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Tejun Heofbf59bc2009-02-20 16:29:08 +09001/*
Tejun Heo88999a82010-04-09 18:57:01 +09002 * mm/percpu.c - percpu memory allocator
Tejun Heofbf59bc2009-02-20 16:29:08 +09003 *
4 * Copyright (C) 2009 SUSE Linux Products GmbH
5 * Copyright (C) 2009 Tejun Heo <tj@kernel.org>
6 *
7 * This file is released under the GPLv2.
8 *
9 * This is percpu allocator which can handle both static and dynamic
Tejun Heo88999a82010-04-09 18:57:01 +090010 * areas. Percpu areas are allocated in chunks. Each chunk is
11 * consisted of boot-time determined number of units and the first
12 * chunk is used for static percpu variables in the kernel image
Tejun Heo2f39e632009-07-04 08:11:00 +090013 * (special boot time alloc/init handling necessary as these areas
14 * need to be brought up before allocation services are running).
15 * Unit grows as necessary and all units grow or shrink in unison.
Tejun Heo88999a82010-04-09 18:57:01 +090016 * When a chunk is filled up, another chunk is allocated.
Tejun Heofbf59bc2009-02-20 16:29:08 +090017 *
18 * c0 c1 c2
19 * ------------------- ------------------- ------------
20 * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
21 * ------------------- ...... ------------------- .... ------------
22 *
23 * Allocation is done in offset-size areas of single unit space. Ie,
24 * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
Tejun Heo2f39e632009-07-04 08:11:00 +090025 * c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to
26 * cpus. On NUMA, the mapping can be non-linear and even sparse.
27 * Percpu access can be done by configuring percpu base registers
28 * according to cpu to unit mapping and pcpu_unit_size.
Tejun Heofbf59bc2009-02-20 16:29:08 +090029 *
Tejun Heo2f39e632009-07-04 08:11:00 +090030 * There are usually many small percpu allocations many of them being
31 * as small as 4 bytes. The allocator organizes chunks into lists
Tejun Heofbf59bc2009-02-20 16:29:08 +090032 * according to free size and tries to allocate from the fullest one.
33 * Each chunk keeps the maximum contiguous area size hint which is
Namhyung Kim4785879e2010-08-11 11:24:10 +090034 * guaranteed to be equal to or larger than the maximum contiguous
Tejun Heofbf59bc2009-02-20 16:29:08 +090035 * area in the chunk. This helps the allocator not to iterate the
36 * chunk maps unnecessarily.
37 *
38 * Allocation state in each chunk is kept using an array of integers
39 * on chunk->map. A positive value in the map represents a free
40 * region and negative allocated. Allocation inside a chunk is done
41 * by scanning this map sequentially and serving the first matching
42 * entry. This is mostly copied from the percpu_modalloc() allocator.
Christoph Lametere1b9aa32009-04-02 13:21:44 +090043 * Chunks can be determined from the address using the index field
44 * in the page struct. The index field contains a pointer to the chunk.
Tejun Heofbf59bc2009-02-20 16:29:08 +090045 *
46 * To use this allocator, arch code should do the followings.
47 *
Tejun Heofbf59bc2009-02-20 16:29:08 +090048 * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
Tejun Heoe0100982009-03-10 16:27:48 +090049 * regular address to percpu pointer and back if they need to be
50 * different from the default
Tejun Heofbf59bc2009-02-20 16:29:08 +090051 *
Tejun Heo8d408b42009-02-24 11:57:21 +090052 * - use pcpu_setup_first_chunk() during percpu area initialization to
53 * setup the first chunk containing the kernel static percpu area
Tejun Heofbf59bc2009-02-20 16:29:08 +090054 */
55
Joe Perches870d4b12016-03-17 14:19:53 -070056#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
57
Tejun Heofbf59bc2009-02-20 16:29:08 +090058#include <linux/bitmap.h>
59#include <linux/bootmem.h>
Tejun Heofd1e8a12009-08-14 15:00:51 +090060#include <linux/err.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090061#include <linux/list.h>
Tejun Heoa530b792009-07-04 08:11:00 +090062#include <linux/log2.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090063#include <linux/mm.h>
64#include <linux/module.h>
65#include <linux/mutex.h>
66#include <linux/percpu.h>
67#include <linux/pfn.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090068#include <linux/slab.h>
Tejun Heoccea34b2009-03-07 00:44:13 +090069#include <linux/spinlock.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090070#include <linux/vmalloc.h>
Tejun Heoa56dbdd2009-03-07 00:44:11 +090071#include <linux/workqueue.h>
Catalin Marinasf528f0b2011-09-26 17:12:53 +010072#include <linux/kmemleak.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>
Vivek Goyal3b034b02009-11-24 15:50:03 +090077#include <asm/io.h>
Tejun Heofbf59bc2009-02-20 16:29:08 +090078
Tejun Heofbf59bc2009-02-20 16:29:08 +090079#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
80#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
Tejun Heo9c824b62014-09-02 14:46:05 -040081#define PCPU_ATOMIC_MAP_MARGIN_LOW 32
82#define PCPU_ATOMIC_MAP_MARGIN_HIGH 64
Tejun Heo1a4d7602014-09-02 14:46:05 -040083#define PCPU_EMPTY_POP_PAGES_LOW 2
84#define PCPU_EMPTY_POP_PAGES_HIGH 4
Tejun Heofbf59bc2009-02-20 16:29:08 +090085
Tejun Heobbddff02010-09-03 18:22:48 +020086#ifdef CONFIG_SMP
Tejun Heoe0100982009-03-10 16:27:48 +090087/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
88#ifndef __addr_to_pcpu_ptr
89#define __addr_to_pcpu_ptr(addr) \
Tejun Heo43cf38e2010-02-02 14:38:57 +090090 (void __percpu *)((unsigned long)(addr) - \
91 (unsigned long)pcpu_base_addr + \
92 (unsigned long)__per_cpu_start)
Tejun Heoe0100982009-03-10 16:27:48 +090093#endif
94#ifndef __pcpu_ptr_to_addr
95#define __pcpu_ptr_to_addr(ptr) \
Tejun Heo43cf38e2010-02-02 14:38:57 +090096 (void __force *)((unsigned long)(ptr) + \
97 (unsigned long)pcpu_base_addr - \
98 (unsigned long)__per_cpu_start)
Tejun Heoe0100982009-03-10 16:27:48 +090099#endif
Tejun Heobbddff02010-09-03 18:22:48 +0200100#else /* CONFIG_SMP */
101/* on UP, it's always identity mapped */
102#define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
103#define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
104#endif /* CONFIG_SMP */
Tejun Heoe0100982009-03-10 16:27:48 +0900105
Tejun Heofbf59bc2009-02-20 16:29:08 +0900106struct pcpu_chunk {
107 struct list_head list; /* linked to pcpu_slot lists */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900108 int free_size; /* free bytes in the chunk */
109 int contig_hint; /* max contiguous size hint */
Tejun Heobba174f2009-08-14 15:00:51 +0900110 void *base_addr; /* base address of this chunk */
Tejun Heo9c824b62014-09-02 14:46:05 -0400111
Al Viro723ad1d2014-03-06 21:13:18 -0500112 int map_used; /* # of map entries used before the sentry */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900113 int map_alloc; /* # of map entries allocated */
114 int *map; /* allocation map */
Tejun Heo9c824b62014-09-02 14:46:05 -0400115 struct work_struct map_extend_work;/* async ->map[] extension */
116
Tejun Heo88999a82010-04-09 18:57:01 +0900117 void *data; /* chunk data */
Al Viro3d331ad2014-03-06 20:52:32 -0500118 int first_free; /* no free below this */
Tejun Heo8d408b42009-02-24 11:57:21 +0900119 bool immutable; /* no [de]population allowed */
Tejun Heob539b872014-09-02 14:46:05 -0400120 int nr_populated; /* # of populated pages */
Tejun Heoce3141a2009-07-04 08:11:00 +0900121 unsigned long populated[]; /* populated bitmap */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900122};
123
Tejun Heo40150d32009-02-24 12:32:28 +0900124static int pcpu_unit_pages __read_mostly;
125static int pcpu_unit_size __read_mostly;
Tejun Heo2f39e632009-07-04 08:11:00 +0900126static int pcpu_nr_units __read_mostly;
Tejun Heo65632972009-08-14 15:00:52 +0900127static int pcpu_atom_size __read_mostly;
Tejun Heo40150d32009-02-24 12:32:28 +0900128static int pcpu_nr_slots __read_mostly;
129static size_t pcpu_chunk_struct_size __read_mostly;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900130
Tejun Heoa855b842011-11-18 10:55:35 -0800131/* cpus with the lowest and highest unit addresses */
132static unsigned int pcpu_low_unit_cpu __read_mostly;
133static unsigned int pcpu_high_unit_cpu __read_mostly;
Tejun Heo2f39e632009-07-04 08:11:00 +0900134
Tejun Heofbf59bc2009-02-20 16:29:08 +0900135/* the address of the first chunk which starts with the kernel static area */
Tejun Heo40150d32009-02-24 12:32:28 +0900136void *pcpu_base_addr __read_mostly;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900137EXPORT_SYMBOL_GPL(pcpu_base_addr);
138
Tejun Heofb435d52009-08-14 15:00:51 +0900139static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
140const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */
Tejun Heo2f39e632009-07-04 08:11:00 +0900141
Tejun Heo65632972009-08-14 15:00:52 +0900142/* group information, used for vm allocation */
143static int pcpu_nr_groups __read_mostly;
144static const unsigned long *pcpu_group_offsets __read_mostly;
145static const size_t *pcpu_group_sizes __read_mostly;
146
Tejun Heoae9e6bc92009-04-02 13:19:54 +0900147/*
148 * The first chunk which always exists. Note that unlike other
149 * chunks, this one can be allocated and mapped in several different
150 * ways and thus often doesn't live in the vmalloc area.
151 */
152static struct pcpu_chunk *pcpu_first_chunk;
153
154/*
155 * Optional reserved chunk. This chunk reserves part of the first
156 * chunk and serves it for reserved allocations. The amount of
157 * reserved offset is in pcpu_reserved_chunk_limit. When reserved
158 * area doesn't exist, the following variables contain NULL and 0
159 * respectively.
160 */
Tejun Heoedcb4632009-03-06 14:33:59 +0900161static struct pcpu_chunk *pcpu_reserved_chunk;
Tejun Heoedcb4632009-03-06 14:33:59 +0900162static int pcpu_reserved_chunk_limit;
163
Tejun Heob38d08f2014-09-02 14:46:02 -0400164static DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
165static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900166
Tejun Heo40150d32009-02-24 12:32:28 +0900167static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900168
Tejun Heob539b872014-09-02 14:46:05 -0400169/*
170 * The number of empty populated pages, protected by pcpu_lock. The
171 * reserved chunk doesn't contribute to the count.
172 */
173static int pcpu_nr_empty_pop_pages;
174
Tejun Heo1a4d7602014-09-02 14:46:05 -0400175/*
176 * Balance work is used to populate or destroy chunks asynchronously. We
177 * try to keep the number of populated free pages between
178 * PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one
179 * empty chunk.
180 */
Tejun Heofe6bd8c2014-09-02 14:46:05 -0400181static void pcpu_balance_workfn(struct work_struct *work);
182static DECLARE_WORK(pcpu_balance_work, pcpu_balance_workfn);
Tejun Heo1a4d7602014-09-02 14:46:05 -0400183static bool pcpu_async_enabled __read_mostly;
184static bool pcpu_atomic_alloc_failed;
185
186static void pcpu_schedule_balance_work(void)
187{
188 if (pcpu_async_enabled)
189 schedule_work(&pcpu_balance_work);
190}
Tejun Heoa56dbdd2009-03-07 00:44:11 +0900191
Tejun Heo020ec652010-04-09 18:57:00 +0900192static bool pcpu_addr_in_first_chunk(void *addr)
193{
194 void *first_start = pcpu_first_chunk->base_addr;
195
196 return addr >= first_start && addr < first_start + pcpu_unit_size;
197}
198
199static bool pcpu_addr_in_reserved_chunk(void *addr)
200{
201 void *first_start = pcpu_first_chunk->base_addr;
202
203 return addr >= first_start &&
204 addr < first_start + pcpu_reserved_chunk_limit;
205}
206
Tejun Heod9b55ee2009-02-24 11:57:21 +0900207static int __pcpu_size_to_slot(int size)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900208{
Tejun Heocae3aeb2009-02-21 16:56:23 +0900209 int highbit = fls(size); /* size is in bytes */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900210 return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
211}
212
Tejun Heod9b55ee2009-02-24 11:57:21 +0900213static int pcpu_size_to_slot(int size)
214{
215 if (size == pcpu_unit_size)
216 return pcpu_nr_slots - 1;
217 return __pcpu_size_to_slot(size);
218}
219
Tejun Heofbf59bc2009-02-20 16:29:08 +0900220static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
221{
222 if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
223 return 0;
224
225 return pcpu_size_to_slot(chunk->free_size);
226}
227
Tejun Heo88999a82010-04-09 18:57:01 +0900228/* set the pointer to a chunk in a page struct */
229static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
230{
231 page->index = (unsigned long)pcpu;
232}
233
234/* obtain pointer to a chunk from a page struct */
235static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
236{
237 return (struct pcpu_chunk *)page->index;
238}
239
240static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900241{
Tejun Heo2f39e632009-07-04 08:11:00 +0900242 return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900243}
244
Tejun Heo9983b6f02010-06-18 11:44:31 +0200245static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
246 unsigned int cpu, int page_idx)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900247{
Tejun Heobba174f2009-08-14 15:00:51 +0900248 return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
Tejun Heofb435d52009-08-14 15:00:51 +0900249 (page_idx << PAGE_SHIFT);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900250}
251
Tejun Heo88999a82010-04-09 18:57:01 +0900252static void __maybe_unused pcpu_next_unpop(struct pcpu_chunk *chunk,
253 int *rs, int *re, int end)
Tejun Heoce3141a2009-07-04 08:11:00 +0900254{
255 *rs = find_next_zero_bit(chunk->populated, end, *rs);
256 *re = find_next_bit(chunk->populated, end, *rs + 1);
257}
258
Tejun Heo88999a82010-04-09 18:57:01 +0900259static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk,
260 int *rs, int *re, int end)
Tejun Heoce3141a2009-07-04 08:11:00 +0900261{
262 *rs = find_next_bit(chunk->populated, end, *rs);
263 *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
264}
265
266/*
267 * (Un)populated page region iterators. Iterate over (un)populated
Uwe Kleine-Königb5950762010-11-01 15:38:34 -0400268 * page regions between @start and @end in @chunk. @rs and @re should
Tejun Heoce3141a2009-07-04 08:11:00 +0900269 * be integer variables and will be set to start and end page index of
270 * the current region.
271 */
272#define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
273 for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
274 (rs) < (re); \
275 (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
276
277#define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
278 for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
279 (rs) < (re); \
280 (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
281
Tejun Heofbf59bc2009-02-20 16:29:08 +0900282/**
Bob Liu90459ce02011-08-04 11:02:33 +0200283 * pcpu_mem_zalloc - allocate memory
Tejun Heo1880d932009-03-07 00:44:09 +0900284 * @size: bytes to allocate
Tejun Heofbf59bc2009-02-20 16:29:08 +0900285 *
Tejun Heo1880d932009-03-07 00:44:09 +0900286 * Allocate @size bytes. If @size is smaller than PAGE_SIZE,
Bob Liu90459ce02011-08-04 11:02:33 +0200287 * kzalloc() is used; otherwise, vzalloc() is used. The returned
Tejun Heo1880d932009-03-07 00:44:09 +0900288 * memory is always zeroed.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900289 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900290 * CONTEXT:
291 * Does GFP_KERNEL allocation.
292 *
Tejun Heofbf59bc2009-02-20 16:29:08 +0900293 * RETURNS:
Tejun Heo1880d932009-03-07 00:44:09 +0900294 * Pointer to the allocated area on success, NULL on failure.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900295 */
Bob Liu90459ce02011-08-04 11:02:33 +0200296static void *pcpu_mem_zalloc(size_t size)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900297{
Tejun Heo099a19d2010-06-27 18:50:00 +0200298 if (WARN_ON_ONCE(!slab_is_available()))
299 return NULL;
300
Tejun Heofbf59bc2009-02-20 16:29:08 +0900301 if (size <= PAGE_SIZE)
Tejun Heo1880d932009-03-07 00:44:09 +0900302 return kzalloc(size, GFP_KERNEL);
Jesper Juhl7af4c092010-10-30 15:56:54 +0200303 else
304 return vzalloc(size);
Tejun Heo1880d932009-03-07 00:44:09 +0900305}
Tejun Heofbf59bc2009-02-20 16:29:08 +0900306
Tejun Heo1880d932009-03-07 00:44:09 +0900307/**
308 * pcpu_mem_free - free memory
309 * @ptr: memory to free
Tejun Heo1880d932009-03-07 00:44:09 +0900310 *
Bob Liu90459ce02011-08-04 11:02:33 +0200311 * Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc().
Tejun Heo1880d932009-03-07 00:44:09 +0900312 */
Tetsuo Handa1d5cfdb2016-01-22 15:11:02 -0800313static void pcpu_mem_free(void *ptr)
Tejun Heo1880d932009-03-07 00:44:09 +0900314{
Tetsuo Handa1d5cfdb2016-01-22 15:11:02 -0800315 kvfree(ptr);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900316}
317
318/**
Tejun Heob539b872014-09-02 14:46:05 -0400319 * pcpu_count_occupied_pages - count the number of pages an area occupies
320 * @chunk: chunk of interest
321 * @i: index of the area in question
322 *
323 * Count the number of pages chunk's @i'th area occupies. When the area's
324 * start and/or end address isn't aligned to page boundary, the straddled
325 * page is included in the count iff the rest of the page is free.
326 */
327static int pcpu_count_occupied_pages(struct pcpu_chunk *chunk, int i)
328{
329 int off = chunk->map[i] & ~1;
330 int end = chunk->map[i + 1] & ~1;
331
332 if (!PAGE_ALIGNED(off) && i > 0) {
333 int prev = chunk->map[i - 1];
334
335 if (!(prev & 1) && prev <= round_down(off, PAGE_SIZE))
336 off = round_down(off, PAGE_SIZE);
337 }
338
339 if (!PAGE_ALIGNED(end) && i + 1 < chunk->map_used) {
340 int next = chunk->map[i + 1];
341 int nend = chunk->map[i + 2] & ~1;
342
343 if (!(next & 1) && nend >= round_up(end, PAGE_SIZE))
344 end = round_up(end, PAGE_SIZE);
345 }
346
347 return max_t(int, PFN_DOWN(end) - PFN_UP(off), 0);
348}
349
350/**
Tejun Heofbf59bc2009-02-20 16:29:08 +0900351 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
352 * @chunk: chunk of interest
353 * @oslot: the previous slot it was on
354 *
355 * This function is called after an allocation or free changed @chunk.
356 * New slot according to the changed state is determined and @chunk is
Tejun Heoedcb4632009-03-06 14:33:59 +0900357 * moved to the slot. Note that the reserved chunk is never put on
358 * chunk slots.
Tejun Heoccea34b2009-03-07 00:44:13 +0900359 *
360 * CONTEXT:
361 * pcpu_lock.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900362 */
363static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
364{
365 int nslot = pcpu_chunk_slot(chunk);
366
Tejun Heoedcb4632009-03-06 14:33:59 +0900367 if (chunk != pcpu_reserved_chunk && oslot != nslot) {
Tejun Heofbf59bc2009-02-20 16:29:08 +0900368 if (oslot < nslot)
369 list_move(&chunk->list, &pcpu_slot[nslot]);
370 else
371 list_move_tail(&chunk->list, &pcpu_slot[nslot]);
372 }
373}
374
Tejun Heofbf59bc2009-02-20 16:29:08 +0900375/**
Tejun Heo833af842009-11-11 15:35:18 +0900376 * pcpu_need_to_extend - determine whether chunk area map needs to be extended
377 * @chunk: chunk of interest
Tejun Heo9c824b62014-09-02 14:46:05 -0400378 * @is_atomic: the allocation context
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900379 *
Tejun Heo9c824b62014-09-02 14:46:05 -0400380 * Determine whether area map of @chunk needs to be extended. If
381 * @is_atomic, only the amount necessary for a new allocation is
382 * considered; however, async extension is scheduled if the left amount is
383 * low. If !@is_atomic, it aims for more empty space. Combined, this
384 * ensures that the map is likely to have enough available space to
385 * accomodate atomic allocations which can't extend maps directly.
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900386 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900387 * CONTEXT:
Tejun Heo833af842009-11-11 15:35:18 +0900388 * pcpu_lock.
Tejun Heoccea34b2009-03-07 00:44:13 +0900389 *
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900390 * RETURNS:
Tejun Heo833af842009-11-11 15:35:18 +0900391 * New target map allocation length if extension is necessary, 0
392 * otherwise.
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900393 */
Tejun Heo9c824b62014-09-02 14:46:05 -0400394static int pcpu_need_to_extend(struct pcpu_chunk *chunk, bool is_atomic)
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900395{
Tejun Heo9c824b62014-09-02 14:46:05 -0400396 int margin, new_alloc;
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900397
Tejun Heo9c824b62014-09-02 14:46:05 -0400398 if (is_atomic) {
399 margin = 3;
400
401 if (chunk->map_alloc <
Tejun Heo1a4d7602014-09-02 14:46:05 -0400402 chunk->map_used + PCPU_ATOMIC_MAP_MARGIN_LOW &&
403 pcpu_async_enabled)
Tejun Heo9c824b62014-09-02 14:46:05 -0400404 schedule_work(&chunk->map_extend_work);
405 } else {
406 margin = PCPU_ATOMIC_MAP_MARGIN_HIGH;
407 }
408
409 if (chunk->map_alloc >= chunk->map_used + margin)
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900410 return 0;
411
412 new_alloc = PCPU_DFL_MAP_ALLOC;
Tejun Heo9c824b62014-09-02 14:46:05 -0400413 while (new_alloc < chunk->map_used + margin)
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900414 new_alloc *= 2;
415
Tejun Heo833af842009-11-11 15:35:18 +0900416 return new_alloc;
417}
418
419/**
420 * pcpu_extend_area_map - extend area map of a chunk
421 * @chunk: chunk of interest
422 * @new_alloc: new target allocation length of the area map
423 *
424 * Extend area map of @chunk to have @new_alloc entries.
425 *
426 * CONTEXT:
427 * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock.
428 *
429 * RETURNS:
430 * 0 on success, -errno on failure.
431 */
432static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
433{
434 int *old = NULL, *new = NULL;
435 size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
436 unsigned long flags;
437
Bob Liu90459ce02011-08-04 11:02:33 +0200438 new = pcpu_mem_zalloc(new_size);
Tejun Heo833af842009-11-11 15:35:18 +0900439 if (!new)
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900440 return -ENOMEM;
Tejun Heoccea34b2009-03-07 00:44:13 +0900441
Tejun Heo833af842009-11-11 15:35:18 +0900442 /* acquire pcpu_lock and switch to new area map */
443 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900444
Tejun Heo833af842009-11-11 15:35:18 +0900445 if (new_alloc <= chunk->map_alloc)
446 goto out_unlock;
447
448 old_size = chunk->map_alloc * sizeof(chunk->map[0]);
Huang Shijiea002d142010-08-08 14:39:07 +0200449 old = chunk->map;
450
451 memcpy(new, old, old_size);
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900452
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900453 chunk->map_alloc = new_alloc;
454 chunk->map = new;
Tejun Heo833af842009-11-11 15:35:18 +0900455 new = NULL;
456
457out_unlock:
458 spin_unlock_irqrestore(&pcpu_lock, flags);
459
460 /*
461 * pcpu_mem_free() might end up calling vfree() which uses
462 * IRQ-unsafe lock and thus can't be called under pcpu_lock.
463 */
Tetsuo Handa1d5cfdb2016-01-22 15:11:02 -0800464 pcpu_mem_free(old);
465 pcpu_mem_free(new);
Tejun Heo833af842009-11-11 15:35:18 +0900466
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900467 return 0;
468}
469
Tejun Heo9c824b62014-09-02 14:46:05 -0400470static void pcpu_map_extend_workfn(struct work_struct *work)
471{
472 struct pcpu_chunk *chunk = container_of(work, struct pcpu_chunk,
473 map_extend_work);
474 int new_alloc;
475
476 spin_lock_irq(&pcpu_lock);
477 new_alloc = pcpu_need_to_extend(chunk, false);
478 spin_unlock_irq(&pcpu_lock);
479
480 if (new_alloc)
481 pcpu_extend_area_map(chunk, new_alloc);
482}
483
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900484/**
Tejun Heoa16037c2014-09-02 14:46:02 -0400485 * pcpu_fit_in_area - try to fit the requested allocation in a candidate area
486 * @chunk: chunk the candidate area belongs to
487 * @off: the offset to the start of the candidate area
488 * @this_size: the size of the candidate area
489 * @size: the size of the target allocation
490 * @align: the alignment of the target allocation
491 * @pop_only: only allocate from already populated region
492 *
493 * We're trying to allocate @size bytes aligned at @align. @chunk's area
494 * at @off sized @this_size is a candidate. This function determines
495 * whether the target allocation fits in the candidate area and returns the
496 * number of bytes to pad after @off. If the target area doesn't fit, -1
497 * is returned.
498 *
499 * If @pop_only is %true, this function only considers the already
500 * populated part of the candidate area.
501 */
502static int pcpu_fit_in_area(struct pcpu_chunk *chunk, int off, int this_size,
503 int size, int align, bool pop_only)
504{
505 int cand_off = off;
506
507 while (true) {
508 int head = ALIGN(cand_off, align) - off;
509 int page_start, page_end, rs, re;
510
511 if (this_size < head + size)
512 return -1;
513
514 if (!pop_only)
515 return head;
516
517 /*
518 * If the first unpopulated page is beyond the end of the
519 * allocation, the whole allocation is populated;
520 * otherwise, retry from the end of the unpopulated area.
521 */
522 page_start = PFN_DOWN(head + off);
523 page_end = PFN_UP(head + off + size);
524
525 rs = page_start;
526 pcpu_next_unpop(chunk, &rs, &re, PFN_UP(off + this_size));
527 if (rs >= page_end)
528 return head;
529 cand_off = re * PAGE_SIZE;
530 }
531}
532
533/**
Tejun Heofbf59bc2009-02-20 16:29:08 +0900534 * pcpu_alloc_area - allocate area from a pcpu_chunk
535 * @chunk: chunk of interest
Tejun Heocae3aeb2009-02-21 16:56:23 +0900536 * @size: wanted size in bytes
Tejun Heofbf59bc2009-02-20 16:29:08 +0900537 * @align: wanted align
Tejun Heoa16037c2014-09-02 14:46:02 -0400538 * @pop_only: allocate only from the populated area
Tejun Heob539b872014-09-02 14:46:05 -0400539 * @occ_pages_p: out param for the number of pages the area occupies
Tejun Heofbf59bc2009-02-20 16:29:08 +0900540 *
541 * Try to allocate @size bytes area aligned at @align from @chunk.
542 * Note that this function only allocates the offset. It doesn't
543 * populate or map the area.
544 *
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900545 * @chunk->map must have at least two free slots.
546 *
Tejun Heoccea34b2009-03-07 00:44:13 +0900547 * CONTEXT:
548 * pcpu_lock.
549 *
Tejun Heofbf59bc2009-02-20 16:29:08 +0900550 * RETURNS:
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900551 * Allocated offset in @chunk on success, -1 if no matching area is
552 * found.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900553 */
Tejun Heoa16037c2014-09-02 14:46:02 -0400554static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align,
Tejun Heob539b872014-09-02 14:46:05 -0400555 bool pop_only, int *occ_pages_p)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900556{
557 int oslot = pcpu_chunk_slot(chunk);
558 int max_contig = 0;
559 int i, off;
Al Viro3d331ad2014-03-06 20:52:32 -0500560 bool seen_free = false;
Al Viro723ad1d2014-03-06 21:13:18 -0500561 int *p;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900562
Al Viro3d331ad2014-03-06 20:52:32 -0500563 for (i = chunk->first_free, p = chunk->map + i; i < chunk->map_used; i++, p++) {
Tejun Heofbf59bc2009-02-20 16:29:08 +0900564 int head, tail;
Al Viro723ad1d2014-03-06 21:13:18 -0500565 int this_size;
566
567 off = *p;
568 if (off & 1)
569 continue;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900570
Al Viro723ad1d2014-03-06 21:13:18 -0500571 this_size = (p[1] & ~1) - off;
Tejun Heoa16037c2014-09-02 14:46:02 -0400572
573 head = pcpu_fit_in_area(chunk, off, this_size, size, align,
574 pop_only);
575 if (head < 0) {
Al Viro3d331ad2014-03-06 20:52:32 -0500576 if (!seen_free) {
577 chunk->first_free = i;
578 seen_free = true;
579 }
Al Viro723ad1d2014-03-06 21:13:18 -0500580 max_contig = max(this_size, max_contig);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900581 continue;
582 }
583
584 /*
585 * If head is small or the previous block is free,
586 * merge'em. Note that 'small' is defined as smaller
587 * than sizeof(int), which is very small but isn't too
588 * uncommon for percpu allocations.
589 */
Al Viro723ad1d2014-03-06 21:13:18 -0500590 if (head && (head < sizeof(int) || !(p[-1] & 1))) {
Jianyu Zhan21ddfd32014-03-28 20:55:21 +0800591 *p = off += head;
Al Viro723ad1d2014-03-06 21:13:18 -0500592 if (p[-1] & 1)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900593 chunk->free_size -= head;
Jianyu Zhan21ddfd32014-03-28 20:55:21 +0800594 else
595 max_contig = max(*p - p[-1], max_contig);
Al Viro723ad1d2014-03-06 21:13:18 -0500596 this_size -= head;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900597 head = 0;
598 }
599
600 /* if tail is small, just keep it around */
Al Viro723ad1d2014-03-06 21:13:18 -0500601 tail = this_size - head - size;
602 if (tail < sizeof(int)) {
Tejun Heofbf59bc2009-02-20 16:29:08 +0900603 tail = 0;
Al Viro723ad1d2014-03-06 21:13:18 -0500604 size = this_size - head;
605 }
Tejun Heofbf59bc2009-02-20 16:29:08 +0900606
607 /* split if warranted */
608 if (head || tail) {
Al Viro706c16f2014-03-06 21:08:24 -0500609 int nr_extra = !!head + !!tail;
610
611 /* insert new subblocks */
Al Viro723ad1d2014-03-06 21:13:18 -0500612 memmove(p + nr_extra + 1, p + 1,
Al Viro706c16f2014-03-06 21:08:24 -0500613 sizeof(chunk->map[0]) * (chunk->map_used - i));
614 chunk->map_used += nr_extra;
615
Tejun Heofbf59bc2009-02-20 16:29:08 +0900616 if (head) {
Al Viro3d331ad2014-03-06 20:52:32 -0500617 if (!seen_free) {
618 chunk->first_free = i;
619 seen_free = true;
620 }
Al Viro723ad1d2014-03-06 21:13:18 -0500621 *++p = off += head;
622 ++i;
Al Viro706c16f2014-03-06 21:08:24 -0500623 max_contig = max(head, max_contig);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900624 }
Al Viro706c16f2014-03-06 21:08:24 -0500625 if (tail) {
Al Viro723ad1d2014-03-06 21:13:18 -0500626 p[1] = off + size;
Al Viro706c16f2014-03-06 21:08:24 -0500627 max_contig = max(tail, max_contig);
628 }
Tejun Heofbf59bc2009-02-20 16:29:08 +0900629 }
630
Al Viro3d331ad2014-03-06 20:52:32 -0500631 if (!seen_free)
632 chunk->first_free = i + 1;
633
Tejun Heofbf59bc2009-02-20 16:29:08 +0900634 /* update hint and mark allocated */
Al Viro723ad1d2014-03-06 21:13:18 -0500635 if (i + 1 == chunk->map_used)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900636 chunk->contig_hint = max_contig; /* fully scanned */
637 else
638 chunk->contig_hint = max(chunk->contig_hint,
639 max_contig);
640
Al Viro723ad1d2014-03-06 21:13:18 -0500641 chunk->free_size -= size;
642 *p |= 1;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900643
Tejun Heob539b872014-09-02 14:46:05 -0400644 *occ_pages_p = pcpu_count_occupied_pages(chunk, i);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900645 pcpu_chunk_relocate(chunk, oslot);
646 return off;
647 }
648
649 chunk->contig_hint = max_contig; /* fully scanned */
650 pcpu_chunk_relocate(chunk, oslot);
651
Tejun Heo9f7dcf22009-03-07 00:44:09 +0900652 /* tell the upper layer that this chunk has no matching area */
653 return -1;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900654}
655
656/**
657 * pcpu_free_area - free area to a pcpu_chunk
658 * @chunk: chunk of interest
659 * @freeme: offset of area to free
Tejun Heob539b872014-09-02 14:46:05 -0400660 * @occ_pages_p: out param for the number of pages the area occupies
Tejun Heofbf59bc2009-02-20 16:29:08 +0900661 *
662 * Free area starting from @freeme to @chunk. Note that this function
663 * only modifies the allocation map. It doesn't depopulate or unmap
664 * the area.
Tejun Heoccea34b2009-03-07 00:44:13 +0900665 *
666 * CONTEXT:
667 * pcpu_lock.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900668 */
Tejun Heob539b872014-09-02 14:46:05 -0400669static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme,
670 int *occ_pages_p)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900671{
672 int oslot = pcpu_chunk_slot(chunk);
Al Viro723ad1d2014-03-06 21:13:18 -0500673 int off = 0;
674 unsigned i, j;
675 int to_free = 0;
676 int *p;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900677
Al Viro723ad1d2014-03-06 21:13:18 -0500678 freeme |= 1; /* we are searching for <given offset, in use> pair */
679
680 i = 0;
681 j = chunk->map_used;
682 while (i != j) {
683 unsigned k = (i + j) / 2;
684 off = chunk->map[k];
685 if (off < freeme)
686 i = k + 1;
687 else if (off > freeme)
688 j = k;
689 else
690 i = j = k;
691 }
Tejun Heofbf59bc2009-02-20 16:29:08 +0900692 BUG_ON(off != freeme);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900693
Al Viro3d331ad2014-03-06 20:52:32 -0500694 if (i < chunk->first_free)
695 chunk->first_free = i;
696
Al Viro723ad1d2014-03-06 21:13:18 -0500697 p = chunk->map + i;
698 *p = off &= ~1;
699 chunk->free_size += (p[1] & ~1) - off;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900700
Tejun Heob539b872014-09-02 14:46:05 -0400701 *occ_pages_p = pcpu_count_occupied_pages(chunk, i);
702
Tejun Heofbf59bc2009-02-20 16:29:08 +0900703 /* merge with next? */
Al Viro723ad1d2014-03-06 21:13:18 -0500704 if (!(p[1] & 1))
705 to_free++;
706 /* merge with previous? */
707 if (i > 0 && !(p[-1] & 1)) {
708 to_free++;
709 i--;
710 p--;
711 }
712 if (to_free) {
713 chunk->map_used -= to_free;
714 memmove(p + 1, p + 1 + to_free,
715 (chunk->map_used - i) * sizeof(chunk->map[0]));
Tejun Heofbf59bc2009-02-20 16:29:08 +0900716 }
717
Al Viro723ad1d2014-03-06 21:13:18 -0500718 chunk->contig_hint = max(chunk->map[i + 1] - chunk->map[i] - 1, chunk->contig_hint);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900719 pcpu_chunk_relocate(chunk, oslot);
720}
721
Tejun Heo60810892010-04-09 18:57:01 +0900722static struct pcpu_chunk *pcpu_alloc_chunk(void)
723{
724 struct pcpu_chunk *chunk;
725
Bob Liu90459ce02011-08-04 11:02:33 +0200726 chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size);
Tejun Heo60810892010-04-09 18:57:01 +0900727 if (!chunk)
728 return NULL;
729
Bob Liu90459ce02011-08-04 11:02:33 +0200730 chunk->map = pcpu_mem_zalloc(PCPU_DFL_MAP_ALLOC *
731 sizeof(chunk->map[0]));
Tejun Heo60810892010-04-09 18:57:01 +0900732 if (!chunk->map) {
Tetsuo Handa1d5cfdb2016-01-22 15:11:02 -0800733 pcpu_mem_free(chunk);
Tejun Heo60810892010-04-09 18:57:01 +0900734 return NULL;
735 }
736
737 chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
Al Viro723ad1d2014-03-06 21:13:18 -0500738 chunk->map[0] = 0;
739 chunk->map[1] = pcpu_unit_size | 1;
740 chunk->map_used = 1;
Tejun Heo60810892010-04-09 18:57:01 +0900741
742 INIT_LIST_HEAD(&chunk->list);
Tejun Heo9c824b62014-09-02 14:46:05 -0400743 INIT_WORK(&chunk->map_extend_work, pcpu_map_extend_workfn);
Tejun Heo60810892010-04-09 18:57:01 +0900744 chunk->free_size = pcpu_unit_size;
745 chunk->contig_hint = pcpu_unit_size;
746
747 return chunk;
748}
749
750static void pcpu_free_chunk(struct pcpu_chunk *chunk)
751{
752 if (!chunk)
753 return;
Tetsuo Handa1d5cfdb2016-01-22 15:11:02 -0800754 pcpu_mem_free(chunk->map);
755 pcpu_mem_free(chunk);
Tejun Heo60810892010-04-09 18:57:01 +0900756}
757
Tejun Heob539b872014-09-02 14:46:05 -0400758/**
759 * pcpu_chunk_populated - post-population bookkeeping
760 * @chunk: pcpu_chunk which got populated
761 * @page_start: the start page
762 * @page_end: the end page
763 *
764 * Pages in [@page_start,@page_end) have been populated to @chunk. Update
765 * the bookkeeping information accordingly. Must be called after each
766 * successful population.
767 */
768static void pcpu_chunk_populated(struct pcpu_chunk *chunk,
769 int page_start, int page_end)
770{
771 int nr = page_end - page_start;
772
773 lockdep_assert_held(&pcpu_lock);
774
775 bitmap_set(chunk->populated, page_start, nr);
776 chunk->nr_populated += nr;
777 pcpu_nr_empty_pop_pages += nr;
778}
779
780/**
781 * pcpu_chunk_depopulated - post-depopulation bookkeeping
782 * @chunk: pcpu_chunk which got depopulated
783 * @page_start: the start page
784 * @page_end: the end page
785 *
786 * Pages in [@page_start,@page_end) have been depopulated from @chunk.
787 * Update the bookkeeping information accordingly. Must be called after
788 * each successful depopulation.
789 */
790static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk,
791 int page_start, int page_end)
792{
793 int nr = page_end - page_start;
794
795 lockdep_assert_held(&pcpu_lock);
796
797 bitmap_clear(chunk->populated, page_start, nr);
798 chunk->nr_populated -= nr;
799 pcpu_nr_empty_pop_pages -= nr;
800}
801
Tejun Heo9f645532010-04-09 18:57:01 +0900802/*
803 * Chunk management implementation.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900804 *
Tejun Heo9f645532010-04-09 18:57:01 +0900805 * To allow different implementations, chunk alloc/free and
806 * [de]population are implemented in a separate file which is pulled
807 * into this file and compiled together. The following functions
808 * should be implemented.
Tejun Heoce3141a2009-07-04 08:11:00 +0900809 *
Tejun Heo9f645532010-04-09 18:57:01 +0900810 * pcpu_populate_chunk - populate the specified range of a chunk
811 * pcpu_depopulate_chunk - depopulate the specified range of a chunk
812 * pcpu_create_chunk - create a new chunk
813 * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
814 * pcpu_addr_to_page - translate address to physical address
815 * pcpu_verify_alloc_info - check alloc_info is acceptable during init
Tejun Heofbf59bc2009-02-20 16:29:08 +0900816 */
Tejun Heo9f645532010-04-09 18:57:01 +0900817static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size);
818static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size);
819static struct pcpu_chunk *pcpu_create_chunk(void);
820static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
821static struct page *pcpu_addr_to_page(void *addr);
822static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
Tejun Heoce3141a2009-07-04 08:11:00 +0900823
Tejun Heob0c97782010-04-09 18:57:01 +0900824#ifdef CONFIG_NEED_PER_CPU_KM
825#include "percpu-km.c"
826#else
Tejun Heo9f645532010-04-09 18:57:01 +0900827#include "percpu-vm.c"
Tejun Heob0c97782010-04-09 18:57:01 +0900828#endif
Tejun Heofbf59bc2009-02-20 16:29:08 +0900829
830/**
Tejun Heo88999a82010-04-09 18:57:01 +0900831 * pcpu_chunk_addr_search - determine chunk containing specified address
832 * @addr: address for which the chunk needs to be determined.
833 *
834 * RETURNS:
835 * The address of the found chunk.
836 */
837static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
838{
839 /* is it in the first chunk? */
840 if (pcpu_addr_in_first_chunk(addr)) {
841 /* is it in the reserved area? */
842 if (pcpu_addr_in_reserved_chunk(addr))
843 return pcpu_reserved_chunk;
844 return pcpu_first_chunk;
845 }
846
847 /*
848 * The address is relative to unit0 which might be unused and
849 * thus unmapped. Offset the address to the unit space of the
850 * current processor before looking it up in the vmalloc
851 * space. Note that any possible cpu id can be used here, so
852 * there's no need to worry about preemption or cpu hotplug.
853 */
854 addr += pcpu_unit_offsets[raw_smp_processor_id()];
Tejun Heo9f645532010-04-09 18:57:01 +0900855 return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
Tejun Heo88999a82010-04-09 18:57:01 +0900856}
857
858/**
Tejun Heoedcb4632009-03-06 14:33:59 +0900859 * pcpu_alloc - the percpu allocator
Tejun Heocae3aeb2009-02-21 16:56:23 +0900860 * @size: size of area to allocate in bytes
Tejun Heofbf59bc2009-02-20 16:29:08 +0900861 * @align: alignment of area (max PAGE_SIZE)
Tejun Heoedcb4632009-03-06 14:33:59 +0900862 * @reserved: allocate from the reserved chunk if available
Tejun Heo5835d962014-09-02 14:46:04 -0400863 * @gfp: allocation flags
Tejun Heofbf59bc2009-02-20 16:29:08 +0900864 *
Tejun Heo5835d962014-09-02 14:46:04 -0400865 * Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't
866 * contain %GFP_KERNEL, the allocation is atomic.
Tejun Heofbf59bc2009-02-20 16:29:08 +0900867 *
868 * RETURNS:
869 * Percpu pointer to the allocated area on success, NULL on failure.
870 */
Tejun Heo5835d962014-09-02 14:46:04 -0400871static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
872 gfp_t gfp)
Tejun Heofbf59bc2009-02-20 16:29:08 +0900873{
Tejun Heof2badb02009-09-29 09:17:58 +0900874 static int warn_limit = 10;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900875 struct pcpu_chunk *chunk;
Tejun Heof2badb02009-09-29 09:17:58 +0900876 const char *err;
Tejun Heo6ae833c7f2014-10-08 12:01:52 -0400877 bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;
Tejun Heob539b872014-09-02 14:46:05 -0400878 int occ_pages = 0;
Tejun Heob38d08f2014-09-02 14:46:02 -0400879 int slot, off, new_alloc, cpu, ret;
Jiri Kosina403a91b2009-10-29 00:25:59 +0900880 unsigned long flags;
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100881 void __percpu *ptr;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900882
Al Viro723ad1d2014-03-06 21:13:18 -0500883 /*
884 * We want the lowest bit of offset available for in-use/free
Viro2f69fa82014-03-17 16:01:27 -0400885 * indicator, so force >= 16bit alignment and make size even.
Al Viro723ad1d2014-03-06 21:13:18 -0500886 */
887 if (unlikely(align < 2))
888 align = 2;
889
Christoph Lameterfb009e32014-06-19 09:59:18 -0500890 size = ALIGN(size, 2);
Viro2f69fa82014-03-17 16:01:27 -0400891
Tejun Heo8d408b42009-02-24 11:57:21 +0900892 if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
Joe Perches756a0252016-03-17 14:19:47 -0700893 WARN(true, "illegal size (%zu) or align (%zu) for percpu allocation\n",
894 size, align);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900895 return NULL;
896 }
897
Jiri Kosina403a91b2009-10-29 00:25:59 +0900898 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900899
Tejun Heoedcb4632009-03-06 14:33:59 +0900900 /* serve reserved allocations from the reserved chunk if available */
901 if (reserved && pcpu_reserved_chunk) {
902 chunk = pcpu_reserved_chunk;
Tejun Heo833af842009-11-11 15:35:18 +0900903
904 if (size > chunk->contig_hint) {
905 err = "alloc from reserved chunk failed";
Tejun Heoccea34b2009-03-07 00:44:13 +0900906 goto fail_unlock;
Tejun Heof2badb02009-09-29 09:17:58 +0900907 }
Tejun Heo833af842009-11-11 15:35:18 +0900908
Tejun Heo9c824b62014-09-02 14:46:05 -0400909 while ((new_alloc = pcpu_need_to_extend(chunk, is_atomic))) {
Tejun Heo833af842009-11-11 15:35:18 +0900910 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heo5835d962014-09-02 14:46:04 -0400911 if (is_atomic ||
912 pcpu_extend_area_map(chunk, new_alloc) < 0) {
Tejun Heo833af842009-11-11 15:35:18 +0900913 err = "failed to extend area map of reserved chunk";
Tejun Heob38d08f2014-09-02 14:46:02 -0400914 goto fail;
Tejun Heo833af842009-11-11 15:35:18 +0900915 }
916 spin_lock_irqsave(&pcpu_lock, flags);
917 }
918
Tejun Heob539b872014-09-02 14:46:05 -0400919 off = pcpu_alloc_area(chunk, size, align, is_atomic,
920 &occ_pages);
Tejun Heoedcb4632009-03-06 14:33:59 +0900921 if (off >= 0)
922 goto area_found;
Tejun Heo833af842009-11-11 15:35:18 +0900923
Tejun Heof2badb02009-09-29 09:17:58 +0900924 err = "alloc from reserved chunk failed";
Tejun Heoccea34b2009-03-07 00:44:13 +0900925 goto fail_unlock;
Tejun Heoedcb4632009-03-06 14:33:59 +0900926 }
927
Tejun Heoccea34b2009-03-07 00:44:13 +0900928restart:
Tejun Heoedcb4632009-03-06 14:33:59 +0900929 /* search through normal chunks */
Tejun Heofbf59bc2009-02-20 16:29:08 +0900930 for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
931 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
932 if (size > chunk->contig_hint)
933 continue;
Tejun Heoccea34b2009-03-07 00:44:13 +0900934
Tejun Heo9c824b62014-09-02 14:46:05 -0400935 new_alloc = pcpu_need_to_extend(chunk, is_atomic);
Tejun Heo833af842009-11-11 15:35:18 +0900936 if (new_alloc) {
Tejun Heo5835d962014-09-02 14:46:04 -0400937 if (is_atomic)
938 continue;
Tejun Heo833af842009-11-11 15:35:18 +0900939 spin_unlock_irqrestore(&pcpu_lock, flags);
940 if (pcpu_extend_area_map(chunk,
941 new_alloc) < 0) {
942 err = "failed to extend area map";
Tejun Heob38d08f2014-09-02 14:46:02 -0400943 goto fail;
Tejun Heo833af842009-11-11 15:35:18 +0900944 }
945 spin_lock_irqsave(&pcpu_lock, flags);
946 /*
947 * pcpu_lock has been dropped, need to
948 * restart cpu_slot list walking.
949 */
950 goto restart;
Tejun Heoccea34b2009-03-07 00:44:13 +0900951 }
952
Tejun Heob539b872014-09-02 14:46:05 -0400953 off = pcpu_alloc_area(chunk, size, align, is_atomic,
954 &occ_pages);
Tejun Heofbf59bc2009-02-20 16:29:08 +0900955 if (off >= 0)
956 goto area_found;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900957 }
958 }
959
Jiri Kosina403a91b2009-10-29 00:25:59 +0900960 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heoccea34b2009-03-07 00:44:13 +0900961
Tejun Heob38d08f2014-09-02 14:46:02 -0400962 /*
963 * No space left. Create a new chunk. We don't want multiple
964 * tasks to create chunks simultaneously. Serialize and create iff
965 * there's still no empty chunk after grabbing the mutex.
966 */
Tejun Heo5835d962014-09-02 14:46:04 -0400967 if (is_atomic)
968 goto fail;
969
Tejun Heob38d08f2014-09-02 14:46:02 -0400970 mutex_lock(&pcpu_alloc_mutex);
971
972 if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
973 chunk = pcpu_create_chunk();
974 if (!chunk) {
Tejun Heo23cb8982014-09-09 08:02:45 +0900975 mutex_unlock(&pcpu_alloc_mutex);
Tejun Heob38d08f2014-09-02 14:46:02 -0400976 err = "failed to allocate new chunk";
977 goto fail;
978 }
979
980 spin_lock_irqsave(&pcpu_lock, flags);
981 pcpu_chunk_relocate(chunk, -1);
982 } else {
983 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heof2badb02009-09-29 09:17:58 +0900984 }
Tejun Heoccea34b2009-03-07 00:44:13 +0900985
Tejun Heob38d08f2014-09-02 14:46:02 -0400986 mutex_unlock(&pcpu_alloc_mutex);
Tejun Heoccea34b2009-03-07 00:44:13 +0900987 goto restart;
Tejun Heofbf59bc2009-02-20 16:29:08 +0900988
989area_found:
Jiri Kosina403a91b2009-10-29 00:25:59 +0900990 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heoccea34b2009-03-07 00:44:13 +0900991
Tejun Heodca49642014-09-02 14:46:01 -0400992 /* populate if not all pages are already there */
Tejun Heo5835d962014-09-02 14:46:04 -0400993 if (!is_atomic) {
Tejun Heoe04d3202014-09-02 14:46:04 -0400994 int page_start, page_end, rs, re;
Tejun Heodca49642014-09-02 14:46:01 -0400995
Tejun Heoe04d3202014-09-02 14:46:04 -0400996 mutex_lock(&pcpu_alloc_mutex);
Tejun Heodca49642014-09-02 14:46:01 -0400997
Tejun Heoe04d3202014-09-02 14:46:04 -0400998 page_start = PFN_DOWN(off);
999 page_end = PFN_UP(off + size);
Tejun Heob38d08f2014-09-02 14:46:02 -04001000
Tejun Heoe04d3202014-09-02 14:46:04 -04001001 pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
1002 WARN_ON(chunk->immutable);
1003
1004 ret = pcpu_populate_chunk(chunk, rs, re);
1005
1006 spin_lock_irqsave(&pcpu_lock, flags);
1007 if (ret) {
1008 mutex_unlock(&pcpu_alloc_mutex);
Tejun Heob539b872014-09-02 14:46:05 -04001009 pcpu_free_area(chunk, off, &occ_pages);
Tejun Heoe04d3202014-09-02 14:46:04 -04001010 err = "failed to populate";
1011 goto fail_unlock;
1012 }
Tejun Heob539b872014-09-02 14:46:05 -04001013 pcpu_chunk_populated(chunk, rs, re);
Tejun Heoe04d3202014-09-02 14:46:04 -04001014 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heodca49642014-09-02 14:46:01 -04001015 }
Tejun Heofbf59bc2009-02-20 16:29:08 +09001016
Tejun Heoe04d3202014-09-02 14:46:04 -04001017 mutex_unlock(&pcpu_alloc_mutex);
1018 }
Tejun Heoccea34b2009-03-07 00:44:13 +09001019
Tejun Heob539b872014-09-02 14:46:05 -04001020 if (chunk != pcpu_reserved_chunk)
1021 pcpu_nr_empty_pop_pages -= occ_pages;
1022
Tejun Heo1a4d7602014-09-02 14:46:05 -04001023 if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
1024 pcpu_schedule_balance_work();
1025
Tejun Heodca49642014-09-02 14:46:01 -04001026 /* clear the areas and return address relative to base address */
1027 for_each_possible_cpu(cpu)
1028 memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
1029
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001030 ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
Larry Finger8a8c35f2015-06-24 16:58:51 -07001031 kmemleak_alloc_percpu(ptr, size, gfp);
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001032 return ptr;
Tejun Heoccea34b2009-03-07 00:44:13 +09001033
1034fail_unlock:
Jiri Kosina403a91b2009-10-29 00:25:59 +09001035 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heob38d08f2014-09-02 14:46:02 -04001036fail:
Tejun Heo5835d962014-09-02 14:46:04 -04001037 if (!is_atomic && warn_limit) {
Joe Perches870d4b12016-03-17 14:19:53 -07001038 pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n",
Joe Perches598d8092016-03-17 14:19:44 -07001039 size, align, is_atomic, err);
Tejun Heof2badb02009-09-29 09:17:58 +09001040 dump_stack();
1041 if (!--warn_limit)
Joe Perches870d4b12016-03-17 14:19:53 -07001042 pr_info("limit reached, disable warning\n");
Tejun Heof2badb02009-09-29 09:17:58 +09001043 }
Tejun Heo1a4d7602014-09-02 14:46:05 -04001044 if (is_atomic) {
1045 /* see the flag handling in pcpu_blance_workfn() */
1046 pcpu_atomic_alloc_failed = true;
1047 pcpu_schedule_balance_work();
1048 }
Tejun Heoccea34b2009-03-07 00:44:13 +09001049 return NULL;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001050}
Tejun Heoedcb4632009-03-06 14:33:59 +09001051
1052/**
Tejun Heo5835d962014-09-02 14:46:04 -04001053 * __alloc_percpu_gfp - allocate dynamic percpu area
Tejun Heoedcb4632009-03-06 14:33:59 +09001054 * @size: size of area to allocate in bytes
1055 * @align: alignment of area (max PAGE_SIZE)
Tejun Heo5835d962014-09-02 14:46:04 -04001056 * @gfp: allocation flags
Tejun Heoedcb4632009-03-06 14:33:59 +09001057 *
Tejun Heo5835d962014-09-02 14:46:04 -04001058 * Allocate zero-filled percpu area of @size bytes aligned at @align. If
1059 * @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can
1060 * be called from any context but is a lot more likely to fail.
Tejun Heoccea34b2009-03-07 00:44:13 +09001061 *
Tejun Heoedcb4632009-03-06 14:33:59 +09001062 * RETURNS:
1063 * Percpu pointer to the allocated area on success, NULL on failure.
1064 */
Tejun Heo5835d962014-09-02 14:46:04 -04001065void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp)
1066{
1067 return pcpu_alloc(size, align, false, gfp);
1068}
1069EXPORT_SYMBOL_GPL(__alloc_percpu_gfp);
1070
1071/**
1072 * __alloc_percpu - allocate dynamic percpu area
1073 * @size: size of area to allocate in bytes
1074 * @align: alignment of area (max PAGE_SIZE)
1075 *
1076 * Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL).
1077 */
Tejun Heo43cf38e2010-02-02 14:38:57 +09001078void __percpu *__alloc_percpu(size_t size, size_t align)
Tejun Heoedcb4632009-03-06 14:33:59 +09001079{
Tejun Heo5835d962014-09-02 14:46:04 -04001080 return pcpu_alloc(size, align, false, GFP_KERNEL);
Tejun Heoedcb4632009-03-06 14:33:59 +09001081}
Tejun Heofbf59bc2009-02-20 16:29:08 +09001082EXPORT_SYMBOL_GPL(__alloc_percpu);
1083
Tejun Heoedcb4632009-03-06 14:33:59 +09001084/**
1085 * __alloc_reserved_percpu - allocate reserved percpu area
1086 * @size: size of area to allocate in bytes
1087 * @align: alignment of area (max PAGE_SIZE)
1088 *
Tejun Heo9329ba92010-09-10 11:01:56 +02001089 * Allocate zero-filled percpu area of @size bytes aligned at @align
1090 * from reserved percpu area if arch has set it up; otherwise,
1091 * allocation is served from the same dynamic area. Might sleep.
1092 * Might trigger writeouts.
Tejun Heoedcb4632009-03-06 14:33:59 +09001093 *
Tejun Heoccea34b2009-03-07 00:44:13 +09001094 * CONTEXT:
1095 * Does GFP_KERNEL allocation.
1096 *
Tejun Heoedcb4632009-03-06 14:33:59 +09001097 * RETURNS:
1098 * Percpu pointer to the allocated area on success, NULL on failure.
1099 */
Tejun Heo43cf38e2010-02-02 14:38:57 +09001100void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
Tejun Heoedcb4632009-03-06 14:33:59 +09001101{
Tejun Heo5835d962014-09-02 14:46:04 -04001102 return pcpu_alloc(size, align, true, GFP_KERNEL);
Tejun Heoedcb4632009-03-06 14:33:59 +09001103}
1104
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001105/**
Tejun Heo1a4d7602014-09-02 14:46:05 -04001106 * pcpu_balance_workfn - manage the amount of free chunks and populated pages
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001107 * @work: unused
1108 *
1109 * Reclaim all fully free chunks except for the first one.
1110 */
Tejun Heofe6bd8c2014-09-02 14:46:05 -04001111static void pcpu_balance_workfn(struct work_struct *work)
Tejun Heofbf59bc2009-02-20 16:29:08 +09001112{
Tejun Heofe6bd8c2014-09-02 14:46:05 -04001113 LIST_HEAD(to_free);
1114 struct list_head *free_head = &pcpu_slot[pcpu_nr_slots - 1];
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001115 struct pcpu_chunk *chunk, *next;
Tejun Heo1a4d7602014-09-02 14:46:05 -04001116 int slot, nr_to_pop, ret;
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001117
Tejun Heo1a4d7602014-09-02 14:46:05 -04001118 /*
1119 * There's no reason to keep around multiple unused chunks and VM
1120 * areas can be scarce. Destroy all free chunks except for one.
1121 */
Tejun Heoccea34b2009-03-07 00:44:13 +09001122 mutex_lock(&pcpu_alloc_mutex);
1123 spin_lock_irq(&pcpu_lock);
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001124
Tejun Heofe6bd8c2014-09-02 14:46:05 -04001125 list_for_each_entry_safe(chunk, next, free_head, list) {
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001126 WARN_ON(chunk->immutable);
1127
1128 /* spare the first one */
Tejun Heofe6bd8c2014-09-02 14:46:05 -04001129 if (chunk == list_first_entry(free_head, struct pcpu_chunk, list))
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001130 continue;
1131
Tejun Heofe6bd8c2014-09-02 14:46:05 -04001132 list_move(&chunk->list, &to_free);
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001133 }
1134
Tejun Heoccea34b2009-03-07 00:44:13 +09001135 spin_unlock_irq(&pcpu_lock);
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001136
Tejun Heofe6bd8c2014-09-02 14:46:05 -04001137 list_for_each_entry_safe(chunk, next, &to_free, list) {
Tejun Heoa93ace42014-09-02 14:46:02 -04001138 int rs, re;
Tejun Heodca49642014-09-02 14:46:01 -04001139
Tejun Heoa93ace42014-09-02 14:46:02 -04001140 pcpu_for_each_pop_region(chunk, rs, re, 0, pcpu_unit_pages) {
1141 pcpu_depopulate_chunk(chunk, rs, re);
Tejun Heob539b872014-09-02 14:46:05 -04001142 spin_lock_irq(&pcpu_lock);
1143 pcpu_chunk_depopulated(chunk, rs, re);
1144 spin_unlock_irq(&pcpu_lock);
Tejun Heoa93ace42014-09-02 14:46:02 -04001145 }
Tejun Heo60810892010-04-09 18:57:01 +09001146 pcpu_destroy_chunk(chunk);
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001147 }
Tejun Heo971f3912009-08-14 15:00:49 +09001148
Tejun Heo1a4d7602014-09-02 14:46:05 -04001149 /*
1150 * Ensure there are certain number of free populated pages for
1151 * atomic allocs. Fill up from the most packed so that atomic
1152 * allocs don't increase fragmentation. If atomic allocation
1153 * failed previously, always populate the maximum amount. This
1154 * should prevent atomic allocs larger than PAGE_SIZE from keeping
1155 * failing indefinitely; however, large atomic allocs are not
1156 * something we support properly and can be highly unreliable and
1157 * inefficient.
1158 */
1159retry_pop:
1160 if (pcpu_atomic_alloc_failed) {
1161 nr_to_pop = PCPU_EMPTY_POP_PAGES_HIGH;
1162 /* best effort anyway, don't worry about synchronization */
1163 pcpu_atomic_alloc_failed = false;
1164 } else {
1165 nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH -
1166 pcpu_nr_empty_pop_pages,
1167 0, PCPU_EMPTY_POP_PAGES_HIGH);
1168 }
1169
1170 for (slot = pcpu_size_to_slot(PAGE_SIZE); slot < pcpu_nr_slots; slot++) {
1171 int nr_unpop = 0, rs, re;
1172
1173 if (!nr_to_pop)
1174 break;
1175
1176 spin_lock_irq(&pcpu_lock);
1177 list_for_each_entry(chunk, &pcpu_slot[slot], list) {
1178 nr_unpop = pcpu_unit_pages - chunk->nr_populated;
1179 if (nr_unpop)
1180 break;
1181 }
1182 spin_unlock_irq(&pcpu_lock);
1183
1184 if (!nr_unpop)
1185 continue;
1186
1187 /* @chunk can't go away while pcpu_alloc_mutex is held */
1188 pcpu_for_each_unpop_region(chunk, rs, re, 0, pcpu_unit_pages) {
1189 int nr = min(re - rs, nr_to_pop);
1190
1191 ret = pcpu_populate_chunk(chunk, rs, rs + nr);
1192 if (!ret) {
1193 nr_to_pop -= nr;
1194 spin_lock_irq(&pcpu_lock);
1195 pcpu_chunk_populated(chunk, rs, rs + nr);
1196 spin_unlock_irq(&pcpu_lock);
1197 } else {
1198 nr_to_pop = 0;
1199 }
1200
1201 if (!nr_to_pop)
1202 break;
1203 }
1204 }
1205
1206 if (nr_to_pop) {
1207 /* ran out of chunks to populate, create a new one and retry */
1208 chunk = pcpu_create_chunk();
1209 if (chunk) {
1210 spin_lock_irq(&pcpu_lock);
1211 pcpu_chunk_relocate(chunk, -1);
1212 spin_unlock_irq(&pcpu_lock);
1213 goto retry_pop;
1214 }
1215 }
1216
Tejun Heo971f3912009-08-14 15:00:49 +09001217 mutex_unlock(&pcpu_alloc_mutex);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001218}
1219
1220/**
1221 * free_percpu - free percpu area
1222 * @ptr: pointer to area to free
1223 *
Tejun Heoccea34b2009-03-07 00:44:13 +09001224 * Free percpu area @ptr.
1225 *
1226 * CONTEXT:
1227 * Can be called from atomic context.
Tejun Heofbf59bc2009-02-20 16:29:08 +09001228 */
Tejun Heo43cf38e2010-02-02 14:38:57 +09001229void free_percpu(void __percpu *ptr)
Tejun Heofbf59bc2009-02-20 16:29:08 +09001230{
Andrew Morton129182e2010-01-08 14:42:39 -08001231 void *addr;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001232 struct pcpu_chunk *chunk;
Tejun Heoccea34b2009-03-07 00:44:13 +09001233 unsigned long flags;
Tejun Heob539b872014-09-02 14:46:05 -04001234 int off, occ_pages;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001235
1236 if (!ptr)
1237 return;
1238
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001239 kmemleak_free_percpu(ptr);
1240
Andrew Morton129182e2010-01-08 14:42:39 -08001241 addr = __pcpu_ptr_to_addr(ptr);
1242
Tejun Heoccea34b2009-03-07 00:44:13 +09001243 spin_lock_irqsave(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001244
1245 chunk = pcpu_chunk_addr_search(addr);
Tejun Heobba174f2009-08-14 15:00:51 +09001246 off = addr - chunk->base_addr;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001247
Tejun Heob539b872014-09-02 14:46:05 -04001248 pcpu_free_area(chunk, off, &occ_pages);
1249
1250 if (chunk != pcpu_reserved_chunk)
1251 pcpu_nr_empty_pop_pages += occ_pages;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001252
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001253 /* if there are more than one fully free chunks, wake up grim reaper */
Tejun Heofbf59bc2009-02-20 16:29:08 +09001254 if (chunk->free_size == pcpu_unit_size) {
1255 struct pcpu_chunk *pos;
1256
Tejun Heoa56dbdd2009-03-07 00:44:11 +09001257 list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
Tejun Heofbf59bc2009-02-20 16:29:08 +09001258 if (pos != chunk) {
Tejun Heo1a4d7602014-09-02 14:46:05 -04001259 pcpu_schedule_balance_work();
Tejun Heofbf59bc2009-02-20 16:29:08 +09001260 break;
1261 }
1262 }
1263
Tejun Heoccea34b2009-03-07 00:44:13 +09001264 spin_unlock_irqrestore(&pcpu_lock, flags);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001265}
1266EXPORT_SYMBOL_GPL(free_percpu);
1267
Vivek Goyal3b034b02009-11-24 15:50:03 +09001268/**
Tejun Heo10fad5e2010-03-10 18:57:54 +09001269 * is_kernel_percpu_address - test whether address is from static percpu area
1270 * @addr: address to test
1271 *
1272 * Test whether @addr belongs to in-kernel static percpu area. Module
1273 * static percpu areas are not considered. For those, use
1274 * is_module_percpu_address().
1275 *
1276 * RETURNS:
1277 * %true if @addr is from in-kernel static percpu area, %false otherwise.
1278 */
1279bool is_kernel_percpu_address(unsigned long addr)
1280{
Tejun Heobbddff02010-09-03 18:22:48 +02001281#ifdef CONFIG_SMP
Tejun Heo10fad5e2010-03-10 18:57:54 +09001282 const size_t static_size = __per_cpu_end - __per_cpu_start;
1283 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
1284 unsigned int cpu;
1285
1286 for_each_possible_cpu(cpu) {
1287 void *start = per_cpu_ptr(base, cpu);
1288
1289 if ((void *)addr >= start && (void *)addr < start + static_size)
1290 return true;
1291 }
Tejun Heobbddff02010-09-03 18:22:48 +02001292#endif
1293 /* on UP, can't distinguish from other static vars, always false */
Tejun Heo10fad5e2010-03-10 18:57:54 +09001294 return false;
1295}
1296
1297/**
Vivek Goyal3b034b02009-11-24 15:50:03 +09001298 * per_cpu_ptr_to_phys - convert translated percpu address to physical address
1299 * @addr: the address to be converted to physical address
1300 *
1301 * Given @addr which is dereferenceable address obtained via one of
1302 * percpu access macros, this function translates it into its physical
1303 * address. The caller is responsible for ensuring @addr stays valid
1304 * until this function finishes.
1305 *
Dave Young67589c72011-11-23 08:20:53 -08001306 * percpu allocator has special setup for the first chunk, which currently
1307 * supports either embedding in linear address space or vmalloc mapping,
1308 * and, from the second one, the backing allocator (currently either vm or
1309 * km) provides translation.
1310 *
Yannick Guerrinibffc4372015-03-06 23:30:42 +01001311 * The addr can be translated simply without checking if it falls into the
Dave Young67589c72011-11-23 08:20:53 -08001312 * first chunk. But the current code reflects better how percpu allocator
1313 * actually works, and the verification can discover both bugs in percpu
1314 * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
1315 * code.
1316 *
Vivek Goyal3b034b02009-11-24 15:50:03 +09001317 * RETURNS:
1318 * The physical address for @addr.
1319 */
1320phys_addr_t per_cpu_ptr_to_phys(void *addr)
1321{
Tejun Heo9983b6f02010-06-18 11:44:31 +02001322 void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
1323 bool in_first_chunk = false;
Tejun Heoa855b842011-11-18 10:55:35 -08001324 unsigned long first_low, first_high;
Tejun Heo9983b6f02010-06-18 11:44:31 +02001325 unsigned int cpu;
1326
1327 /*
Tejun Heoa855b842011-11-18 10:55:35 -08001328 * The following test on unit_low/high isn't strictly
Tejun Heo9983b6f02010-06-18 11:44:31 +02001329 * necessary but will speed up lookups of addresses which
1330 * aren't in the first chunk.
1331 */
Tejun Heoa855b842011-11-18 10:55:35 -08001332 first_low = pcpu_chunk_addr(pcpu_first_chunk, pcpu_low_unit_cpu, 0);
1333 first_high = pcpu_chunk_addr(pcpu_first_chunk, pcpu_high_unit_cpu,
1334 pcpu_unit_pages);
1335 if ((unsigned long)addr >= first_low &&
1336 (unsigned long)addr < first_high) {
Tejun Heo9983b6f02010-06-18 11:44:31 +02001337 for_each_possible_cpu(cpu) {
1338 void *start = per_cpu_ptr(base, cpu);
1339
1340 if (addr >= start && addr < start + pcpu_unit_size) {
1341 in_first_chunk = true;
1342 break;
1343 }
1344 }
1345 }
1346
1347 if (in_first_chunk) {
David Howellseac522e2011-03-28 12:53:29 +01001348 if (!is_vmalloc_addr(addr))
Tejun Heo020ec652010-04-09 18:57:00 +09001349 return __pa(addr);
1350 else
Eugene Surovegin9f57bd42011-12-15 11:25:59 -08001351 return page_to_phys(vmalloc_to_page(addr)) +
1352 offset_in_page(addr);
Tejun Heo020ec652010-04-09 18:57:00 +09001353 } else
Eugene Surovegin9f57bd42011-12-15 11:25:59 -08001354 return page_to_phys(pcpu_addr_to_page(addr)) +
1355 offset_in_page(addr);
Vivek Goyal3b034b02009-11-24 15:50:03 +09001356}
1357
Tejun Heofbf59bc2009-02-20 16:29:08 +09001358/**
Tejun Heofd1e8a12009-08-14 15:00:51 +09001359 * pcpu_alloc_alloc_info - allocate percpu allocation info
1360 * @nr_groups: the number of groups
1361 * @nr_units: the number of units
Tejun Heo033e48f2009-08-14 15:00:51 +09001362 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001363 * Allocate ai which is large enough for @nr_groups groups containing
1364 * @nr_units units. The returned ai's groups[0].cpu_map points to the
1365 * cpu_map array which is long enough for @nr_units and filled with
1366 * NR_CPUS. It's the caller's responsibility to initialize cpu_map
1367 * pointer of other groups.
Tejun Heo033e48f2009-08-14 15:00:51 +09001368 *
1369 * RETURNS:
Tejun Heofd1e8a12009-08-14 15:00:51 +09001370 * Pointer to the allocated pcpu_alloc_info on success, NULL on
1371 * failure.
Tejun Heo033e48f2009-08-14 15:00:51 +09001372 */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001373struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
1374 int nr_units)
1375{
1376 struct pcpu_alloc_info *ai;
1377 size_t base_size, ai_size;
1378 void *ptr;
1379 int unit;
1380
1381 base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
1382 __alignof__(ai->groups[0].cpu_map[0]));
1383 ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
1384
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08001385 ptr = memblock_virt_alloc_nopanic(PFN_ALIGN(ai_size), 0);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001386 if (!ptr)
1387 return NULL;
1388 ai = ptr;
1389 ptr += base_size;
1390
1391 ai->groups[0].cpu_map = ptr;
1392
1393 for (unit = 0; unit < nr_units; unit++)
1394 ai->groups[0].cpu_map[unit] = NR_CPUS;
1395
1396 ai->nr_groups = nr_groups;
1397 ai->__ai_size = PFN_ALIGN(ai_size);
1398
1399 return ai;
1400}
1401
1402/**
1403 * pcpu_free_alloc_info - free percpu allocation info
1404 * @ai: pcpu_alloc_info to free
1405 *
1406 * Free @ai which was allocated by pcpu_alloc_alloc_info().
1407 */
1408void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
1409{
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08001410 memblock_free_early(__pa(ai), ai->__ai_size);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001411}
1412
1413/**
Tejun Heofd1e8a12009-08-14 15:00:51 +09001414 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
1415 * @lvl: loglevel
1416 * @ai: allocation info to dump
1417 *
1418 * Print out information about @ai using loglevel @lvl.
1419 */
1420static void pcpu_dump_alloc_info(const char *lvl,
1421 const struct pcpu_alloc_info *ai)
Tejun Heo033e48f2009-08-14 15:00:51 +09001422{
Tejun Heofd1e8a12009-08-14 15:00:51 +09001423 int group_width = 1, cpu_width = 1, width;
Tejun Heo033e48f2009-08-14 15:00:51 +09001424 char empty_str[] = "--------";
Tejun Heofd1e8a12009-08-14 15:00:51 +09001425 int alloc = 0, alloc_end = 0;
1426 int group, v;
1427 int upa, apl; /* units per alloc, allocs per line */
Tejun Heo033e48f2009-08-14 15:00:51 +09001428
Tejun Heofd1e8a12009-08-14 15:00:51 +09001429 v = ai->nr_groups;
Tejun Heo033e48f2009-08-14 15:00:51 +09001430 while (v /= 10)
Tejun Heofd1e8a12009-08-14 15:00:51 +09001431 group_width++;
Tejun Heo033e48f2009-08-14 15:00:51 +09001432
Tejun Heofd1e8a12009-08-14 15:00:51 +09001433 v = num_possible_cpus();
1434 while (v /= 10)
1435 cpu_width++;
1436 empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
Tejun Heo033e48f2009-08-14 15:00:51 +09001437
Tejun Heofd1e8a12009-08-14 15:00:51 +09001438 upa = ai->alloc_size / ai->unit_size;
1439 width = upa * (cpu_width + 1) + group_width + 3;
1440 apl = rounddown_pow_of_two(max(60 / width, 1));
Tejun Heo033e48f2009-08-14 15:00:51 +09001441
Tejun Heofd1e8a12009-08-14 15:00:51 +09001442 printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
1443 lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
1444 ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
1445
1446 for (group = 0; group < ai->nr_groups; group++) {
1447 const struct pcpu_group_info *gi = &ai->groups[group];
1448 int unit = 0, unit_end = 0;
1449
1450 BUG_ON(gi->nr_units % upa);
1451 for (alloc_end += gi->nr_units / upa;
1452 alloc < alloc_end; alloc++) {
1453 if (!(alloc % apl)) {
Joe Perches11705322016-03-17 14:19:50 -07001454 pr_cont("\n");
Tejun Heofd1e8a12009-08-14 15:00:51 +09001455 printk("%spcpu-alloc: ", lvl);
1456 }
Joe Perches11705322016-03-17 14:19:50 -07001457 pr_cont("[%0*d] ", group_width, group);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001458
1459 for (unit_end += upa; unit < unit_end; unit++)
1460 if (gi->cpu_map[unit] != NR_CPUS)
Joe Perches11705322016-03-17 14:19:50 -07001461 pr_cont("%0*d ",
1462 cpu_width, gi->cpu_map[unit]);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001463 else
Joe Perches11705322016-03-17 14:19:50 -07001464 pr_cont("%s ", empty_str);
Tejun Heo033e48f2009-08-14 15:00:51 +09001465 }
Tejun Heo033e48f2009-08-14 15:00:51 +09001466 }
Joe Perches11705322016-03-17 14:19:50 -07001467 pr_cont("\n");
Tejun Heo033e48f2009-08-14 15:00:51 +09001468}
Tejun Heo033e48f2009-08-14 15:00:51 +09001469
Tejun Heofbf59bc2009-02-20 16:29:08 +09001470/**
Tejun Heo8d408b42009-02-24 11:57:21 +09001471 * pcpu_setup_first_chunk - initialize the first percpu chunk
Tejun Heofd1e8a12009-08-14 15:00:51 +09001472 * @ai: pcpu_alloc_info describing how to percpu area is shaped
Tejun Heo38a6be52009-07-04 08:10:59 +09001473 * @base_addr: mapped address
Tejun Heofbf59bc2009-02-20 16:29:08 +09001474 *
Tejun Heo8d408b42009-02-24 11:57:21 +09001475 * Initialize the first percpu chunk which contains the kernel static
1476 * perpcu area. This function is to be called from arch percpu area
Tejun Heo38a6be52009-07-04 08:10:59 +09001477 * setup path.
Tejun Heo8d408b42009-02-24 11:57:21 +09001478 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001479 * @ai contains all information necessary to initialize the first
1480 * chunk and prime the dynamic percpu allocator.
Tejun Heo8d408b42009-02-24 11:57:21 +09001481 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001482 * @ai->static_size is the size of static percpu area.
1483 *
1484 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
Tejun Heoedcb4632009-03-06 14:33:59 +09001485 * reserve after the static area in the first chunk. This reserves
1486 * the first chunk such that it's available only through reserved
1487 * percpu allocation. This is primarily used to serve module percpu
1488 * static areas on architectures where the addressing model has
1489 * limited offset range for symbol relocations to guarantee module
1490 * percpu symbols fall inside the relocatable range.
1491 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001492 * @ai->dyn_size determines the number of bytes available for dynamic
1493 * allocation in the first chunk. The area between @ai->static_size +
1494 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
Tejun Heo6074d5b2009-03-10 16:27:48 +09001495 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001496 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
1497 * and equal to or larger than @ai->static_size + @ai->reserved_size +
1498 * @ai->dyn_size.
Tejun Heo8d408b42009-02-24 11:57:21 +09001499 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001500 * @ai->atom_size is the allocation atom size and used as alignment
1501 * for vm areas.
Tejun Heo8d408b42009-02-24 11:57:21 +09001502 *
Tejun Heofd1e8a12009-08-14 15:00:51 +09001503 * @ai->alloc_size is the allocation size and always multiple of
1504 * @ai->atom_size. This is larger than @ai->atom_size if
1505 * @ai->unit_size is larger than @ai->atom_size.
1506 *
1507 * @ai->nr_groups and @ai->groups describe virtual memory layout of
1508 * percpu areas. Units which should be colocated are put into the
1509 * same group. Dynamic VM areas will be allocated according to these
1510 * groupings. If @ai->nr_groups is zero, a single group containing
1511 * all units is assumed.
Tejun Heo8d408b42009-02-24 11:57:21 +09001512 *
Tejun Heo38a6be52009-07-04 08:10:59 +09001513 * The caller should have mapped the first chunk at @base_addr and
1514 * copied static data to each unit.
Tejun Heofbf59bc2009-02-20 16:29:08 +09001515 *
Tejun Heoedcb4632009-03-06 14:33:59 +09001516 * If the first chunk ends up with both reserved and dynamic areas, it
1517 * is served by two chunks - one to serve the core static and reserved
1518 * areas and the other for the dynamic area. They share the same vm
1519 * and page map but uses different area allocation map to stay away
1520 * from each other. The latter chunk is circulated in the chunk slots
1521 * and available for dynamic allocation like any other chunks.
1522 *
Tejun Heofbf59bc2009-02-20 16:29:08 +09001523 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09001524 * 0 on success, -errno on failure.
Tejun Heofbf59bc2009-02-20 16:29:08 +09001525 */
Tejun Heofb435d52009-08-14 15:00:51 +09001526int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
1527 void *base_addr)
Tejun Heofbf59bc2009-02-20 16:29:08 +09001528{
Tejun Heo099a19d2010-06-27 18:50:00 +02001529 static int smap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
1530 static int dmap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001531 size_t dyn_size = ai->dyn_size;
1532 size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
Tejun Heoedcb4632009-03-06 14:33:59 +09001533 struct pcpu_chunk *schunk, *dchunk = NULL;
Tejun Heo65632972009-08-14 15:00:52 +09001534 unsigned long *group_offsets;
1535 size_t *group_sizes;
Tejun Heofb435d52009-08-14 15:00:51 +09001536 unsigned long *unit_off;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001537 unsigned int cpu;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001538 int *unit_map;
1539 int group, unit, i;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001540
Tejun Heo635b75f2009-09-24 09:43:11 +09001541#define PCPU_SETUP_BUG_ON(cond) do { \
1542 if (unlikely(cond)) { \
Joe Perches870d4b12016-03-17 14:19:53 -07001543 pr_emerg("failed to initialize, %s\n", #cond); \
1544 pr_emerg("cpu_possible_mask=%*pb\n", \
Tejun Heo807de072015-02-13 14:37:34 -08001545 cpumask_pr_args(cpu_possible_mask)); \
Tejun Heo635b75f2009-09-24 09:43:11 +09001546 pcpu_dump_alloc_info(KERN_EMERG, ai); \
1547 BUG(); \
1548 } \
1549} while (0)
1550
Tejun Heo2f39e632009-07-04 08:11:00 +09001551 /* sanity checks */
Tejun Heo635b75f2009-09-24 09:43:11 +09001552 PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
Tejun Heobbddff02010-09-03 18:22:48 +02001553#ifdef CONFIG_SMP
Tejun Heo635b75f2009-09-24 09:43:11 +09001554 PCPU_SETUP_BUG_ON(!ai->static_size);
Alexander Kuleshovf09f1242015-11-05 18:46:43 -08001555 PCPU_SETUP_BUG_ON(offset_in_page(__per_cpu_start));
Tejun Heobbddff02010-09-03 18:22:48 +02001556#endif
Tejun Heo635b75f2009-09-24 09:43:11 +09001557 PCPU_SETUP_BUG_ON(!base_addr);
Alexander Kuleshovf09f1242015-11-05 18:46:43 -08001558 PCPU_SETUP_BUG_ON(offset_in_page(base_addr));
Tejun Heo635b75f2009-09-24 09:43:11 +09001559 PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
Alexander Kuleshovf09f1242015-11-05 18:46:43 -08001560 PCPU_SETUP_BUG_ON(offset_in_page(ai->unit_size));
Tejun Heo635b75f2009-09-24 09:43:11 +09001561 PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
Tejun Heo099a19d2010-06-27 18:50:00 +02001562 PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
Tejun Heo9f645532010-04-09 18:57:01 +09001563 PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
Tejun Heo8d408b42009-02-24 11:57:21 +09001564
Tejun Heo65632972009-08-14 15:00:52 +09001565 /* process group information and build config tables accordingly */
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08001566 group_offsets = memblock_virt_alloc(ai->nr_groups *
1567 sizeof(group_offsets[0]), 0);
1568 group_sizes = memblock_virt_alloc(ai->nr_groups *
1569 sizeof(group_sizes[0]), 0);
1570 unit_map = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_map[0]), 0);
1571 unit_off = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_off[0]), 0);
Tejun Heo2f39e632009-07-04 08:11:00 +09001572
Tejun Heofd1e8a12009-08-14 15:00:51 +09001573 for (cpu = 0; cpu < nr_cpu_ids; cpu++)
Tejun Heoffe0d5a2009-09-29 09:17:56 +09001574 unit_map[cpu] = UINT_MAX;
Tejun Heoa855b842011-11-18 10:55:35 -08001575
1576 pcpu_low_unit_cpu = NR_CPUS;
1577 pcpu_high_unit_cpu = NR_CPUS;
Tejun Heo2f39e632009-07-04 08:11:00 +09001578
Tejun Heofd1e8a12009-08-14 15:00:51 +09001579 for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
1580 const struct pcpu_group_info *gi = &ai->groups[group];
Tejun Heo2f39e632009-07-04 08:11:00 +09001581
Tejun Heo65632972009-08-14 15:00:52 +09001582 group_offsets[group] = gi->base_offset;
1583 group_sizes[group] = gi->nr_units * ai->unit_size;
1584
Tejun Heofd1e8a12009-08-14 15:00:51 +09001585 for (i = 0; i < gi->nr_units; i++) {
1586 cpu = gi->cpu_map[i];
1587 if (cpu == NR_CPUS)
1588 continue;
1589
Dan Carpenter9f295662014-10-29 11:45:04 +03001590 PCPU_SETUP_BUG_ON(cpu >= nr_cpu_ids);
Tejun Heo635b75f2009-09-24 09:43:11 +09001591 PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
1592 PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001593
1594 unit_map[cpu] = unit + i;
Tejun Heofb435d52009-08-14 15:00:51 +09001595 unit_off[cpu] = gi->base_offset + i * ai->unit_size;
1596
Tejun Heoa855b842011-11-18 10:55:35 -08001597 /* determine low/high unit_cpu */
1598 if (pcpu_low_unit_cpu == NR_CPUS ||
1599 unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
1600 pcpu_low_unit_cpu = cpu;
1601 if (pcpu_high_unit_cpu == NR_CPUS ||
1602 unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
1603 pcpu_high_unit_cpu = cpu;
Tejun Heo2f39e632009-07-04 08:11:00 +09001604 }
Tejun Heo2f39e632009-07-04 08:11:00 +09001605 }
Tejun Heofd1e8a12009-08-14 15:00:51 +09001606 pcpu_nr_units = unit;
1607
1608 for_each_possible_cpu(cpu)
Tejun Heo635b75f2009-09-24 09:43:11 +09001609 PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
1610
1611 /* we're done parsing the input, undefine BUG macro and dump config */
1612#undef PCPU_SETUP_BUG_ON
Tejun Heobcbea792010-12-22 14:19:14 +01001613 pcpu_dump_alloc_info(KERN_DEBUG, ai);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001614
Tejun Heo65632972009-08-14 15:00:52 +09001615 pcpu_nr_groups = ai->nr_groups;
1616 pcpu_group_offsets = group_offsets;
1617 pcpu_group_sizes = group_sizes;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001618 pcpu_unit_map = unit_map;
Tejun Heofb435d52009-08-14 15:00:51 +09001619 pcpu_unit_offsets = unit_off;
Tejun Heo2f39e632009-07-04 08:11:00 +09001620
1621 /* determine basic parameters */
Tejun Heofd1e8a12009-08-14 15:00:51 +09001622 pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
Tejun Heod9b55ee2009-02-24 11:57:21 +09001623 pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
Tejun Heo65632972009-08-14 15:00:52 +09001624 pcpu_atom_size = ai->atom_size;
Tejun Heoce3141a2009-07-04 08:11:00 +09001625 pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
1626 BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
Tejun Heocafe8812009-03-06 14:33:59 +09001627
Tejun Heod9b55ee2009-02-24 11:57:21 +09001628 /*
1629 * Allocate chunk slots. The additional last slot is for
1630 * empty chunks.
1631 */
1632 pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08001633 pcpu_slot = memblock_virt_alloc(
1634 pcpu_nr_slots * sizeof(pcpu_slot[0]), 0);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001635 for (i = 0; i < pcpu_nr_slots; i++)
1636 INIT_LIST_HEAD(&pcpu_slot[i]);
1637
Tejun Heoedcb4632009-03-06 14:33:59 +09001638 /*
1639 * Initialize static chunk. If reserved_size is zero, the
1640 * static chunk covers static area + dynamic allocation area
1641 * in the first chunk. If reserved_size is not zero, it
1642 * covers static area + reserved area (mostly used for module
1643 * static percpu allocation).
1644 */
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08001645 schunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
Tejun Heo2441d152009-03-06 14:33:59 +09001646 INIT_LIST_HEAD(&schunk->list);
Tejun Heo9c824b62014-09-02 14:46:05 -04001647 INIT_WORK(&schunk->map_extend_work, pcpu_map_extend_workfn);
Tejun Heobba174f2009-08-14 15:00:51 +09001648 schunk->base_addr = base_addr;
Tejun Heo61ace7f2009-03-06 14:33:59 +09001649 schunk->map = smap;
1650 schunk->map_alloc = ARRAY_SIZE(smap);
Tejun Heo38a6be52009-07-04 08:10:59 +09001651 schunk->immutable = true;
Tejun Heoce3141a2009-07-04 08:11:00 +09001652 bitmap_fill(schunk->populated, pcpu_unit_pages);
Tejun Heob539b872014-09-02 14:46:05 -04001653 schunk->nr_populated = pcpu_unit_pages;
Tejun Heoedcb4632009-03-06 14:33:59 +09001654
Tejun Heofd1e8a12009-08-14 15:00:51 +09001655 if (ai->reserved_size) {
1656 schunk->free_size = ai->reserved_size;
Tejun Heoae9e6bc92009-04-02 13:19:54 +09001657 pcpu_reserved_chunk = schunk;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001658 pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
Tejun Heoedcb4632009-03-06 14:33:59 +09001659 } else {
1660 schunk->free_size = dyn_size;
1661 dyn_size = 0; /* dynamic area covered */
1662 }
Tejun Heo2441d152009-03-06 14:33:59 +09001663 schunk->contig_hint = schunk->free_size;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001664
Al Viro723ad1d2014-03-06 21:13:18 -05001665 schunk->map[0] = 1;
1666 schunk->map[1] = ai->static_size;
1667 schunk->map_used = 1;
Tejun Heo61ace7f2009-03-06 14:33:59 +09001668 if (schunk->free_size)
Baoquan He292c24a2015-07-20 22:55:28 +08001669 schunk->map[++schunk->map_used] = ai->static_size + schunk->free_size;
1670 schunk->map[schunk->map_used] |= 1;
Tejun Heo61ace7f2009-03-06 14:33:59 +09001671
Tejun Heoedcb4632009-03-06 14:33:59 +09001672 /* init dynamic chunk if necessary */
1673 if (dyn_size) {
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08001674 dchunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
Tejun Heoedcb4632009-03-06 14:33:59 +09001675 INIT_LIST_HEAD(&dchunk->list);
Tejun Heo9c824b62014-09-02 14:46:05 -04001676 INIT_WORK(&dchunk->map_extend_work, pcpu_map_extend_workfn);
Tejun Heobba174f2009-08-14 15:00:51 +09001677 dchunk->base_addr = base_addr;
Tejun Heoedcb4632009-03-06 14:33:59 +09001678 dchunk->map = dmap;
1679 dchunk->map_alloc = ARRAY_SIZE(dmap);
Tejun Heo38a6be52009-07-04 08:10:59 +09001680 dchunk->immutable = true;
Tejun Heoce3141a2009-07-04 08:11:00 +09001681 bitmap_fill(dchunk->populated, pcpu_unit_pages);
Tejun Heob539b872014-09-02 14:46:05 -04001682 dchunk->nr_populated = pcpu_unit_pages;
Tejun Heoedcb4632009-03-06 14:33:59 +09001683
1684 dchunk->contig_hint = dchunk->free_size = dyn_size;
Al Viro723ad1d2014-03-06 21:13:18 -05001685 dchunk->map[0] = 1;
1686 dchunk->map[1] = pcpu_reserved_chunk_limit;
1687 dchunk->map[2] = (pcpu_reserved_chunk_limit + dchunk->free_size) | 1;
1688 dchunk->map_used = 2;
Tejun Heoedcb4632009-03-06 14:33:59 +09001689 }
1690
Tejun Heo2441d152009-03-06 14:33:59 +09001691 /* link the first chunk in */
Tejun Heoae9e6bc92009-04-02 13:19:54 +09001692 pcpu_first_chunk = dchunk ?: schunk;
Tejun Heob539b872014-09-02 14:46:05 -04001693 pcpu_nr_empty_pop_pages +=
1694 pcpu_count_occupied_pages(pcpu_first_chunk, 1);
Tejun Heoae9e6bc92009-04-02 13:19:54 +09001695 pcpu_chunk_relocate(pcpu_first_chunk, -1);
Tejun Heofbf59bc2009-02-20 16:29:08 +09001696
1697 /* we're done */
Tejun Heobba174f2009-08-14 15:00:51 +09001698 pcpu_base_addr = base_addr;
Tejun Heofb435d52009-08-14 15:00:51 +09001699 return 0;
Tejun Heofbf59bc2009-02-20 16:29:08 +09001700}
Tejun Heo66c3a752009-03-10 16:27:48 +09001701
Tejun Heobbddff02010-09-03 18:22:48 +02001702#ifdef CONFIG_SMP
1703
Andi Kleen17f36092012-10-04 17:12:07 -07001704const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = {
Tejun Heof58dc012009-08-14 15:00:50 +09001705 [PCPU_FC_AUTO] = "auto",
1706 [PCPU_FC_EMBED] = "embed",
1707 [PCPU_FC_PAGE] = "page",
Tejun Heof58dc012009-08-14 15:00:50 +09001708};
Tejun Heo66c3a752009-03-10 16:27:48 +09001709
Tejun Heof58dc012009-08-14 15:00:50 +09001710enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
1711
1712static int __init percpu_alloc_setup(char *str)
Tejun Heo66c3a752009-03-10 16:27:48 +09001713{
Cyrill Gorcunov5479c782012-11-25 01:17:13 +04001714 if (!str)
1715 return -EINVAL;
1716
Tejun Heof58dc012009-08-14 15:00:50 +09001717 if (0)
1718 /* nada */;
1719#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
1720 else if (!strcmp(str, "embed"))
1721 pcpu_chosen_fc = PCPU_FC_EMBED;
1722#endif
1723#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1724 else if (!strcmp(str, "page"))
1725 pcpu_chosen_fc = PCPU_FC_PAGE;
1726#endif
Tejun Heof58dc012009-08-14 15:00:50 +09001727 else
Joe Perches870d4b12016-03-17 14:19:53 -07001728 pr_warn("unknown allocator %s specified\n", str);
Tejun Heo66c3a752009-03-10 16:27:48 +09001729
Tejun Heof58dc012009-08-14 15:00:50 +09001730 return 0;
Tejun Heo66c3a752009-03-10 16:27:48 +09001731}
Tejun Heof58dc012009-08-14 15:00:50 +09001732early_param("percpu_alloc", percpu_alloc_setup);
Tejun Heo66c3a752009-03-10 16:27:48 +09001733
Tejun Heo3c9a0242010-09-09 18:00:15 +02001734/*
1735 * pcpu_embed_first_chunk() is used by the generic percpu setup.
1736 * Build it if needed by the arch config or the generic setup is going
1737 * to be used.
1738 */
Tejun Heo08fc4582009-08-14 15:00:49 +09001739#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
1740 !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
Tejun Heo3c9a0242010-09-09 18:00:15 +02001741#define BUILD_EMBED_FIRST_CHUNK
1742#endif
1743
1744/* build pcpu_page_first_chunk() iff needed by the arch config */
1745#if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
1746#define BUILD_PAGE_FIRST_CHUNK
1747#endif
1748
1749/* pcpu_build_alloc_info() is used by both embed and page first chunk */
1750#if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
1751/**
Tejun Heofbf59bc2009-02-20 16:29:08 +09001752 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
1753 * @reserved_size: the size of reserved percpu area in bytes
1754 * @dyn_size: minimum free size for dynamic allocation in bytes
1755 * @atom_size: allocation atom size
1756 * @cpu_distance_fn: callback to determine distance between cpus, optional
1757 *
1758 * This function determines grouping of units, their mappings to cpus
1759 * and other parameters considering needed percpu size, allocation
1760 * atom size and distances between CPUs.
1761 *
Yannick Guerrinibffc4372015-03-06 23:30:42 +01001762 * Groups are always multiples of atom size and CPUs which are of
Tejun Heofbf59bc2009-02-20 16:29:08 +09001763 * LOCAL_DISTANCE both ways are grouped together and share space for
1764 * units in the same group. The returned configuration is guaranteed
1765 * to have CPUs on different nodes on different groups and >=75% usage
1766 * of allocated virtual address space.
1767 *
1768 * RETURNS:
1769 * On success, pointer to the new allocation_info is returned. On
1770 * failure, ERR_PTR value is returned.
1771 */
1772static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
1773 size_t reserved_size, size_t dyn_size,
1774 size_t atom_size,
1775 pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
1776{
1777 static int group_map[NR_CPUS] __initdata;
1778 static int group_cnt[NR_CPUS] __initdata;
1779 const size_t static_size = __per_cpu_end - __per_cpu_start;
1780 int nr_groups = 1, nr_units = 0;
1781 size_t size_sum, min_unit_size, alloc_size;
1782 int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
1783 int last_allocs, group, unit;
1784 unsigned int cpu, tcpu;
1785 struct pcpu_alloc_info *ai;
1786 unsigned int *cpu_map;
1787
1788 /* this function may be called multiple times */
1789 memset(group_map, 0, sizeof(group_map));
1790 memset(group_cnt, 0, sizeof(group_cnt));
1791
1792 /* calculate size_sum and ensure dyn_size is enough for early alloc */
1793 size_sum = PFN_ALIGN(static_size + reserved_size +
1794 max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
1795 dyn_size = size_sum - static_size - reserved_size;
1796
1797 /*
1798 * Determine min_unit_size, alloc_size and max_upa such that
1799 * alloc_size is multiple of atom_size and is the smallest
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001800 * which can accommodate 4k aligned segments which are equal to
Tejun Heofbf59bc2009-02-20 16:29:08 +09001801 * or larger than min_unit_size.
1802 */
1803 min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
1804
1805 alloc_size = roundup(min_unit_size, atom_size);
1806 upa = alloc_size / min_unit_size;
Alexander Kuleshovf09f1242015-11-05 18:46:43 -08001807 while (alloc_size % upa || (offset_in_page(alloc_size / upa)))
Tejun Heofbf59bc2009-02-20 16:29:08 +09001808 upa--;
1809 max_upa = upa;
1810
1811 /* group cpus according to their proximity */
1812 for_each_possible_cpu(cpu) {
1813 group = 0;
1814 next_group:
1815 for_each_possible_cpu(tcpu) {
1816 if (cpu == tcpu)
1817 break;
1818 if (group_map[tcpu] == group && cpu_distance_fn &&
1819 (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
1820 cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
1821 group++;
1822 nr_groups = max(nr_groups, group + 1);
1823 goto next_group;
1824 }
1825 }
1826 group_map[cpu] = group;
1827 group_cnt[group]++;
1828 }
1829
1830 /*
1831 * Expand unit size until address space usage goes over 75%
1832 * and then as much as possible without using more address
1833 * space.
1834 */
1835 last_allocs = INT_MAX;
1836 for (upa = max_upa; upa; upa--) {
1837 int allocs = 0, wasted = 0;
1838
Alexander Kuleshovf09f1242015-11-05 18:46:43 -08001839 if (alloc_size % upa || (offset_in_page(alloc_size / upa)))
Tejun Heofbf59bc2009-02-20 16:29:08 +09001840 continue;
1841
1842 for (group = 0; group < nr_groups; group++) {
1843 int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
1844 allocs += this_allocs;
1845 wasted += this_allocs * upa - group_cnt[group];
1846 }
1847
1848 /*
1849 * Don't accept if wastage is over 1/3. The
1850 * greater-than comparison ensures upa==1 always
1851 * passes the following check.
1852 */
1853 if (wasted > num_possible_cpus() / 3)
1854 continue;
1855
1856 /* and then don't consume more memory */
1857 if (allocs > last_allocs)
1858 break;
1859 last_allocs = allocs;
1860 best_upa = upa;
1861 }
1862 upa = best_upa;
1863
1864 /* allocate and fill alloc_info */
1865 for (group = 0; group < nr_groups; group++)
1866 nr_units += roundup(group_cnt[group], upa);
1867
1868 ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
1869 if (!ai)
1870 return ERR_PTR(-ENOMEM);
1871 cpu_map = ai->groups[0].cpu_map;
1872
1873 for (group = 0; group < nr_groups; group++) {
1874 ai->groups[group].cpu_map = cpu_map;
1875 cpu_map += roundup(group_cnt[group], upa);
1876 }
1877
1878 ai->static_size = static_size;
1879 ai->reserved_size = reserved_size;
1880 ai->dyn_size = dyn_size;
1881 ai->unit_size = alloc_size / upa;
1882 ai->atom_size = atom_size;
1883 ai->alloc_size = alloc_size;
1884
1885 for (group = 0, unit = 0; group_cnt[group]; group++) {
1886 struct pcpu_group_info *gi = &ai->groups[group];
1887
1888 /*
1889 * Initialize base_offset as if all groups are located
1890 * back-to-back. The caller should update this to
1891 * reflect actual allocation.
1892 */
1893 gi->base_offset = unit * ai->unit_size;
1894
1895 for_each_possible_cpu(cpu)
1896 if (group_map[cpu] == group)
1897 gi->cpu_map[gi->nr_units++] = cpu;
1898 gi->nr_units = roundup(gi->nr_units, upa);
1899 unit += gi->nr_units;
1900 }
1901 BUG_ON(unit != nr_units);
1902
1903 return ai;
1904}
Tejun Heo3c9a0242010-09-09 18:00:15 +02001905#endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
Tejun Heofbf59bc2009-02-20 16:29:08 +09001906
Tejun Heo3c9a0242010-09-09 18:00:15 +02001907#if defined(BUILD_EMBED_FIRST_CHUNK)
Tejun Heo66c3a752009-03-10 16:27:48 +09001908/**
1909 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
Tejun Heo66c3a752009-03-10 16:27:48 +09001910 * @reserved_size: the size of reserved percpu area in bytes
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001911 * @dyn_size: minimum free size for dynamic allocation in bytes
Tejun Heoc8826dd2009-08-14 15:00:52 +09001912 * @atom_size: allocation atom size
1913 * @cpu_distance_fn: callback to determine distance between cpus, optional
1914 * @alloc_fn: function to allocate percpu page
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001915 * @free_fn: function to free percpu page
Tejun Heo66c3a752009-03-10 16:27:48 +09001916 *
1917 * This is a helper to ease setting up embedded first percpu chunk and
1918 * can be called where pcpu_setup_first_chunk() is expected.
1919 *
1920 * If this function is used to setup the first chunk, it is allocated
Tejun Heoc8826dd2009-08-14 15:00:52 +09001921 * by calling @alloc_fn and used as-is without being mapped into
1922 * vmalloc area. Allocations are always whole multiples of @atom_size
1923 * aligned to @atom_size.
1924 *
1925 * This enables the first chunk to piggy back on the linear physical
1926 * mapping which often uses larger page size. Please note that this
1927 * can result in very sparse cpu->unit mapping on NUMA machines thus
1928 * requiring large vmalloc address space. Don't use this allocator if
1929 * vmalloc space is not orders of magnitude larger than distances
1930 * between node memory addresses (ie. 32bit NUMA machines).
Tejun Heo66c3a752009-03-10 16:27:48 +09001931 *
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001932 * @dyn_size specifies the minimum dynamic area size.
Tejun Heo66c3a752009-03-10 16:27:48 +09001933 *
1934 * If the needed size is smaller than the minimum or specified unit
Tejun Heoc8826dd2009-08-14 15:00:52 +09001935 * size, the leftover is returned using @free_fn.
Tejun Heo66c3a752009-03-10 16:27:48 +09001936 *
1937 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09001938 * 0 on success, -errno on failure.
Tejun Heo66c3a752009-03-10 16:27:48 +09001939 */
Tejun Heo4ba6ce22010-06-27 18:49:59 +02001940int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
Tejun Heoc8826dd2009-08-14 15:00:52 +09001941 size_t atom_size,
1942 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
1943 pcpu_fc_alloc_fn_t alloc_fn,
1944 pcpu_fc_free_fn_t free_fn)
Tejun Heo66c3a752009-03-10 16:27:48 +09001945{
Tejun Heoc8826dd2009-08-14 15:00:52 +09001946 void *base = (void *)ULONG_MAX;
1947 void **areas = NULL;
Tejun Heofd1e8a12009-08-14 15:00:51 +09001948 struct pcpu_alloc_info *ai;
Tejun Heo6ea529a2009-09-24 18:46:01 +09001949 size_t size_sum, areas_size, max_distance;
Tejun Heoc8826dd2009-08-14 15:00:52 +09001950 int group, i, rc;
Tejun Heo66c3a752009-03-10 16:27:48 +09001951
Tejun Heoc8826dd2009-08-14 15:00:52 +09001952 ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
1953 cpu_distance_fn);
Tejun Heofd1e8a12009-08-14 15:00:51 +09001954 if (IS_ERR(ai))
1955 return PTR_ERR(ai);
Tejun Heo66c3a752009-03-10 16:27:48 +09001956
Tejun Heofd1e8a12009-08-14 15:00:51 +09001957 size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
Tejun Heoc8826dd2009-08-14 15:00:52 +09001958 areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
Tejun Heo66c3a752009-03-10 16:27:48 +09001959
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08001960 areas = memblock_virt_alloc_nopanic(areas_size, 0);
Tejun Heoc8826dd2009-08-14 15:00:52 +09001961 if (!areas) {
Tejun Heofb435d52009-08-14 15:00:51 +09001962 rc = -ENOMEM;
Tejun Heoc8826dd2009-08-14 15:00:52 +09001963 goto out_free;
Tejun Heofa8a7092009-06-22 11:56:24 +09001964 }
Tejun Heo66c3a752009-03-10 16:27:48 +09001965
Tejun Heoc8826dd2009-08-14 15:00:52 +09001966 /* allocate, copy and determine base address */
1967 for (group = 0; group < ai->nr_groups; group++) {
1968 struct pcpu_group_info *gi = &ai->groups[group];
1969 unsigned int cpu = NR_CPUS;
1970 void *ptr;
Tejun Heo66c3a752009-03-10 16:27:48 +09001971
Tejun Heoc8826dd2009-08-14 15:00:52 +09001972 for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
1973 cpu = gi->cpu_map[i];
1974 BUG_ON(cpu == NR_CPUS);
1975
1976 /* allocate space for the whole group */
1977 ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
1978 if (!ptr) {
1979 rc = -ENOMEM;
1980 goto out_free_areas;
1981 }
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001982 /* kmemleak tracks the percpu allocations separately */
1983 kmemleak_free(ptr);
Tejun Heoc8826dd2009-08-14 15:00:52 +09001984 areas[group] = ptr;
1985
1986 base = min(ptr, base);
Tejun Heo42b64282012-04-27 08:42:53 -07001987 }
1988
1989 /*
1990 * Copy data and free unused parts. This should happen after all
1991 * allocations are complete; otherwise, we may end up with
1992 * overlapping groups.
1993 */
1994 for (group = 0; group < ai->nr_groups; group++) {
1995 struct pcpu_group_info *gi = &ai->groups[group];
1996 void *ptr = areas[group];
Tejun Heoc8826dd2009-08-14 15:00:52 +09001997
1998 for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
1999 if (gi->cpu_map[i] == NR_CPUS) {
2000 /* unused unit, free whole */
2001 free_fn(ptr, ai->unit_size);
2002 continue;
2003 }
2004 /* copy and return the unused part */
2005 memcpy(ptr, __per_cpu_load, ai->static_size);
2006 free_fn(ptr + size_sum, ai->unit_size - size_sum);
2007 }
Tejun Heo66c3a752009-03-10 16:27:48 +09002008 }
2009
Tejun Heoc8826dd2009-08-14 15:00:52 +09002010 /* base address is now known, determine group base offsets */
Tejun Heo6ea529a2009-09-24 18:46:01 +09002011 max_distance = 0;
2012 for (group = 0; group < ai->nr_groups; group++) {
Tejun Heoc8826dd2009-08-14 15:00:52 +09002013 ai->groups[group].base_offset = areas[group] - base;
Tejun Heo1a0c3292009-10-04 09:31:05 +09002014 max_distance = max_t(size_t, max_distance,
2015 ai->groups[group].base_offset);
Tejun Heo6ea529a2009-09-24 18:46:01 +09002016 }
2017 max_distance += ai->unit_size;
2018
2019 /* warn if maximum distance is further than 75% of vmalloc space */
Laura Abbott8a092172014-01-02 13:53:21 -08002020 if (max_distance > VMALLOC_TOTAL * 3 / 4) {
Joe Perches870d4b12016-03-17 14:19:53 -07002021 pr_warn("max_distance=0x%zx too large for vmalloc space 0x%lx\n",
Joe Perches598d8092016-03-17 14:19:44 -07002022 max_distance, VMALLOC_TOTAL);
Tejun Heo6ea529a2009-09-24 18:46:01 +09002023#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
2024 /* and fail if we have fallback */
2025 rc = -EINVAL;
2026 goto out_free;
2027#endif
2028 }
Tejun Heoc8826dd2009-08-14 15:00:52 +09002029
Joe Perches870d4b12016-03-17 14:19:53 -07002030 pr_info("Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
Tejun Heofd1e8a12009-08-14 15:00:51 +09002031 PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
2032 ai->dyn_size, ai->unit_size);
Tejun Heo66c3a752009-03-10 16:27:48 +09002033
Tejun Heofb435d52009-08-14 15:00:51 +09002034 rc = pcpu_setup_first_chunk(ai, base);
Tejun Heoc8826dd2009-08-14 15:00:52 +09002035 goto out_free;
2036
2037out_free_areas:
2038 for (group = 0; group < ai->nr_groups; group++)
Michael Holzheuf851c8d2013-09-17 16:57:34 +02002039 if (areas[group])
2040 free_fn(areas[group],
2041 ai->groups[group].nr_units * ai->unit_size);
Tejun Heoc8826dd2009-08-14 15:00:52 +09002042out_free:
Tejun Heofd1e8a12009-08-14 15:00:51 +09002043 pcpu_free_alloc_info(ai);
Tejun Heoc8826dd2009-08-14 15:00:52 +09002044 if (areas)
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08002045 memblock_free_early(__pa(areas), areas_size);
Tejun Heofb435d52009-08-14 15:00:51 +09002046 return rc;
Tejun Heod4b95f82009-07-04 08:10:59 +09002047}
Tejun Heo3c9a0242010-09-09 18:00:15 +02002048#endif /* BUILD_EMBED_FIRST_CHUNK */
Tejun Heod4b95f82009-07-04 08:10:59 +09002049
Tejun Heo3c9a0242010-09-09 18:00:15 +02002050#ifdef BUILD_PAGE_FIRST_CHUNK
Tejun Heod4b95f82009-07-04 08:10:59 +09002051/**
Tejun Heo00ae4062009-08-14 15:00:49 +09002052 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
Tejun Heod4b95f82009-07-04 08:10:59 +09002053 * @reserved_size: the size of reserved percpu area in bytes
2054 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002055 * @free_fn: function to free percpu page, always called with PAGE_SIZE
Tejun Heod4b95f82009-07-04 08:10:59 +09002056 * @populate_pte_fn: function to populate pte
2057 *
Tejun Heo00ae4062009-08-14 15:00:49 +09002058 * This is a helper to ease setting up page-remapped first percpu
2059 * chunk and can be called where pcpu_setup_first_chunk() is expected.
Tejun Heod4b95f82009-07-04 08:10:59 +09002060 *
2061 * This is the basic allocator. Static percpu area is allocated
2062 * page-by-page into vmalloc area.
2063 *
2064 * RETURNS:
Tejun Heofb435d52009-08-14 15:00:51 +09002065 * 0 on success, -errno on failure.
Tejun Heod4b95f82009-07-04 08:10:59 +09002066 */
Tejun Heofb435d52009-08-14 15:00:51 +09002067int __init pcpu_page_first_chunk(size_t reserved_size,
2068 pcpu_fc_alloc_fn_t alloc_fn,
2069 pcpu_fc_free_fn_t free_fn,
2070 pcpu_fc_populate_pte_fn_t populate_pte_fn)
Tejun Heod4b95f82009-07-04 08:10:59 +09002071{
Tejun Heo8f05a6a2009-07-04 08:10:59 +09002072 static struct vm_struct vm;
Tejun Heofd1e8a12009-08-14 15:00:51 +09002073 struct pcpu_alloc_info *ai;
Tejun Heo00ae4062009-08-14 15:00:49 +09002074 char psize_str[16];
Tejun Heoce3141a2009-07-04 08:11:00 +09002075 int unit_pages;
Tejun Heod4b95f82009-07-04 08:10:59 +09002076 size_t pages_size;
Tejun Heoce3141a2009-07-04 08:11:00 +09002077 struct page **pages;
Tejun Heofb435d52009-08-14 15:00:51 +09002078 int unit, i, j, rc;
Tejun Heod4b95f82009-07-04 08:10:59 +09002079
Tejun Heo00ae4062009-08-14 15:00:49 +09002080 snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
2081
Tejun Heo4ba6ce22010-06-27 18:49:59 +02002082 ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
Tejun Heofd1e8a12009-08-14 15:00:51 +09002083 if (IS_ERR(ai))
2084 return PTR_ERR(ai);
2085 BUG_ON(ai->nr_groups != 1);
2086 BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
2087
2088 unit_pages = ai->unit_size >> PAGE_SHIFT;
Tejun Heod4b95f82009-07-04 08:10:59 +09002089
2090 /* unaligned allocations can't be freed, round up to page size */
Tejun Heofd1e8a12009-08-14 15:00:51 +09002091 pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
2092 sizeof(pages[0]));
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08002093 pages = memblock_virt_alloc(pages_size, 0);
Tejun Heod4b95f82009-07-04 08:10:59 +09002094
Tejun Heo8f05a6a2009-07-04 08:10:59 +09002095 /* allocate pages */
Tejun Heod4b95f82009-07-04 08:10:59 +09002096 j = 0;
Tejun Heofd1e8a12009-08-14 15:00:51 +09002097 for (unit = 0; unit < num_possible_cpus(); unit++)
Tejun Heoce3141a2009-07-04 08:11:00 +09002098 for (i = 0; i < unit_pages; i++) {
Tejun Heofd1e8a12009-08-14 15:00:51 +09002099 unsigned int cpu = ai->groups[0].cpu_map[unit];
Tejun Heod4b95f82009-07-04 08:10:59 +09002100 void *ptr;
2101
Tejun Heo3cbc8562009-08-14 15:00:50 +09002102 ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
Tejun Heod4b95f82009-07-04 08:10:59 +09002103 if (!ptr) {
Joe Perches870d4b12016-03-17 14:19:53 -07002104 pr_warn("failed to allocate %s page for cpu%u\n",
Joe Perches598d8092016-03-17 14:19:44 -07002105 psize_str, cpu);
Tejun Heod4b95f82009-07-04 08:10:59 +09002106 goto enomem;
2107 }
Catalin Marinasf528f0b2011-09-26 17:12:53 +01002108 /* kmemleak tracks the percpu allocations separately */
2109 kmemleak_free(ptr);
Tejun Heoce3141a2009-07-04 08:11:00 +09002110 pages[j++] = virt_to_page(ptr);
Tejun Heod4b95f82009-07-04 08:10:59 +09002111 }
2112
Tejun Heo8f05a6a2009-07-04 08:10:59 +09002113 /* allocate vm area, map the pages and copy static data */
2114 vm.flags = VM_ALLOC;
Tejun Heofd1e8a12009-08-14 15:00:51 +09002115 vm.size = num_possible_cpus() * ai->unit_size;
Tejun Heo8f05a6a2009-07-04 08:10:59 +09002116 vm_area_register_early(&vm, PAGE_SIZE);
2117
Tejun Heofd1e8a12009-08-14 15:00:51 +09002118 for (unit = 0; unit < num_possible_cpus(); unit++) {
Tejun Heo1d9d3252009-08-14 15:00:50 +09002119 unsigned long unit_addr =
Tejun Heofd1e8a12009-08-14 15:00:51 +09002120 (unsigned long)vm.addr + unit * ai->unit_size;
Tejun Heo8f05a6a2009-07-04 08:10:59 +09002121
Tejun Heoce3141a2009-07-04 08:11:00 +09002122 for (i = 0; i < unit_pages; i++)
Tejun Heo8f05a6a2009-07-04 08:10:59 +09002123 populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
2124
2125 /* pte already populated, the following shouldn't fail */
Tejun Heofb435d52009-08-14 15:00:51 +09002126 rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
2127 unit_pages);
2128 if (rc < 0)
2129 panic("failed to map percpu area, err=%d\n", rc);
Tejun Heo8f05a6a2009-07-04 08:10:59 +09002130
2131 /*
2132 * FIXME: Archs with virtual cache should flush local
2133 * cache for the linear mapping here - something
2134 * equivalent to flush_cache_vmap() on the local cpu.
2135 * flush_cache_vmap() can't be used as most supporting
2136 * data structures are not set up yet.
2137 */
2138
2139 /* copy static data */
Tejun Heofd1e8a12009-08-14 15:00:51 +09002140 memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
Tejun Heo66c3a752009-03-10 16:27:48 +09002141 }
2142
2143 /* we're ready, commit */
Joe Perches870d4b12016-03-17 14:19:53 -07002144 pr_info("%d %s pages/cpu @%p s%zu r%zu d%zu\n",
Tejun Heofd1e8a12009-08-14 15:00:51 +09002145 unit_pages, psize_str, vm.addr, ai->static_size,
2146 ai->reserved_size, ai->dyn_size);
Tejun Heo66c3a752009-03-10 16:27:48 +09002147
Tejun Heofb435d52009-08-14 15:00:51 +09002148 rc = pcpu_setup_first_chunk(ai, vm.addr);
Tejun Heod4b95f82009-07-04 08:10:59 +09002149 goto out_free_ar;
2150
2151enomem:
2152 while (--j >= 0)
Tejun Heoce3141a2009-07-04 08:11:00 +09002153 free_fn(page_address(pages[j]), PAGE_SIZE);
Tejun Heofb435d52009-08-14 15:00:51 +09002154 rc = -ENOMEM;
Tejun Heod4b95f82009-07-04 08:10:59 +09002155out_free_ar:
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08002156 memblock_free_early(__pa(pages), pages_size);
Tejun Heofd1e8a12009-08-14 15:00:51 +09002157 pcpu_free_alloc_info(ai);
Tejun Heofb435d52009-08-14 15:00:51 +09002158 return rc;
Tejun Heo66c3a752009-03-10 16:27:48 +09002159}
Tejun Heo3c9a0242010-09-09 18:00:15 +02002160#endif /* BUILD_PAGE_FIRST_CHUNK */
Tejun Heod4b95f82009-07-04 08:10:59 +09002161
Tejun Heobbddff02010-09-03 18:22:48 +02002162#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
Tejun Heo8c4bfc62009-07-04 08:10:59 +09002163/*
Tejun Heobbddff02010-09-03 18:22:48 +02002164 * Generic SMP percpu area setup.
Tejun Heoe74e3962009-03-30 19:07:44 +09002165 *
2166 * The embedding helper is used because its behavior closely resembles
2167 * the original non-dynamic generic percpu area setup. This is
2168 * important because many archs have addressing restrictions and might
2169 * fail if the percpu area is located far away from the previous
2170 * location. As an added bonus, in non-NUMA cases, embedding is
2171 * generally a good idea TLB-wise because percpu area can piggy back
2172 * on the physical linear memory mapping which uses large page
2173 * mappings on applicable archs.
2174 */
Tejun Heoe74e3962009-03-30 19:07:44 +09002175unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
2176EXPORT_SYMBOL(__per_cpu_offset);
2177
Tejun Heoc8826dd2009-08-14 15:00:52 +09002178static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
2179 size_t align)
2180{
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08002181 return memblock_virt_alloc_from_nopanic(
2182 size, align, __pa(MAX_DMA_ADDRESS));
Tejun Heoc8826dd2009-08-14 15:00:52 +09002183}
2184
2185static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
2186{
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08002187 memblock_free_early(__pa(ptr), size);
Tejun Heoc8826dd2009-08-14 15:00:52 +09002188}
2189
Tejun Heoe74e3962009-03-30 19:07:44 +09002190void __init setup_per_cpu_areas(void)
2191{
Tejun Heoe74e3962009-03-30 19:07:44 +09002192 unsigned long delta;
2193 unsigned int cpu;
Tejun Heofb435d52009-08-14 15:00:51 +09002194 int rc;
Tejun Heoe74e3962009-03-30 19:07:44 +09002195
2196 /*
2197 * Always reserve area for module percpu variables. That's
2198 * what the legacy allocator did.
2199 */
Tejun Heofb435d52009-08-14 15:00:51 +09002200 rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
Tejun Heoc8826dd2009-08-14 15:00:52 +09002201 PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
2202 pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
Tejun Heofb435d52009-08-14 15:00:51 +09002203 if (rc < 0)
Tejun Heobbddff02010-09-03 18:22:48 +02002204 panic("Failed to initialize percpu areas.");
Tejun Heoe74e3962009-03-30 19:07:44 +09002205
2206 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
2207 for_each_possible_cpu(cpu)
Tejun Heofb435d52009-08-14 15:00:51 +09002208 __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
Tejun Heoe74e3962009-03-30 19:07:44 +09002209}
Tejun Heobbddff02010-09-03 18:22:48 +02002210#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
2211
2212#else /* CONFIG_SMP */
2213
2214/*
2215 * UP percpu area setup.
2216 *
2217 * UP always uses km-based percpu allocator with identity mapping.
2218 * Static percpu variables are indistinguishable from the usual static
2219 * variables and don't require any special preparation.
2220 */
2221void __init setup_per_cpu_areas(void)
2222{
2223 const size_t unit_size =
2224 roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
2225 PERCPU_DYNAMIC_RESERVE));
2226 struct pcpu_alloc_info *ai;
2227 void *fc;
2228
2229 ai = pcpu_alloc_alloc_info(1, 1);
Santosh Shilimkar999c17e2014-01-21 15:50:40 -08002230 fc = memblock_virt_alloc_from_nopanic(unit_size,
2231 PAGE_SIZE,
2232 __pa(MAX_DMA_ADDRESS));
Tejun Heobbddff02010-09-03 18:22:48 +02002233 if (!ai || !fc)
2234 panic("Failed to allocate memory for percpu areas.");
Catalin Marinas100d13c2012-05-09 16:55:19 +01002235 /* kmemleak tracks the percpu allocations separately */
2236 kmemleak_free(fc);
Tejun Heobbddff02010-09-03 18:22:48 +02002237
2238 ai->dyn_size = unit_size;
2239 ai->unit_size = unit_size;
2240 ai->atom_size = unit_size;
2241 ai->alloc_size = unit_size;
2242 ai->groups[0].nr_units = 1;
2243 ai->groups[0].cpu_map[0] = 0;
2244
2245 if (pcpu_setup_first_chunk(ai, fc) < 0)
2246 panic("Failed to initialize percpu areas.");
2247}
2248
2249#endif /* CONFIG_SMP */
Tejun Heo099a19d2010-06-27 18:50:00 +02002250
2251/*
2252 * First and reserved chunks are initialized with temporary allocation
2253 * map in initdata so that they can be used before slab is online.
2254 * This function is called after slab is brought up and replaces those
2255 * with properly allocated maps.
2256 */
2257void __init percpu_init_late(void)
2258{
2259 struct pcpu_chunk *target_chunks[] =
2260 { pcpu_first_chunk, pcpu_reserved_chunk, NULL };
2261 struct pcpu_chunk *chunk;
2262 unsigned long flags;
2263 int i;
2264
2265 for (i = 0; (chunk = target_chunks[i]); i++) {
2266 int *map;
2267 const size_t size = PERCPU_DYNAMIC_EARLY_SLOTS * sizeof(map[0]);
2268
2269 BUILD_BUG_ON(size > PAGE_SIZE);
2270
Bob Liu90459ce02011-08-04 11:02:33 +02002271 map = pcpu_mem_zalloc(size);
Tejun Heo099a19d2010-06-27 18:50:00 +02002272 BUG_ON(!map);
2273
2274 spin_lock_irqsave(&pcpu_lock, flags);
2275 memcpy(map, chunk->map, size);
2276 chunk->map = map;
2277 spin_unlock_irqrestore(&pcpu_lock, flags);
2278 }
2279}
Tejun Heo1a4d7602014-09-02 14:46:05 -04002280
2281/*
2282 * Percpu allocator is initialized early during boot when neither slab or
2283 * workqueue is available. Plug async management until everything is up
2284 * and running.
2285 */
2286static int __init percpu_enable_async(void)
2287{
2288 pcpu_async_enabled = true;
2289 return 0;
2290}
2291subsys_initcall(percpu_enable_async);