, VMALLOC_END - VMALLOC_START);
1976#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1977 /* and fail if we have fallback */
1978 rc = -EINVAL;
1979 goto out_free;
1980#endif
1981 }
c8826dd5 1982
004018e2 1983 pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
fd1e8a1f
TH
1984 PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
1985 ai->dyn_size, ai->unit_size);
d4b95f80 1986
fb435d52 1987 rc = pcpu_setup_first_chunk(ai, base);
c8826dd5
TH
1988 goto out_free;
1989
1990out_free_areas:
1991 for (group = 0; group < ai->nr_groups; group++)
1992 free_fn(areas[group],
1993 ai->groups[group].nr_units * ai->unit_size);
1994out_free:
fd1e8a1f 1995 pcpu_free_alloc_info(ai);
c8826dd5
TH
1996 if (areas)
1997 free_bootmem(__pa(areas), areas_size);
fb435d52 1998 return rc;
d4b95f80 1999}
08fc4580
TH
2000#endif /* CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK ||
2001 !CONFIG_HAVE_SETUP_PER_CPU_AREA */
d4b95f80 2002
08fc4580 2003#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
d4b95f80 2004/**
00ae4064 2005 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
d4b95f80
TH
2006 * @reserved_size: the size of reserved percpu area in bytes
2007 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
2008 * @free_fn: funtion to free percpu page, always called with PAGE_SIZE
2009 * @populate_pte_fn: function to populate pte
2010 *
00ae4064
TH
2011 * This is a helper to ease setting up page-remapped first percpu
2012 * chunk and can be called where pcpu_setup_first_chunk() is expected.
d4b95f80
TH
2013 *
2014 * This is the basic allocator. Static percpu area is allocated
2015 * page-by-page into vmalloc area.
2016 *
2017 * RETURNS:
fb435d52 2018 * 0 on success, -errno on failure.
d4b95f80 2019 */
fb435d52
TH
2020int __init pcpu_page_first_chunk(size_t reserved_size,
2021 pcpu_fc_alloc_fn_t alloc_fn,
2022 pcpu_fc_free_fn_t free_fn,
2023 pcpu_fc_populate_pte_fn_t populate_pte_fn)
d4b95f80 2024{
8f05a6a6 2025 static struct vm_struct vm;
fd1e8a1f 2026 struct pcpu_alloc_info *ai;
00ae4064 2027 char psize_str[16];
ce3141a2 2028 int unit_pages;
d4b95f80 2029 size_t pages_size;
ce3141a2 2030 struct page **pages;
fb435d52 2031 int unit, i, j, rc;
d4b95f80 2032
00ae4064
TH
2033 snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
2034
fd1e8a1f
TH
2035 ai = pcpu_build_alloc_info(reserved_size, -1, PAGE_SIZE, NULL);
2036 if (IS_ERR(ai))
2037 return PTR_ERR(ai);
2038 BUG_ON(ai->nr_groups != 1);
2039 BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
2040
2041 unit_pages = ai->unit_size >> PAGE_SHIFT;
d4b95f80
TH
2042
2043 /* unaligned allocations can't be freed, round up to page size */
fd1e8a1f
TH
2044 pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
2045 sizeof(pages[0]));
ce3141a2 2046 pages = alloc_bootmem(pages_size);
d4b95f80 2047
8f05a6a6 2048 /* allocate pages */
d4b95f80 2049 j = 0;
fd1e8a1f 2050 for (unit = 0; unit < num_possible_cpus(); unit++)
ce3141a2 2051 for (i = 0; i < unit_pages; i++) {
fd1e8a1f 2052 unsigned int cpu = ai->groups[0].cpu_map[unit];
d4b95f80
TH
2053 void *ptr;
2054
3cbc8565 2055 ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
d4b95f80 2056 if (!ptr) {
00ae4064
TH
2057 pr_warning("PERCPU: failed to allocate %s page "
2058 "for cpu%u\n", psize_str, cpu);
d4b95f80
TH
2059 goto enomem;
2060 }
ce3141a2 2061 pages[j++] = virt_to_page(ptr);
d4b95f80
TH
2062 }
2063
8f05a6a6
TH
2064 /* allocate vm area, map the pages and copy static data */
2065 vm.flags = VM_ALLOC;
fd1e8a1f 2066 vm.size = num_possible_cpus() * ai->unit_size;
8f05a6a6
TH
2067 vm_area_register_early(&vm, PAGE_SIZE);
2068
fd1e8a1f 2069 for (unit = 0; unit < num_possible_cpus(); unit++) {
1d9d3257 2070 unsigned long unit_addr =
fd1e8a1f 2071 (unsigned long)vm.addr + unit * ai->unit_size;
8f05a6a6 2072
ce3141a2 2073 for (i = 0; i < unit_pages; i++)
8f05a6a6
TH
2074 populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
2075
2076 /* pte already populated, the following shouldn't fail */
fb435d52
TH
2077 rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
2078 unit_pages);
2079 if (rc < 0)
2080 panic("failed to map percpu area, err=%d\n", rc);
66c3a757 2081
8f05a6a6
TH
2082 /*
2083 * FIXME: Archs with virtual cache should flush local
2084 * cache for the linear mapping here - something
2085 * equivalent to flush_cache_vmap() on the local cpu.
2086 * flush_cache_vmap() can't be used as most supporting
2087 * data structures are not set up yet.
2088 */
2089
2090 /* copy static data */
fd1e8a1f 2091 memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
66c3a757
TH
2092 }
2093
2094 /* we're ready, commit */
1d9d3257 2095 pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
fd1e8a1f
TH
2096 unit_pages, psize_str, vm.addr, ai->static_size,
2097 ai->reserved_size, ai->dyn_size);
d4b95f80 2098
fb435d52 2099 rc = pcpu_setup_first_chunk(ai, vm.addr);
d4b95f80
TH
2100 goto out_free_ar;
2101
2102enomem:
2103 while (--j >= 0)
ce3141a2 2104 free_fn(page_address(pages[j]), PAGE_SIZE);
fb435d52 2105 rc = -ENOMEM;
d4b95f80 2106out_free_ar:
ce3141a2 2107 free_bootmem(__pa(pages), pages_size);
fd1e8a1f 2108 pcpu_free_alloc_info(ai);
fb435d52 2109 return rc;
d4b95f80 2110}
08fc4580 2111#endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */
d4b95f80 2112
e74e3962
TH
2113/*
2114 * Generic percpu area setup.
2115 *
2116 * The embedding helper is used because its behavior closely resembles
2117 * the original non-dynamic generic percpu area setup. This is
2118 * important because many archs have addressing restrictions and might
2119 * fail if the percpu area is located far away from the previous
2120 * location. As an added bonus, in non-NUMA cases, embedding is
2121 * generally a good idea TLB-wise because percpu area can piggy back
2122 * on the physical linear memory mapping which uses large page
2123 * mappings on applicable archs.
2124 */
2125#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
2126unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
2127EXPORT_SYMBOL(__per_cpu_offset);
2128
c8826dd5
TH
2129static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
2130 size_t align)
2131{
2132 return __alloc_bootmem_nopanic(size, align, __pa(MAX_DMA_ADDRESS));
2133}
66c3a757 2134
c8826dd5
TH
2135static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
2136{
2137 free_bootmem(__pa(ptr), size);
2138}
2139
e74e3962
TH
2140void __init setup_per_cpu_areas(void)
2141{
e74e3962
TH
2142 unsigned long delta;
2143 unsigned int cpu;
fb435d52 2144 int rc;
e74e3962
TH
2145
2146 /*
2147 * Always reserve area for module percpu variables. That's
2148 * what the legacy allocator did.
2149 */
fb435d52 2150 rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
c8826dd5
TH
2151 PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
2152 pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
fb435d52 2153 if (rc < 0)
e74e3962
TH
2154 panic("Failed to initialized percpu areas.");
2155
2156 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
2157 for_each_possible_cpu(cpu)
fb435d52 2158 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
66c3a757 2159}
e74e3962 2160#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */