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Tejun Heofbf59bc2009-02-20 16:29:08 +09001/*
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
Tejun Heo2f39e632009-07-04 08:11:00 +090011 * 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
Tejun Heofbf59bc2009-02-20 16:29:08 +090018 *
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,
Tejun Heo2f39e632009-07-04 08:11:00 +090026 * 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.
Tejun Heofbf59bc2009-02-20 16:29:08 +090030 *
Tejun Heo2f39e632009-07-04 08:11:00 +090031 * There are usually many small percpu allocations many of them being
32 * as small as 4 bytes. The allocator organizes chunks into lists
Tejun Heofbf59bc2009-02-20 16:29:08 +090033 * 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.
Christoph Lametere1b9aa32009-04-02 13:21:44 +090044 * 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.
Tejun Heofbf59bc2009-02-20 16:29:08 +090046 *
47 * To use this allocator, arch code should do the followings.
48 *
Tejun Heoe74e3962009-03-30 19:07:44 +090049 * - drop CONFIG_HAVE_LEGACY_PER_CPU_AREA
Tejun Heofbf59bc2009-02-20 16:29:08 +090050 *
51 * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
Tejun Heoe0100982009-03-10 16:27:48 +090052 * regular address to percpu pointer and back if they need to be
53 * different from the default
Tejun Heofbf59bc2009-02-20 16:29:08 +090054 *
Tejun Heo8d408b42009-02-24 11:57:21 +090055 * - use pcpu_setup_first_chunk() during percpu area initialization to
56 * setup the first chunk containing the kernel static percpu area
Tejun Heofbf59bc2009-02-20 16:29:08 +090057 */
58
59#include <linux/bitmap.h>
60#include <linux/bootmem.h>
Tejun Heofd1e8a12009-08-14 15:00:51 +090061#include <linux/err.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090062#include <linux/list.h>
Tejun Heoa530b792009-07-04 08:11:00 +090063#include <linux/log2.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090064#include <linux/mm.h>
65#include <linux/module.h>
66#include <linux/mutex.h>
67#include <linux/percpu.h>
68#include <linux/pfn.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090069#include <linux/slab.h>
Tejun Heoccea34b2009-03-07 00:44:13 +090070#include <linux/spinlock.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090071#include <linux/vmalloc.h>
Tejun Heoa56dbdd2009-03-07 00:44:11 +090072#include <linux/workqueue.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090073
74#include <asm/cacheflush.h>
Tejun Heoe0100982009-03-10 16:27:48 +090075#include <asm/sections.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090076#include <asm/tlbflush.h>
77
Tejun Heofbf59bc2009-02-20 16:29:08 +090078#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
79#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
80
Tejun Heoe0100982009-03-10 16:27:48 +090081/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
82#ifndef __addr_to_pcpu_ptr
83#define __addr_to_pcpu_ptr(addr) \
84 (void *)((unsigned long)(addr) - (unsigned long)pcpu_base_addr \
85 + (unsigned long)__per_cpu_start)
86#endif
87#ifndef __pcpu_ptr_to_addr
88#define __pcpu_ptr_to_addr(ptr) \
89 (void *)((unsigned long)(ptr) + (unsigned long)pcpu_base_addr \
90 - (unsigned long)__per_cpu_start)
91#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 */
97 struct vm_struct *vm; /* mapped vmalloc region */
98 int map_used; /* # of map entries used */
99 int map_alloc; /* # of map entries allocated */
100 int *map; /* allocation map */
Tejun Heo8d408b42009-02-24 11:57:21 +0900101 bool immutable; /* no [de]population allowed */
Tejun Heoce3141a2009-07-04 08:11:00 +0900102 unsigned long populated[]; /* populated bitmap */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900103};
104
Tejun Heo40150d32009-02-24 12:32:28 +0900105static int pcpu_unit_pages __read_mostly;
106static int pcpu_unit_size __read_mostly;
Tejun Heo2f39e632009-07-04 08:11:00 +0900107static int pcpu_nr_units __read_mostly;
Tejun Heo40150d32009-02-24 12:32:28 +0900108static int pcpu_chunk_size __read_mostly;
109static int pcpu_nr_slots __read_mostly;
110static size_t pcpu_chunk_struct_size __read_mostly;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900111
Tejun Heo2f39e632009-07-04 08:11:00 +0900112/* cpus with the lowest and highest unit numbers */
113static unsigned int pcpu_first_unit_cpu __read_mostly;
114static unsigned int pcpu_last_unit_cpu __read_mostly;
115
Tejun Heofbf59bc2009-02-20 16:29:08 +0900116/* the address of the first chunk which starts with the kernel static area */
Tejun Heo40150d32009-02-24 12:32:28 +0900117void *pcpu_base_addr __read_mostly;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900118EXPORT_SYMBOL_GPL(pcpu_base_addr);
119
Tejun Heofb435d52009-08-14 15:00:51 +0900120static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
121const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */
Tejun Heo2f39e632009-07-04 08:11:00 +0900122
Tejun Heoae9e6bc92009-04-02 13:19:54 +0900123/*
124 * The first chunk which always exists. Note that unlike other
125 * chunks, this one can be allocated and mapped in several different
126 * ways and thus often doesn't live in the vmalloc area.
127 */
128static struct pcpu_chunk *pcpu_first_chunk;
129
130/*
131 * Optional reserved chunk. This chunk reserves part of the first
132 * chunk and serves it for reserved allocations. The amount of
133 * reserved offset is in pcpu_reserved_chunk_limit. When reserved
134 * area doesn't exist, the following variables contain NULL and 0
135 * respectively.
136 */
Tejun Heoedcb4632009-03-06 14:33:59 +0900137static struct pcpu_chunk *pcpu_reserved_chunk;
Tejun Heoedcb4632009-03-06 14:33:59 +0900138static int pcpu_reserved_chunk_limit;
139
Tejun Heofbf59bc2009-02-20 16:29:08 +0900140/*
Tejun Heoccea34b2009-03-07 00:44:13 +0900141 * Synchronization rules.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900142 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900143 * There are two locks - pcpu_alloc_mutex and pcpu_lock. The former
Tejun Heoce3141a2009-07-04 08:11:00 +0900144 * protects allocation/reclaim paths, chunks, populated bitmap and
145 * vmalloc mapping. The latter is a spinlock and protects the index
146 * data structures - chunk slots, chunks and area maps in chunks.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900147 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900148 * During allocation, pcpu_alloc_mutex is kept locked all the time and
149 * pcpu_lock is grabbed and released as necessary. All actual memory
150 * allocations are done using GFP_KERNEL with pcpu_lock released.
151 *
152 * Free path accesses and alters only the index data structures, so it
153 * can be safely called from atomic context. When memory needs to be
154 * returned to the system, free path schedules reclaim_work which
155 * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be
156 * reclaimed, release both locks and frees the chunks. Note that it's
157 * necessary to grab both locks to remove a chunk from circulation as
158 * allocation path might be referencing the chunk with only
159 * pcpu_alloc_mutex locked.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900160 */
Tejun Heoccea34b2009-03-07 00:44:13 +0900161static DEFINE_MUTEX(pcpu_alloc_mutex); /* protects whole alloc and reclaim */
162static DEFINE_SPINLOCK(pcpu_lock); /* protects index data structures */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900163
Tejun Heo40150d32009-02-24 12:32:28 +0900164static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900165
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900166/* reclaim work to release fully free chunks, scheduled from free path */
167static void pcpu_reclaim(struct work_struct *work);
168static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim);
169
Tejun Heod9b55ee2009-02-24 11:57:21 +0900170static int __pcpu_size_to_slot(int size)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900171{
Tejun Heocae3aeb2009-02-21 16:56:23 +0900172 int highbit = fls(size); /* size is in bytes */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900173 return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
174}
175
Tejun Heod9b55ee2009-02-24 11:57:21 +0900176static int pcpu_size_to_slot(int size)
177{
178 if (size == pcpu_unit_size)
179 return pcpu_nr_slots - 1;
180 return __pcpu_size_to_slot(size);
181}
182
Tejun Heofbf59bc2009-02-20 16:29:08 +0900183static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
184{
185 if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
186 return 0;
187
188 return pcpu_size_to_slot(chunk->free_size);
189}
190
191static int pcpu_page_idx(unsigned int cpu, int page_idx)
192{
Tejun Heo2f39e632009-07-04 08:11:00 +0900193 return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900194}
195
Tejun Heofbf59bc2009-02-20 16:29:08 +0900196static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
197 unsigned int cpu, int page_idx)
198{
Tejun Heofb435d52009-08-14 15:00:51 +0900199 return (unsigned long)chunk->vm->addr + pcpu_unit_offsets[cpu] +
200 (page_idx << PAGE_SHIFT);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900201}
202
Tejun Heoce3141a2009-07-04 08:11:00 +0900203static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
204 unsigned int cpu, int page_idx)
Tejun Heoc8a51be2009-07-04 08:10:59 +0900205{
Tejun Heoce3141a2009-07-04 08:11:00 +0900206 /* must not be used on pre-mapped chunk */
207 WARN_ON(chunk->immutable);
Tejun Heoc8a51be2009-07-04 08:10:59 +0900208
Tejun Heoce3141a2009-07-04 08:11:00 +0900209 return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
Tejun Heofbf59bc2009-02-20 16:29:08 +0900210}
211
Christoph Lametere1b9aa32009-04-02 13:21:44 +0900212/* set the pointer to a chunk in a page struct */
213static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
214{
215 page->index = (unsigned long)pcpu;
216}
217
218/* obtain pointer to a chunk from a page struct */
219static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
220{
221 return (struct pcpu_chunk *)page->index;
222}
223
Tejun Heoce3141a2009-07-04 08:11:00 +0900224static void pcpu_next_unpop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
225{
226 *rs = find_next_zero_bit(chunk->populated, end, *rs);
227 *re = find_next_bit(chunk->populated, end, *rs + 1);
228}
229
230static void pcpu_next_pop(struct pcpu_chunk *chunk, int *rs, int *re, int end)
231{
232 *rs = find_next_bit(chunk->populated, end, *rs);
233 *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
234}
235
236/*
237 * (Un)populated page region iterators. Iterate over (un)populated
238 * page regions betwen @start and @end in @chunk. @rs and @re should
239 * be integer variables and will be set to start and end page index of
240 * the current region.
241 */
242#define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
243 for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
244 (rs) < (re); \
245 (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
246
247#define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
248 for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
249 (rs) < (re); \
250 (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
251
Tejun Heofbf59bc2009-02-20 16:29:08 +0900252/**
Tejun Heo1880d932009-03-07 00:44:09 +0900253 * pcpu_mem_alloc - allocate memory
254 * @size: bytes to allocate
Tejun Heofbf59bc2009-02-20 16:29:08 +0900255 *
Tejun Heo1880d932009-03-07 00:44:09 +0900256 * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
257 * kzalloc() is used; otherwise, vmalloc() is used. The returned
258 * memory is always zeroed.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900259 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900260 * CONTEXT:
261 * Does GFP_KERNEL allocation.
262 *
Tejun Heofbf59bc2009-02-20 16:29:08 +0900263 * RETURNS:
Tejun Heo1880d932009-03-07 00:44:09 +0900264 * Pointer to the allocated area on success, NULL on failure.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900265 */
Tejun Heo1880d932009-03-07 00:44:09 +0900266static void *pcpu_mem_alloc(size_t size)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900267{
Tejun Heofbf59bc2009-02-20 16:29:08 +0900268 if (size <= PAGE_SIZE)
Tejun Heo1880d932009-03-07 00:44:09 +0900269 return kzalloc(size, GFP_KERNEL);
270 else {
271 void *ptr = vmalloc(size);
272 if (ptr)
273 memset(ptr, 0, size);
274 return ptr;
275 }
276}
Tejun Heofbf59bc2009-02-20 16:29:08 +0900277
Tejun Heo1880d932009-03-07 00:44:09 +0900278/**
279 * pcpu_mem_free - free memory
280 * @ptr: memory to free
281 * @size: size of the area
282 *
283 * Free @ptr. @ptr should have been allocated using pcpu_mem_alloc().
284 */
285static void pcpu_mem_free(void *ptr, size_t size)
286{
287 if (size <= PAGE_SIZE)
288 kfree(ptr);
289 else
290 vfree(ptr);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900291}
292
293/**
294 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
295 * @chunk: chunk of interest
296 * @oslot: the previous slot it was on
297 *
298 * This function is called after an allocation or free changed @chunk.
299 * New slot according to the changed state is determined and @chunk is
Tejun Heoedcb4632009-03-06 14:33:59 +0900300 * moved to the slot. Note that the reserved chunk is never put on
301 * chunk slots.
Tejun Heoccea34b2009-03-07 00:44:13 +0900302 *
303 * CONTEXT:
304 * pcpu_lock.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900305 */
306static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
307{
308 int nslot = pcpu_chunk_slot(chunk);
309
Tejun Heoedcb4632009-03-06 14:33:59 +0900310 if (chunk != pcpu_reserved_chunk && oslot != nslot) {
Tejun Heofbf59bc2009-02-20 16:29:08 +0900311 if (oslot < nslot)
312 list_move(&chunk->list, &pcpu_slot[nslot]);
313 else
314 list_move_tail(&chunk->list, &pcpu_slot[nslot]);
315 }
316}
317
Tejun Heofbf59bc2009-02-20 16:29:08 +0900318/**
Christoph Lametere1b9aa32009-04-02 13:21:44 +0900319 * pcpu_chunk_addr_search - determine chunk containing specified address
320 * @addr: address for which the chunk needs to be determined.
Tejun Heoccea34b2009-03-07 00:44:13 +0900321 *
Tejun Heofbf59bc2009-02-20 16:29:08 +0900322 * RETURNS:
323 * The address of the found chunk.
324 */
325static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
326{
Tejun Heoae9e6bc92009-04-02 13:19:54 +0900327 void *first_start = pcpu_first_chunk->vm->addr;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900328
Tejun Heoae9e6bc92009-04-02 13:19:54 +0900329 /* is it in the first chunk? */
Tejun Heo79ba6ac2009-07-04 08:10:58 +0900330 if (addr >= first_start && addr < first_start + pcpu_unit_size) {
Tejun Heoae9e6bc92009-04-02 13:19:54 +0900331 /* is it in the reserved area? */
332 if (addr < first_start + pcpu_reserved_chunk_limit)
Tejun Heoedcb4632009-03-06 14:33:59 +0900333 return pcpu_reserved_chunk;
Tejun Heoae9e6bc92009-04-02 13:19:54 +0900334 return pcpu_first_chunk;
Tejun Heoedcb4632009-03-06 14:33:59 +0900335 }
336
Tejun Heo2f39e632009-07-04 08:11:00 +0900337 /*
338 * The address is relative to unit0 which might be unused and
339 * thus unmapped. Offset the address to the unit space of the
340 * current processor before looking it up in the vmalloc
341 * space. Note that any possible cpu id can be used here, so
342 * there's no need to worry about preemption or cpu hotplug.
343 */
Tejun Heofb435d52009-08-14 15:00:51 +0900344 addr += pcpu_unit_offsets[smp_processor_id()];
Christoph Lametere1b9aa32009-04-02 13:21:44 +0900345 return pcpu_get_page_chunk(vmalloc_to_page(addr));
Tejun Heofbf59bc2009-02-20 16:29:08 +0900346}
347
348/**
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900349 * pcpu_extend_area_map - extend area map for allocation
350 * @chunk: target chunk
351 *
352 * Extend area map of @chunk so that it can accomodate an allocation.
353 * A single allocation can split an area into three areas, so this
354 * function makes sure that @chunk->map has at least two extra slots.
355 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900356 * CONTEXT:
357 * pcpu_alloc_mutex, pcpu_lock. pcpu_lock is released and reacquired
358 * if area map is extended.
359 *
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900360 * RETURNS:
361 * 0 if noop, 1 if successfully extended, -errno on failure.
362 */
363static int pcpu_extend_area_map(struct pcpu_chunk *chunk)
364{
365 int new_alloc;
366 int *new;
367 size_t size;
368
369 /* has enough? */
370 if (chunk->map_alloc >= chunk->map_used + 2)
371 return 0;
372
Tejun Heoccea34b2009-03-07 00:44:13 +0900373 spin_unlock_irq(&pcpu_lock);
374
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900375 new_alloc = PCPU_DFL_MAP_ALLOC;
376 while (new_alloc < chunk->map_used + 2)
377 new_alloc *= 2;
378
379 new = pcpu_mem_alloc(new_alloc * sizeof(new[0]));
Tejun Heoccea34b2009-03-07 00:44:13 +0900380 if (!new) {
381 spin_lock_irq(&pcpu_lock);
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900382 return -ENOMEM;
Tejun Heoccea34b2009-03-07 00:44:13 +0900383 }
384
385 /*
386 * Acquire pcpu_lock and switch to new area map. Only free
387 * could have happened inbetween, so map_used couldn't have
388 * grown.
389 */
390 spin_lock_irq(&pcpu_lock);
391 BUG_ON(new_alloc < chunk->map_used + 2);
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900392
393 size = chunk->map_alloc * sizeof(chunk->map[0]);
394 memcpy(new, chunk->map, size);
395
396 /*
397 * map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is
398 * one of the first chunks and still using static map.
399 */
400 if (chunk->map_alloc >= PCPU_DFL_MAP_ALLOC)
401 pcpu_mem_free(chunk->map, size);
402
403 chunk->map_alloc = new_alloc;
404 chunk->map = new;
405 return 0;
406}
407
408/**
Tejun Heofbf59bc2009-02-20 16:29:08 +0900409 * pcpu_split_block - split a map block
410 * @chunk: chunk of interest
411 * @i: index of map block to split
Tejun Heocae3aeb2009-02-21 16:56:23 +0900412 * @head: head size in bytes (can be 0)
413 * @tail: tail size in bytes (can be 0)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900414 *
415 * Split the @i'th map block into two or three blocks. If @head is
416 * non-zero, @head bytes block is inserted before block @i moving it
417 * to @i+1 and reducing its size by @head bytes.
418 *
419 * If @tail is non-zero, the target block, which can be @i or @i+1
420 * depending on @head, is reduced by @tail bytes and @tail byte block
421 * is inserted after the target block.
422 *
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900423 * @chunk->map must have enough free slots to accomodate the split.
Tejun Heoccea34b2009-03-07 00:44:13 +0900424 *
425 * CONTEXT:
426 * pcpu_lock.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900427 */
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900428static void pcpu_split_block(struct pcpu_chunk *chunk, int i,
429 int head, int tail)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900430{
431 int nr_extra = !!head + !!tail;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900432
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900433 BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900434
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900435 /* insert new subblocks */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900436 memmove(&chunk->map[i + nr_extra], &chunk->map[i],
437 sizeof(chunk->map[0]) * (chunk->map_used - i));
438 chunk->map_used += nr_extra;
439
440 if (head) {
441 chunk->map[i + 1] = chunk->map[i] - head;
442 chunk->map[i++] = head;
443 }
444 if (tail) {
445 chunk->map[i++] -= tail;
446 chunk->map[i] = tail;
447 }
Tejun Heofbf59bc2009-02-20 16:29:08 +0900448}
449
450/**
451 * pcpu_alloc_area - allocate area from a pcpu_chunk
452 * @chunk: chunk of interest
Tejun Heocae3aeb2009-02-21 16:56:23 +0900453 * @size: wanted size in bytes
Tejun Heofbf59bc2009-02-20 16:29:08 +0900454 * @align: wanted align
455 *
456 * Try to allocate @size bytes area aligned at @align from @chunk.
457 * Note that this function only allocates the offset. It doesn't
458 * populate or map the area.
459 *
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900460 * @chunk->map must have at least two free slots.
461 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900462 * CONTEXT:
463 * pcpu_lock.
464 *
Tejun Heofbf59bc2009-02-20 16:29:08 +0900465 * RETURNS:
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900466 * Allocated offset in @chunk on success, -1 if no matching area is
467 * found.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900468 */
469static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
470{
471 int oslot = pcpu_chunk_slot(chunk);
472 int max_contig = 0;
473 int i, off;
474
Tejun Heofbf59bc2009-02-20 16:29:08 +0900475 for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) {
476 bool is_last = i + 1 == chunk->map_used;
477 int head, tail;
478
479 /* extra for alignment requirement */
480 head = ALIGN(off, align) - off;
481 BUG_ON(i == 0 && head != 0);
482
483 if (chunk->map[i] < 0)
484 continue;
485 if (chunk->map[i] < head + size) {
486 max_contig = max(chunk->map[i], max_contig);
487 continue;
488 }
489
490 /*
491 * If head is small or the previous block is free,
492 * merge'em. Note that 'small' is defined as smaller
493 * than sizeof(int), which is very small but isn't too
494 * uncommon for percpu allocations.
495 */
496 if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) {
497 if (chunk->map[i - 1] > 0)
498 chunk->map[i - 1] += head;
499 else {
500 chunk->map[i - 1] -= head;
501 chunk->free_size -= head;
502 }
503 chunk->map[i] -= head;
504 off += head;
505 head = 0;
506 }
507
508 /* if tail is small, just keep it around */
509 tail = chunk->map[i] - head - size;
510 if (tail < sizeof(int))
511 tail = 0;
512
513 /* split if warranted */
514 if (head || tail) {
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900515 pcpu_split_block(chunk, i, head, tail);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900516 if (head) {
517 i++;
518 off += head;
519 max_contig = max(chunk->map[i - 1], max_contig);
520 }
521 if (tail)
522 max_contig = max(chunk->map[i + 1], max_contig);
523 }
524
525 /* update hint and mark allocated */
526 if (is_last)
527 chunk->contig_hint = max_contig; /* fully scanned */
528 else
529 chunk->contig_hint = max(chunk->contig_hint,
530 max_contig);
531
532 chunk->free_size -= chunk->map[i];
533 chunk->map[i] = -chunk->map[i];
534
535 pcpu_chunk_relocate(chunk, oslot);
536 return off;
537 }
538
539 chunk->contig_hint = max_contig; /* fully scanned */
540 pcpu_chunk_relocate(chunk, oslot);
541
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900542 /* tell the upper layer that this chunk has no matching area */
543 return -1;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900544}
545
546/**
547 * pcpu_free_area - free area to a pcpu_chunk
548 * @chunk: chunk of interest
549 * @freeme: offset of area to free
550 *
551 * Free area starting from @freeme to @chunk. Note that this function
552 * only modifies the allocation map. It doesn't depopulate or unmap
553 * the area.
Tejun Heoccea34b2009-03-07 00:44:13 +0900554 *
555 * CONTEXT:
556 * pcpu_lock.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900557 */
558static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
559{
560 int oslot = pcpu_chunk_slot(chunk);
561 int i, off;
562
563 for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++]))
564 if (off == freeme)
565 break;
566 BUG_ON(off != freeme);
567 BUG_ON(chunk->map[i] > 0);
568
569 chunk->map[i] = -chunk->map[i];
570 chunk->free_size += chunk->map[i];
571
572 /* merge with previous? */
573 if (i > 0 && chunk->map[i - 1] >= 0) {
574 chunk->map[i - 1] += chunk->map[i];
575 chunk->map_used--;
576 memmove(&chunk->map[i], &chunk->map[i + 1],
577 (chunk->map_used - i) * sizeof(chunk->map[0]));
578 i--;
579 }
580 /* merge with next? */
581 if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) {
582 chunk->map[i] += chunk->map[i + 1];
583 chunk->map_used--;
584 memmove(&chunk->map[i + 1], &chunk->map[i + 2],
585 (chunk->map_used - (i + 1)) * sizeof(chunk->map[0]));
586 }
587
588 chunk->contig_hint = max(chunk->map[i], chunk->contig_hint);
589 pcpu_chunk_relocate(chunk, oslot);
590}
591
592/**
Tejun Heoce3141a2009-07-04 08:11:00 +0900593 * pcpu_get_pages_and_bitmap - get temp pages array and bitmap
Tejun Heofbf59bc2009-02-20 16:29:08 +0900594 * @chunk: chunk of interest
Tejun Heoce3141a2009-07-04 08:11:00 +0900595 * @bitmapp: output parameter for bitmap
596 * @may_alloc: may allocate the array
Tejun Heofbf59bc2009-02-20 16:29:08 +0900597 *
Tejun Heoce3141a2009-07-04 08:11:00 +0900598 * Returns pointer to array of pointers to struct page and bitmap,
599 * both of which can be indexed with pcpu_page_idx(). The returned
600 * array is cleared to zero and *@bitmapp is copied from
601 * @chunk->populated. Note that there is only one array and bitmap
602 * and access exclusion is the caller's responsibility.
603 *
604 * CONTEXT:
605 * pcpu_alloc_mutex and does GFP_KERNEL allocation if @may_alloc.
606 * Otherwise, don't care.
607 *
608 * RETURNS:
609 * Pointer to temp pages array on success, NULL on failure.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900610 */
Tejun Heoce3141a2009-07-04 08:11:00 +0900611static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
612 unsigned long **bitmapp,
613 bool may_alloc)
614{
615 static struct page **pages;
616 static unsigned long *bitmap;
Tejun Heo2f39e632009-07-04 08:11:00 +0900617 size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
Tejun Heoce3141a2009-07-04 08:11:00 +0900618 size_t bitmap_size = BITS_TO_LONGS(pcpu_unit_pages) *
619 sizeof(unsigned long);
620
621 if (!pages || !bitmap) {
622 if (may_alloc && !pages)
623 pages = pcpu_mem_alloc(pages_size);
624 if (may_alloc && !bitmap)
625 bitmap = pcpu_mem_alloc(bitmap_size);
626 if (!pages || !bitmap)
627 return NULL;
628 }
629
630 memset(pages, 0, pages_size);
631 bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages);
632
633 *bitmapp = bitmap;
634 return pages;
635}
636
637/**
638 * pcpu_free_pages - free pages which were allocated for @chunk
639 * @chunk: chunk pages were allocated for
640 * @pages: array of pages to be freed, indexed by pcpu_page_idx()
641 * @populated: populated bitmap
642 * @page_start: page index of the first page to be freed
643 * @page_end: page index of the last page to be freed + 1
644 *
645 * Free pages [@page_start and @page_end) in @pages for all units.
646 * The pages were allocated for @chunk.
647 */
648static void pcpu_free_pages(struct pcpu_chunk *chunk,
649 struct page **pages, unsigned long *populated,
650 int page_start, int page_end)
651{
652 unsigned int cpu;
653 int i;
654
655 for_each_possible_cpu(cpu) {
656 for (i = page_start; i < page_end; i++) {
657 struct page *page = pages[pcpu_page_idx(cpu, i)];
658
659 if (page)
660 __free_page(page);
661 }
662 }
663}
664
665/**
666 * pcpu_alloc_pages - allocates pages for @chunk
667 * @chunk: target chunk
668 * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
669 * @populated: populated bitmap
670 * @page_start: page index of the first page to be allocated
671 * @page_end: page index of the last page to be allocated + 1
672 *
673 * Allocate pages [@page_start,@page_end) into @pages for all units.
674 * The allocation is for @chunk. Percpu core doesn't care about the
675 * content of @pages and will pass it verbatim to pcpu_map_pages().
676 */
677static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
678 struct page **pages, unsigned long *populated,
679 int page_start, int page_end)
680{
681 const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
682 unsigned int cpu;
683 int i;
684
685 for_each_possible_cpu(cpu) {
686 for (i = page_start; i < page_end; i++) {
687 struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
688
689 *pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
690 if (!*pagep) {
691 pcpu_free_pages(chunk, pages, populated,
692 page_start, page_end);
693 return -ENOMEM;
694 }
695 }
696 }
697 return 0;
698}
699
700/**
701 * pcpu_pre_unmap_flush - flush cache prior to unmapping
702 * @chunk: chunk the regions to be flushed belongs to
703 * @page_start: page index of the first page to be flushed
704 * @page_end: page index of the last page to be flushed + 1
705 *
706 * Pages in [@page_start,@page_end) of @chunk are about to be
707 * unmapped. Flush cache. As each flushing trial can be very
708 * expensive, issue flush on the whole region at once rather than
709 * doing it for each cpu. This could be an overkill but is more
710 * scalable.
711 */
712static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
713 int page_start, int page_end)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900714{
Tejun Heo2f39e632009-07-04 08:11:00 +0900715 flush_cache_vunmap(
716 pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
717 pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
Tejun Heoce3141a2009-07-04 08:11:00 +0900718}
Tejun Heofbf59bc2009-02-20 16:29:08 +0900719
Tejun Heoce3141a2009-07-04 08:11:00 +0900720static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
721{
722 unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
723}
Tejun Heofbf59bc2009-02-20 16:29:08 +0900724
Tejun Heoce3141a2009-07-04 08:11:00 +0900725/**
726 * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
727 * @chunk: chunk of interest
728 * @pages: pages array which can be used to pass information to free
729 * @populated: populated bitmap
730 * @page_start: page index of the first page to unmap
731 * @page_end: page index of the last page to unmap + 1
732 *
733 * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
734 * Corresponding elements in @pages were cleared by the caller and can
735 * be used to carry information to pcpu_free_pages() which will be
736 * called after all unmaps are finished. The caller should call
737 * proper pre/post flush functions.
738 */
739static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
740 struct page **pages, unsigned long *populated,
741 int page_start, int page_end)
742{
743 unsigned int cpu;
744 int i;
745
746 for_each_possible_cpu(cpu) {
747 for (i = page_start; i < page_end; i++) {
748 struct page *page;
749
750 page = pcpu_chunk_page(chunk, cpu, i);
751 WARN_ON(!page);
752 pages[pcpu_page_idx(cpu, i)] = page;
753 }
754 __pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
755 page_end - page_start);
756 }
757
758 for (i = page_start; i < page_end; i++)
759 __clear_bit(i, populated);
760}
761
762/**
763 * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
764 * @chunk: pcpu_chunk the regions to be flushed belong to
765 * @page_start: page index of the first page to be flushed
766 * @page_end: page index of the last page to be flushed + 1
767 *
768 * Pages [@page_start,@page_end) of @chunk have been unmapped. Flush
769 * TLB for the regions. This can be skipped if the area is to be
770 * returned to vmalloc as vmalloc will handle TLB flushing lazily.
771 *
772 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
773 * for the whole region.
774 */
775static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
776 int page_start, int page_end)
777{
Tejun Heo2f39e632009-07-04 08:11:00 +0900778 flush_tlb_kernel_range(
779 pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
780 pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
Tejun Heofbf59bc2009-02-20 16:29:08 +0900781}
782
Tejun Heoc8a51be2009-07-04 08:10:59 +0900783static int __pcpu_map_pages(unsigned long addr, struct page **pages,
784 int nr_pages)
785{
786 return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
787 PAGE_KERNEL, pages);
788}
789
790/**
Tejun Heoce3141a2009-07-04 08:11:00 +0900791 * pcpu_map_pages - map pages into a pcpu_chunk
Tejun Heoc8a51be2009-07-04 08:10:59 +0900792 * @chunk: chunk of interest
Tejun Heoce3141a2009-07-04 08:11:00 +0900793 * @pages: pages array containing pages to be mapped
794 * @populated: populated bitmap
Tejun Heoc8a51be2009-07-04 08:10:59 +0900795 * @page_start: page index of the first page to map
796 * @page_end: page index of the last page to map + 1
797 *
Tejun Heoce3141a2009-07-04 08:11:00 +0900798 * For each cpu, map pages [@page_start,@page_end) into @chunk. The
799 * caller is responsible for calling pcpu_post_map_flush() after all
800 * mappings are complete.
801 *
802 * This function is responsible for setting corresponding bits in
803 * @chunk->populated bitmap and whatever is necessary for reverse
804 * lookup (addr -> chunk).
Tejun Heoc8a51be2009-07-04 08:10:59 +0900805 */
Tejun Heoce3141a2009-07-04 08:11:00 +0900806static int pcpu_map_pages(struct pcpu_chunk *chunk,
807 struct page **pages, unsigned long *populated,
808 int page_start, int page_end)
Tejun Heoc8a51be2009-07-04 08:10:59 +0900809{
Tejun Heoce3141a2009-07-04 08:11:00 +0900810 unsigned int cpu, tcpu;
811 int i, err;
Tejun Heoc8a51be2009-07-04 08:10:59 +0900812
813 for_each_possible_cpu(cpu) {
814 err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
Tejun Heoce3141a2009-07-04 08:11:00 +0900815 &pages[pcpu_page_idx(cpu, page_start)],
Tejun Heoc8a51be2009-07-04 08:10:59 +0900816 page_end - page_start);
817 if (err < 0)
Tejun Heoce3141a2009-07-04 08:11:00 +0900818 goto err;
Tejun Heoc8a51be2009-07-04 08:10:59 +0900819 }
820
Tejun Heoce3141a2009-07-04 08:11:00 +0900821 /* mapping successful, link chunk and mark populated */
822 for (i = page_start; i < page_end; i++) {
823 for_each_possible_cpu(cpu)
824 pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
825 chunk);
826 __set_bit(i, populated);
827 }
828
829 return 0;
830
831err:
832 for_each_possible_cpu(tcpu) {
833 if (tcpu == cpu)
834 break;
835 __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
836 page_end - page_start);
837 }
838 return err;
839}
840
841/**
842 * pcpu_post_map_flush - flush cache after mapping
843 * @chunk: pcpu_chunk the regions to be flushed belong to
844 * @page_start: page index of the first page to be flushed
845 * @page_end: page index of the last page to be flushed + 1
846 *
847 * Pages [@page_start,@page_end) of @chunk have been mapped. Flush
848 * cache.
849 *
850 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
851 * for the whole region.
852 */
853static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
854 int page_start, int page_end)
855{
Tejun Heo2f39e632009-07-04 08:11:00 +0900856 flush_cache_vmap(
857 pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
858 pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
Tejun Heoc8a51be2009-07-04 08:10:59 +0900859}
860
Tejun Heofbf59bc2009-02-20 16:29:08 +0900861/**
862 * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
863 * @chunk: chunk to depopulate
864 * @off: offset to the area to depopulate
Tejun Heocae3aeb2009-02-21 16:56:23 +0900865 * @size: size of the area to depopulate in bytes
Tejun Heofbf59bc2009-02-20 16:29:08 +0900866 * @flush: whether to flush cache and tlb or not
867 *
868 * For each cpu, depopulate and unmap pages [@page_start,@page_end)
869 * from @chunk. If @flush is true, vcache is flushed before unmapping
870 * and tlb after.
Tejun Heoccea34b2009-03-07 00:44:13 +0900871 *
872 * CONTEXT:
873 * pcpu_alloc_mutex.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900874 */
Tejun Heoce3141a2009-07-04 08:11:00 +0900875static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900876{
877 int page_start = PFN_DOWN(off);
878 int page_end = PFN_UP(off + size);
Tejun Heoce3141a2009-07-04 08:11:00 +0900879 struct page **pages;
880 unsigned long *populated;
881 int rs, re;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900882
Tejun Heoce3141a2009-07-04 08:11:00 +0900883 /* quick path, check whether it's empty already */
884 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
885 if (rs == page_start && re == page_end)
886 return;
887 break;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900888 }
889
Tejun Heoce3141a2009-07-04 08:11:00 +0900890 /* immutable chunks can't be depopulated */
891 WARN_ON(chunk->immutable);
892
893 /*
894 * If control reaches here, there must have been at least one
895 * successful population attempt so the temp pages array must
896 * be available now.
897 */
898 pages = pcpu_get_pages_and_bitmap(chunk, &populated, false);
899 BUG_ON(!pages);
900
901 /* unmap and free */
902 pcpu_pre_unmap_flush(chunk, page_start, page_end);
903
904 pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
905 pcpu_unmap_pages(chunk, pages, populated, rs, re);
906
907 /* no need to flush tlb, vmalloc will handle it lazily */
908
909 pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
910 pcpu_free_pages(chunk, pages, populated, rs, re);
911
912 /* commit new bitmap */
913 bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900914}
915
Tejun Heofbf59bc2009-02-20 16:29:08 +0900916/**
917 * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
918 * @chunk: chunk of interest
919 * @off: offset to the area to populate
Tejun Heocae3aeb2009-02-21 16:56:23 +0900920 * @size: size of the area to populate in bytes
Tejun Heofbf59bc2009-02-20 16:29:08 +0900921 *
922 * For each cpu, populate and map pages [@page_start,@page_end) into
923 * @chunk. The area is cleared on return.
Tejun Heoccea34b2009-03-07 00:44:13 +0900924 *
925 * CONTEXT:
926 * pcpu_alloc_mutex, does GFP_KERNEL allocation.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900927 */
928static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
929{
Tejun Heofbf59bc2009-02-20 16:29:08 +0900930 int page_start = PFN_DOWN(off);
931 int page_end = PFN_UP(off + size);
Tejun Heoce3141a2009-07-04 08:11:00 +0900932 int free_end = page_start, unmap_end = page_start;
933 struct page **pages;
934 unsigned long *populated;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900935 unsigned int cpu;
Tejun Heoce3141a2009-07-04 08:11:00 +0900936 int rs, re, rc;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900937
Tejun Heoce3141a2009-07-04 08:11:00 +0900938 /* quick path, check whether all pages are already there */
939 pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end) {
940 if (rs == page_start && re == page_end)
941 goto clear;
942 break;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900943 }
944
Tejun Heoce3141a2009-07-04 08:11:00 +0900945 /* need to allocate and map pages, this chunk can't be immutable */
946 WARN_ON(chunk->immutable);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900947
Tejun Heoce3141a2009-07-04 08:11:00 +0900948 pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
949 if (!pages)
950 return -ENOMEM;
951
952 /* alloc and map */
953 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
954 rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
955 if (rc)
956 goto err_free;
957 free_end = re;
958 }
959
960 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
961 rc = pcpu_map_pages(chunk, pages, populated, rs, re);
962 if (rc)
963 goto err_unmap;
964 unmap_end = re;
965 }
966 pcpu_post_map_flush(chunk, page_start, page_end);
967
968 /* commit new bitmap */
969 bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
970clear:
Tejun Heofbf59bc2009-02-20 16:29:08 +0900971 for_each_possible_cpu(cpu)
Tejun Heo2f39e632009-07-04 08:11:00 +0900972 memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900973 return 0;
Tejun Heoce3141a2009-07-04 08:11:00 +0900974
975err_unmap:
976 pcpu_pre_unmap_flush(chunk, page_start, unmap_end);
977 pcpu_for_each_unpop_region(chunk, rs, re, page_start, unmap_end)
978 pcpu_unmap_pages(chunk, pages, populated, rs, re);
979 pcpu_post_unmap_tlb_flush(chunk, page_start, unmap_end);
980err_free:
981 pcpu_for_each_unpop_region(chunk, rs, re, page_start, free_end)
982 pcpu_free_pages(chunk, pages, populated, rs, re);
983 return rc;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900984}
985
986static void free_pcpu_chunk(struct pcpu_chunk *chunk)
987{
988 if (!chunk)
989 return;
990 if (chunk->vm)
991 free_vm_area(chunk->vm);
Tejun Heo1880d932009-03-07 00:44:09 +0900992 pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
Tejun Heofbf59bc2009-02-20 16:29:08 +0900993 kfree(chunk);
994}
995
996static struct pcpu_chunk *alloc_pcpu_chunk(void)
997{
998 struct pcpu_chunk *chunk;
999
1000 chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL);
1001 if (!chunk)
1002 return NULL;
1003
Tejun Heo1880d932009-03-07 00:44:09 +09001004 chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
Tejun Heofbf59bc2009-02-20 16:29:08 +09001005 chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
1006 chunk->map[chunk->map_used++] = pcpu_unit_size;
1007
Amerigo Wang142d44b2009-08-13 02:00:13 -04001008 chunk->vm = get_vm_area(pcpu_chunk_size, VM_ALLOC);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001009 if (!chunk->vm) {
1010 free_pcpu_chunk(chunk);
1011 return NULL;
1012 }
1013
1014 INIT_LIST_HEAD(&chunk->list);
1015 chunk->free_size = pcpu_unit_size;
1016 chunk->contig_hint = pcpu_unit_size;
1017
1018 return chunk;
1019}
1020
1021/**
Tejun Heoedcb4632009-03-06 14:33:59 +09001022 * pcpu_alloc - the percpu allocator
Tejun Heocae3aeb2009-02-21 16:56:23 +09001023 * @size: size of area to allocate in bytes
Tejun Heofbf59bc2009-02-20 16:29:08 +09001024 * @align: alignment of area (max PAGE_SIZE)
Tejun Heoedcb4632009-03-06 14:33:59 +09001025 * @reserved: allocate from the reserved chunk if available
Tejun Heofbf59bc2009-02-20 16:29:08 +09001026 *
Tejun Heoccea34b2009-03-07 00:44:13 +09001027 * Allocate percpu area of @size bytes aligned at @align.
1028 *
1029 * CONTEXT:
1030 * Does GFP_KERNEL allocation.
Tejun Heofbf59bc2009-02-20 16:29:08 +09001031 *
1032 * RETURNS:
1033 * Percpu pointer to the allocated area on success, NULL on failure.
1034 */
Tejun Heoedcb4632009-03-06 14:33:59 +09001035static void *pcpu_alloc(size_t size, size_t align, bool reserved)
Tejun Heofbf59bc2009-02-20 16:29:08 +09001036{
Tejun Heofbf59bc2009-02-20 16:29:08 +09001037 struct pcpu_chunk *chunk;
1038 int slot, off;
1039
Tejun Heo8d408b42009-02-24 11:57:21 +09001040 if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
Tejun Heofbf59bc2009-02-20 16:29:08 +09001041 WARN(true, "illegal size (%zu) or align (%zu) for "
1042 "percpu allocation\n", size, align);
1043 return NULL;
1044 }
1045
Tejun Heoccea34b2009-03-07 00:44:13 +09001046 mutex_lock(&pcpu_alloc_mutex);
1047 spin_lock_irq(&pcpu_lock);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001048
Tejun Heoedcb4632009-03-06 14:33:59 +09001049 /* serve reserved allocations from the reserved chunk if available */
1050 if (reserved && pcpu_reserved_chunk) {
1051 chunk = pcpu_reserved_chunk;
Tejun Heo9f7dcf22009-03-07 00:44:09 +09001052 if (size > chunk->contig_hint ||
1053 pcpu_extend_area_map(chunk) < 0)
Tejun Heoccea34b2009-03-07 00:44:13 +09001054 goto fail_unlock;
Tejun Heoedcb4632009-03-06 14:33:59 +09001055 off = pcpu_alloc_area(chunk, size, align);
1056 if (off >= 0)
1057 goto area_found;
Tejun Heoccea34b2009-03-07 00:44:13 +09001058 goto fail_unlock;
Tejun Heoedcb4632009-03-06 14:33:59 +09001059 }
1060
Tejun Heoccea34b2009-03-07 00:44:13 +09001061restart:
Tejun Heoedcb4632009-03-06 14:33:59 +09001062 /* search through normal chunks */
Tejun Heofbf59bc2009-02-20 16:29:08 +09001063 for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
1064 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
1065 if (size > chunk->contig_hint)
1066 continue;
Tejun Heoccea34b2009-03-07 00:44:13 +09001067
1068 switch (pcpu_extend_area_map(chunk)) {
1069 case 0:
1070 break;
1071 case 1:
1072 goto restart; /* pcpu_lock dropped, restart */
1073 default:
1074 goto fail_unlock;
1075 }
1076
Tejun Heofbf59bc2009-02-20 16:29:08 +09001077 off = pcpu_alloc_area(chunk, size, align);
1078 if (off >= 0)
1079 goto area_found;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001080 }
1081 }
1082
1083 /* hmmm... no space left, create a new chunk */
Tejun Heoccea34b2009-03-07 00:44:13 +09001084 spin_unlock_irq(&pcpu_lock);
1085
Tejun Heofbf59bc2009-02-20 16:29:08 +09001086 chunk = alloc_pcpu_chunk();
1087 if (!chunk)
Tejun Heoccea34b2009-03-07 00:44:13 +09001088 goto fail_unlock_mutex;
1089
1090 spin_lock_irq(&pcpu_lock);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001091 pcpu_chunk_relocate(chunk, -1);
Tejun Heoccea34b2009-03-07 00:44:13 +09001092 goto restart;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001093
1094area_found:
Tejun Heoccea34b2009-03-07 00:44:13 +09001095 spin_unlock_irq(&pcpu_lock);
1096
Tejun Heofbf59bc2009-02-20 16:29:08 +09001097 /* populate, map and clear the area */
1098 if (pcpu_populate_chunk(chunk, off, size)) {
Tejun Heoccea34b2009-03-07 00:44:13 +09001099 spin_lock_irq(&pcpu_lock);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001100 pcpu_free_area(chunk, off);
Tejun Heoccea34b2009-03-07 00:44:13 +09001101 goto fail_unlock;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001102 }
1103
Tejun Heoccea34b2009-03-07 00:44:13 +09001104 mutex_unlock(&pcpu_alloc_mutex);
1105
Tejun Heo2f39e632009-07-04 08:11:00 +09001106 /* return address relative to unit0 */
Tejun Heoccea34b2009-03-07 00:44:13 +09001107 return __addr_to_pcpu_ptr(chunk->vm->addr + off);
1108
1109fail_unlock:
1110 spin_unlock_irq(&pcpu_lock);
1111fail_unlock_mutex:
1112 mutex_unlock(&pcpu_alloc_mutex);
1113 return NULL;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001114}
Tejun Heoedcb4632009-03-06 14:33:59 +09001115
1116/**
1117 * __alloc_percpu - allocate dynamic percpu area
1118 * @size: size of area to allocate in bytes
1119 * @align: alignment of area (max PAGE_SIZE)
1120 *
1121 * Allocate percpu area of @size bytes aligned at @align. Might
1122 * sleep. Might trigger writeouts.
1123 *
Tejun Heoccea34b2009-03-07 00:44:13 +09001124 * CONTEXT:
1125 * Does GFP_KERNEL allocation.
1126 *
Tejun Heoedcb4632009-03-06 14:33:59 +09001127 * RETURNS:
1128 * Percpu pointer to the allocated area on success, NULL on failure.
1129 */
1130void *__alloc_percpu(size_t size, size_t align)
1131{
1132 return pcpu_alloc(size, align, false);
1133}
Tejun Heofbf59bc2009-02-20 16:29:08 +09001134EXPORT_SYMBOL_GPL(__alloc_percpu);
1135
Tejun Heoedcb4632009-03-06 14:33:59 +09001136/**
1137 * __alloc_reserved_percpu - allocate reserved percpu area
1138 * @size: size of area to allocate in bytes
1139 * @align: alignment of area (max PAGE_SIZE)
1140 *
1141 * Allocate percpu area of @size bytes aligned at @align from reserved
1142 * percpu area if arch has set it up; otherwise, allocation is served
1143 * from the same dynamic area. Might sleep. Might trigger writeouts.
1144 *
Tejun Heoccea34b2009-03-07 00:44:13 +09001145 * CONTEXT:
1146 * Does GFP_KERNEL allocation.
1147 *
Tejun Heoedcb4632009-03-06 14:33:59 +09001148 * RETURNS:
1149 * Percpu pointer to the allocated area on success, NULL on failure.
1150 */
1151void *__alloc_reserved_percpu(size_t size, size_t align)
1152{
1153 return pcpu_alloc(size, align, true);
1154}
1155
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001156/**
1157 * pcpu_reclaim - reclaim fully free chunks, workqueue function
1158 * @work: unused
1159 *
1160 * Reclaim all fully free chunks except for the first one.
Tejun Heoccea34b2009-03-07 00:44:13 +09001161 *
1162 * CONTEXT:
1163 * workqueue context.
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001164 */
1165static void pcpu_reclaim(struct work_struct *work)
Tejun Heofbf59bc2009-02-20 16:29:08 +09001166{
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001167 LIST_HEAD(todo);
1168 struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1];
1169 struct pcpu_chunk *chunk, *next;
1170
Tejun Heoccea34b2009-03-07 00:44:13 +09001171 mutex_lock(&pcpu_alloc_mutex);
1172 spin_lock_irq(&pcpu_lock);
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001173
1174 list_for_each_entry_safe(chunk, next, head, list) {
1175 WARN_ON(chunk->immutable);
1176
1177 /* spare the first one */
1178 if (chunk == list_first_entry(head, struct pcpu_chunk, list))
1179 continue;
1180
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001181 list_move(&chunk->list, &todo);
1182 }
1183
Tejun Heoccea34b2009-03-07 00:44:13 +09001184 spin_unlock_irq(&pcpu_lock);
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001185
1186 list_for_each_entry_safe(chunk, next, &todo, list) {
Tejun Heoce3141a2009-07-04 08:11:00 +09001187 pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001188 free_pcpu_chunk(chunk);
1189 }
Tejun Heo971f3912009-08-14 15:00:49 +09001190
1191 mutex_unlock(&pcpu_alloc_mutex);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001192}
1193
1194/**
1195 * free_percpu - free percpu area
1196 * @ptr: pointer to area to free
1197 *
Tejun Heoccea34b2009-03-07 00:44:13 +09001198 * Free percpu area @ptr.
1199 *
1200 * CONTEXT:
1201 * Can be called from atomic context.
Tejun Heofbf59bc2009-02-20 16:29:08 +09001202 */
1203void free_percpu(void *ptr)
1204{
1205 void *addr = __pcpu_ptr_to_addr(ptr);
1206 struct pcpu_chunk *chunk;
Tejun Heoccea34b2009-03-07 00:44:13 +09001207 unsigned long flags;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001208 int off;
1209
1210 if (!ptr)
1211 return;
1212
Tejun Heoccea34b2009-03-07 00:44:13 +09001213 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001214
1215 chunk = pcpu_chunk_addr_search(addr);
1216 off = addr - chunk->vm->addr;
1217
1218 pcpu_free_area(chunk, off);
1219
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001220 /* if there are more than one fully free chunks, wake up grim reaper */
Tejun Heofbf59bc2009-02-20 16:29:08 +09001221 if (chunk->free_size == pcpu_unit_size) {
1222 struct pcpu_chunk *pos;
1223
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001224 list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
Tejun Heofbf59bc2009-02-20 16:29:08 +09001225 if (pos != chunk) {
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001226 schedule_work(&pcpu_reclaim_work);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001227 break;
1228 }
1229 }
1230
Tejun Heoccea34b2009-03-07 00:44:13 +09001231 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001232}
1233EXPORT_SYMBOL_GPL(free_percpu);
1234
Tejun Heo033e48f2009-08-14 15:00:51 +09001235static inline size_t pcpu_calc_fc_sizes(size_t static_size,
1236 size_t reserved_size,
1237 ssize_t *dyn_sizep)
1238{
1239 size_t size_sum;
1240
1241 size_sum = PFN_ALIGN(static_size + reserved_size +
1242 (*dyn_sizep >= 0 ? *dyn_sizep : 0));
1243 if (*dyn_sizep != 0)
1244 *dyn_sizep = size_sum - static_size - reserved_size;
1245
1246 return size_sum;
1247}
1248
Tejun Heo033e48f2009-08-14 15:00:51 +09001249/**
Tejun Heofd1e8a12009-08-14 15:00:51 +09001250 * pcpu_alloc_alloc_info - allocate percpu allocation info
1251 * @nr_groups: the number of groups
1252 * @nr_units: the number of units
Tejun Heo033e48f2009-08-14 15:00:51 +09001253 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001254 * Allocate ai which is large enough for @nr_groups groups containing
1255 * @nr_units units. The returned ai's groups[0].cpu_map points to the
1256 * cpu_map array which is long enough for @nr_units and filled with
1257 * NR_CPUS. It's the caller's responsibility to initialize cpu_map
1258 * pointer of other groups.
Tejun Heo033e48f2009-08-14 15:00:51 +09001259 *
1260 * RETURNS:
Tejun Heofd1e8a12009-08-14 15:00:51 +09001261 * Pointer to the allocated pcpu_alloc_info on success, NULL on
1262 * failure.
Tejun Heo033e48f2009-08-14 15:00:51 +09001263 */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001264struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
1265 int nr_units)
1266{
1267 struct pcpu_alloc_info *ai;
1268 size_t base_size, ai_size;
1269 void *ptr;
1270 int unit;
1271
1272 base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
1273 __alignof__(ai->groups[0].cpu_map[0]));
1274 ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
1275
1276 ptr = alloc_bootmem_nopanic(PFN_ALIGN(ai_size));
1277 if (!ptr)
1278 return NULL;
1279 ai = ptr;
1280 ptr += base_size;
1281
1282 ai->groups[0].cpu_map = ptr;
1283
1284 for (unit = 0; unit < nr_units; unit++)
1285 ai->groups[0].cpu_map[unit] = NR_CPUS;
1286
1287 ai->nr_groups = nr_groups;
1288 ai->__ai_size = PFN_ALIGN(ai_size);
1289
1290 return ai;
1291}
1292
1293/**
1294 * pcpu_free_alloc_info - free percpu allocation info
1295 * @ai: pcpu_alloc_info to free
1296 *
1297 * Free @ai which was allocated by pcpu_alloc_alloc_info().
1298 */
1299void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
1300{
1301 free_bootmem(__pa(ai), ai->__ai_size);
1302}
1303
1304/**
1305 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
1306 * @reserved_size: the size of reserved percpu area in bytes
1307 * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
1308 * @atom_size: allocation atom size
1309 * @cpu_distance_fn: callback to determine distance between cpus, optional
1310 *
1311 * This function determines grouping of units, their mappings to cpus
1312 * and other parameters considering needed percpu size, allocation
1313 * atom size and distances between CPUs.
1314 *
1315 * Groups are always mutliples of atom size and CPUs which are of
1316 * LOCAL_DISTANCE both ways are grouped together and share space for
1317 * units in the same group. The returned configuration is guaranteed
1318 * to have CPUs on different nodes on different groups and >=75% usage
1319 * of allocated virtual address space.
1320 *
1321 * RETURNS:
1322 * On success, pointer to the new allocation_info is returned. On
1323 * failure, ERR_PTR value is returned.
1324 */
1325struct pcpu_alloc_info * __init pcpu_build_alloc_info(
1326 size_t reserved_size, ssize_t dyn_size,
1327 size_t atom_size,
1328 pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
Tejun Heo033e48f2009-08-14 15:00:51 +09001329{
1330 static int group_map[NR_CPUS] __initdata;
1331 static int group_cnt[NR_CPUS] __initdata;
1332 const size_t static_size = __per_cpu_end - __per_cpu_start;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001333 int group_cnt_max = 0, nr_groups = 1, nr_units = 0;
Tejun Heo033e48f2009-08-14 15:00:51 +09001334 size_t size_sum, min_unit_size, alloc_size;
1335 int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001336 int last_allocs, group, unit;
Tejun Heo033e48f2009-08-14 15:00:51 +09001337 unsigned int cpu, tcpu;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001338 struct pcpu_alloc_info *ai;
1339 unsigned int *cpu_map;
Tejun Heo033e48f2009-08-14 15:00:51 +09001340
1341 /*
1342 * Determine min_unit_size, alloc_size and max_upa such that
Tejun Heofd1e8a12009-08-14 15:00:51 +09001343 * alloc_size is multiple of atom_size and is the smallest
Tejun Heo033e48f2009-08-14 15:00:51 +09001344 * which can accomodate 4k aligned segments which are equal to
1345 * or larger than min_unit_size.
1346 */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001347 size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size);
Tejun Heo033e48f2009-08-14 15:00:51 +09001348 min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
1349
Tejun Heofd1e8a12009-08-14 15:00:51 +09001350 alloc_size = roundup(min_unit_size, atom_size);
Tejun Heo033e48f2009-08-14 15:00:51 +09001351 upa = alloc_size / min_unit_size;
1352 while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1353 upa--;
1354 max_upa = upa;
1355
1356 /* group cpus according to their proximity */
1357 for_each_possible_cpu(cpu) {
1358 group = 0;
1359 next_group:
1360 for_each_possible_cpu(tcpu) {
1361 if (cpu == tcpu)
1362 break;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001363 if (group_map[tcpu] == group && cpu_distance_fn &&
Tejun Heo033e48f2009-08-14 15:00:51 +09001364 (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
1365 cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
1366 group++;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001367 nr_groups = max(nr_groups, group + 1);
Tejun Heo033e48f2009-08-14 15:00:51 +09001368 goto next_group;
1369 }
1370 }
1371 group_map[cpu] = group;
1372 group_cnt[group]++;
1373 group_cnt_max = max(group_cnt_max, group_cnt[group]);
1374 }
1375
1376 /*
1377 * Expand unit size until address space usage goes over 75%
1378 * and then as much as possible without using more address
1379 * space.
1380 */
1381 last_allocs = INT_MAX;
1382 for (upa = max_upa; upa; upa--) {
1383 int allocs = 0, wasted = 0;
1384
1385 if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1386 continue;
1387
Tejun Heofd1e8a12009-08-14 15:00:51 +09001388 for (group = 0; group < nr_groups; group++) {
Tejun Heo033e48f2009-08-14 15:00:51 +09001389 int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
1390 allocs += this_allocs;
1391 wasted += this_allocs * upa - group_cnt[group];
1392 }
1393
1394 /*
1395 * Don't accept if wastage is over 25%. The
1396 * greater-than comparison ensures upa==1 always
1397 * passes the following check.
1398 */
1399 if (wasted > num_possible_cpus() / 3)
1400 continue;
1401
1402 /* and then don't consume more memory */
1403 if (allocs > last_allocs)
1404 break;
1405 last_allocs = allocs;
1406 best_upa = upa;
1407 }
Tejun Heofd1e8a12009-08-14 15:00:51 +09001408 upa = best_upa;
Tejun Heo033e48f2009-08-14 15:00:51 +09001409
Tejun Heofd1e8a12009-08-14 15:00:51 +09001410 /* allocate and fill alloc_info */
1411 for (group = 0; group < nr_groups; group++)
1412 nr_units += roundup(group_cnt[group], upa);
1413
1414 ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
1415 if (!ai)
1416 return ERR_PTR(-ENOMEM);
1417 cpu_map = ai->groups[0].cpu_map;
1418
1419 for (group = 0; group < nr_groups; group++) {
1420 ai->groups[group].cpu_map = cpu_map;
1421 cpu_map += roundup(group_cnt[group], upa);
Tejun Heo033e48f2009-08-14 15:00:51 +09001422 }
1423
Tejun Heofd1e8a12009-08-14 15:00:51 +09001424 ai->static_size = static_size;
1425 ai->reserved_size = reserved_size;
1426 ai->dyn_size = dyn_size;
1427 ai->unit_size = alloc_size / upa;
1428 ai->atom_size = atom_size;
1429 ai->alloc_size = alloc_size;
1430
1431 for (group = 0, unit = 0; group_cnt[group]; group++) {
1432 struct pcpu_group_info *gi = &ai->groups[group];
1433
1434 /*
1435 * Initialize base_offset as if all groups are located
1436 * back-to-back. The caller should update this to
1437 * reflect actual allocation.
1438 */
1439 gi->base_offset = unit * ai->unit_size;
1440
1441 for_each_possible_cpu(cpu)
1442 if (group_map[cpu] == group)
1443 gi->cpu_map[gi->nr_units++] = cpu;
1444 gi->nr_units = roundup(gi->nr_units, upa);
1445 unit += gi->nr_units;
1446 }
1447 BUG_ON(unit != nr_units);
1448
1449 return ai;
Tejun Heo033e48f2009-08-14 15:00:51 +09001450}
1451
Tejun Heofd1e8a12009-08-14 15:00:51 +09001452/**
1453 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
1454 * @lvl: loglevel
1455 * @ai: allocation info to dump
1456 *
1457 * Print out information about @ai using loglevel @lvl.
1458 */
1459static void pcpu_dump_alloc_info(const char *lvl,
1460 const struct pcpu_alloc_info *ai)
Tejun Heo033e48f2009-08-14 15:00:51 +09001461{
Tejun Heofd1e8a12009-08-14 15:00:51 +09001462 int group_width = 1, cpu_width = 1, width;
Tejun Heo033e48f2009-08-14 15:00:51 +09001463 char empty_str[] = "--------";
Tejun Heofd1e8a12009-08-14 15:00:51 +09001464 int alloc = 0, alloc_end = 0;
1465 int group, v;
1466 int upa, apl; /* units per alloc, allocs per line */
Tejun Heo033e48f2009-08-14 15:00:51 +09001467
Tejun Heofd1e8a12009-08-14 15:00:51 +09001468 v = ai->nr_groups;
Tejun Heo033e48f2009-08-14 15:00:51 +09001469 while (v /= 10)
Tejun Heofd1e8a12009-08-14 15:00:51 +09001470 group_width++;
Tejun Heo033e48f2009-08-14 15:00:51 +09001471
Tejun Heofd1e8a12009-08-14 15:00:51 +09001472 v = num_possible_cpus();
1473 while (v /= 10)
1474 cpu_width++;
1475 empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
Tejun Heo033e48f2009-08-14 15:00:51 +09001476
Tejun Heofd1e8a12009-08-14 15:00:51 +09001477 upa = ai->alloc_size / ai->unit_size;
1478 width = upa * (cpu_width + 1) + group_width + 3;
1479 apl = rounddown_pow_of_two(max(60 / width, 1));
Tejun Heo033e48f2009-08-14 15:00:51 +09001480
Tejun Heofd1e8a12009-08-14 15:00:51 +09001481 printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
1482 lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
1483 ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
1484
1485 for (group = 0; group < ai->nr_groups; group++) {
1486 const struct pcpu_group_info *gi = &ai->groups[group];
1487 int unit = 0, unit_end = 0;
1488
1489 BUG_ON(gi->nr_units % upa);
1490 for (alloc_end += gi->nr_units / upa;
1491 alloc < alloc_end; alloc++) {
1492 if (!(alloc % apl)) {
Tejun Heo033e48f2009-08-14 15:00:51 +09001493 printk("\n");
Tejun Heofd1e8a12009-08-14 15:00:51 +09001494 printk("%spcpu-alloc: ", lvl);
1495 }
1496 printk("[%0*d] ", group_width, group);
1497
1498 for (unit_end += upa; unit < unit_end; unit++)
1499 if (gi->cpu_map[unit] != NR_CPUS)
1500 printk("%0*d ", cpu_width,
1501 gi->cpu_map[unit]);
1502 else
1503 printk("%s ", empty_str);
Tejun Heo033e48f2009-08-14 15:00:51 +09001504 }
Tejun Heo033e48f2009-08-14 15:00:51 +09001505 }
1506 printk("\n");
1507}
Tejun Heo033e48f2009-08-14 15:00:51 +09001508
Tejun Heofbf59bc2009-02-20 16:29:08 +09001509/**
Tejun Heo8d408b42009-02-24 11:57:21 +09001510 * pcpu_setup_first_chunk - initialize the first percpu chunk
Tejun Heofd1e8a12009-08-14 15:00:51 +09001511 * @ai: pcpu_alloc_info describing how to percpu area is shaped
Tejun Heo38a6be52009-07-04 08:10:59 +09001512 * @base_addr: mapped address
Tejun Heofbf59bc2009-02-20 16:29:08 +09001513 *
Tejun Heo8d408b42009-02-24 11:57:21 +09001514 * Initialize the first percpu chunk which contains the kernel static
1515 * perpcu area. This function is to be called from arch percpu area
Tejun Heo38a6be52009-07-04 08:10:59 +09001516 * setup path.
Tejun Heo8d408b42009-02-24 11:57:21 +09001517 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001518 * @ai contains all information necessary to initialize the first
1519 * chunk and prime the dynamic percpu allocator.
1520 *
1521 * @ai->static_size is the size of static percpu area.
1522 *
1523 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
Tejun Heoedcb4632009-03-06 14:33:59 +09001524 * reserve after the static area in the first chunk. This reserves
1525 * the first chunk such that it's available only through reserved
1526 * percpu allocation. This is primarily used to serve module percpu
1527 * static areas on architectures where the addressing model has
1528 * limited offset range for symbol relocations to guarantee module
1529 * percpu symbols fall inside the relocatable range.
1530 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001531 * @ai->dyn_size determines the number of bytes available for dynamic
1532 * allocation in the first chunk. The area between @ai->static_size +
1533 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
Tejun Heo6074d5b2009-03-10 16:27:48 +09001534 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001535 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
1536 * and equal to or larger than @ai->static_size + @ai->reserved_size +
1537 * @ai->dyn_size.
1538 *
1539 * @ai->atom_size is the allocation atom size and used as alignment
1540 * for vm areas.
1541 *
1542 * @ai->alloc_size is the allocation size and always multiple of
1543 * @ai->atom_size. This is larger than @ai->atom_size if
1544 * @ai->unit_size is larger than @ai->atom_size.
1545 *
1546 * @ai->nr_groups and @ai->groups describe virtual memory layout of
1547 * percpu areas. Units which should be colocated are put into the
1548 * same group. Dynamic VM areas will be allocated according to these
1549 * groupings. If @ai->nr_groups is zero, a single group containing
1550 * all units is assumed.
Tejun Heo8d408b42009-02-24 11:57:21 +09001551 *
Tejun Heo38a6be52009-07-04 08:10:59 +09001552 * The caller should have mapped the first chunk at @base_addr and
1553 * copied static data to each unit.
Tejun Heofbf59bc2009-02-20 16:29:08 +09001554 *
Tejun Heoedcb4632009-03-06 14:33:59 +09001555 * If the first chunk ends up with both reserved and dynamic areas, it
1556 * is served by two chunks - one to serve the core static and reserved
1557 * areas and the other for the dynamic area. They share the same vm
1558 * and page map but uses different area allocation map to stay away
1559 * from each other. The latter chunk is circulated in the chunk slots
1560 * and available for dynamic allocation like any other chunks.
1561 *
Tejun Heofbf59bc2009-02-20 16:29:08 +09001562 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09001563 * 0 on success, -errno on failure.
Tejun Heofbf59bc2009-02-20 16:29:08 +09001564 */
Tejun Heofb435d52009-08-14 15:00:51 +09001565int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
1566 void *base_addr)
Tejun Heofbf59bc2009-02-20 16:29:08 +09001567{
Tejun Heo2441d152009-03-06 14:33:59 +09001568 static struct vm_struct first_vm;
Tejun Heoedcb4632009-03-06 14:33:59 +09001569 static int smap[2], dmap[2];
Tejun Heofd1e8a12009-08-14 15:00:51 +09001570 size_t dyn_size = ai->dyn_size;
1571 size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
Tejun Heoedcb4632009-03-06 14:33:59 +09001572 struct pcpu_chunk *schunk, *dchunk = NULL;
Tejun Heofb435d52009-08-14 15:00:51 +09001573 unsigned long *unit_off;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001574 unsigned int cpu;
1575 int *unit_map;
1576 int group, unit, i;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001577
Tejun Heo2f39e632009-07-04 08:11:00 +09001578 /* sanity checks */
Tejun Heoedcb4632009-03-06 14:33:59 +09001579 BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
1580 ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001581 BUG_ON(ai->nr_groups <= 0);
1582 BUG_ON(!ai->static_size);
Tejun Heo38a6be52009-07-04 08:10:59 +09001583 BUG_ON(!base_addr);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001584 BUG_ON(ai->unit_size < size_sum);
1585 BUG_ON(ai->unit_size & ~PAGE_MASK);
1586 BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
1587
1588 pcpu_dump_alloc_info(KERN_DEBUG, ai);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001589
Tejun Heofb435d52009-08-14 15:00:51 +09001590 /* determine number of units and initialize unit_map and base */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001591 unit_map = alloc_bootmem(nr_cpu_ids * sizeof(unit_map[0]));
Tejun Heofb435d52009-08-14 15:00:51 +09001592 unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0]));
Tejun Heo2f39e632009-07-04 08:11:00 +09001593
Tejun Heofd1e8a12009-08-14 15:00:51 +09001594 for (cpu = 0; cpu < nr_cpu_ids; cpu++)
1595 unit_map[cpu] = NR_CPUS;
1596 pcpu_first_unit_cpu = NR_CPUS;
Tejun Heo2f39e632009-07-04 08:11:00 +09001597
Tejun Heofd1e8a12009-08-14 15:00:51 +09001598 for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
1599 const struct pcpu_group_info *gi = &ai->groups[group];
Tejun Heo2f39e632009-07-04 08:11:00 +09001600
Tejun Heofd1e8a12009-08-14 15:00:51 +09001601 for (i = 0; i < gi->nr_units; i++) {
1602 cpu = gi->cpu_map[i];
1603 if (cpu == NR_CPUS)
1604 continue;
1605
1606 BUG_ON(cpu > nr_cpu_ids || !cpu_possible(cpu));
1607 BUG_ON(unit_map[cpu] != NR_CPUS);
1608
1609 unit_map[cpu] = unit + i;
Tejun Heofb435d52009-08-14 15:00:51 +09001610 unit_off[cpu] = gi->base_offset + i * ai->unit_size;
1611
Tejun Heofd1e8a12009-08-14 15:00:51 +09001612 if (pcpu_first_unit_cpu == NR_CPUS)
Tejun Heo2f39e632009-07-04 08:11:00 +09001613 pcpu_first_unit_cpu = cpu;
Tejun Heo2f39e632009-07-04 08:11:00 +09001614 }
Tejun Heo2f39e632009-07-04 08:11:00 +09001615 }
Tejun Heofd1e8a12009-08-14 15:00:51 +09001616 pcpu_last_unit_cpu = cpu;
1617 pcpu_nr_units = unit;
1618
1619 for_each_possible_cpu(cpu)
1620 BUG_ON(unit_map[cpu] == NR_CPUS);
1621
1622 pcpu_unit_map = unit_map;
Tejun Heofb435d52009-08-14 15:00:51 +09001623 pcpu_unit_offsets = unit_off;
Tejun Heo2f39e632009-07-04 08:11:00 +09001624
1625 /* determine basic parameters */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001626 pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
Tejun Heod9b55ee2009-02-24 11:57:21 +09001627 pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
Tejun Heo2f39e632009-07-04 08:11:00 +09001628 pcpu_chunk_size = pcpu_nr_units * pcpu_unit_size;
Tejun Heoce3141a2009-07-04 08:11:00 +09001629 pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
1630 BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001631
Tejun Heo38a6be52009-07-04 08:10:59 +09001632 first_vm.flags = VM_ALLOC;
1633 first_vm.size = pcpu_chunk_size;
1634 first_vm.addr = base_addr;
1635
Tejun Heod9b55ee2009-02-24 11:57:21 +09001636 /*
1637 * Allocate chunk slots. The additional last slot is for
1638 * empty chunks.
1639 */
1640 pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001641 pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0]));
1642 for (i = 0; i < pcpu_nr_slots; i++)
1643 INIT_LIST_HEAD(&pcpu_slot[i]);
1644
Tejun Heoedcb4632009-03-06 14:33:59 +09001645 /*
1646 * Initialize static chunk. If reserved_size is zero, the
1647 * static chunk covers static area + dynamic allocation area
1648 * in the first chunk. If reserved_size is not zero, it
1649 * covers static area + reserved area (mostly used for module
1650 * static percpu allocation).
1651 */
Tejun Heo2441d152009-03-06 14:33:59 +09001652 schunk = alloc_bootmem(pcpu_chunk_struct_size);
1653 INIT_LIST_HEAD(&schunk->list);
1654 schunk->vm = &first_vm;
Tejun Heo61ace7f2009-03-06 14:33:59 +09001655 schunk->map = smap;
1656 schunk->map_alloc = ARRAY_SIZE(smap);
Tejun Heo38a6be52009-07-04 08:10:59 +09001657 schunk->immutable = true;
Tejun Heoce3141a2009-07-04 08:11:00 +09001658 bitmap_fill(schunk->populated, pcpu_unit_pages);
Tejun Heoedcb4632009-03-06 14:33:59 +09001659
Tejun Heofd1e8a12009-08-14 15:00:51 +09001660 if (ai->reserved_size) {
1661 schunk->free_size = ai->reserved_size;
Tejun Heoae9e6bc92009-04-02 13:19:54 +09001662 pcpu_reserved_chunk = schunk;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001663 pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
Tejun Heoedcb4632009-03-06 14:33:59 +09001664 } else {
1665 schunk->free_size = dyn_size;
1666 dyn_size = 0; /* dynamic area covered */
1667 }
Tejun Heo2441d152009-03-06 14:33:59 +09001668 schunk->contig_hint = schunk->free_size;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001669
Tejun Heofd1e8a12009-08-14 15:00:51 +09001670 schunk->map[schunk->map_used++] = -ai->static_size;
Tejun Heo61ace7f2009-03-06 14:33:59 +09001671 if (schunk->free_size)
1672 schunk->map[schunk->map_used++] = schunk->free_size;
1673
Tejun Heoedcb4632009-03-06 14:33:59 +09001674 /* init dynamic chunk if necessary */
1675 if (dyn_size) {
Tejun Heoce3141a2009-07-04 08:11:00 +09001676 dchunk = alloc_bootmem(pcpu_chunk_struct_size);
Tejun Heoedcb4632009-03-06 14:33:59 +09001677 INIT_LIST_HEAD(&dchunk->list);
1678 dchunk->vm = &first_vm;
1679 dchunk->map = dmap;
1680 dchunk->map_alloc = ARRAY_SIZE(dmap);
Tejun Heo38a6be52009-07-04 08:10:59 +09001681 dchunk->immutable = true;
Tejun Heoce3141a2009-07-04 08:11:00 +09001682 bitmap_fill(dchunk->populated, pcpu_unit_pages);
Tejun Heoedcb4632009-03-06 14:33:59 +09001683
1684 dchunk->contig_hint = dchunk->free_size = dyn_size;
1685 dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit;
1686 dchunk->map[dchunk->map_used++] = dchunk->free_size;
1687 }
1688
Tejun Heo2441d152009-03-06 14:33:59 +09001689 /* link the first chunk in */
Tejun Heoae9e6bc92009-04-02 13:19:54 +09001690 pcpu_first_chunk = dchunk ?: schunk;
1691 pcpu_chunk_relocate(pcpu_first_chunk, -1);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001692
1693 /* we're done */
Tejun Heo2f39e632009-07-04 08:11:00 +09001694 pcpu_base_addr = schunk->vm->addr;
Tejun Heofb435d52009-08-14 15:00:51 +09001695 return 0;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001696}
Tejun Heo66c3a752009-03-10 16:27:48 +09001697
Tejun Heof58dc012009-08-14 15:00:50 +09001698const char *pcpu_fc_names[PCPU_FC_NR] __initdata = {
1699 [PCPU_FC_AUTO] = "auto",
1700 [PCPU_FC_EMBED] = "embed",
1701 [PCPU_FC_PAGE] = "page",
1702 [PCPU_FC_LPAGE] = "lpage",
1703};
1704
1705enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
1706
1707static int __init percpu_alloc_setup(char *str)
1708{
1709 if (0)
1710 /* nada */;
1711#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
1712 else if (!strcmp(str, "embed"))
1713 pcpu_chosen_fc = PCPU_FC_EMBED;
1714#endif
1715#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1716 else if (!strcmp(str, "page"))
1717 pcpu_chosen_fc = PCPU_FC_PAGE;
1718#endif
1719#ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
1720 else if (!strcmp(str, "lpage"))
1721 pcpu_chosen_fc = PCPU_FC_LPAGE;
1722#endif
1723 else
1724 pr_warning("PERCPU: unknown allocator %s specified\n", str);
1725
1726 return 0;
1727}
1728early_param("percpu_alloc", percpu_alloc_setup);
1729
Tejun Heo08fc4582009-08-14 15:00:49 +09001730#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
1731 !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
Tejun Heo66c3a752009-03-10 16:27:48 +09001732/**
1733 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
Tejun Heo66c3a752009-03-10 16:27:48 +09001734 * @reserved_size: the size of reserved percpu area in bytes
1735 * @dyn_size: free size for dynamic allocation in bytes, -1 for auto
Tejun Heo66c3a752009-03-10 16:27:48 +09001736 *
1737 * This is a helper to ease setting up embedded first percpu chunk and
1738 * can be called where pcpu_setup_first_chunk() is expected.
1739 *
1740 * If this function is used to setup the first chunk, it is allocated
1741 * as a contiguous area using bootmem allocator and used as-is without
1742 * being mapped into vmalloc area. This enables the first chunk to
1743 * piggy back on the linear physical mapping which often uses larger
1744 * page size.
1745 *
1746 * When @dyn_size is positive, dynamic area might be larger than
Tejun Heo788e5ab2009-07-04 08:10:58 +09001747 * specified to fill page alignment. When @dyn_size is auto,
1748 * @dyn_size is just big enough to fill page alignment after static
1749 * and reserved areas.
Tejun Heo66c3a752009-03-10 16:27:48 +09001750 *
1751 * If the needed size is smaller than the minimum or specified unit
1752 * size, the leftover is returned to the bootmem allocator.
1753 *
1754 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09001755 * 0 on success, -errno on failure.
Tejun Heo66c3a752009-03-10 16:27:48 +09001756 */
Tejun Heofb435d52009-08-14 15:00:51 +09001757int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size)
Tejun Heo66c3a752009-03-10 16:27:48 +09001758{
Tejun Heofd1e8a12009-08-14 15:00:51 +09001759 struct pcpu_alloc_info *ai;
1760 size_t size_sum, chunk_size;
Tejun Heoce3141a2009-07-04 08:11:00 +09001761 void *base;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001762 int unit;
Tejun Heofb435d52009-08-14 15:00:51 +09001763 int rc;
Tejun Heo66c3a752009-03-10 16:27:48 +09001764
Tejun Heofd1e8a12009-08-14 15:00:51 +09001765 ai = pcpu_build_alloc_info(reserved_size, dyn_size, PAGE_SIZE, NULL);
1766 if (IS_ERR(ai))
1767 return PTR_ERR(ai);
1768 BUG_ON(ai->nr_groups != 1);
1769 BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
Tejun Heo66c3a752009-03-10 16:27:48 +09001770
Tejun Heofd1e8a12009-08-14 15:00:51 +09001771 size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
1772 chunk_size = ai->unit_size * num_possible_cpus();
Tejun Heofa8a7092009-06-22 11:56:24 +09001773
Tejun Heoce3141a2009-07-04 08:11:00 +09001774 base = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE,
1775 __pa(MAX_DMA_ADDRESS));
1776 if (!base) {
Tejun Heofa8a7092009-06-22 11:56:24 +09001777 pr_warning("PERCPU: failed to allocate %zu bytes for "
1778 "embedding\n", chunk_size);
Tejun Heofb435d52009-08-14 15:00:51 +09001779 rc = -ENOMEM;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001780 goto out_free_ai;
Tejun Heofa8a7092009-06-22 11:56:24 +09001781 }
Tejun Heo66c3a752009-03-10 16:27:48 +09001782
1783 /* return the leftover and copy */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001784 for (unit = 0; unit < num_possible_cpus(); unit++) {
1785 void *ptr = base + unit * ai->unit_size;
Tejun Heo66c3a752009-03-10 16:27:48 +09001786
Tejun Heofd1e8a12009-08-14 15:00:51 +09001787 free_bootmem(__pa(ptr + size_sum), ai->unit_size - size_sum);
1788 memcpy(ptr, __per_cpu_load, ai->static_size);
Tejun Heo66c3a752009-03-10 16:27:48 +09001789 }
1790
1791 /* we're ready, commit */
Tejun Heo004018e2009-08-14 15:00:49 +09001792 pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
Tejun Heofd1e8a12009-08-14 15:00:51 +09001793 PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
1794 ai->dyn_size, ai->unit_size);
Tejun Heo66c3a752009-03-10 16:27:48 +09001795
Tejun Heofb435d52009-08-14 15:00:51 +09001796 rc = pcpu_setup_first_chunk(ai, base);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001797out_free_ai:
1798 pcpu_free_alloc_info(ai);
Tejun Heofb435d52009-08-14 15:00:51 +09001799 return rc;
Tejun Heod4b95f82009-07-04 08:10:59 +09001800}
Tejun Heo08fc4582009-08-14 15:00:49 +09001801#endif /* CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK ||
1802 !CONFIG_HAVE_SETUP_PER_CPU_AREA */
Tejun Heod4b95f82009-07-04 08:10:59 +09001803
Tejun Heo08fc4582009-08-14 15:00:49 +09001804#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
Tejun Heod4b95f82009-07-04 08:10:59 +09001805/**
Tejun Heo00ae4062009-08-14 15:00:49 +09001806 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
Tejun Heod4b95f82009-07-04 08:10:59 +09001807 * @reserved_size: the size of reserved percpu area in bytes
1808 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
1809 * @free_fn: funtion to free percpu page, always called with PAGE_SIZE
1810 * @populate_pte_fn: function to populate pte
1811 *
Tejun Heo00ae4062009-08-14 15:00:49 +09001812 * This is a helper to ease setting up page-remapped first percpu
1813 * chunk and can be called where pcpu_setup_first_chunk() is expected.
Tejun Heod4b95f82009-07-04 08:10:59 +09001814 *
1815 * This is the basic allocator. Static percpu area is allocated
1816 * page-by-page into vmalloc area.
1817 *
1818 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09001819 * 0 on success, -errno on failure.
Tejun Heod4b95f82009-07-04 08:10:59 +09001820 */
Tejun Heofb435d52009-08-14 15:00:51 +09001821int __init pcpu_page_first_chunk(size_t reserved_size,
1822 pcpu_fc_alloc_fn_t alloc_fn,
1823 pcpu_fc_free_fn_t free_fn,
1824 pcpu_fc_populate_pte_fn_t populate_pte_fn)
Tejun Heod4b95f82009-07-04 08:10:59 +09001825{
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001826 static struct vm_struct vm;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001827 struct pcpu_alloc_info *ai;
Tejun Heo00ae4062009-08-14 15:00:49 +09001828 char psize_str[16];
Tejun Heoce3141a2009-07-04 08:11:00 +09001829 int unit_pages;
Tejun Heod4b95f82009-07-04 08:10:59 +09001830 size_t pages_size;
Tejun Heoce3141a2009-07-04 08:11:00 +09001831 struct page **pages;
Tejun Heofb435d52009-08-14 15:00:51 +09001832 int unit, i, j, rc;
Tejun Heod4b95f82009-07-04 08:10:59 +09001833
Tejun Heo00ae4062009-08-14 15:00:49 +09001834 snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
1835
Tejun Heofd1e8a12009-08-14 15:00:51 +09001836 ai = pcpu_build_alloc_info(reserved_size, -1, PAGE_SIZE, NULL);
1837 if (IS_ERR(ai))
1838 return PTR_ERR(ai);
1839 BUG_ON(ai->nr_groups != 1);
1840 BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
1841
1842 unit_pages = ai->unit_size >> PAGE_SHIFT;
Tejun Heod4b95f82009-07-04 08:10:59 +09001843
1844 /* unaligned allocations can't be freed, round up to page size */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001845 pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
1846 sizeof(pages[0]));
Tejun Heoce3141a2009-07-04 08:11:00 +09001847 pages = alloc_bootmem(pages_size);
Tejun Heod4b95f82009-07-04 08:10:59 +09001848
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001849 /* allocate pages */
Tejun Heod4b95f82009-07-04 08:10:59 +09001850 j = 0;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001851 for (unit = 0; unit < num_possible_cpus(); unit++)
Tejun Heoce3141a2009-07-04 08:11:00 +09001852 for (i = 0; i < unit_pages; i++) {
Tejun Heofd1e8a12009-08-14 15:00:51 +09001853 unsigned int cpu = ai->groups[0].cpu_map[unit];
Tejun Heod4b95f82009-07-04 08:10:59 +09001854 void *ptr;
1855
Tejun Heo3cbc8562009-08-14 15:00:50 +09001856 ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
Tejun Heod4b95f82009-07-04 08:10:59 +09001857 if (!ptr) {
Tejun Heo00ae4062009-08-14 15:00:49 +09001858 pr_warning("PERCPU: failed to allocate %s page "
1859 "for cpu%u\n", psize_str, cpu);
Tejun Heod4b95f82009-07-04 08:10:59 +09001860 goto enomem;
1861 }
Tejun Heoce3141a2009-07-04 08:11:00 +09001862 pages[j++] = virt_to_page(ptr);
Tejun Heod4b95f82009-07-04 08:10:59 +09001863 }
1864
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001865 /* allocate vm area, map the pages and copy static data */
1866 vm.flags = VM_ALLOC;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001867 vm.size = num_possible_cpus() * ai->unit_size;
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001868 vm_area_register_early(&vm, PAGE_SIZE);
1869
Tejun Heofd1e8a12009-08-14 15:00:51 +09001870 for (unit = 0; unit < num_possible_cpus(); unit++) {
Tejun Heo1d9d3252009-08-14 15:00:50 +09001871 unsigned long unit_addr =
Tejun Heofd1e8a12009-08-14 15:00:51 +09001872 (unsigned long)vm.addr + unit * ai->unit_size;
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001873
Tejun Heoce3141a2009-07-04 08:11:00 +09001874 for (i = 0; i < unit_pages; i++)
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001875 populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
1876
1877 /* pte already populated, the following shouldn't fail */
Tejun Heofb435d52009-08-14 15:00:51 +09001878 rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
1879 unit_pages);
1880 if (rc < 0)
1881 panic("failed to map percpu area, err=%d\n", rc);
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001882
1883 /*
1884 * FIXME: Archs with virtual cache should flush local
1885 * cache for the linear mapping here - something
1886 * equivalent to flush_cache_vmap() on the local cpu.
1887 * flush_cache_vmap() can't be used as most supporting
1888 * data structures are not set up yet.
1889 */
1890
1891 /* copy static data */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001892 memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
Tejun Heo8f05a6a2009-07-04 08:10:59 +09001893 }
1894
Tejun Heod4b95f82009-07-04 08:10:59 +09001895 /* we're ready, commit */
Tejun Heo1d9d3252009-08-14 15:00:50 +09001896 pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
Tejun Heofd1e8a12009-08-14 15:00:51 +09001897 unit_pages, psize_str, vm.addr, ai->static_size,
1898 ai->reserved_size, ai->dyn_size);
Tejun Heod4b95f82009-07-04 08:10:59 +09001899
Tejun Heofb435d52009-08-14 15:00:51 +09001900 rc = pcpu_setup_first_chunk(ai, vm.addr);
Tejun Heod4b95f82009-07-04 08:10:59 +09001901 goto out_free_ar;
1902
1903enomem:
1904 while (--j >= 0)
Tejun Heoce3141a2009-07-04 08:11:00 +09001905 free_fn(page_address(pages[j]), PAGE_SIZE);
Tejun Heofb435d52009-08-14 15:00:51 +09001906 rc = -ENOMEM;
Tejun Heod4b95f82009-07-04 08:10:59 +09001907out_free_ar:
Tejun Heoce3141a2009-07-04 08:11:00 +09001908 free_bootmem(__pa(pages), pages_size);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001909 pcpu_free_alloc_info(ai);
Tejun Heofb435d52009-08-14 15:00:51 +09001910 return rc;
Tejun Heod4b95f82009-07-04 08:10:59 +09001911}
Tejun Heo08fc4582009-08-14 15:00:49 +09001912#endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */
Tejun Heod4b95f82009-07-04 08:10:59 +09001913
Tejun Heo08fc4582009-08-14 15:00:49 +09001914#ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001915struct pcpul_ent {
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001916 void *ptr;
Tejun Heoa530b792009-07-04 08:11:00 +09001917 void *map_addr;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001918};
1919
1920static size_t pcpul_size;
Tejun Heoa530b792009-07-04 08:11:00 +09001921static size_t pcpul_lpage_size;
1922static int pcpul_nr_lpages;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001923static struct pcpul_ent *pcpul_map;
Tejun Heoa530b792009-07-04 08:11:00 +09001924
Tejun Heofd1e8a12009-08-14 15:00:51 +09001925static bool __init pcpul_unit_to_cpu(int unit, const struct pcpu_alloc_info *ai,
Tejun Heoa530b792009-07-04 08:11:00 +09001926 unsigned int *cpup)
1927{
Tejun Heofd1e8a12009-08-14 15:00:51 +09001928 int group, cunit;
Tejun Heoa530b792009-07-04 08:11:00 +09001929
Tejun Heofd1e8a12009-08-14 15:00:51 +09001930 for (group = 0, cunit = 0; group < ai->nr_groups; group++) {
1931 const struct pcpu_group_info *gi = &ai->groups[group];
1932
1933 if (unit < cunit + gi->nr_units) {
Tejun Heoa530b792009-07-04 08:11:00 +09001934 if (cpup)
Tejun Heofd1e8a12009-08-14 15:00:51 +09001935 *cpup = gi->cpu_map[unit - cunit];
Tejun Heoa530b792009-07-04 08:11:00 +09001936 return true;
1937 }
Tejun Heofd1e8a12009-08-14 15:00:51 +09001938 cunit += gi->nr_units;
1939 }
Tejun Heoa530b792009-07-04 08:11:00 +09001940
1941 return false;
1942}
1943
Tejun Heofd1e8a12009-08-14 15:00:51 +09001944static int __init pcpul_cpu_to_unit(int cpu, const struct pcpu_alloc_info *ai)
1945{
1946 int group, unit, i;
1947
1948 for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
1949 const struct pcpu_group_info *gi = &ai->groups[group];
1950
1951 for (i = 0; i < gi->nr_units; i++)
1952 if (gi->cpu_map[i] == cpu)
1953 return unit + i;
1954 }
1955 BUG();
1956}
1957
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001958/**
1959 * pcpu_lpage_first_chunk - remap the first percpu chunk using large page
Tejun Heofd1e8a12009-08-14 15:00:51 +09001960 * @ai: pcpu_alloc_info
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001961 * @alloc_fn: function to allocate percpu lpage, always called with lpage_size
1962 * @free_fn: function to free percpu memory, @size <= lpage_size
1963 * @map_fn: function to map percpu lpage, always called with lpage_size
1964 *
Tejun Heoa530b792009-07-04 08:11:00 +09001965 * This allocator uses large page to build and map the first chunk.
Tejun Heofd1e8a12009-08-14 15:00:51 +09001966 * Unlike other helpers, the caller should provide fully initialized
1967 * @ai. This can be done using pcpu_build_alloc_info(). This two
1968 * stage initialization is to allow arch code to evaluate the
Tejun Heoa530b792009-07-04 08:11:00 +09001969 * parameters before committing to it.
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001970 *
Tejun Heoa530b792009-07-04 08:11:00 +09001971 * Large pages are allocated as directed by @unit_map and other
1972 * parameters and mapped to vmalloc space. Unused holes are returned
1973 * to the page allocator. Note that these holes end up being actively
1974 * mapped twice - once to the physical mapping and to the vmalloc area
1975 * for the first percpu chunk. Depending on architecture, this might
1976 * cause problem when changing page attributes of the returned area.
1977 * These double mapped areas can be detected using
1978 * pcpu_lpage_remapped().
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001979 *
1980 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09001981 * 0 on success, -errno on failure.
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001982 */
Tejun Heofb435d52009-08-14 15:00:51 +09001983int __init pcpu_lpage_first_chunk(const struct pcpu_alloc_info *ai,
1984 pcpu_fc_alloc_fn_t alloc_fn,
1985 pcpu_fc_free_fn_t free_fn,
1986 pcpu_fc_map_fn_t map_fn)
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001987{
Tejun Heoa530b792009-07-04 08:11:00 +09001988 static struct vm_struct vm;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001989 const size_t lpage_size = ai->atom_size;
1990 size_t chunk_size, map_size;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001991 unsigned int cpu;
Tejun Heofb435d52009-08-14 15:00:51 +09001992 int i, j, unit, nr_units, rc;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001993
Tejun Heofd1e8a12009-08-14 15:00:51 +09001994 nr_units = 0;
1995 for (i = 0; i < ai->nr_groups; i++)
1996 nr_units += ai->groups[i].nr_units;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09001997
Tejun Heofd1e8a12009-08-14 15:00:51 +09001998 chunk_size = ai->unit_size * nr_units;
Tejun Heoa530b792009-07-04 08:11:00 +09001999 BUG_ON(chunk_size % lpage_size);
2000
Tejun Heofd1e8a12009-08-14 15:00:51 +09002001 pcpul_size = ai->static_size + ai->reserved_size + ai->dyn_size;
Tejun Heoa530b792009-07-04 08:11:00 +09002002 pcpul_lpage_size = lpage_size;
2003 pcpul_nr_lpages = chunk_size / lpage_size;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002004
2005 /* allocate pointer array and alloc large pages */
Tejun Heoa530b792009-07-04 08:11:00 +09002006 map_size = pcpul_nr_lpages * sizeof(pcpul_map[0]);
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002007 pcpul_map = alloc_bootmem(map_size);
2008
Tejun Heoa530b792009-07-04 08:11:00 +09002009 /* allocate all pages */
2010 for (i = 0; i < pcpul_nr_lpages; i++) {
2011 size_t offset = i * lpage_size;
Tejun Heofd1e8a12009-08-14 15:00:51 +09002012 int first_unit = offset / ai->unit_size;
2013 int last_unit = (offset + lpage_size - 1) / ai->unit_size;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002014 void *ptr;
2015
Tejun Heoa530b792009-07-04 08:11:00 +09002016 /* find out which cpu is mapped to this unit */
2017 for (unit = first_unit; unit <= last_unit; unit++)
Tejun Heofd1e8a12009-08-14 15:00:51 +09002018 if (pcpul_unit_to_cpu(unit, ai, &cpu))
Tejun Heoa530b792009-07-04 08:11:00 +09002019 goto found;
2020 continue;
2021 found:
Tejun Heo3cbc8562009-08-14 15:00:50 +09002022 ptr = alloc_fn(cpu, lpage_size, lpage_size);
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002023 if (!ptr) {
2024 pr_warning("PERCPU: failed to allocate large page "
2025 "for cpu%u\n", cpu);
2026 goto enomem;
2027 }
2028
Tejun Heoa530b792009-07-04 08:11:00 +09002029 pcpul_map[i].ptr = ptr;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002030 }
2031
Tejun Heoa530b792009-07-04 08:11:00 +09002032 /* return unused holes */
2033 for (unit = 0; unit < nr_units; unit++) {
Tejun Heofd1e8a12009-08-14 15:00:51 +09002034 size_t start = unit * ai->unit_size;
2035 size_t end = start + ai->unit_size;
Tejun Heoa530b792009-07-04 08:11:00 +09002036 size_t off, next;
2037
2038 /* don't free used part of occupied unit */
Tejun Heofd1e8a12009-08-14 15:00:51 +09002039 if (pcpul_unit_to_cpu(unit, ai, NULL))
Tejun Heoa530b792009-07-04 08:11:00 +09002040 start += pcpul_size;
2041
2042 /* unit can span more than one page, punch the holes */
2043 for (off = start; off < end; off = next) {
2044 void *ptr = pcpul_map[off / lpage_size].ptr;
2045 next = min(roundup(off + 1, lpage_size), end);
2046 if (ptr)
2047 free_fn(ptr + off % lpage_size, next - off);
2048 }
2049 }
2050
2051 /* allocate address, map and copy */
2052 vm.flags = VM_ALLOC;
2053 vm.size = chunk_size;
Tejun Heofd1e8a12009-08-14 15:00:51 +09002054 vm_area_register_early(&vm, ai->unit_size);
Tejun Heoa530b792009-07-04 08:11:00 +09002055
2056 for (i = 0; i < pcpul_nr_lpages; i++) {
2057 if (!pcpul_map[i].ptr)
2058 continue;
2059 pcpul_map[i].map_addr = vm.addr + i * lpage_size;
2060 map_fn(pcpul_map[i].ptr, lpage_size, pcpul_map[i].map_addr);
2061 }
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002062
2063 for_each_possible_cpu(cpu)
Tejun Heofd1e8a12009-08-14 15:00:51 +09002064 memcpy(vm.addr + pcpul_cpu_to_unit(cpu, ai) * ai->unit_size,
2065 __per_cpu_load, ai->static_size);
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002066
2067 /* we're ready, commit */
Tejun Heo004018e2009-08-14 15:00:49 +09002068 pr_info("PERCPU: large pages @%p s%zu r%zu d%zu u%zu\n",
Tejun Heofd1e8a12009-08-14 15:00:51 +09002069 vm.addr, ai->static_size, ai->reserved_size, ai->dyn_size,
2070 ai->unit_size);
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002071
Tejun Heofb435d52009-08-14 15:00:51 +09002072 rc = pcpu_setup_first_chunk(ai, vm.addr);
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002073
Tejun Heoa530b792009-07-04 08:11:00 +09002074 /*
2075 * Sort pcpul_map array for pcpu_lpage_remapped(). Unmapped
2076 * lpages are pushed to the end and trimmed.
2077 */
2078 for (i = 0; i < pcpul_nr_lpages - 1; i++)
2079 for (j = i + 1; j < pcpul_nr_lpages; j++) {
2080 struct pcpul_ent tmp;
2081
2082 if (!pcpul_map[j].ptr)
2083 continue;
2084 if (pcpul_map[i].ptr &&
2085 pcpul_map[i].ptr < pcpul_map[j].ptr)
2086 continue;
2087
2088 tmp = pcpul_map[i];
2089 pcpul_map[i] = pcpul_map[j];
2090 pcpul_map[j] = tmp;
2091 }
2092
2093 while (pcpul_nr_lpages && !pcpul_map[pcpul_nr_lpages - 1].ptr)
2094 pcpul_nr_lpages--;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002095
Tejun Heofb435d52009-08-14 15:00:51 +09002096 return rc;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002097
2098enomem:
Tejun Heoa530b792009-07-04 08:11:00 +09002099 for (i = 0; i < pcpul_nr_lpages; i++)
2100 if (pcpul_map[i].ptr)
2101 free_fn(pcpul_map[i].ptr, lpage_size);
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002102 free_bootmem(__pa(pcpul_map), map_size);
2103 return -ENOMEM;
2104}
2105
2106/**
2107 * pcpu_lpage_remapped - determine whether a kaddr is in pcpul recycled area
2108 * @kaddr: the kernel address in question
2109 *
2110 * Determine whether @kaddr falls in the pcpul recycled area. This is
2111 * used by pageattr to detect VM aliases and break up the pcpu large
2112 * page mapping such that the same physical page is not mapped under
2113 * different attributes.
2114 *
2115 * The recycled area is always at the tail of a partially used large
2116 * page.
2117 *
2118 * RETURNS:
2119 * Address of corresponding remapped pcpu address if match is found;
2120 * otherwise, NULL.
2121 */
2122void *pcpu_lpage_remapped(void *kaddr)
2123{
Tejun Heoa530b792009-07-04 08:11:00 +09002124 unsigned long lpage_mask = pcpul_lpage_size - 1;
2125 void *lpage_addr = (void *)((unsigned long)kaddr & ~lpage_mask);
2126 unsigned long offset = (unsigned long)kaddr & lpage_mask;
2127 int left = 0, right = pcpul_nr_lpages - 1;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002128 int pos;
2129
2130 /* pcpul in use at all? */
2131 if (!pcpul_map)
2132 return NULL;
2133
2134 /* okay, perform binary search */
2135 while (left <= right) {
2136 pos = (left + right) / 2;
2137
2138 if (pcpul_map[pos].ptr < lpage_addr)
2139 left = pos + 1;
2140 else if (pcpul_map[pos].ptr > lpage_addr)
2141 right = pos - 1;
Tejun Heoa530b792009-07-04 08:11:00 +09002142 else
2143 return pcpul_map[pos].map_addr + offset;
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002144 }
2145
2146 return NULL;
2147}
Tejun Heo08fc4582009-08-14 15:00:49 +09002148#endif /* CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK */
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002149
2150/*
Tejun Heoe74e3962009-03-30 19:07:44 +09002151 * Generic percpu area setup.
2152 *
2153 * The embedding helper is used because its behavior closely resembles
2154 * the original non-dynamic generic percpu area setup. This is
2155 * important because many archs have addressing restrictions and might
2156 * fail if the percpu area is located far away from the previous
2157 * location. As an added bonus, in non-NUMA cases, embedding is
2158 * generally a good idea TLB-wise because percpu area can piggy back
2159 * on the physical linear memory mapping which uses large page
2160 * mappings on applicable archs.
2161 */
2162#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
2163unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
2164EXPORT_SYMBOL(__per_cpu_offset);
2165
2166void __init setup_per_cpu_areas(void)
2167{
Tejun Heoe74e3962009-03-30 19:07:44 +09002168 unsigned long delta;
2169 unsigned int cpu;
Tejun Heofb435d52009-08-14 15:00:51 +09002170 int rc;
Tejun Heoe74e3962009-03-30 19:07:44 +09002171
2172 /*
2173 * Always reserve area for module percpu variables. That's
2174 * what the legacy allocator did.
2175 */
Tejun Heofb435d52009-08-14 15:00:51 +09002176 rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
2177 PERCPU_DYNAMIC_RESERVE);
2178 if (rc < 0)
Tejun Heoe74e3962009-03-30 19:07:44 +09002179 panic("Failed to initialized percpu areas.");
2180
2181 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
2182 for_each_possible_cpu(cpu)
Tejun Heofb435d52009-08-14 15:00:51 +09002183 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
Tejun Heoe74e3962009-03-30 19:07:44 +09002184}
2185#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */