blob: c76ef3891e0da1c71ac3d1b2d4b1db0abdfe8b9f [file] [log] [blame]
Tejun Heofbf59bc2009-02-20 16:29:08 +09001/*
Tejun Heo88999a82010-04-09 18:57:01 +09002 * mm/percpu.c - percpu memory allocator
Tejun Heofbf59bc2009-02-20 16:29:08 +09003 *
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
Tejun Heo88999a82010-04-09 18:57:01 +090010 * areas. Percpu areas are allocated in chunks. Each chunk is
11 * consisted of boot-time determined number of units and the first
12 * chunk is used for static percpu variables in the kernel image
Tejun Heo2f39e632009-07-04 08:11:00 +090013 * (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.
Tejun Heo88999a82010-04-09 18:57:01 +090016 * When a chunk is filled up, another chunk is allocated.
Tejun Heofbf59bc2009-02-20 16:29:08 +090017 *
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,
Tejun Heo2f39e632009-07-04 08:11:00 +090025 * c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to
26 * cpus. On NUMA, the mapping can be non-linear and even sparse.
27 * Percpu access can be done by configuring percpu base registers
28 * according to cpu to unit mapping and pcpu_unit_size.
Tejun Heofbf59bc2009-02-20 16:29:08 +090029 *
Tejun Heo2f39e632009-07-04 08:11:00 +090030 * There are usually many small percpu allocations many of them being
31 * as small as 4 bytes. The allocator organizes chunks into lists
Tejun Heofbf59bc2009-02-20 16:29:08 +090032 * according to free size and tries to allocate from the fullest one.
33 * Each chunk keeps the maximum contiguous area size hint which is
34 * guaranteed to be eqaul to or larger than the maximum contiguous
35 * area in the chunk. This helps the allocator not to iterate the
36 * chunk maps unnecessarily.
37 *
38 * Allocation state in each chunk is kept using an array of integers
39 * on chunk->map. A positive value in the map represents a free
40 * region and negative allocated. Allocation inside a chunk is done
41 * by scanning this map sequentially and serving the first matching
42 * entry. This is mostly copied from the percpu_modalloc() allocator.
Christoph Lametere1b9aa32009-04-02 13:21:44 +090043 * Chunks can be determined from the address using the index field
44 * in the page struct. The index field contains a pointer to the chunk.
Tejun Heofbf59bc2009-02-20 16:29:08 +090045 *
46 * To use this allocator, arch code should do the followings.
47 *
Tejun Heofbf59bc2009-02-20 16:29:08 +090048 * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
Tejun Heoe0100982009-03-10 16:27:48 +090049 * regular address to percpu pointer and back if they need to be
50 * different from the default
Tejun Heofbf59bc2009-02-20 16:29:08 +090051 *
Tejun Heo8d408b42009-02-24 11:57:21 +090052 * - use pcpu_setup_first_chunk() during percpu area initialization to
53 * setup the first chunk containing the kernel static percpu area
Tejun Heofbf59bc2009-02-20 16:29:08 +090054 */
55
56#include <linux/bitmap.h>
57#include <linux/bootmem.h>
Tejun Heofd1e8a12009-08-14 15:00:51 +090058#include <linux/err.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090059#include <linux/list.h>
Tejun Heoa530b792009-07-04 08:11:00 +090060#include <linux/log2.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090061#include <linux/mm.h>
62#include <linux/module.h>
63#include <linux/mutex.h>
64#include <linux/percpu.h>
65#include <linux/pfn.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090066#include <linux/slab.h>
Tejun Heoccea34b2009-03-07 00:44:13 +090067#include <linux/spinlock.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090068#include <linux/vmalloc.h>
Tejun Heoa56dbdd2009-03-07 00:44:11 +090069#include <linux/workqueue.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090070
71#include <asm/cacheflush.h>
Tejun Heoe0100982009-03-10 16:27:48 +090072#include <asm/sections.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090073#include <asm/tlbflush.h>
Vivek Goyal3b034b02009-11-24 15:50:03 +090074#include <asm/io.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090075
Tejun Heofbf59bc2009-02-20 16:29:08 +090076#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
77#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
78
Tejun Heoe0100982009-03-10 16:27:48 +090079/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
80#ifndef __addr_to_pcpu_ptr
81#define __addr_to_pcpu_ptr(addr) \
Tejun Heo43cf38e2010-02-02 14:38:57 +090082 (void __percpu *)((unsigned long)(addr) - \
83 (unsigned long)pcpu_base_addr + \
84 (unsigned long)__per_cpu_start)
Tejun Heoe0100982009-03-10 16:27:48 +090085#endif
86#ifndef __pcpu_ptr_to_addr
87#define __pcpu_ptr_to_addr(ptr) \
Tejun Heo43cf38e2010-02-02 14:38:57 +090088 (void __force *)((unsigned long)(ptr) + \
89 (unsigned long)pcpu_base_addr - \
90 (unsigned long)__per_cpu_start)
Tejun Heoe0100982009-03-10 16:27:48 +090091#endif
92
Tejun Heofbf59bc2009-02-20 16:29:08 +090093struct pcpu_chunk {
94 struct list_head list; /* linked to pcpu_slot lists */
Tejun Heofbf59bc2009-02-20 16:29:08 +090095 int free_size; /* free bytes in the chunk */
96 int contig_hint; /* max contiguous size hint */
Tejun Heobba174f2009-08-14 15:00:51 +090097 void *base_addr; /* base address of this chunk */
Tejun Heofbf59bc2009-02-20 16:29:08 +090098 int map_used; /* # of map entries used */
99 int map_alloc; /* # of map entries allocated */
100 int *map; /* allocation map */
Tejun Heo88999a82010-04-09 18:57:01 +0900101 void *data; /* chunk data */
Tejun Heo8d408b42009-02-24 11:57:21 +0900102 bool immutable; /* no [de]population allowed */
Tejun Heoce3141a2009-07-04 08:11:00 +0900103 unsigned long populated[]; /* populated bitmap */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900104};
105
Tejun Heo40150d32009-02-24 12:32:28 +0900106static int pcpu_unit_pages __read_mostly;
107static int pcpu_unit_size __read_mostly;
Tejun Heo2f39e632009-07-04 08:11:00 +0900108static int pcpu_nr_units __read_mostly;
Tejun Heo65632972009-08-14 15:00:52 +0900109static int pcpu_atom_size __read_mostly;
Tejun Heo40150d32009-02-24 12:32:28 +0900110static int pcpu_nr_slots __read_mostly;
111static size_t pcpu_chunk_struct_size __read_mostly;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900112
Tejun Heo2f39e632009-07-04 08:11:00 +0900113/* cpus with the lowest and highest unit numbers */
114static unsigned int pcpu_first_unit_cpu __read_mostly;
115static unsigned int pcpu_last_unit_cpu __read_mostly;
116
Tejun Heofbf59bc2009-02-20 16:29:08 +0900117/* the address of the first chunk which starts with the kernel static area */
Tejun Heo40150d32009-02-24 12:32:28 +0900118void *pcpu_base_addr __read_mostly;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900119EXPORT_SYMBOL_GPL(pcpu_base_addr);
120
Tejun Heofb435d52009-08-14 15:00:51 +0900121static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
122const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */
Tejun Heo2f39e632009-07-04 08:11:00 +0900123
Tejun Heo65632972009-08-14 15:00:52 +0900124/* group information, used for vm allocation */
125static int pcpu_nr_groups __read_mostly;
126static const unsigned long *pcpu_group_offsets __read_mostly;
127static const size_t *pcpu_group_sizes __read_mostly;
128
Tejun Heoae9e6bc92009-04-02 13:19:54 +0900129/*
130 * The first chunk which always exists. Note that unlike other
131 * chunks, this one can be allocated and mapped in several different
132 * ways and thus often doesn't live in the vmalloc area.
133 */
134static struct pcpu_chunk *pcpu_first_chunk;
135
136/*
137 * Optional reserved chunk. This chunk reserves part of the first
138 * chunk and serves it for reserved allocations. The amount of
139 * reserved offset is in pcpu_reserved_chunk_limit. When reserved
140 * area doesn't exist, the following variables contain NULL and 0
141 * respectively.
142 */
Tejun Heoedcb4632009-03-06 14:33:59 +0900143static struct pcpu_chunk *pcpu_reserved_chunk;
Tejun Heoedcb4632009-03-06 14:33:59 +0900144static int pcpu_reserved_chunk_limit;
145
Tejun Heofbf59bc2009-02-20 16:29:08 +0900146/*
Tejun Heoccea34b2009-03-07 00:44:13 +0900147 * Synchronization rules.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900148 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900149 * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former
Tejun Heoce3141a2009-07-04 08:11:00 +0900150 * protects allocation/reclaim paths, chunks, populated bitmap and
151 * vmalloc mapping. The latter is a spinlock and protects the index
152 * data structures - chunk slots, chunks and area maps in chunks.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900153 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900154 * During allocation, pcpu_alloc_mutex is kept locked all the time and
155 * pcpu_lock is grabbed and released as necessary. All actual memory
Jiri Kosina403a91b2009-10-29 00:25:59 +0900156 * allocations are done using GFP_KERNEL with pcpu_lock released. In
157 * general, percpu memory can't be allocated with irq off but
158 * irqsave/restore are still used in alloc path so that it can be used
159 * from early init path - sched_init() specifically.
Tejun Heoccea34b2009-03-07 00:44:13 +0900160 *
161 * Free path accesses and alters only the index data structures, so it
162 * can be safely called from atomic context. When memory needs to be
163 * returned to the system, free path schedules reclaim_work which
164 * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be
165 * reclaimed, release both locks and frees the chunks. Note that it's
166 * necessary to grab both locks to remove a chunk from circulation as
167 * allocation path might be referencing the chunk with only
168 * pcpu_alloc_mutex locked.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900169 */
Tejun Heoccea34b2009-03-07 00:44:13 +0900170static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */
171static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900172
Tejun Heo40150d32009-02-24 12:32:28 +0900173static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900174
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900175/* reclaim work to release fully free chunks, scheduled from free path */
176static void pcpu_reclaim(struct work_struct *work);
177static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim);
178
Tejun Heo020ec652010-04-09 18:57:00 +0900179static bool pcpu_addr_in_first_chunk(void *addr)
180{
181 void *first_start = pcpu_first_chunk->base_addr;
182
183 return addr >= first_start && addr < first_start + pcpu_unit_size;
184}
185
186static bool pcpu_addr_in_reserved_chunk(void *addr)
187{
188 void *first_start = pcpu_first_chunk->base_addr;
189
190 return addr >= first_start &&
191 addr < first_start + pcpu_reserved_chunk_limit;
192}
193
Tejun Heod9b55ee2009-02-24 11:57:21 +0900194static int __pcpu_size_to_slot(int size)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900195{
Tejun Heocae3aeb2009-02-21 16:56:23 +0900196 int highbit = fls(size); /* size is in bytes */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900197 return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
198}
199
Tejun Heod9b55ee2009-02-24 11:57:21 +0900200static int pcpu_size_to_slot(int size)
201{
202 if (size == pcpu_unit_size)
203 return pcpu_nr_slots - 1;
204 return __pcpu_size_to_slot(size);
205}
206
Tejun Heofbf59bc2009-02-20 16:29:08 +0900207static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
208{
209 if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
210 return 0;
211
212 return pcpu_size_to_slot(chunk->free_size);
213}
214
Tejun Heo88999a82010-04-09 18:57:01 +0900215/* set the pointer to a chunk in a page struct */
216static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
217{
218 page->index = (unsigned long)pcpu;
219}
220
221/* obtain pointer to a chunk from a page struct */
222static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
223{
224 return (struct pcpu_chunk *)page->index;
225}
226
227static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900228{
Tejun Heo2f39e632009-07-04 08:11:00 +0900229 return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900230}
231
Tejun Heo9983b6f02010-06-18 11:44:31 +0200232static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
233 unsigned int cpu, int page_idx)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900234{
Tejun Heobba174f2009-08-14 15:00:51 +0900235 return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
Tejun Heofb435d52009-08-14 15:00:51 +0900236 (page_idx << PAGE_SHIFT);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900237}
238
Tejun Heo88999a82010-04-09 18:57:01 +0900239static void __maybe_unused pcpu_next_unpop(struct pcpu_chunk *chunk,
240 int *rs, int *re, int end)
Tejun Heoce3141a2009-07-04 08:11:00 +0900241{
242 *rs = find_next_zero_bit(chunk->populated, end, *rs);
243 *re = find_next_bit(chunk->populated, end, *rs + 1);
244}
245
Tejun Heo88999a82010-04-09 18:57:01 +0900246static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk,
247 int *rs, int *re, int end)
Tejun Heoce3141a2009-07-04 08:11:00 +0900248{
249 *rs = find_next_bit(chunk->populated, end, *rs);
250 *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
251}
252
253/*
254 * (Un)populated page region iterators. Iterate over (un)populated
255 * page regions betwen @start and @end in @chunk. @rs and @re should
256 * be integer variables and will be set to start and end page index of
257 * the current region.
258 */
259#define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
260 for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
261 (rs) < (re); \
262 (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
263
264#define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
265 for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
266 (rs) < (re); \
267 (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
268
Tejun Heofbf59bc2009-02-20 16:29:08 +0900269/**
Tejun Heo1880d932009-03-07 00:44:09 +0900270 * pcpu_mem_alloc - allocate memory
271 * @size: bytes to allocate
Tejun Heofbf59bc2009-02-20 16:29:08 +0900272 *
Tejun Heo1880d932009-03-07 00:44:09 +0900273 * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
274 * kzalloc() is used; otherwise, vmalloc() is used. The returned
275 * memory is always zeroed.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900276 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900277 * CONTEXT:
278 * Does GFP_KERNEL allocation.
279 *
Tejun Heofbf59bc2009-02-20 16:29:08 +0900280 * RETURNS:
Tejun Heo1880d932009-03-07 00:44:09 +0900281 * Pointer to the allocated area on success, NULL on failure.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900282 */
Tejun Heo1880d932009-03-07 00:44:09 +0900283static void *pcpu_mem_alloc(size_t size)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900284{
Tejun Heo099a19d2010-06-27 18:50:00 +0200285 if (WARN_ON_ONCE(!slab_is_available()))
286 return NULL;
287
Tejun Heofbf59bc2009-02-20 16:29:08 +0900288 if (size <= PAGE_SIZE)
Tejun Heo1880d932009-03-07 00:44:09 +0900289 return kzalloc(size, GFP_KERNEL);
290 else {
291 void *ptr = vmalloc(size);
292 if (ptr)
293 memset(ptr, 0, size);
294 return ptr;
295 }
296}
Tejun Heofbf59bc2009-02-20 16:29:08 +0900297
Tejun Heo1880d932009-03-07 00:44:09 +0900298/**
299 * pcpu_mem_free - free memory
300 * @ptr: memory to free
301 * @size: size of the area
302 *
303 * Free @ptr. @ptr should have been allocated using pcpu_mem_alloc().
304 */
305static void pcpu_mem_free(void *ptr, size_t size)
306{
307 if (size <= PAGE_SIZE)
308 kfree(ptr);
309 else
310 vfree(ptr);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900311}
312
313/**
314 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
315 * @chunk: chunk of interest
316 * @oslot: the previous slot it was on
317 *
318 * This function is called after an allocation or free changed @chunk.
319 * New slot according to the changed state is determined and @chunk is
Tejun Heoedcb4632009-03-06 14:33:59 +0900320 * moved to the slot. Note that the reserved chunk is never put on
321 * chunk slots.
Tejun Heoccea34b2009-03-07 00:44:13 +0900322 *
323 * CONTEXT:
324 * pcpu_lock.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900325 */
326static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
327{
328 int nslot = pcpu_chunk_slot(chunk);
329
Tejun Heoedcb4632009-03-06 14:33:59 +0900330 if (chunk != pcpu_reserved_chunk && oslot != nslot) {
Tejun Heofbf59bc2009-02-20 16:29:08 +0900331 if (oslot < nslot)
332 list_move(&chunk->list, &pcpu_slot[nslot]);
333 else
334 list_move_tail(&chunk->list, &pcpu_slot[nslot]);
335 }
336}
337
Tejun Heofbf59bc2009-02-20 16:29:08 +0900338/**
Tejun Heo833af842009-11-11 15:35:18 +0900339 * pcpu_need_to_extend - determine whether chunk area map needs to be extended
340 * @chunk: chunk of interest
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900341 *
Tejun Heo833af842009-11-11 15:35:18 +0900342 * Determine whether area map of @chunk needs to be extended to
343 * accomodate a new allocation.
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900344 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900345 * CONTEXT:
Tejun Heo833af842009-11-11 15:35:18 +0900346 * pcpu_lock.
Tejun Heoccea34b2009-03-07 00:44:13 +0900347 *
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900348 * RETURNS:
Tejun Heo833af842009-11-11 15:35:18 +0900349 * New target map allocation length if extension is necessary, 0
350 * otherwise.
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900351 */
Tejun Heo833af842009-11-11 15:35:18 +0900352static int pcpu_need_to_extend(struct pcpu_chunk *chunk)
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900353{
354 int new_alloc;
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900355
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900356 if (chunk->map_alloc >= chunk->map_used + 2)
357 return 0;
358
359 new_alloc = PCPU_DFL_MAP_ALLOC;
360 while (new_alloc < chunk->map_used + 2)
361 new_alloc *= 2;
362
Tejun Heo833af842009-11-11 15:35:18 +0900363 return new_alloc;
364}
365
366/**
367 * pcpu_extend_area_map - extend area map of a chunk
368 * @chunk: chunk of interest
369 * @new_alloc: new target allocation length of the area map
370 *
371 * Extend area map of @chunk to have @new_alloc entries.
372 *
373 * CONTEXT:
374 * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock.
375 *
376 * RETURNS:
377 * 0 on success, -errno on failure.
378 */
379static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
380{
381 int *old = NULL, *new = NULL;
382 size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
383 unsigned long flags;
384
385 new = pcpu_mem_alloc(new_size);
386 if (!new)
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900387 return -ENOMEM;
Tejun Heoccea34b2009-03-07 00:44:13 +0900388
Tejun Heo833af842009-11-11 15:35:18 +0900389 /* acquire pcpu_lock and switch to new area map */
390 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900391
Tejun Heo833af842009-11-11 15:35:18 +0900392 if (new_alloc <= chunk->map_alloc)
393 goto out_unlock;
394
395 old_size = chunk->map_alloc * sizeof(chunk->map[0]);
Huang Shijiea002d142010-08-08 14:39:07 +0200396 old = chunk->map;
397
398 memcpy(new, old, old_size);
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900399
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900400 chunk->map_alloc = new_alloc;
401 chunk->map = new;
Tejun Heo833af842009-11-11 15:35:18 +0900402 new = NULL;
403
404out_unlock:
405 spin_unlock_irqrestore(&pcpu_lock, flags);
406
407 /*
408 * pcpu_mem_free() might end up calling vfree() which uses
409 * IRQ-unsafe lock and thus can't be called under pcpu_lock.
410 */
411 pcpu_mem_free(old, old_size);
412 pcpu_mem_free(new, new_size);
413
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900414 return 0;
415}
416
417/**
Tejun Heofbf59bc2009-02-20 16:29:08 +0900418 * pcpu_split_block - split a map block
419 * @chunk: chunk of interest
420 * @i: index of map block to split
Tejun Heocae3aeb2009-02-21 16:56:23 +0900421 * @head: head size in bytes (can be 0)
422 * @tail: tail size in bytes (can be 0)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900423 *
424 * Split the @i'th map block into two or three blocks. If @head is
425 * non-zero, @head bytes block is inserted before block @i moving it
426 * to @i+1 and reducing its size by @head bytes.
427 *
428 * If @tail is non-zero, the target block, which can be @i or @i+1
429 * depending on @head, is reduced by @tail bytes and @tail byte block
430 * is inserted after the target block.
431 *
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900432 * @chunk->map must have enough free slots to accomodate the split.
Tejun Heoccea34b2009-03-07 00:44:13 +0900433 *
434 * CONTEXT:
435 * pcpu_lock.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900436 */
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900437static void pcpu_split_block(struct pcpu_chunk *chunk, int i,
438 int head, int tail)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900439{
440 int nr_extra = !!head + !!tail;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900441
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900442 BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900443
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900444 /* insert new subblocks */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900445 memmove(&chunk->map[i + nr_extra], &chunk->map[i],
446 sizeof(chunk->map[0]) * (chunk->map_used - i));
447 chunk->map_used += nr_extra;
448
449 if (head) {
450 chunk->map[i + 1] = chunk->map[i] - head;
451 chunk->map[i++] = head;
452 }
453 if (tail) {
454 chunk->map[i++] -= tail;
455 chunk->map[i] = tail;
456 }
Tejun Heofbf59bc2009-02-20 16:29:08 +0900457}
458
459/**
460 * pcpu_alloc_area - allocate area from a pcpu_chunk
461 * @chunk: chunk of interest
Tejun Heocae3aeb2009-02-21 16:56:23 +0900462 * @size: wanted size in bytes
Tejun Heofbf59bc2009-02-20 16:29:08 +0900463 * @align: wanted align
464 *
465 * Try to allocate @size bytes area aligned at @align from @chunk.
466 * Note that this function only allocates the offset. It doesn't
467 * populate or map the area.
468 *
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900469 * @chunk->map must have at least two free slots.
470 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900471 * CONTEXT:
472 * pcpu_lock.
473 *
Tejun Heofbf59bc2009-02-20 16:29:08 +0900474 * RETURNS:
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900475 * Allocated offset in @chunk on success, -1 if no matching area is
476 * found.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900477 */
478static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
479{
480 int oslot = pcpu_chunk_slot(chunk);
481 int max_contig = 0;
482 int i, off;
483
Tejun Heofbf59bc2009-02-20 16:29:08 +0900484 for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) {
485 bool is_last = i + 1 == chunk->map_used;
486 int head, tail;
487
488 /* extra for alignment requirement */
489 head = ALIGN(off, align) - off;
490 BUG_ON(i == 0 && head != 0);
491
492 if (chunk->map[i] < 0)
493 continue;
494 if (chunk->map[i] < head + size) {
495 max_contig = max(chunk->map[i], max_contig);
496 continue;
497 }
498
499 /*
500 * If head is small or the previous block is free,
501 * merge'em. Note that 'small' is defined as smaller
502 * than sizeof(int), which is very small but isn't too
503 * uncommon for percpu allocations.
504 */
505 if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) {
506 if (chunk->map[i - 1] > 0)
507 chunk->map[i - 1] += head;
508 else {
509 chunk->map[i - 1] -= head;
510 chunk->free_size -= head;
511 }
512 chunk->map[i] -= head;
513 off += head;
514 head = 0;
515 }
516
517 /* if tail is small, just keep it around */
518 tail = chunk->map[i] - head - size;
519 if (tail < sizeof(int))
520 tail = 0;
521
522 /* split if warranted */
523 if (head || tail) {
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900524 pcpu_split_block(chunk, i, head, tail);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900525 if (head) {
526 i++;
527 off += head;
528 max_contig = max(chunk->map[i - 1], max_contig);
529 }
530 if (tail)
531 max_contig = max(chunk->map[i + 1], max_contig);
532 }
533
534 /* update hint and mark allocated */
535 if (is_last)
536 chunk->contig_hint = max_contig; /* fully scanned */
537 else
538 chunk->contig_hint = max(chunk->contig_hint,
539 max_contig);
540
541 chunk->free_size -= chunk->map[i];
542 chunk->map[i] = -chunk->map[i];
543
544 pcpu_chunk_relocate(chunk, oslot);
545 return off;
546 }
547
548 chunk->contig_hint = max_contig; /* fully scanned */
549 pcpu_chunk_relocate(chunk, oslot);
550
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900551 /* tell the upper layer that this chunk has no matching area */
552 return -1;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900553}
554
555/**
556 * pcpu_free_area - free area to a pcpu_chunk
557 * @chunk: chunk of interest
558 * @freeme: offset of area to free
559 *
560 * Free area starting from @freeme to @chunk. Note that this function
561 * only modifies the allocation map. It doesn't depopulate or unmap
562 * the area.
Tejun Heoccea34b2009-03-07 00:44:13 +0900563 *
564 * CONTEXT:
565 * pcpu_lock.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900566 */
567static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
568{
569 int oslot = pcpu_chunk_slot(chunk);
570 int i, off;
571
572 for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++]))
573 if (off == freeme)
574 break;
575 BUG_ON(off != freeme);
576 BUG_ON(chunk->map[i] > 0);
577
578 chunk->map[i] = -chunk->map[i];
579 chunk->free_size += chunk->map[i];
580
581 /* merge with previous? */
582 if (i > 0 && chunk->map[i - 1] >= 0) {
583 chunk->map[i - 1] += chunk->map[i];
584 chunk->map_used--;
585 memmove(&chunk->map[i], &chunk->map[i + 1],
586 (chunk->map_used - i) * sizeof(chunk->map[0]));
587 i--;
588 }
589 /* merge with next? */
590 if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) {
591 chunk->map[i] += chunk->map[i + 1];
592 chunk->map_used--;
593 memmove(&chunk->map[i + 1], &chunk->map[i + 2],
594 (chunk->map_used - (i + 1)) * sizeof(chunk->map[0]));
595 }
596
597 chunk->contig_hint = max(chunk->map[i], chunk->contig_hint);
598 pcpu_chunk_relocate(chunk, oslot);
599}
600
Tejun Heo60810892010-04-09 18:57:01 +0900601static struct pcpu_chunk *pcpu_alloc_chunk(void)
602{
603 struct pcpu_chunk *chunk;
604
Tejun Heo099a19d2010-06-27 18:50:00 +0200605 chunk = pcpu_mem_alloc(pcpu_chunk_struct_size);
Tejun Heo60810892010-04-09 18:57:01 +0900606 if (!chunk)
607 return NULL;
608
609 chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
610 if (!chunk->map) {
611 kfree(chunk);
612 return NULL;
613 }
614
615 chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
616 chunk->map[chunk->map_used++] = pcpu_unit_size;
617
618 INIT_LIST_HEAD(&chunk->list);
619 chunk->free_size = pcpu_unit_size;
620 chunk->contig_hint = pcpu_unit_size;
621
622 return chunk;
623}
624
625static void pcpu_free_chunk(struct pcpu_chunk *chunk)
626{
627 if (!chunk)
628 return;
629 pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
630 kfree(chunk);
631}
632
Tejun Heo9f645532010-04-09 18:57:01 +0900633/*
634 * Chunk management implementation.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900635 *
Tejun Heo9f645532010-04-09 18:57:01 +0900636 * To allow different implementations, chunk alloc/free and
637 * [de]population are implemented in a separate file which is pulled
638 * into this file and compiled together. The following functions
639 * should be implemented.
Tejun Heoce3141a2009-07-04 08:11:00 +0900640 *
Tejun Heo9f645532010-04-09 18:57:01 +0900641 * pcpu_populate_chunk - populate the specified range of a chunk
642 * pcpu_depopulate_chunk - depopulate the specified range of a chunk
643 * pcpu_create_chunk - create a new chunk
644 * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
645 * pcpu_addr_to_page - translate address to physical address
646 * pcpu_verify_alloc_info - check alloc_info is acceptable during init
Tejun Heofbf59bc2009-02-20 16:29:08 +0900647 */
Tejun Heo9f645532010-04-09 18:57:01 +0900648static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size);
649static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size);
650static struct pcpu_chunk *pcpu_create_chunk(void);
651static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
652static struct page *pcpu_addr_to_page(void *addr);
653static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
Tejun Heoce3141a2009-07-04 08:11:00 +0900654
Tejun Heob0c97782010-04-09 18:57:01 +0900655#ifdef CONFIG_NEED_PER_CPU_KM
656#include "percpu-km.c"
657#else
Tejun Heo9f645532010-04-09 18:57:01 +0900658#include "percpu-vm.c"
Tejun Heob0c97782010-04-09 18:57:01 +0900659#endif
Tejun Heofbf59bc2009-02-20 16:29:08 +0900660
661/**
Tejun Heo88999a82010-04-09 18:57:01 +0900662 * pcpu_chunk_addr_search - determine chunk containing specified address
663 * @addr: address for which the chunk needs to be determined.
664 *
665 * RETURNS:
666 * The address of the found chunk.
667 */
668static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
669{
670 /* is it in the first chunk? */
671 if (pcpu_addr_in_first_chunk(addr)) {
672 /* is it in the reserved area? */
673 if (pcpu_addr_in_reserved_chunk(addr))
674 return pcpu_reserved_chunk;
675 return pcpu_first_chunk;
676 }
677
678 /*
679 * The address is relative to unit0 which might be unused and
680 * thus unmapped. Offset the address to the unit space of the
681 * current processor before looking it up in the vmalloc
682 * space. Note that any possible cpu id can be used here, so
683 * there's no need to worry about preemption or cpu hotplug.
684 */
685 addr += pcpu_unit_offsets[raw_smp_processor_id()];
Tejun Heo9f645532010-04-09 18:57:01 +0900686 return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
Tejun Heo88999a82010-04-09 18:57:01 +0900687}
688
689/**
Tejun Heoedcb4632009-03-06 14:33:59 +0900690 * pcpu_alloc - the percpu allocator
Tejun Heocae3aeb2009-02-21 16:56:23 +0900691 * @size: size of area to allocate in bytes
Tejun Heofbf59bc2009-02-20 16:29:08 +0900692 * @align: alignment of area (max PAGE_SIZE)
Tejun Heoedcb4632009-03-06 14:33:59 +0900693 * @reserved: allocate from the reserved chunk if available
Tejun Heofbf59bc2009-02-20 16:29:08 +0900694 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900695 * Allocate percpu area of @size bytes aligned at @align.
696 *
697 * CONTEXT:
698 * Does GFP_KERNEL allocation.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900699 *
700 * RETURNS:
701 * Percpu pointer to the allocated area on success, NULL on failure.
702 */
Tejun Heo43cf38e2010-02-02 14:38:57 +0900703static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900704{
Tejun Heof2badb02009-09-29 09:17:58 +0900705 static int warn_limit = 10;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900706 struct pcpu_chunk *chunk;
Tejun Heof2badb02009-09-29 09:17:58 +0900707 const char *err;
Tejun Heo833af842009-11-11 15:35:18 +0900708 int slot, off, new_alloc;
Jiri Kosina403a91b2009-10-29 00:25:59 +0900709 unsigned long flags;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900710
Tejun Heo8d408b42009-02-24 11:57:21 +0900711 if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
Tejun Heofbf59bc2009-02-20 16:29:08 +0900712 WARN(true, "illegal size (%zu) or align (%zu) for "
713 "percpu allocation\n", size, align);
714 return NULL;
715 }
716
Tejun Heoccea34b2009-03-07 00:44:13 +0900717 mutex_lock(&pcpu_alloc_mutex);
Jiri Kosina403a91b2009-10-29 00:25:59 +0900718 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900719
Tejun Heoedcb4632009-03-06 14:33:59 +0900720 /* serve reserved allocations from the reserved chunk if available */
721 if (reserved && pcpu_reserved_chunk) {
722 chunk = pcpu_reserved_chunk;
Tejun Heo833af842009-11-11 15:35:18 +0900723
724 if (size > chunk->contig_hint) {
725 err = "alloc from reserved chunk failed";
Tejun Heoccea34b2009-03-07 00:44:13 +0900726 goto fail_unlock;
Tejun Heof2badb02009-09-29 09:17:58 +0900727 }
Tejun Heo833af842009-11-11 15:35:18 +0900728
729 while ((new_alloc = pcpu_need_to_extend(chunk))) {
730 spin_unlock_irqrestore(&pcpu_lock, flags);
731 if (pcpu_extend_area_map(chunk, new_alloc) < 0) {
732 err = "failed to extend area map of reserved chunk";
733 goto fail_unlock_mutex;
734 }
735 spin_lock_irqsave(&pcpu_lock, flags);
736 }
737
Tejun Heoedcb4632009-03-06 14:33:59 +0900738 off = pcpu_alloc_area(chunk, size, align);
739 if (off >= 0)
740 goto area_found;
Tejun Heo833af842009-11-11 15:35:18 +0900741
Tejun Heof2badb02009-09-29 09:17:58 +0900742 err = "alloc from reserved chunk failed";
Tejun Heoccea34b2009-03-07 00:44:13 +0900743 goto fail_unlock;
Tejun Heoedcb4632009-03-06 14:33:59 +0900744 }
745
Tejun Heoccea34b2009-03-07 00:44:13 +0900746restart:
Tejun Heoedcb4632009-03-06 14:33:59 +0900747 /* search through normal chunks */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900748 for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
749 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
750 if (size > chunk->contig_hint)
751 continue;
Tejun Heoccea34b2009-03-07 00:44:13 +0900752
Tejun Heo833af842009-11-11 15:35:18 +0900753 new_alloc = pcpu_need_to_extend(chunk);
754 if (new_alloc) {
755 spin_unlock_irqrestore(&pcpu_lock, flags);
756 if (pcpu_extend_area_map(chunk,
757 new_alloc) < 0) {
758 err = "failed to extend area map";
759 goto fail_unlock_mutex;
760 }
761 spin_lock_irqsave(&pcpu_lock, flags);
762 /*
763 * pcpu_lock has been dropped, need to
764 * restart cpu_slot list walking.
765 */
766 goto restart;
Tejun Heoccea34b2009-03-07 00:44:13 +0900767 }
768
Tejun Heofbf59bc2009-02-20 16:29:08 +0900769 off = pcpu_alloc_area(chunk, size, align);
770 if (off >= 0)
771 goto area_found;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900772 }
773 }
774
775 /* hmmm... no space left, create a new chunk */
Jiri Kosina403a91b2009-10-29 00:25:59 +0900776 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heoccea34b2009-03-07 00:44:13 +0900777
Tejun Heo60810892010-04-09 18:57:01 +0900778 chunk = pcpu_create_chunk();
Tejun Heof2badb02009-09-29 09:17:58 +0900779 if (!chunk) {
780 err = "failed to allocate new chunk";
Tejun Heoccea34b2009-03-07 00:44:13 +0900781 goto fail_unlock_mutex;
Tejun Heof2badb02009-09-29 09:17:58 +0900782 }
Tejun Heoccea34b2009-03-07 00:44:13 +0900783
Jiri Kosina403a91b2009-10-29 00:25:59 +0900784 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900785 pcpu_chunk_relocate(chunk, -1);
Tejun Heoccea34b2009-03-07 00:44:13 +0900786 goto restart;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900787
788area_found:
Jiri Kosina403a91b2009-10-29 00:25:59 +0900789 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heoccea34b2009-03-07 00:44:13 +0900790
Tejun Heofbf59bc2009-02-20 16:29:08 +0900791 /* populate, map and clear the area */
792 if (pcpu_populate_chunk(chunk, off, size)) {
Jiri Kosina403a91b2009-10-29 00:25:59 +0900793 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900794 pcpu_free_area(chunk, off);
Tejun Heof2badb02009-09-29 09:17:58 +0900795 err = "failed to populate";
Tejun Heoccea34b2009-03-07 00:44:13 +0900796 goto fail_unlock;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900797 }
798
Tejun Heoccea34b2009-03-07 00:44:13 +0900799 mutex_unlock(&pcpu_alloc_mutex);
800
Tejun Heobba174f2009-08-14 15:00:51 +0900801 /* return address relative to base address */
802 return __addr_to_pcpu_ptr(chunk->base_addr + off);
Tejun Heoccea34b2009-03-07 00:44:13 +0900803
804fail_unlock:
Jiri Kosina403a91b2009-10-29 00:25:59 +0900805 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heoccea34b2009-03-07 00:44:13 +0900806fail_unlock_mutex:
807 mutex_unlock(&pcpu_alloc_mutex);
Tejun Heof2badb02009-09-29 09:17:58 +0900808 if (warn_limit) {
809 pr_warning("PERCPU: allocation failed, size=%zu align=%zu, "
810 "%s\n", size, align, err);
811 dump_stack();
812 if (!--warn_limit)
813 pr_info("PERCPU: limit reached, disable warning\n");
814 }
Tejun Heoccea34b2009-03-07 00:44:13 +0900815 return NULL;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900816}
Tejun Heoedcb4632009-03-06 14:33:59 +0900817
818/**
819 * __alloc_percpu - allocate dynamic percpu area
820 * @size: size of area to allocate in bytes
821 * @align: alignment of area (max PAGE_SIZE)
822 *
823 * Allocate percpu area of @size bytes aligned at @align. Might
824 * sleep. Might trigger writeouts.
825 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900826 * CONTEXT:
827 * Does GFP_KERNEL allocation.
828 *
Tejun Heoedcb4632009-03-06 14:33:59 +0900829 * RETURNS:
830 * Percpu pointer to the allocated area on success, NULL on failure.
831 */
Tejun Heo43cf38e2010-02-02 14:38:57 +0900832void __percpu *__alloc_percpu(size_t size, size_t align)
Tejun Heoedcb4632009-03-06 14:33:59 +0900833{
834 return pcpu_alloc(size, align, false);
835}
Tejun Heofbf59bc2009-02-20 16:29:08 +0900836EXPORT_SYMBOL_GPL(__alloc_percpu);
837
Tejun Heoedcb4632009-03-06 14:33:59 +0900838/**
839 * __alloc_reserved_percpu - allocate reserved percpu area
840 * @size: size of area to allocate in bytes
841 * @align: alignment of area (max PAGE_SIZE)
842 *
843 * Allocate percpu area of @size bytes aligned at @align from reserved
844 * percpu area if arch has set it up; otherwise, allocation is served
845 * from the same dynamic area. Might sleep. Might trigger writeouts.
846 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900847 * CONTEXT:
848 * Does GFP_KERNEL allocation.
849 *
Tejun Heoedcb4632009-03-06 14:33:59 +0900850 * RETURNS:
851 * Percpu pointer to the allocated area on success, NULL on failure.
852 */
Tejun Heo43cf38e2010-02-02 14:38:57 +0900853void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
Tejun Heoedcb4632009-03-06 14:33:59 +0900854{
855 return pcpu_alloc(size, align, true);
856}
857
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900858/**
859 * pcpu_reclaim - reclaim fully free chunks, workqueue function
860 * @work: unused
861 *
862 * Reclaim all fully free chunks except for the first one.
Tejun Heoccea34b2009-03-07 00:44:13 +0900863 *
864 * CONTEXT:
865 * workqueue context.
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900866 */
867static void pcpu_reclaim(struct work_struct *work)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900868{
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900869 LIST_HEAD(todo);
870 struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1];
871 struct pcpu_chunk *chunk, *next;
872
Tejun Heoccea34b2009-03-07 00:44:13 +0900873 mutex_lock(&pcpu_alloc_mutex);
874 spin_lock_irq(&pcpu_lock);
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900875
876 list_for_each_entry_safe(chunk, next, head, list) {
877 WARN_ON(chunk->immutable);
878
879 /* spare the first one */
880 if (chunk == list_first_entry(head, struct pcpu_chunk, list))
881 continue;
882
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900883 list_move(&chunk->list, &todo);
884 }
885
Tejun Heoccea34b2009-03-07 00:44:13 +0900886 spin_unlock_irq(&pcpu_lock);
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900887
888 list_for_each_entry_safe(chunk, next, &todo, list) {
Tejun Heoce3141a2009-07-04 08:11:00 +0900889 pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
Tejun Heo60810892010-04-09 18:57:01 +0900890 pcpu_destroy_chunk(chunk);
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900891 }
Tejun Heo971f3912009-08-14 15:00:49 +0900892
893 mutex_unlock(&pcpu_alloc_mutex);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900894}
895
896/**
897 * free_percpu - free percpu area
898 * @ptr: pointer to area to free
899 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900900 * Free percpu area @ptr.
901 *
902 * CONTEXT:
903 * Can be called from atomic context.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900904 */
Tejun Heo43cf38e2010-02-02 14:38:57 +0900905void free_percpu(void __percpu *ptr)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900906{
Andrew Morton129182e2010-01-08 14:42:39 -0800907 void *addr;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900908 struct pcpu_chunk *chunk;
Tejun Heoccea34b2009-03-07 00:44:13 +0900909 unsigned long flags;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900910 int off;
911
912 if (!ptr)
913 return;
914
Andrew Morton129182e2010-01-08 14:42:39 -0800915 addr = __pcpu_ptr_to_addr(ptr);
916
Tejun Heoccea34b2009-03-07 00:44:13 +0900917 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900918
919 chunk = pcpu_chunk_addr_search(addr);
Tejun Heobba174f2009-08-14 15:00:51 +0900920 off = addr - chunk->base_addr;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900921
922 pcpu_free_area(chunk, off);
923
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900924 /* if there are more than one fully free chunks, wake up grim reaper */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900925 if (chunk->free_size == pcpu_unit_size) {
926 struct pcpu_chunk *pos;
927
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900928 list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900929 if (pos != chunk) {
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900930 schedule_work(&pcpu_reclaim_work);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900931 break;
932 }
933 }
934
Tejun Heoccea34b2009-03-07 00:44:13 +0900935 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900936}
937EXPORT_SYMBOL_GPL(free_percpu);
938
Vivek Goyal3b034b02009-11-24 15:50:03 +0900939/**
Tejun Heo10fad5e2010-03-10 18:57:54 +0900940 * is_kernel_percpu_address - test whether address is from static percpu area
941 * @addr: address to test
942 *
943 * Test whether @addr belongs to in-kernel static percpu area. Module
944 * static percpu areas are not considered. For those, use
945 * is_module_percpu_address().
946 *
947 * RETURNS:
948 * %true if @addr is from in-kernel static percpu area, %false otherwise.
949 */
950bool is_kernel_percpu_address(unsigned long addr)
951{
952 const size_t static_size = __per_cpu_end - __per_cpu_start;
953 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
954 unsigned int cpu;
955
956 for_each_possible_cpu(cpu) {
957 void *start = per_cpu_ptr(base, cpu);
958
959 if ((void *)addr >= start && (void *)addr < start + static_size)
960 return true;
961 }
962 return false;
963}
964
965/**
Vivek Goyal3b034b02009-11-24 15:50:03 +0900966 * per_cpu_ptr_to_phys - convert translated percpu address to physical address
967 * @addr: the address to be converted to physical address
968 *
969 * Given @addr which is dereferenceable address obtained via one of
970 * percpu access macros, this function translates it into its physical
971 * address. The caller is responsible for ensuring @addr stays valid
972 * until this function finishes.
973 *
974 * RETURNS:
975 * The physical address for @addr.
976 */
977phys_addr_t per_cpu_ptr_to_phys(void *addr)
978{
Tejun Heo9983b6f02010-06-18 11:44:31 +0200979 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
980 bool in_first_chunk = false;
981 unsigned long first_start, first_end;
982 unsigned int cpu;
983
984 /*
985 * The following test on first_start/end isn't strictly
986 * necessary but will speed up lookups of addresses which
987 * aren't in the first chunk.
988 */
989 first_start = pcpu_chunk_addr(pcpu_first_chunk, pcpu_first_unit_cpu, 0);
990 first_end = pcpu_chunk_addr(pcpu_first_chunk, pcpu_last_unit_cpu,
991 pcpu_unit_pages);
992 if ((unsigned long)addr >= first_start &&
993 (unsigned long)addr < first_end) {
994 for_each_possible_cpu(cpu) {
995 void *start = per_cpu_ptr(base, cpu);
996
997 if (addr >= start && addr < start + pcpu_unit_size) {
998 in_first_chunk = true;
999 break;
1000 }
1001 }
1002 }
1003
1004 if (in_first_chunk) {
Tejun Heo020ec652010-04-09 18:57:00 +09001005 if ((unsigned long)addr < VMALLOC_START ||
1006 (unsigned long)addr >= VMALLOC_END)
1007 return __pa(addr);
1008 else
1009 return page_to_phys(vmalloc_to_page(addr));
1010 } else
Tejun Heo9f645532010-04-09 18:57:01 +09001011 return page_to_phys(pcpu_addr_to_page(addr));
Vivek Goyal3b034b02009-11-24 15:50:03 +09001012}
1013
Tejun Heofbf59bc2009-02-20 16:29:08 +09001014/**
Tejun Heofd1e8a12009-08-14 15:00:51 +09001015 * pcpu_alloc_alloc_info - allocate percpu allocation info
1016 * @nr_groups: the number of groups
1017 * @nr_units: the number of units
Tejun Heo033e48f2009-08-14 15:00:51 +09001018 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001019 * Allocate ai which is large enough for @nr_groups groups containing
1020 * @nr_units units. The returned ai's groups[0].cpu_map points to the
1021 * cpu_map array which is long enough for @nr_units and filled with
1022 * NR_CPUS. It's the caller's responsibility to initialize cpu_map
1023 * pointer of other groups.
Tejun Heo033e48f2009-08-14 15:00:51 +09001024 *
1025 * RETURNS:
Tejun Heofd1e8a12009-08-14 15:00:51 +09001026 * Pointer to the allocated pcpu_alloc_info on success, NULL on
1027 * failure.
Tejun Heo033e48f2009-08-14 15:00:51 +09001028 */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001029struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
1030 int nr_units)
1031{
1032 struct pcpu_alloc_info *ai;
1033 size_t base_size, ai_size;
1034 void *ptr;
1035 int unit;
1036
1037 base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
1038 __alignof__(ai->groups[0].cpu_map[0]));
1039 ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
1040
1041 ptr = alloc_bootmem_nopanic(PFN_ALIGN(ai_size));
1042 if (!ptr)
1043 return NULL;
1044 ai = ptr;
1045 ptr += base_size;
1046
1047 ai->groups[0].cpu_map = ptr;
1048
1049 for (unit = 0; unit < nr_units; unit++)
1050 ai->groups[0].cpu_map[unit] = NR_CPUS;
1051
1052 ai->nr_groups = nr_groups;
1053 ai->__ai_size = PFN_ALIGN(ai_size);
1054
1055 return ai;
1056}
1057
1058/**
1059 * pcpu_free_alloc_info - free percpu allocation info
1060 * @ai: pcpu_alloc_info to free
1061 *
1062 * Free @ai which was allocated by pcpu_alloc_alloc_info().
1063 */
1064void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
1065{
1066 free_bootmem(__pa(ai), ai->__ai_size);
1067}
1068
1069/**
1070 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
Tejun Heoedcb4632009-03-06 14:33:59 +09001071 * @reserved_size: the size of reserved percpu area in bytes
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001072 * @dyn_size: minimum free size for dynamic allocation in bytes
Tejun Heofd1e8a12009-08-14 15:00:51 +09001073 * @atom_size: allocation atom size
1074 * @cpu_distance_fn: callback to determine distance between cpus, optional
1075 *
1076 * This function determines grouping of units, their mappings to cpus
1077 * and other parameters considering needed percpu size, allocation
1078 * atom size and distances between CPUs.
1079 *
1080 * Groups are always mutliples of atom size and CPUs which are of
1081 * LOCAL_DISTANCE both ways are grouped together and share space for
1082 * units in the same group. The returned configuration is guaranteed
1083 * to have CPUs on different nodes on different groups and >=75% usage
1084 * of allocated virtual address space.
1085 *
1086 * RETURNS:
1087 * On success, pointer to the new allocation_info is returned. On
1088 * failure, ERR_PTR value is returned.
1089 */
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001090static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
1091 size_t reserved_size, size_t dyn_size,
Tejun Heofd1e8a12009-08-14 15:00:51 +09001092 size_t atom_size,
1093 pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
Tejun Heo033e48f2009-08-14 15:00:51 +09001094{
1095 static int group_map[NR_CPUS] __initdata;
1096 static int group_cnt[NR_CPUS] __initdata;
1097 const size_t static_size = __per_cpu_end - __per_cpu_start;
Pavel V. Panteleeva92d3ff2010-06-17 10:07:25 +02001098 int nr_groups = 1, nr_units = 0;
Tejun Heo033e48f2009-08-14 15:00:51 +09001099 size_t size_sum, min_unit_size, alloc_size;
1100 int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001101 int last_allocs, group, unit;
Tejun Heo033e48f2009-08-14 15:00:51 +09001102 unsigned int cpu, tcpu;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001103 struct pcpu_alloc_info *ai;
1104 unsigned int *cpu_map;
Tejun Heo033e48f2009-08-14 15:00:51 +09001105
Tejun Heofb59e722009-09-24 18:50:34 +09001106 /* this function may be called multiple times */
1107 memset(group_map, 0, sizeof(group_map));
Pavel V. Panteleeva92d3ff2010-06-17 10:07:25 +02001108 memset(group_cnt, 0, sizeof(group_cnt));
Tejun Heofb59e722009-09-24 18:50:34 +09001109
Tejun Heo099a19d2010-06-27 18:50:00 +02001110 /* calculate size_sum and ensure dyn_size is enough for early alloc */
1111 size_sum = PFN_ALIGN(static_size + reserved_size +
1112 max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001113 dyn_size = size_sum - static_size - reserved_size;
1114
Tejun Heo033e48f2009-08-14 15:00:51 +09001115 /*
1116 * Determine min_unit_size, alloc_size and max_upa such that
Tejun Heofd1e8a12009-08-14 15:00:51 +09001117 * alloc_size is multiple of atom_size and is the smallest
Tejun Heo033e48f2009-08-14 15:00:51 +09001118 * which can accomodate 4k aligned segments which are equal to
1119 * or larger than min_unit_size.
1120 */
Tejun Heo033e48f2009-08-14 15:00:51 +09001121 min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
1122
Tejun Heofd1e8a12009-08-14 15:00:51 +09001123 alloc_size = roundup(min_unit_size, atom_size);
Tejun Heo033e48f2009-08-14 15:00:51 +09001124 upa = alloc_size / min_unit_size;
1125 while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1126 upa--;
1127 max_upa = upa;
1128
1129 /* group cpus according to their proximity */
1130 for_each_possible_cpu(cpu) {
1131 group = 0;
1132 next_group:
1133 for_each_possible_cpu(tcpu) {
1134 if (cpu == tcpu)
1135 break;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001136 if (group_map[tcpu] == group && cpu_distance_fn &&
Tejun Heo033e48f2009-08-14 15:00:51 +09001137 (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
1138 cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
1139 group++;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001140 nr_groups = max(nr_groups, group + 1);
Tejun Heo033e48f2009-08-14 15:00:51 +09001141 goto next_group;
1142 }
1143 }
1144 group_map[cpu] = group;
1145 group_cnt[group]++;
Tejun Heo033e48f2009-08-14 15:00:51 +09001146 }
1147
1148 /*
1149 * Expand unit size until address space usage goes over 75%
1150 * and then as much as possible without using more address
1151 * space.
1152 */
1153 last_allocs = INT_MAX;
1154 for (upa = max_upa; upa; upa--) {
1155 int allocs = 0, wasted = 0;
1156
1157 if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1158 continue;
1159
Tejun Heofd1e8a12009-08-14 15:00:51 +09001160 for (group = 0; group < nr_groups; group++) {
Tejun Heo033e48f2009-08-14 15:00:51 +09001161 int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
1162 allocs += this_allocs;
1163 wasted += this_allocs * upa - group_cnt[group];
1164 }
1165
1166 /*
Namhyung Kim54157c42010-08-11 11:19:19 +09001167 * Don't accept if wastage is over 1/3. The
Tejun Heo033e48f2009-08-14 15:00:51 +09001168 * greater-than comparison ensures upa==1 always
1169 * passes the following check.
1170 */
1171 if (wasted > num_possible_cpus() / 3)
1172 continue;
1173
1174 /* and then don't consume more memory */
1175 if (allocs > last_allocs)
1176 break;
1177 last_allocs = allocs;
1178 best_upa = upa;
1179 }
Tejun Heofd1e8a12009-08-14 15:00:51 +09001180 upa = best_upa;
Tejun Heo033e48f2009-08-14 15:00:51 +09001181
Tejun Heofd1e8a12009-08-14 15:00:51 +09001182 /* allocate and fill alloc_info */
1183 for (group = 0; group < nr_groups; group++)
1184 nr_units += roundup(group_cnt[group], upa);
1185
1186 ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
1187 if (!ai)
1188 return ERR_PTR(-ENOMEM);
1189 cpu_map = ai->groups[0].cpu_map;
1190
1191 for (group = 0; group < nr_groups; group++) {
1192 ai->groups[group].cpu_map = cpu_map;
1193 cpu_map += roundup(group_cnt[group], upa);
Tejun Heo033e48f2009-08-14 15:00:51 +09001194 }
1195
Tejun Heofd1e8a12009-08-14 15:00:51 +09001196 ai->static_size = static_size;
1197 ai->reserved_size = reserved_size;
1198 ai->dyn_size = dyn_size;
1199 ai->unit_size = alloc_size / upa;
1200 ai->atom_size = atom_size;
1201 ai->alloc_size = alloc_size;
1202
1203 for (group = 0, unit = 0; group_cnt[group]; group++) {
1204 struct pcpu_group_info *gi = &ai->groups[group];
1205
1206 /*
1207 * Initialize base_offset as if all groups are located
1208 * back-to-back. The caller should update this to
1209 * reflect actual allocation.
1210 */
1211 gi->base_offset = unit * ai->unit_size;
1212
1213 for_each_possible_cpu(cpu)
1214 if (group_map[cpu] == group)
1215 gi->cpu_map[gi->nr_units++] = cpu;
1216 gi->nr_units = roundup(gi->nr_units, upa);
1217 unit += gi->nr_units;
1218 }
1219 BUG_ON(unit != nr_units);
1220
1221 return ai;
Tejun Heo033e48f2009-08-14 15:00:51 +09001222}
1223
Tejun Heofd1e8a12009-08-14 15:00:51 +09001224/**
1225 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
1226 * @lvl: loglevel
1227 * @ai: allocation info to dump
1228 *
1229 * Print out information about @ai using loglevel @lvl.
1230 */
1231static void pcpu_dump_alloc_info(const char *lvl,
1232 const struct pcpu_alloc_info *ai)
Tejun Heo033e48f2009-08-14 15:00:51 +09001233{
Tejun Heofd1e8a12009-08-14 15:00:51 +09001234 int group_width = 1, cpu_width = 1, width;
Tejun Heo033e48f2009-08-14 15:00:51 +09001235 char empty_str[] = "--------";
Tejun Heofd1e8a12009-08-14 15:00:51 +09001236 int alloc = 0, alloc_end = 0;
1237 int group, v;
1238 int upa, apl; /* units per alloc, allocs per line */
Tejun Heo033e48f2009-08-14 15:00:51 +09001239
Tejun Heofd1e8a12009-08-14 15:00:51 +09001240 v = ai->nr_groups;
Tejun Heo033e48f2009-08-14 15:00:51 +09001241 while (v /= 10)
Tejun Heofd1e8a12009-08-14 15:00:51 +09001242 group_width++;
Tejun Heo033e48f2009-08-14 15:00:51 +09001243
Tejun Heofd1e8a12009-08-14 15:00:51 +09001244 v = num_possible_cpus();
1245 while (v /= 10)
1246 cpu_width++;
1247 empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
Tejun Heo033e48f2009-08-14 15:00:51 +09001248
Tejun Heofd1e8a12009-08-14 15:00:51 +09001249 upa = ai->alloc_size / ai->unit_size;
1250 width = upa * (cpu_width + 1) + group_width + 3;
1251 apl = rounddown_pow_of_two(max(60 / width, 1));
Tejun Heo033e48f2009-08-14 15:00:51 +09001252
Tejun Heofd1e8a12009-08-14 15:00:51 +09001253 printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
1254 lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
1255 ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
1256
1257 for (group = 0; group < ai->nr_groups; group++) {
1258 const struct pcpu_group_info *gi = &ai->groups[group];
1259 int unit = 0, unit_end = 0;
1260
1261 BUG_ON(gi->nr_units % upa);
1262 for (alloc_end += gi->nr_units / upa;
1263 alloc < alloc_end; alloc++) {
1264 if (!(alloc % apl)) {
Tejun Heo033e48f2009-08-14 15:00:51 +09001265 printk("\n");
Tejun Heofd1e8a12009-08-14 15:00:51 +09001266 printk("%spcpu-alloc: ", lvl);
1267 }
1268 printk("[%0*d] ", group_width, group);
1269
1270 for (unit_end += upa; unit < unit_end; unit++)
1271 if (gi->cpu_map[unit] != NR_CPUS)
1272 printk("%0*d ", cpu_width,
1273 gi->cpu_map[unit]);
1274 else
1275 printk("%s ", empty_str);
Tejun Heo033e48f2009-08-14 15:00:51 +09001276 }
Tejun Heo033e48f2009-08-14 15:00:51 +09001277 }
1278 printk("\n");
1279}
Tejun Heo033e48f2009-08-14 15:00:51 +09001280
Tejun Heofbf59bc2009-02-20 16:29:08 +09001281/**
1282 * pcpu_setup_first_chunk - initialize the first percpu chunk
Tejun Heofd1e8a12009-08-14 15:00:51 +09001283 * @ai: pcpu_alloc_info describing how to percpu area is shaped
Tejun Heo38a6be52009-07-04 08:10:59 +09001284 * @base_addr: mapped address
Tejun Heofbf59bc2009-02-20 16:29:08 +09001285 *
Tejun Heo8d408b42009-02-24 11:57:21 +09001286 * Initialize the first percpu chunk which contains the kernel static
1287 * perpcu area. This function is to be called from arch percpu area
Tejun Heo38a6be52009-07-04 08:10:59 +09001288 * setup path.
Tejun Heo8d408b42009-02-24 11:57:21 +09001289 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001290 * @ai contains all information necessary to initialize the first
1291 * chunk and prime the dynamic percpu allocator.
Tejun Heo8d408b42009-02-24 11:57:21 +09001292 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001293 * @ai->static_size is the size of static percpu area.
1294 *
1295 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
Tejun Heoedcb4632009-03-06 14:33:59 +09001296 * reserve after the static area in the first chunk. This reserves
1297 * the first chunk such that it's available only through reserved
1298 * percpu allocation. This is primarily used to serve module percpu
1299 * static areas on architectures where the addressing model has
1300 * limited offset range for symbol relocations to guarantee module
1301 * percpu symbols fall inside the relocatable range.
1302 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001303 * @ai->dyn_size determines the number of bytes available for dynamic
1304 * allocation in the first chunk. The area between @ai->static_size +
1305 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
Tejun Heo6074d5b2009-03-10 16:27:48 +09001306 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001307 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
1308 * and equal to or larger than @ai->static_size + @ai->reserved_size +
1309 * @ai->dyn_size.
Tejun Heo8d408b42009-02-24 11:57:21 +09001310 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001311 * @ai->atom_size is the allocation atom size and used as alignment
1312 * for vm areas.
Tejun Heo8d408b42009-02-24 11:57:21 +09001313 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001314 * @ai->alloc_size is the allocation size and always multiple of
1315 * @ai->atom_size. This is larger than @ai->atom_size if
1316 * @ai->unit_size is larger than @ai->atom_size.
1317 *
1318 * @ai->nr_groups and @ai->groups describe virtual memory layout of
1319 * percpu areas. Units which should be colocated are put into the
1320 * same group. Dynamic VM areas will be allocated according to these
1321 * groupings. If @ai->nr_groups is zero, a single group containing
1322 * all units is assumed.
Tejun Heo8d408b42009-02-24 11:57:21 +09001323 *
Tejun Heo38a6be52009-07-04 08:10:59 +09001324 * The caller should have mapped the first chunk at @base_addr and
1325 * copied static data to each unit.
Tejun Heofbf59bc2009-02-20 16:29:08 +09001326 *
Tejun Heoedcb4632009-03-06 14:33:59 +09001327 * If the first chunk ends up with both reserved and dynamic areas, it
1328 * is served by two chunks - one to serve the core static and reserved
1329 * areas and the other for the dynamic area. They share the same vm
1330 * and page map but uses different area allocation map to stay away
1331 * from each other. The latter chunk is circulated in the chunk slots
1332 * and available for dynamic allocation like any other chunks.
1333 *
Tejun Heofbf59bc2009-02-20 16:29:08 +09001334 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09001335 * 0 on success, -errno on failure.
Tejun Heofbf59bc2009-02-20 16:29:08 +09001336 */
Tejun Heofb435d52009-08-14 15:00:51 +09001337int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
1338 void *base_addr)
Tejun Heofbf59bc2009-02-20 16:29:08 +09001339{
Tejun Heo635b75f2009-09-24 09:43:11 +09001340 static char cpus_buf[4096] __initdata;
Tejun Heo099a19d2010-06-27 18:50:00 +02001341 static int smap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
1342 static int dmap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001343 size_t dyn_size = ai->dyn_size;
1344 size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
Tejun Heoedcb4632009-03-06 14:33:59 +09001345 struct pcpu_chunk *schunk, *dchunk = NULL;
Tejun Heo65632972009-08-14 15:00:52 +09001346 unsigned long *group_offsets;
1347 size_t *group_sizes;
Tejun Heofb435d52009-08-14 15:00:51 +09001348 unsigned long *unit_off;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001349 unsigned int cpu;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001350 int *unit_map;
1351 int group, unit, i;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001352
Tejun Heo635b75f2009-09-24 09:43:11 +09001353 cpumask_scnprintf(cpus_buf, sizeof(cpus_buf), cpu_possible_mask);
1354
1355#define PCPU_SETUP_BUG_ON(cond) do { \
1356 if (unlikely(cond)) { \
1357 pr_emerg("PERCPU: failed to initialize, %s", #cond); \
1358 pr_emerg("PERCPU: cpu_possible_mask=%s\n", cpus_buf); \
1359 pcpu_dump_alloc_info(KERN_EMERG, ai); \
1360 BUG(); \
1361 } \
1362} while (0)
1363
Tejun Heo2f39e632009-07-04 08:11:00 +09001364 /* sanity checks */
Tejun Heo635b75f2009-09-24 09:43:11 +09001365 PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
1366 PCPU_SETUP_BUG_ON(!ai->static_size);
1367 PCPU_SETUP_BUG_ON(!base_addr);
1368 PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
1369 PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
1370 PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
Tejun Heo099a19d2010-06-27 18:50:00 +02001371 PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
Tejun Heo9f645532010-04-09 18:57:01 +09001372 PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
Tejun Heo8d408b42009-02-24 11:57:21 +09001373
Tejun Heo65632972009-08-14 15:00:52 +09001374 /* process group information and build config tables accordingly */
1375 group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0]));
1376 group_sizes = alloc_bootmem(ai->nr_groups * sizeof(group_sizes[0]));
Tejun Heofd1e8a12009-08-14 15:00:51 +09001377 unit_map = alloc_bootmem(nr_cpu_ids * sizeof(unit_map[0]));
Tejun Heofb435d52009-08-14 15:00:51 +09001378 unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0]));
Tejun Heo2f39e632009-07-04 08:11:00 +09001379
Tejun Heofd1e8a12009-08-14 15:00:51 +09001380 for (cpu = 0; cpu < nr_cpu_ids; cpu++)
Tejun Heoffe0d5a2009-09-29 09:17:56 +09001381 unit_map[cpu] = UINT_MAX;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001382 pcpu_first_unit_cpu = NR_CPUS;
Tejun Heo2f39e632009-07-04 08:11:00 +09001383
Tejun Heofd1e8a12009-08-14 15:00:51 +09001384 for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
1385 const struct pcpu_group_info *gi = &ai->groups[group];
Tejun Heo2f39e632009-07-04 08:11:00 +09001386
Tejun Heo65632972009-08-14 15:00:52 +09001387 group_offsets[group] = gi->base_offset;
1388 group_sizes[group] = gi->nr_units * ai->unit_size;
1389
Tejun Heofd1e8a12009-08-14 15:00:51 +09001390 for (i = 0; i < gi->nr_units; i++) {
1391 cpu = gi->cpu_map[i];
1392 if (cpu == NR_CPUS)
1393 continue;
1394
Tejun Heo635b75f2009-09-24 09:43:11 +09001395 PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids);
1396 PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
1397 PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001398
1399 unit_map[cpu] = unit + i;
Tejun Heofb435d52009-08-14 15:00:51 +09001400 unit_off[cpu] = gi->base_offset + i * ai->unit_size;
1401
Tejun Heofd1e8a12009-08-14 15:00:51 +09001402 if (pcpu_first_unit_cpu == NR_CPUS)
Tejun Heo2f39e632009-07-04 08:11:00 +09001403 pcpu_first_unit_cpu = cpu;
Tejun Heo46b30ea2010-09-21 07:57:19 +02001404 pcpu_last_unit_cpu = cpu;
Tejun Heo2f39e632009-07-04 08:11:00 +09001405 }
Tejun Heo2f39e632009-07-04 08:11:00 +09001406 }
Tejun Heofd1e8a12009-08-14 15:00:51 +09001407 pcpu_nr_units = unit;
1408
1409 for_each_possible_cpu(cpu)
Tejun Heo635b75f2009-09-24 09:43:11 +09001410 PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
1411
1412 /* we're done parsing the input, undefine BUG macro and dump config */
1413#undef PCPU_SETUP_BUG_ON
1414 pcpu_dump_alloc_info(KERN_INFO, ai);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001415
Tejun Heo65632972009-08-14 15:00:52 +09001416 pcpu_nr_groups = ai->nr_groups;
1417 pcpu_group_offsets = group_offsets;
1418 pcpu_group_sizes = group_sizes;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001419 pcpu_unit_map = unit_map;
Tejun Heofb435d52009-08-14 15:00:51 +09001420 pcpu_unit_offsets = unit_off;
Tejun Heo2f39e632009-07-04 08:11:00 +09001421
1422 /* determine basic parameters */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001423 pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
Tejun Heod9b55ee2009-02-24 11:57:21 +09001424 pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
Tejun Heo65632972009-08-14 15:00:52 +09001425 pcpu_atom_size = ai->atom_size;
Tejun Heoce3141a2009-07-04 08:11:00 +09001426 pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
1427 BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
Tejun Heocafe8812009-03-06 14:33:59 +09001428
Tejun Heod9b55ee2009-02-24 11:57:21 +09001429 /*
1430 * Allocate chunk slots. The additional last slot is for
1431 * empty chunks.
1432 */
1433 pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001434 pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0]));
1435 for (i = 0; i < pcpu_nr_slots; i++)
1436 INIT_LIST_HEAD(&pcpu_slot[i]);
1437
Tejun Heoedcb4632009-03-06 14:33:59 +09001438 /*
1439 * Initialize static chunk. If reserved_size is zero, the
1440 * static chunk covers static area + dynamic allocation area
1441 * in the first chunk. If reserved_size is not zero, it
1442 * covers static area + reserved area (mostly used for module
1443 * static percpu allocation).
1444 */
Tejun Heo2441d152009-03-06 14:33:59 +09001445 schunk = alloc_bootmem(pcpu_chunk_struct_size);
1446 INIT_LIST_HEAD(&schunk->list);
Tejun Heobba174f2009-08-14 15:00:51 +09001447 schunk->base_addr = base_addr;
Tejun Heo61ace7f2009-03-06 14:33:59 +09001448 schunk->map = smap;
1449 schunk->map_alloc = ARRAY_SIZE(smap);
Tejun Heo38a6be52009-07-04 08:10:59 +09001450 schunk->immutable = true;
Tejun Heoce3141a2009-07-04 08:11:00 +09001451 bitmap_fill(schunk->populated, pcpu_unit_pages);
Tejun Heoedcb4632009-03-06 14:33:59 +09001452
Tejun Heofd1e8a12009-08-14 15:00:51 +09001453 if (ai->reserved_size) {
1454 schunk->free_size = ai->reserved_size;
Tejun Heoae9e6bc92009-04-02 13:19:54 +09001455 pcpu_reserved_chunk = schunk;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001456 pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
Tejun Heoedcb4632009-03-06 14:33:59 +09001457 } else {
1458 schunk->free_size = dyn_size;
1459 dyn_size = 0; /* dynamic area covered */
1460 }
Tejun Heo2441d152009-03-06 14:33:59 +09001461 schunk->contig_hint = schunk->free_size;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001462
Tejun Heofd1e8a12009-08-14 15:00:51 +09001463 schunk->map[schunk->map_used++] = -ai->static_size;
Tejun Heo61ace7f2009-03-06 14:33:59 +09001464 if (schunk->free_size)
1465 schunk->map[schunk->map_used++] = schunk->free_size;
1466
Tejun Heoedcb4632009-03-06 14:33:59 +09001467 /* init dynamic chunk if necessary */
1468 if (dyn_size) {
Tejun Heoce3141a2009-07-04 08:11:00 +09001469 dchunk = alloc_bootmem(pcpu_chunk_struct_size);
Tejun Heoedcb4632009-03-06 14:33:59 +09001470 INIT_LIST_HEAD(&dchunk->list);
Tejun Heobba174f2009-08-14 15:00:51 +09001471 dchunk->base_addr = base_addr;
Tejun Heoedcb4632009-03-06 14:33:59 +09001472 dchunk->map = dmap;
1473 dchunk->map_alloc = ARRAY_SIZE(dmap);
Tejun Heo38a6be52009-07-04 08:10:59 +09001474 dchunk->immutable = true;
Tejun Heoce3141a2009-07-04 08:11:00 +09001475 bitmap_fill(dchunk->populated, pcpu_unit_pages);
Tejun Heoedcb4632009-03-06 14:33:59 +09001476
1477 dchunk->contig_hint = dchunk->free_size = dyn_size;
1478 dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit;
1479 dchunk->map[dchunk->map_used++] = dchunk->free_size;
1480 }
1481
Tejun Heo2441d152009-03-06 14:33:59 +09001482 /* link the first chunk in */
Tejun Heoae9e6bc92009-04-02 13:19:54 +09001483 pcpu_first_chunk = dchunk ?: schunk;
1484 pcpu_chunk_relocate(pcpu_first_chunk, -1);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001485
1486 /* we're done */
Tejun Heobba174f2009-08-14 15:00:51 +09001487 pcpu_base_addr = base_addr;
Tejun Heofb435d52009-08-14 15:00:51 +09001488 return 0;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001489}
Tejun Heo66c3a752009-03-10 16:27:48 +09001490
Tejun Heof58dc012009-08-14 15:00:50 +09001491const char *pcpu_fc_names[PCPU_FC_NR] __initdata = {
1492 [PCPU_FC_AUTO] = "auto",
1493 [PCPU_FC_EMBED] = "embed",
1494 [PCPU_FC_PAGE] = "page",
Tejun Heof58dc012009-08-14 15:00:50 +09001495};
Tejun Heo66c3a752009-03-10 16:27:48 +09001496
Tejun Heof58dc012009-08-14 15:00:50 +09001497enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
1498
1499static int __init percpu_alloc_setup(char *str)
Tejun Heo66c3a752009-03-10 16:27:48 +09001500{
Tejun Heof58dc012009-08-14 15:00:50 +09001501 if (0)
1502 /* nada */;
1503#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
1504 else if (!strcmp(str, "embed"))
1505 pcpu_chosen_fc = PCPU_FC_EMBED;
1506#endif
1507#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1508 else if (!strcmp(str, "page"))
1509 pcpu_chosen_fc = PCPU_FC_PAGE;
1510#endif
Tejun Heof58dc012009-08-14 15:00:50 +09001511 else
1512 pr_warning("PERCPU: unknown allocator %s specified\n", str);
Tejun Heo66c3a752009-03-10 16:27:48 +09001513
Tejun Heof58dc012009-08-14 15:00:50 +09001514 return 0;
Tejun Heo66c3a752009-03-10 16:27:48 +09001515}
Tejun Heof58dc012009-08-14 15:00:50 +09001516early_param("percpu_alloc", percpu_alloc_setup);
Tejun Heo66c3a752009-03-10 16:27:48 +09001517
Tejun Heo08fc4582009-08-14 15:00:49 +09001518#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
1519 !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
Tejun Heo66c3a752009-03-10 16:27:48 +09001520/**
1521 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
Tejun Heo66c3a752009-03-10 16:27:48 +09001522 * @reserved_size: the size of reserved percpu area in bytes
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001523 * @dyn_size: minimum free size for dynamic allocation in bytes
Tejun Heoc8826dd2009-08-14 15:00:52 +09001524 * @atom_size: allocation atom size
1525 * @cpu_distance_fn: callback to determine distance between cpus, optional
1526 * @alloc_fn: function to allocate percpu page
1527 * @free_fn: funtion to free percpu page
Tejun Heo66c3a752009-03-10 16:27:48 +09001528 *
1529 * This is a helper to ease setting up embedded first percpu chunk and
1530 * can be called where pcpu_setup_first_chunk() is expected.
1531 *
1532 * If this function is used to setup the first chunk, it is allocated
Tejun Heoc8826dd2009-08-14 15:00:52 +09001533 * by calling @alloc_fn and used as-is without being mapped into
1534 * vmalloc area. Allocations are always whole multiples of @atom_size
1535 * aligned to @atom_size.
1536 *
1537 * This enables the first chunk to piggy back on the linear physical
1538 * mapping which often uses larger page size. Please note that this
1539 * can result in very sparse cpu->unit mapping on NUMA machines thus
1540 * requiring large vmalloc address space. Don't use this allocator if
1541 * vmalloc space is not orders of magnitude larger than distances
1542 * between node memory addresses (ie. 32bit NUMA machines).
Tejun Heo66c3a752009-03-10 16:27:48 +09001543 *
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001544 * @dyn_size specifies the minimum dynamic area size.
Tejun Heo66c3a752009-03-10 16:27:48 +09001545 *
1546 * If the needed size is smaller than the minimum or specified unit
Tejun Heoc8826dd2009-08-14 15:00:52 +09001547 * size, the leftover is returned using @free_fn.
Tejun Heo66c3a752009-03-10 16:27:48 +09001548 *
1549 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09001550 * 0 on success, -errno on failure.
Tejun Heo66c3a752009-03-10 16:27:48 +09001551 */
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001552int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
Tejun Heoc8826dd2009-08-14 15:00:52 +09001553 size_t atom_size,
1554 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
1555 pcpu_fc_alloc_fn_t alloc_fn,
1556 pcpu_fc_free_fn_t free_fn)
Tejun Heo66c3a752009-03-10 16:27:48 +09001557{
Tejun Heoc8826dd2009-08-14 15:00:52 +09001558 void *base = (void *)ULONG_MAX;
1559 void **areas = NULL;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001560 struct pcpu_alloc_info *ai;
Tejun Heo6ea529a2009-09-24 18:46:01 +09001561 size_t size_sum, areas_size, max_distance;
Tejun Heoc8826dd2009-08-14 15:00:52 +09001562 int group, i, rc;
Tejun Heo66c3a752009-03-10 16:27:48 +09001563
Tejun Heoc8826dd2009-08-14 15:00:52 +09001564 ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
1565 cpu_distance_fn);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001566 if (IS_ERR(ai))
1567 return PTR_ERR(ai);
Tejun Heo66c3a752009-03-10 16:27:48 +09001568
Tejun Heofd1e8a12009-08-14 15:00:51 +09001569 size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
Tejun Heoc8826dd2009-08-14 15:00:52 +09001570 areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
Tejun Heo66c3a752009-03-10 16:27:48 +09001571
Tejun Heoc8826dd2009-08-14 15:00:52 +09001572 areas = alloc_bootmem_nopanic(areas_size);
1573 if (!areas) {
Tejun Heofb435d52009-08-14 15:00:51 +09001574 rc = -ENOMEM;
Tejun Heoc8826dd2009-08-14 15:00:52 +09001575 goto out_free;
Tejun Heofa8a7092009-06-22 11:56:24 +09001576 }
Tejun Heo66c3a752009-03-10 16:27:48 +09001577
Tejun Heoc8826dd2009-08-14 15:00:52 +09001578 /* allocate, copy and determine base address */
1579 for (group = 0; group < ai->nr_groups; group++) {
1580 struct pcpu_group_info *gi = &ai->groups[group];
1581 unsigned int cpu = NR_CPUS;
1582 void *ptr;
Tejun Heo66c3a752009-03-10 16:27:48 +09001583
Tejun Heoc8826dd2009-08-14 15:00:52 +09001584 for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
1585 cpu = gi->cpu_map[i];
1586 BUG_ON(cpu == NR_CPUS);
1587
1588 /* allocate space for the whole group */
1589 ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
1590 if (!ptr) {
1591 rc = -ENOMEM;
1592 goto out_free_areas;
1593 }
1594 areas[group] = ptr;
1595
1596 base = min(ptr, base);
1597
1598 for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
1599 if (gi->cpu_map[i] == NR_CPUS) {
1600 /* unused unit, free whole */
1601 free_fn(ptr, ai->unit_size);
1602 continue;
1603 }
1604 /* copy and return the unused part */
1605 memcpy(ptr, __per_cpu_load, ai->static_size);
1606 free_fn(ptr + size_sum, ai->unit_size - size_sum);
1607 }
Tejun Heo66c3a752009-03-10 16:27:48 +09001608 }
1609
Tejun Heoc8826dd2009-08-14 15:00:52 +09001610 /* base address is now known, determine group base offsets */
Tejun Heo6ea529a2009-09-24 18:46:01 +09001611 max_distance = 0;
1612 for (group = 0; group < ai->nr_groups; group++) {
Tejun Heoc8826dd2009-08-14 15:00:52 +09001613 ai->groups[group].base_offset = areas[group] - base;
Tejun Heo1a0c3292009-10-04 09:31:05 +09001614 max_distance = max_t(size_t, max_distance,
1615 ai->groups[group].base_offset);
Tejun Heo6ea529a2009-09-24 18:46:01 +09001616 }
1617 max_distance += ai->unit_size;
1618
1619 /* warn if maximum distance is further than 75% of vmalloc space */
1620 if (max_distance > (VMALLOC_END - VMALLOC_START) * 3 / 4) {
Tejun Heo1a0c3292009-10-04 09:31:05 +09001621 pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc "
Tejun Heo6ea529a2009-09-24 18:46:01 +09001622 "space 0x%lx\n",
1623 max_distance, VMALLOC_END - VMALLOC_START);
1624#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1625 /* and fail if we have fallback */
1626 rc = -EINVAL;
1627 goto out_free;
1628#endif
1629 }
Tejun Heoc8826dd2009-08-14 15:00:52 +09001630
Tejun Heo004018e2009-08-14 15:00:49 +09001631 pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
Tejun Heofd1e8a12009-08-14 15:00:51 +09001632 PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
1633 ai->dyn_size, ai->unit_size);
Tejun Heo66c3a752009-03-10 16:27:48 +09001634
Tejun Heofb435d52009-08-14 15:00:51 +09001635 rc = pcpu_setup_first_chunk(ai, base);
Tejun Heoc8826dd2009-08-14 15:00:52 +09001636 goto out_free;
1637
1638out_free_areas:
1639 for (group = 0; group < ai->nr_groups; group++)
1640 free_fn(areas[group],
1641 ai->groups[group].nr_units * ai->unit_size);
1642out_free:
Tejun Heofd1e8a12009-08-14 15:00:51 +09001643 pcpu_free_alloc_info(ai);
Tejun Heoc8826dd2009-08-14 15:00:52 +09001644 if (areas)
1645 free_bootmem(__pa(areas), areas_size);
Tejun Heofb435d52009-08-14 15:00:51 +09001646 return rc;
Tejun Heod4b95f82009-07-04 08:10:59 +09001647}
Tejun Heo08fc4582009-08-14 15:00:49 +09001648#endif /* CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK ||
1649 !CONFIG_HAVE_SETUP_PER_CPU_AREA */
Tejun Heod4b95f82009-07-04 08:10:59 +09001650
Tejun Heo08fc4582009-08-14 15:00:49 +09001651#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
Tejun Heod4b95f82009-07-04 08:10:59 +09001652/**
Tejun Heo00ae4062009-08-14 15:00:49 +09001653 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
Tejun Heod4b95f82009-07-04 08:10:59 +09001654 * @reserved_size: the size of reserved percpu area in bytes
1655 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
1656 * @free_fn: funtion to free percpu page, always called with PAGE_SIZE
1657 * @populate_pte_fn: function to populate pte
1658 *
Tejun Heo00ae4062009-08-14 15:00:49 +09001659 * This is a helper to ease setting up page-remapped first percpu
1660 * chunk and can be called where pcpu_setup_first_chunk() is expected.
Tejun Heod4b95f82009-07-04 08:10:59 +09001661 *
1662 * This is the basic allocator. Static percpu area is allocated
1663 * page-by-page into vmalloc area.
1664 *
1665 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09001666 * 0 on success, -errno on failure.
Tejun Heod4b95f82009-07-04 08:10:59 +09001667 */
Tejun Heofb435d52009-08-14 15:00:51 +09001668int __init pcpu_page_first_chunk(size_t reserved_size,
1669 pcpu_fc_alloc_fn_t alloc_fn,
1670 pcpu_fc_free_fn_t free_fn,
1671 pcpu_fc_populate_pte_fn_t populate_pte_fn)
Tejun Heod4b95f82009-07-04 08:10:59 +09001672{
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001673 static struct vm_struct vm;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001674 struct pcpu_alloc_info *ai;
Tejun Heo00ae4062009-08-14 15:00:49 +09001675 char psize_str[16];
Tejun Heoce3141a2009-07-04 08:11:00 +09001676 int unit_pages;
Tejun Heod4b95f82009-07-04 08:10:59 +09001677 size_t pages_size;
Tejun Heoce3141a2009-07-04 08:11:00 +09001678 struct page **pages;
Tejun Heofb435d52009-08-14 15:00:51 +09001679 int unit, i, j, rc;
Tejun Heod4b95f82009-07-04 08:10:59 +09001680
Tejun Heo00ae4062009-08-14 15:00:49 +09001681 snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
1682
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001683 ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001684 if (IS_ERR(ai))
1685 return PTR_ERR(ai);
1686 BUG_ON(ai->nr_groups != 1);
1687 BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
1688
1689 unit_pages = ai->unit_size >> PAGE_SHIFT;
Tejun Heod4b95f82009-07-04 08:10:59 +09001690
1691 /* unaligned allocations can't be freed, round up to page size */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001692 pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
1693 sizeof(pages[0]));
Tejun Heoce3141a2009-07-04 08:11:00 +09001694 pages = alloc_bootmem(pages_size);
Tejun Heod4b95f82009-07-04 08:10:59 +09001695
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001696 /* allocate pages */
Tejun Heod4b95f82009-07-04 08:10:59 +09001697 j = 0;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001698 for (unit = 0; unit < num_possible_cpus(); unit++)
Tejun Heoce3141a2009-07-04 08:11:00 +09001699 for (i = 0; i < unit_pages; i++) {
Tejun Heofd1e8a12009-08-14 15:00:51 +09001700 unsigned int cpu = ai->groups[0].cpu_map[unit];
Tejun Heod4b95f82009-07-04 08:10:59 +09001701 void *ptr;
1702
Tejun Heo3cbc8562009-08-14 15:00:50 +09001703 ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
Tejun Heod4b95f82009-07-04 08:10:59 +09001704 if (!ptr) {
Tejun Heo00ae4062009-08-14 15:00:49 +09001705 pr_warning("PERCPU: failed to allocate %s page "
1706 "for cpu%u\n", psize_str, cpu);
Tejun Heod4b95f82009-07-04 08:10:59 +09001707 goto enomem;
1708 }
Tejun Heoce3141a2009-07-04 08:11:00 +09001709 pages[j++] = virt_to_page(ptr);
Tejun Heod4b95f82009-07-04 08:10:59 +09001710 }
1711
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001712 /* allocate vm area, map the pages and copy static data */
1713 vm.flags = VM_ALLOC;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001714 vm.size = num_possible_cpus() * ai->unit_size;
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001715 vm_area_register_early(&vm, PAGE_SIZE);
1716
Tejun Heofd1e8a12009-08-14 15:00:51 +09001717 for (unit = 0; unit < num_possible_cpus(); unit++) {
Tejun Heo1d9d3252009-08-14 15:00:50 +09001718 unsigned long unit_addr =
Tejun Heofd1e8a12009-08-14 15:00:51 +09001719 (unsigned long)vm.addr + unit * ai->unit_size;
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001720
Tejun Heoce3141a2009-07-04 08:11:00 +09001721 for (i = 0; i < unit_pages; i++)
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001722 populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
1723
1724 /* pte already populated, the following shouldn't fail */
Tejun Heofb435d52009-08-14 15:00:51 +09001725 rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
1726 unit_pages);
1727 if (rc < 0)
1728 panic("failed to map percpu area, err=%d\n", rc);
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001729
1730 /*
1731 * FIXME: Archs with virtual cache should flush local
1732 * cache for the linear mapping here - something
1733 * equivalent to flush_cache_vmap() on the local cpu.
1734 * flush_cache_vmap() can't be used as most supporting
1735 * data structures are not set up yet.
1736 */
1737
1738 /* copy static data */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001739 memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
Tejun Heo66c3a752009-03-10 16:27:48 +09001740 }
1741
1742 /* we're ready, commit */
Tejun Heo1d9d3252009-08-14 15:00:50 +09001743 pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
Tejun Heofd1e8a12009-08-14 15:00:51 +09001744 unit_pages, psize_str, vm.addr, ai->static_size,
1745 ai->reserved_size, ai->dyn_size);
Tejun Heo66c3a752009-03-10 16:27:48 +09001746
Tejun Heofb435d52009-08-14 15:00:51 +09001747 rc = pcpu_setup_first_chunk(ai, vm.addr);
Tejun Heod4b95f82009-07-04 08:10:59 +09001748 goto out_free_ar;
1749
1750enomem:
1751 while (--j >= 0)
Tejun Heoce3141a2009-07-04 08:11:00 +09001752 free_fn(page_address(pages[j]), PAGE_SIZE);
Tejun Heofb435d52009-08-14 15:00:51 +09001753 rc = -ENOMEM;
Tejun Heod4b95f82009-07-04 08:10:59 +09001754out_free_ar:
Tejun Heoce3141a2009-07-04 08:11:00 +09001755 free_bootmem(__pa(pages), pages_size);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001756 pcpu_free_alloc_info(ai);
Tejun Heofb435d52009-08-14 15:00:51 +09001757 return rc;
Tejun Heo66c3a752009-03-10 16:27:48 +09001758}
Tejun Heo08fc4582009-08-14 15:00:49 +09001759#endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */
Tejun Heod4b95f82009-07-04 08:10:59 +09001760
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001761/*
Tejun Heoe74e3962009-03-30 19:07:44 +09001762 * Generic percpu area setup.
1763 *
1764 * The embedding helper is used because its behavior closely resembles
1765 * the original non-dynamic generic percpu area setup. This is
1766 * important because many archs have addressing restrictions and might
1767 * fail if the percpu area is located far away from the previous
1768 * location. As an added bonus, in non-NUMA cases, embedding is
1769 * generally a good idea TLB-wise because percpu area can piggy back
1770 * on the physical linear memory mapping which uses large page
1771 * mappings on applicable archs.
1772 */
1773#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
1774unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
1775EXPORT_SYMBOL(__per_cpu_offset);
1776
Tejun Heoc8826dd2009-08-14 15:00:52 +09001777static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
1778 size_t align)
1779{
1780 return __alloc_bootmem_nopanic(size, align, __pa(MAX_DMA_ADDRESS));
1781}
1782
1783static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
1784{
1785 free_bootmem(__pa(ptr), size);
1786}
1787
Tejun Heoe74e3962009-03-30 19:07:44 +09001788void __init setup_per_cpu_areas(void)
1789{
Tejun Heoe74e3962009-03-30 19:07:44 +09001790 unsigned long delta;
1791 unsigned int cpu;
Tejun Heofb435d52009-08-14 15:00:51 +09001792 int rc;
Tejun Heoe74e3962009-03-30 19:07:44 +09001793
1794 /*
1795 * Always reserve area for module percpu variables. That's
1796 * what the legacy allocator did.
1797 */
Tejun Heofb435d52009-08-14 15:00:51 +09001798 rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
Tejun Heoc8826dd2009-08-14 15:00:52 +09001799 PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
1800 pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
Tejun Heofb435d52009-08-14 15:00:51 +09001801 if (rc < 0)
Tejun Heoe74e3962009-03-30 19:07:44 +09001802 panic("Failed to initialized percpu areas.");
1803
1804 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
1805 for_each_possible_cpu(cpu)
Tejun Heofb435d52009-08-14 15:00:51 +09001806 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
Tejun Heoe74e3962009-03-30 19:07:44 +09001807}
1808#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
Tejun Heo099a19d2010-06-27 18:50:00 +02001809
1810/*
1811 * First and reserved chunks are initialized with temporary allocation
1812 * map in initdata so that they can be used before slab is online.
1813 * This function is called after slab is brought up and replaces those
1814 * with properly allocated maps.
1815 */
1816void __init percpu_init_late(void)
1817{
1818 struct pcpu_chunk *target_chunks[] =
1819 { pcpu_first_chunk, pcpu_reserved_chunk, NULL };
1820 struct pcpu_chunk *chunk;
1821 unsigned long flags;
1822 int i;
1823
1824 for (i = 0; (chunk = target_chunks[i]); i++) {
1825 int *map;
1826 const size_t size = PERCPU_DYNAMIC_EARLY_SLOTS * sizeof(map[0]);
1827
1828 BUILD_BUG_ON(size > PAGE_SIZE);
1829
1830 map = pcpu_mem_alloc(size);
1831 BUG_ON(!map);
1832
1833 spin_lock_irqsave(&pcpu_lock, flags);
1834 memcpy(map, chunk->map, size);
1835 chunk->map = map;
1836 spin_unlock_irqrestore(&pcpu_lock, flags);
1837 }
1838}