1 // SPDX-License-Identifier: GPL-2.0-only <<
2 /* 1 /*
3 * z3fold.c 2 * z3fold.c
4 * 3 *
5 * Author: Vitaly Wool <vitaly.wool@konsulko.c 4 * Author: Vitaly Wool <vitaly.wool@konsulko.com>
6 * Copyright (C) 2016, Sony Mobile Communicati 5 * Copyright (C) 2016, Sony Mobile Communications Inc.
7 * 6 *
8 * This implementation is based on zbud writte 7 * This implementation is based on zbud written by Seth Jennings.
9 * 8 *
10 * z3fold is an special purpose allocator for 9 * z3fold is an special purpose allocator for storing compressed pages. It
11 * can store up to three compressed pages per 10 * can store up to three compressed pages per page which improves the
12 * compression ratio of zbud while retaining i 11 * compression ratio of zbud while retaining its main concepts (e. g. always
13 * storing an integral number of objects per p 12 * storing an integral number of objects per page) and simplicity.
14 * It still has simple and deterministic recla 13 * It still has simple and deterministic reclaim properties that make it
15 * preferable to a higher density approach (wi 14 * preferable to a higher density approach (with no requirement on integral
16 * number of object per page) when reclaim is 15 * number of object per page) when reclaim is used.
17 * 16 *
18 * As in zbud, pages are divided into "chunks" 17 * As in zbud, pages are divided into "chunks". The size of the chunks is
19 * fixed at compile time and is determined by 18 * fixed at compile time and is determined by NCHUNKS_ORDER below.
20 * 19 *
21 * z3fold doesn't export any API and is meant 20 * z3fold doesn't export any API and is meant to be used via zpool API.
22 */ 21 */
23 22
24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25 24
26 #include <linux/atomic.h> 25 #include <linux/atomic.h>
27 #include <linux/sched.h> 26 #include <linux/sched.h>
28 #include <linux/cpumask.h> <<
29 #include <linux/list.h> 27 #include <linux/list.h>
30 #include <linux/mm.h> 28 #include <linux/mm.h>
31 #include <linux/module.h> 29 #include <linux/module.h>
32 #include <linux/page-flags.h> <<
33 #include <linux/migrate.h> <<
34 #include <linux/node.h> <<
35 #include <linux/compaction.h> <<
36 #include <linux/percpu.h> 30 #include <linux/percpu.h>
37 #include <linux/preempt.h> 31 #include <linux/preempt.h>
38 #include <linux/workqueue.h> 32 #include <linux/workqueue.h>
39 #include <linux/slab.h> 33 #include <linux/slab.h>
40 #include <linux/spinlock.h> 34 #include <linux/spinlock.h>
41 #include <linux/zpool.h> 35 #include <linux/zpool.h>
42 #include <linux/kmemleak.h> <<
43 <<
44 /* <<
45 * NCHUNKS_ORDER determines the internal alloc <<
46 * adjusting internal fragmentation. It also <<
47 * freelists maintained in each pool. NCHUNKS_ <<
48 * allocation granularity will be in chunks of <<
49 * in the beginning of an allocated page are o <<
50 * NCHUNKS will be calculated to 63 (or 62 in <<
51 * which shows the max number of free chunks i <<
52 * be 63, or 62, respectively, freelists per p <<
53 */ <<
54 #define NCHUNKS_ORDER 6 <<
55 <<
56 #define CHUNK_SHIFT (PAGE_SHIFT - NCHUNKS_ <<
57 #define CHUNK_SIZE (1 << CHUNK_SHIFT) <<
58 #define ZHDR_SIZE_ALIGNED round_up(sizeof(stru <<
59 #define ZHDR_CHUNKS (ZHDR_SIZE_ALIGNED >> <<
60 #define TOTAL_CHUNKS (PAGE_SIZE >> CHUNK_SH <<
61 #define NCHUNKS (TOTAL_CHUNKS - ZHDR_C <<
62 <<
63 #define BUDDY_MASK (0x3) <<
64 #define BUDDY_SHIFT 2 <<
65 #define SLOTS_ALIGN (0x40) <<
66 36
67 /***************** 37 /*****************
68 * Structures 38 * Structures
69 *****************/ 39 *****************/
70 struct z3fold_pool; 40 struct z3fold_pool;
>> 41 struct z3fold_ops {
>> 42 int (*evict)(struct z3fold_pool *pool, unsigned long handle);
>> 43 };
71 44
72 enum buddy { 45 enum buddy {
73 HEADLESS = 0, 46 HEADLESS = 0,
74 FIRST, 47 FIRST,
75 MIDDLE, 48 MIDDLE,
76 LAST, 49 LAST,
77 BUDDIES_MAX = LAST !! 50 BUDDIES_MAX
78 }; 51 };
79 52
80 struct z3fold_buddy_slots { <<
81 /* <<
82 * we are using BUDDY_MASK in handle_t <<
83 * be enough slots to hold all possibl <<
84 */ <<
85 unsigned long slot[BUDDY_MASK + 1]; <<
86 unsigned long pool; /* back link */ <<
87 rwlock_t lock; <<
88 }; <<
89 #define HANDLE_FLAG_MASK (0x03) <<
90 <<
91 /* 53 /*
92 * struct z3fold_header - z3fold page metadata 54 * struct z3fold_header - z3fold page metadata occupying first chunks of each
93 * z3fold page, except fo 55 * z3fold page, except for HEADLESS pages
94 * @buddy: links the z3fold page 56 * @buddy: links the z3fold page into the relevant list in the
95 * pool 57 * pool
96 * @page_lock: per-page lock 58 * @page_lock: per-page lock
97 * @refcount: reference count for th 59 * @refcount: reference count for the z3fold page
98 * @work: work_struct for page l 60 * @work: work_struct for page layout optimization
99 * @slots: pointer to the structu !! 61 * @pool: pointer to the pool which this page belongs to
100 * @pool: pointer to the contain <<
101 * @cpu: CPU which this page "b 62 * @cpu: CPU which this page "belongs" to
102 * @first_chunks: the size of the first 63 * @first_chunks: the size of the first buddy in chunks, 0 if free
103 * @middle_chunks: the size of the middle 64 * @middle_chunks: the size of the middle buddy in chunks, 0 if free
104 * @last_chunks: the size of the last b 65 * @last_chunks: the size of the last buddy in chunks, 0 if free
105 * @first_num: the starting number (f 66 * @first_num: the starting number (for the first handle)
106 * @mapped_count: the number of objects <<
107 */ 67 */
108 struct z3fold_header { 68 struct z3fold_header {
109 struct list_head buddy; 69 struct list_head buddy;
110 spinlock_t page_lock; 70 spinlock_t page_lock;
111 struct kref refcount; 71 struct kref refcount;
112 struct work_struct work; 72 struct work_struct work;
113 struct z3fold_buddy_slots *slots; <<
114 struct z3fold_pool *pool; 73 struct z3fold_pool *pool;
115 short cpu; 74 short cpu;
116 unsigned short first_chunks; 75 unsigned short first_chunks;
117 unsigned short middle_chunks; 76 unsigned short middle_chunks;
118 unsigned short last_chunks; 77 unsigned short last_chunks;
119 unsigned short start_middle; 78 unsigned short start_middle;
120 unsigned short first_num:2; 79 unsigned short first_num:2;
121 unsigned short mapped_count:2; <<
122 unsigned short foreign_handles:2; <<
123 }; 80 };
124 81
>> 82 /*
>> 83 * NCHUNKS_ORDER determines the internal allocation granularity, effectively
>> 84 * adjusting internal fragmentation. It also determines the number of
>> 85 * freelists maintained in each pool. NCHUNKS_ORDER of 6 means that the
>> 86 * allocation granularity will be in chunks of size PAGE_SIZE/64. Some chunks
>> 87 * in the beginning of an allocated page are occupied by z3fold header, so
>> 88 * NCHUNKS will be calculated to 63 (or 62 in case CONFIG_DEBUG_SPINLOCK=y),
>> 89 * which shows the max number of free chunks in z3fold page, also there will
>> 90 * be 63, or 62, respectively, freelists per pool.
>> 91 */
>> 92 #define NCHUNKS_ORDER 6
>> 93
>> 94 #define CHUNK_SHIFT (PAGE_SHIFT - NCHUNKS_ORDER)
>> 95 #define CHUNK_SIZE (1 << CHUNK_SHIFT)
>> 96 #define ZHDR_SIZE_ALIGNED round_up(sizeof(struct z3fold_header), CHUNK_SIZE)
>> 97 #define ZHDR_CHUNKS (ZHDR_SIZE_ALIGNED >> CHUNK_SHIFT)
>> 98 #define TOTAL_CHUNKS (PAGE_SIZE >> CHUNK_SHIFT)
>> 99 #define NCHUNKS ((PAGE_SIZE - ZHDR_SIZE_ALIGNED) >> CHUNK_SHIFT)
>> 100
>> 101 #define BUDDY_MASK (0x3)
>> 102
125 /** 103 /**
126 * struct z3fold_pool - stores metadata for ea 104 * struct z3fold_pool - stores metadata for each z3fold pool
127 * @name: pool name 105 * @name: pool name
128 * @lock: protects pool unbuddied lists !! 106 * @lock: protects pool unbuddied/lru lists
129 * @stale_lock: protects pool stale page list 107 * @stale_lock: protects pool stale page list
130 * @unbuddied: per-cpu array of lists trackin 108 * @unbuddied: per-cpu array of lists tracking z3fold pages that contain 2-
131 * buddies; the list each z3fold 109 * buddies; the list each z3fold page is added to depends on
132 * the size of its free region. 110 * the size of its free region.
>> 111 * @lru: list tracking the z3fold pages in LRU order by most recently
>> 112 * added buddy.
133 * @stale: list of pages marked for freei 113 * @stale: list of pages marked for freeing
134 * @pages_nr: number of z3fold pages in the 114 * @pages_nr: number of z3fold pages in the pool.
135 * @c_handle: cache for z3fold_buddy_slots a !! 115 * @ops: pointer to a structure of user defined operations specified at
>> 116 * pool creation time.
136 * @compact_wq: workqueue for page layout back 117 * @compact_wq: workqueue for page layout background optimization
137 * @release_wq: workqueue for safe page releas 118 * @release_wq: workqueue for safe page release
138 * @work: work_struct for safe page rele 119 * @work: work_struct for safe page release
139 * 120 *
140 * This structure is allocated at pool creatio 121 * This structure is allocated at pool creation time and maintains metadata
141 * pertaining to a particular z3fold pool. 122 * pertaining to a particular z3fold pool.
142 */ 123 */
143 struct z3fold_pool { 124 struct z3fold_pool {
144 const char *name; 125 const char *name;
145 spinlock_t lock; 126 spinlock_t lock;
146 spinlock_t stale_lock; 127 spinlock_t stale_lock;
147 struct list_head __percpu *unbuddied; !! 128 struct list_head *unbuddied;
>> 129 struct list_head lru;
148 struct list_head stale; 130 struct list_head stale;
149 atomic64_t pages_nr; 131 atomic64_t pages_nr;
150 struct kmem_cache *c_handle; !! 132 const struct z3fold_ops *ops;
>> 133 struct zpool *zpool;
>> 134 const struct zpool_ops *zpool_ops;
151 struct workqueue_struct *compact_wq; 135 struct workqueue_struct *compact_wq;
152 struct workqueue_struct *release_wq; 136 struct workqueue_struct *release_wq;
153 struct work_struct work; 137 struct work_struct work;
154 }; 138 };
155 139
156 /* 140 /*
157 * Internal z3fold page flags 141 * Internal z3fold page flags
158 */ 142 */
159 enum z3fold_page_flags { 143 enum z3fold_page_flags {
160 PAGE_HEADLESS = 0, 144 PAGE_HEADLESS = 0,
161 MIDDLE_CHUNK_MAPPED, 145 MIDDLE_CHUNK_MAPPED,
162 NEEDS_COMPACTING, 146 NEEDS_COMPACTING,
163 PAGE_STALE, !! 147 PAGE_STALE
164 PAGE_CLAIMED, /* by either reclaim or <<
165 PAGE_MIGRATED, /* page is migrated and <<
166 }; 148 };
167 149
168 /* <<
169 * handle flags, go under HANDLE_FLAG_MASK <<
170 */ <<
171 enum z3fold_handle_flags { <<
172 HANDLES_NOFREE = 0, <<
173 }; <<
174 <<
175 /* <<
176 * Forward declarations <<
177 */ <<
178 static struct z3fold_header *__z3fold_alloc(st <<
179 static void compact_page_work(struct work_stru <<
180 <<
181 /***************** 150 /*****************
182 * Helpers 151 * Helpers
183 *****************/ 152 *****************/
184 153
185 /* Converts an allocation size in bytes to siz 154 /* Converts an allocation size in bytes to size in z3fold chunks */
186 static int size_to_chunks(size_t size) 155 static int size_to_chunks(size_t size)
187 { 156 {
188 return (size + CHUNK_SIZE - 1) >> CHUN 157 return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
189 } 158 }
190 159
191 #define for_each_unbuddied_list(_iter, _begin) 160 #define for_each_unbuddied_list(_iter, _begin) \
192 for ((_iter) = (_begin); (_iter) < NCH 161 for ((_iter) = (_begin); (_iter) < NCHUNKS; (_iter)++)
193 162
194 static inline struct z3fold_buddy_slots *alloc !! 163 static void compact_page_work(struct work_struct *w);
195 <<
196 { <<
197 struct z3fold_buddy_slots *slots = kme <<
198 <<
199 <<
200 if (slots) { <<
201 /* It will be freed separately <<
202 kmemleak_not_leak(slots); <<
203 slots->pool = (unsigned long)p <<
204 rwlock_init(&slots->lock); <<
205 } <<
206 <<
207 return slots; <<
208 } <<
209 <<
210 static inline struct z3fold_pool *slots_to_poo <<
211 { <<
212 return (struct z3fold_pool *)(s->pool <<
213 } <<
214 <<
215 static inline struct z3fold_buddy_slots *handl <<
216 { <<
217 return (struct z3fold_buddy_slots *)(h <<
218 } <<
219 <<
220 /* Lock a z3fold page */ <<
221 static inline void z3fold_page_lock(struct z3f <<
222 { <<
223 spin_lock(&zhdr->page_lock); <<
224 } <<
225 <<
226 /* Try to lock a z3fold page */ <<
227 static inline int z3fold_page_trylock(struct z <<
228 { <<
229 return spin_trylock(&zhdr->page_lock); <<
230 } <<
231 <<
232 /* Unlock a z3fold page */ <<
233 static inline void z3fold_page_unlock(struct z <<
234 { <<
235 spin_unlock(&zhdr->page_lock); <<
236 } <<
237 <<
238 /* return locked z3fold page if it's not headl <<
239 static inline struct z3fold_header *get_z3fold <<
240 { <<
241 struct z3fold_buddy_slots *slots; <<
242 struct z3fold_header *zhdr; <<
243 int locked = 0; <<
244 <<
245 if (!(handle & (1 << PAGE_HEADLESS))) <<
246 slots = handle_to_slots(handle <<
247 do { <<
248 unsigned long addr; <<
249 <<
250 read_lock(&slots->lock <<
251 addr = *(unsigned long <<
252 zhdr = (struct z3fold_ <<
253 locked = z3fold_page_t <<
254 read_unlock(&slots->lo <<
255 if (locked) { <<
256 struct page *p <<
257 <<
258 if (!test_bit( <<
259 break; <<
260 z3fold_page_un <<
261 } <<
262 cpu_relax(); <<
263 } while (true); <<
264 } else { <<
265 zhdr = (struct z3fold_header * <<
266 } <<
267 <<
268 return zhdr; <<
269 } <<
270 <<
271 static inline void put_z3fold_header(struct z3 <<
272 { <<
273 struct page *page = virt_to_page(zhdr) <<
274 <<
275 if (!test_bit(PAGE_HEADLESS, &page->pr <<
276 z3fold_page_unlock(zhdr); <<
277 } <<
278 <<
279 static inline void free_handle(unsigned long h <<
280 { <<
281 struct z3fold_buddy_slots *slots; <<
282 int i; <<
283 bool is_free; <<
284 <<
285 if (WARN_ON(*(unsigned long *)handle = <<
286 return; <<
287 <<
288 slots = handle_to_slots(handle); <<
289 write_lock(&slots->lock); <<
290 *(unsigned long *)handle = 0; <<
291 <<
292 if (test_bit(HANDLES_NOFREE, &slots->p <<
293 write_unlock(&slots->lock); <<
294 return; /* simple case, nothin <<
295 } <<
296 <<
297 if (zhdr->slots != slots) <<
298 zhdr->foreign_handles--; <<
299 <<
300 is_free = true; <<
301 for (i = 0; i <= BUDDY_MASK; i++) { <<
302 if (slots->slot[i]) { <<
303 is_free = false; <<
304 break; <<
305 } <<
306 } <<
307 write_unlock(&slots->lock); <<
308 <<
309 if (is_free) { <<
310 struct z3fold_pool *pool = slo <<
311 <<
312 if (zhdr->slots == slots) <<
313 zhdr->slots = NULL; <<
314 kmem_cache_free(pool->c_handle <<
315 } <<
316 } <<
317 164
318 /* Initializes the z3fold header of a newly al 165 /* Initializes the z3fold header of a newly allocated z3fold page */
319 static struct z3fold_header *init_z3fold_page( !! 166 static struct z3fold_header *init_z3fold_page(struct page *page,
320 struct !! 167 struct z3fold_pool *pool)
321 { 168 {
322 struct z3fold_header *zhdr = page_addr 169 struct z3fold_header *zhdr = page_address(page);
323 struct z3fold_buddy_slots *slots; <<
324 170
>> 171 INIT_LIST_HEAD(&page->lru);
325 clear_bit(PAGE_HEADLESS, &page->privat 172 clear_bit(PAGE_HEADLESS, &page->private);
326 clear_bit(MIDDLE_CHUNK_MAPPED, &page-> 173 clear_bit(MIDDLE_CHUNK_MAPPED, &page->private);
327 clear_bit(NEEDS_COMPACTING, &page->pri 174 clear_bit(NEEDS_COMPACTING, &page->private);
328 clear_bit(PAGE_STALE, &page->private); 175 clear_bit(PAGE_STALE, &page->private);
329 clear_bit(PAGE_CLAIMED, &page->private <<
330 clear_bit(PAGE_MIGRATED, &page->privat <<
331 if (headless) <<
332 return zhdr; <<
333 <<
334 slots = alloc_slots(pool, gfp); <<
335 if (!slots) <<
336 return NULL; <<
337 176
338 memset(zhdr, 0, sizeof(*zhdr)); <<
339 spin_lock_init(&zhdr->page_lock); 177 spin_lock_init(&zhdr->page_lock);
340 kref_init(&zhdr->refcount); 178 kref_init(&zhdr->refcount);
>> 179 zhdr->first_chunks = 0;
>> 180 zhdr->middle_chunks = 0;
>> 181 zhdr->last_chunks = 0;
>> 182 zhdr->first_num = 0;
>> 183 zhdr->start_middle = 0;
341 zhdr->cpu = -1; 184 zhdr->cpu = -1;
342 zhdr->slots = slots; <<
343 zhdr->pool = pool; 185 zhdr->pool = pool;
344 INIT_LIST_HEAD(&zhdr->buddy); 186 INIT_LIST_HEAD(&zhdr->buddy);
345 INIT_WORK(&zhdr->work, compact_page_wo 187 INIT_WORK(&zhdr->work, compact_page_work);
346 return zhdr; 188 return zhdr;
347 } 189 }
348 190
349 /* Resets the struct page fields and frees the 191 /* Resets the struct page fields and frees the page */
350 static void free_z3fold_page(struct page *page !! 192 static void free_z3fold_page(struct page *page)
351 { 193 {
352 if (!headless) { <<
353 lock_page(page); <<
354 __ClearPageMovable(page); <<
355 unlock_page(page); <<
356 } <<
357 __free_page(page); 194 __free_page(page);
358 } 195 }
359 196
360 /* Helper function to build the index */ !! 197 /* Lock a z3fold page */
361 static inline int __idx(struct z3fold_header * !! 198 static inline void z3fold_page_lock(struct z3fold_header *zhdr)
362 { 199 {
363 return (bud + zhdr->first_num) & BUDDY !! 200 spin_lock(&zhdr->page_lock);
364 } 201 }
365 202
366 /* !! 203 /* Try to lock a z3fold page */
367 * Encodes the handle of a particular buddy wi !! 204 static inline int z3fold_page_trylock(struct z3fold_header *zhdr)
368 * Zhdr->page_lock should be held as this func <<
369 * if bud != HEADLESS. <<
370 */ <<
371 static unsigned long __encode_handle(struct z3 <<
372 struct z3fold_ <<
373 enum buddy bud <<
374 { 205 {
375 unsigned long h = (unsigned long)zhdr; !! 206 return spin_trylock(&zhdr->page_lock);
376 int idx = 0; !! 207 }
377 <<
378 /* <<
379 * For a headless page, its handle is <<
380 * PAGE_HEADLESS bit set <<
381 */ <<
382 if (bud == HEADLESS) <<
383 return h | (1 << PAGE_HEADLESS <<
384 208
385 /* otherwise, return pointer to encode !! 209 /* Unlock a z3fold page */
386 idx = __idx(zhdr, bud); !! 210 static inline void z3fold_page_unlock(struct z3fold_header *zhdr)
387 h += idx; !! 211 {
388 if (bud == LAST) !! 212 spin_unlock(&zhdr->page_lock);
389 h |= (zhdr->last_chunks << BUD <<
390 <<
391 write_lock(&slots->lock); <<
392 slots->slot[idx] = h; <<
393 write_unlock(&slots->lock); <<
394 return (unsigned long)&slots->slot[idx <<
395 } 213 }
396 214
>> 215 /*
>> 216 * Encodes the handle of a particular buddy within a z3fold page
>> 217 * Pool lock should be held as this function accesses first_num
>> 218 */
397 static unsigned long encode_handle(struct z3fo 219 static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud)
398 { 220 {
399 return __encode_handle(zhdr, zhdr->slo !! 221 unsigned long handle;
>> 222
>> 223 handle = (unsigned long)zhdr;
>> 224 if (bud != HEADLESS)
>> 225 handle += (bud + zhdr->first_num) & BUDDY_MASK;
>> 226 return handle;
400 } 227 }
401 228
402 /* only for LAST bud, returns zero otherwise * !! 229 /* Returns the z3fold page where a given handle is stored */
403 static unsigned short handle_to_chunks(unsigne !! 230 static struct z3fold_header *handle_to_z3fold_header(unsigned long handle)
404 { 231 {
405 struct z3fold_buddy_slots *slots = han !! 232 return (struct z3fold_header *)(handle & PAGE_MASK);
406 unsigned long addr; <<
407 <<
408 read_lock(&slots->lock); <<
409 addr = *(unsigned long *)handle; <<
410 read_unlock(&slots->lock); <<
411 return (addr & ~PAGE_MASK) >> BUDDY_SH <<
412 } 233 }
413 234
414 /* 235 /*
415 * (handle & BUDDY_MASK) < zhdr->first_num is 236 * (handle & BUDDY_MASK) < zhdr->first_num is possible in encode_handle
416 * but that doesn't matter. because the maski 237 * but that doesn't matter. because the masking will result in the
417 * correct buddy number. 238 * correct buddy number.
418 */ 239 */
419 static enum buddy handle_to_buddy(unsigned lon 240 static enum buddy handle_to_buddy(unsigned long handle)
420 { 241 {
421 struct z3fold_header *zhdr; !! 242 struct z3fold_header *zhdr = handle_to_z3fold_header(handle);
422 struct z3fold_buddy_slots *slots = han !! 243 return (handle - zhdr->first_num) & BUDDY_MASK;
423 unsigned long addr; <<
424 <<
425 read_lock(&slots->lock); <<
426 WARN_ON(handle & (1 << PAGE_HEADLESS)) <<
427 addr = *(unsigned long *)handle; <<
428 read_unlock(&slots->lock); <<
429 zhdr = (struct z3fold_header *)(addr & <<
430 return (addr - zhdr->first_num) & BUDD <<
431 } <<
432 <<
433 static inline struct z3fold_pool *zhdr_to_pool <<
434 { <<
435 return zhdr->pool; <<
436 } 244 }
437 245
438 static void __release_z3fold_page(struct z3fol 246 static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked)
439 { 247 {
440 struct page *page = virt_to_page(zhdr) 248 struct page *page = virt_to_page(zhdr);
441 struct z3fold_pool *pool = zhdr_to_poo !! 249 struct z3fold_pool *pool = zhdr->pool;
442 250
443 WARN_ON(!list_empty(&zhdr->buddy)); 251 WARN_ON(!list_empty(&zhdr->buddy));
444 set_bit(PAGE_STALE, &page->private); 252 set_bit(PAGE_STALE, &page->private);
445 clear_bit(NEEDS_COMPACTING, &page->pri 253 clear_bit(NEEDS_COMPACTING, &page->private);
446 spin_lock(&pool->lock); 254 spin_lock(&pool->lock);
>> 255 if (!list_empty(&page->lru))
>> 256 list_del(&page->lru);
447 spin_unlock(&pool->lock); 257 spin_unlock(&pool->lock);
448 <<
449 if (locked) 258 if (locked)
450 z3fold_page_unlock(zhdr); 259 z3fold_page_unlock(zhdr);
451 <<
452 spin_lock(&pool->stale_lock); 260 spin_lock(&pool->stale_lock);
453 list_add(&zhdr->buddy, &pool->stale); 261 list_add(&zhdr->buddy, &pool->stale);
454 queue_work(pool->release_wq, &pool->wo 262 queue_work(pool->release_wq, &pool->work);
455 spin_unlock(&pool->stale_lock); 263 spin_unlock(&pool->stale_lock);
>> 264 }
456 265
457 atomic64_dec(&pool->pages_nr); !! 266 static void __attribute__((__unused__))
>> 267 release_z3fold_page(struct kref *ref)
>> 268 {
>> 269 struct z3fold_header *zhdr = container_of(ref, struct z3fold_header,
>> 270 refcount);
>> 271 __release_z3fold_page(zhdr, false);
458 } 272 }
459 273
460 static void release_z3fold_page_locked(struct 274 static void release_z3fold_page_locked(struct kref *ref)
461 { 275 {
462 struct z3fold_header *zhdr = container 276 struct z3fold_header *zhdr = container_of(ref, struct z3fold_header,
463 277 refcount);
464 WARN_ON(z3fold_page_trylock(zhdr)); 278 WARN_ON(z3fold_page_trylock(zhdr));
465 __release_z3fold_page(zhdr, true); 279 __release_z3fold_page(zhdr, true);
466 } 280 }
467 281
468 static void release_z3fold_page_locked_list(st 282 static void release_z3fold_page_locked_list(struct kref *ref)
469 { 283 {
470 struct z3fold_header *zhdr = container 284 struct z3fold_header *zhdr = container_of(ref, struct z3fold_header,
471 285 refcount);
472 struct z3fold_pool *pool = zhdr_to_poo !! 286 spin_lock(&zhdr->pool->lock);
473 <<
474 spin_lock(&pool->lock); <<
475 list_del_init(&zhdr->buddy); 287 list_del_init(&zhdr->buddy);
476 spin_unlock(&pool->lock); !! 288 spin_unlock(&zhdr->pool->lock);
477 289
478 WARN_ON(z3fold_page_trylock(zhdr)); 290 WARN_ON(z3fold_page_trylock(zhdr));
479 __release_z3fold_page(zhdr, true); 291 __release_z3fold_page(zhdr, true);
480 } 292 }
481 293
482 static inline int put_z3fold_locked(struct z3f <<
483 { <<
484 return kref_put(&zhdr->refcount, relea <<
485 } <<
486 <<
487 static inline int put_z3fold_locked_list(struc <<
488 { <<
489 return kref_put(&zhdr->refcount, relea <<
490 } <<
491 <<
492 static void free_pages_work(struct work_struct 294 static void free_pages_work(struct work_struct *w)
493 { 295 {
494 struct z3fold_pool *pool = container_o 296 struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work);
495 297
496 spin_lock(&pool->stale_lock); 298 spin_lock(&pool->stale_lock);
497 while (!list_empty(&pool->stale)) { 299 while (!list_empty(&pool->stale)) {
498 struct z3fold_header *zhdr = l 300 struct z3fold_header *zhdr = list_first_entry(&pool->stale,
499 301 struct z3fold_header, buddy);
500 struct page *page = virt_to_pa 302 struct page *page = virt_to_page(zhdr);
501 303
502 list_del(&zhdr->buddy); 304 list_del(&zhdr->buddy);
503 if (WARN_ON(!test_bit(PAGE_STA 305 if (WARN_ON(!test_bit(PAGE_STALE, &page->private)))
504 continue; 306 continue;
505 spin_unlock(&pool->stale_lock) 307 spin_unlock(&pool->stale_lock);
506 cancel_work_sync(&zhdr->work); 308 cancel_work_sync(&zhdr->work);
507 free_z3fold_page(page, false); !! 309 free_z3fold_page(page);
508 cond_resched(); 310 cond_resched();
509 spin_lock(&pool->stale_lock); 311 spin_lock(&pool->stale_lock);
510 } 312 }
511 spin_unlock(&pool->stale_lock); 313 spin_unlock(&pool->stale_lock);
512 } 314 }
513 315
514 /* 316 /*
515 * Returns the number of free chunks in a z3fo 317 * Returns the number of free chunks in a z3fold page.
516 * NB: can't be used with HEADLESS pages. 318 * NB: can't be used with HEADLESS pages.
517 */ 319 */
518 static int num_free_chunks(struct z3fold_heade 320 static int num_free_chunks(struct z3fold_header *zhdr)
519 { 321 {
520 int nfree; 322 int nfree;
521 /* 323 /*
522 * If there is a middle object, pick u 324 * If there is a middle object, pick up the bigger free space
523 * either before or after it. Otherwis 325 * either before or after it. Otherwise just subtract the number
524 * of chunks occupied by the first and 326 * of chunks occupied by the first and the last objects.
525 */ 327 */
526 if (zhdr->middle_chunks != 0) { 328 if (zhdr->middle_chunks != 0) {
527 int nfree_before = zhdr->first 329 int nfree_before = zhdr->first_chunks ?
528 0 : zhdr->start_middle 330 0 : zhdr->start_middle - ZHDR_CHUNKS;
529 int nfree_after = zhdr->last_c 331 int nfree_after = zhdr->last_chunks ?
530 0 : TOTAL_CHUNKS - 332 0 : TOTAL_CHUNKS -
531 (zhdr->start_m 333 (zhdr->start_middle + zhdr->middle_chunks);
532 nfree = max(nfree_before, nfre 334 nfree = max(nfree_before, nfree_after);
533 } else 335 } else
534 nfree = NCHUNKS - zhdr->first_ 336 nfree = NCHUNKS - zhdr->first_chunks - zhdr->last_chunks;
535 return nfree; 337 return nfree;
536 } 338 }
537 339
538 /* Add to the appropriate unbuddied list */ <<
539 static inline void add_to_unbuddied(struct z3f <<
540 struct z3fold_ <<
541 { <<
542 if (zhdr->first_chunks == 0 || zhdr->l <<
543 zhdr->middle_chunks == <<
544 struct list_head *unbuddied; <<
545 int freechunks = num_free_chun <<
546 <<
547 migrate_disable(); <<
548 unbuddied = this_cpu_ptr(pool- <<
549 spin_lock(&pool->lock); <<
550 list_add(&zhdr->buddy, &unbudd <<
551 spin_unlock(&pool->lock); <<
552 zhdr->cpu = smp_processor_id() <<
553 migrate_enable(); <<
554 } <<
555 } <<
556 <<
557 static inline enum buddy get_free_buddy(struct <<
558 { <<
559 enum buddy bud = HEADLESS; <<
560 <<
561 if (zhdr->middle_chunks) { <<
562 if (!zhdr->first_chunks && <<
563 chunks <= zhdr->start_midd <<
564 bud = FIRST; <<
565 else if (!zhdr->last_chunks) <<
566 bud = LAST; <<
567 } else { <<
568 if (!zhdr->first_chunks) <<
569 bud = FIRST; <<
570 else if (!zhdr->last_chunks) <<
571 bud = LAST; <<
572 else <<
573 bud = MIDDLE; <<
574 } <<
575 <<
576 return bud; <<
577 } <<
578 <<
579 static inline void *mchunk_memmove(struct z3fo 340 static inline void *mchunk_memmove(struct z3fold_header *zhdr,
580 unsigned short 341 unsigned short dst_chunk)
581 { 342 {
582 void *beg = zhdr; 343 void *beg = zhdr;
583 return memmove(beg + (dst_chunk << CHU 344 return memmove(beg + (dst_chunk << CHUNK_SHIFT),
584 beg + (zhdr->start_midd 345 beg + (zhdr->start_middle << CHUNK_SHIFT),
585 zhdr->middle_chunks << 346 zhdr->middle_chunks << CHUNK_SHIFT);
586 } 347 }
587 348
588 static inline bool buddy_single(struct z3fold_ <<
589 { <<
590 return !((zhdr->first_chunks && zhdr-> <<
591 (zhdr->first_chunks && <<
592 (zhdr->middle_chunks & <<
593 } <<
594 <<
595 static struct z3fold_header *compact_single_bu <<
596 { <<
597 struct z3fold_pool *pool = zhdr_to_poo <<
598 void *p = zhdr; <<
599 unsigned long old_handle = 0; <<
600 size_t sz = 0; <<
601 struct z3fold_header *new_zhdr = NULL; <<
602 int first_idx = __idx(zhdr, FIRST); <<
603 int middle_idx = __idx(zhdr, MIDDLE); <<
604 int last_idx = __idx(zhdr, LAST); <<
605 unsigned short *moved_chunks = NULL; <<
606 <<
607 /* <<
608 * No need to protect slots here -- al <<
609 * the page lock is already taken <<
610 */ <<
611 if (zhdr->first_chunks && zhdr->slots- <<
612 p += ZHDR_SIZE_ALIGNED; <<
613 sz = zhdr->first_chunks << CHU <<
614 old_handle = (unsigned long)&z <<
615 moved_chunks = &zhdr->first_ch <<
616 } else if (zhdr->middle_chunks && zhdr <<
617 p += zhdr->start_middle << CHU <<
618 sz = zhdr->middle_chunks << CH <<
619 old_handle = (unsigned long)&z <<
620 moved_chunks = &zhdr->middle_c <<
621 } else if (zhdr->last_chunks && zhdr-> <<
622 p += PAGE_SIZE - (zhdr->last_c <<
623 sz = zhdr->last_chunks << CHUN <<
624 old_handle = (unsigned long)&z <<
625 moved_chunks = &zhdr->last_chu <<
626 } <<
627 <<
628 if (sz > 0) { <<
629 enum buddy new_bud = HEADLESS; <<
630 short chunks = size_to_chunks( <<
631 void *q; <<
632 <<
633 new_zhdr = __z3fold_alloc(pool <<
634 if (!new_zhdr) <<
635 return NULL; <<
636 <<
637 if (WARN_ON(new_zhdr == zhdr)) <<
638 goto out_fail; <<
639 <<
640 new_bud = get_free_buddy(new_z <<
641 q = new_zhdr; <<
642 switch (new_bud) { <<
643 case FIRST: <<
644 new_zhdr->first_chunks <<
645 q += ZHDR_SIZE_ALIGNED <<
646 break; <<
647 case MIDDLE: <<
648 new_zhdr->middle_chunk <<
649 new_zhdr->start_middle <<
650 new_zhdr->firs <<
651 q += new_zhdr->start_m <<
652 break; <<
653 case LAST: <<
654 new_zhdr->last_chunks <<
655 q += PAGE_SIZE - (new_ <<
656 break; <<
657 default: <<
658 goto out_fail; <<
659 } <<
660 new_zhdr->foreign_handles++; <<
661 memcpy(q, p, sz); <<
662 write_lock(&zhdr->slots->lock) <<
663 *(unsigned long *)old_handle = <<
664 __idx(new_zhdr, new_bu <<
665 if (new_bud == LAST) <<
666 *(unsigned long *)old_ <<
667 (new_z <<
668 write_unlock(&zhdr->slots->loc <<
669 add_to_unbuddied(pool, new_zhd <<
670 z3fold_page_unlock(new_zhdr); <<
671 <<
672 *moved_chunks = 0; <<
673 } <<
674 <<
675 return new_zhdr; <<
676 <<
677 out_fail: <<
678 if (new_zhdr && !put_z3fold_locked(new <<
679 add_to_unbuddied(pool, new_zhd <<
680 z3fold_page_unlock(new_zhdr); <<
681 } <<
682 return NULL; <<
683 <<
684 } <<
685 <<
686 #define BIG_CHUNK_GAP 3 349 #define BIG_CHUNK_GAP 3
687 /* Has to be called with lock held */ 350 /* Has to be called with lock held */
688 static int z3fold_compact_page(struct z3fold_h 351 static int z3fold_compact_page(struct z3fold_header *zhdr)
689 { 352 {
690 struct page *page = virt_to_page(zhdr) 353 struct page *page = virt_to_page(zhdr);
691 354
692 if (test_bit(MIDDLE_CHUNK_MAPPED, &pag 355 if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private))
693 return 0; /* can't move middle 356 return 0; /* can't move middle chunk, it's used */
694 357
695 if (unlikely(PageIsolated(page))) <<
696 return 0; <<
697 <<
698 if (zhdr->middle_chunks == 0) 358 if (zhdr->middle_chunks == 0)
699 return 0; /* nothing to compac 359 return 0; /* nothing to compact */
700 360
701 if (zhdr->first_chunks == 0 && zhdr->l 361 if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) {
702 /* move to the beginning */ 362 /* move to the beginning */
703 mchunk_memmove(zhdr, ZHDR_CHUN 363 mchunk_memmove(zhdr, ZHDR_CHUNKS);
704 zhdr->first_chunks = zhdr->mid 364 zhdr->first_chunks = zhdr->middle_chunks;
705 zhdr->middle_chunks = 0; 365 zhdr->middle_chunks = 0;
706 zhdr->start_middle = 0; 366 zhdr->start_middle = 0;
707 zhdr->first_num++; 367 zhdr->first_num++;
708 return 1; 368 return 1;
709 } 369 }
710 370
711 /* 371 /*
712 * moving data is expensive, so let's 372 * moving data is expensive, so let's only do that if
713 * there's substantial gain (at least 373 * there's substantial gain (at least BIG_CHUNK_GAP chunks)
714 */ 374 */
715 if (zhdr->first_chunks != 0 && zhdr->l 375 if (zhdr->first_chunks != 0 && zhdr->last_chunks == 0 &&
716 zhdr->start_middle - (zhdr->first_ 376 zhdr->start_middle - (zhdr->first_chunks + ZHDR_CHUNKS) >=
717 BIG_CHUNK_GAP) { 377 BIG_CHUNK_GAP) {
718 mchunk_memmove(zhdr, zhdr->fir 378 mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS);
719 zhdr->start_middle = zhdr->fir 379 zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS;
720 return 1; 380 return 1;
721 } else if (zhdr->last_chunks != 0 && z 381 } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 &&
722 TOTAL_CHUNKS - (zhdr->last_ 382 TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle
723 + zhdr 383 + zhdr->middle_chunks) >=
724 BIG_CHUNK_GAP) { 384 BIG_CHUNK_GAP) {
725 unsigned short new_start = TOT 385 unsigned short new_start = TOTAL_CHUNKS - zhdr->last_chunks -
726 zhdr->middle_chunks; 386 zhdr->middle_chunks;
727 mchunk_memmove(zhdr, new_start 387 mchunk_memmove(zhdr, new_start);
728 zhdr->start_middle = new_start 388 zhdr->start_middle = new_start;
729 return 1; 389 return 1;
730 } 390 }
731 391
732 return 0; 392 return 0;
733 } 393 }
734 394
735 static void do_compact_page(struct z3fold_head 395 static void do_compact_page(struct z3fold_header *zhdr, bool locked)
736 { 396 {
737 struct z3fold_pool *pool = zhdr_to_poo !! 397 struct z3fold_pool *pool = zhdr->pool;
738 struct page *page; 398 struct page *page;
>> 399 struct list_head *unbuddied;
>> 400 int fchunks;
739 401
740 page = virt_to_page(zhdr); 402 page = virt_to_page(zhdr);
741 if (locked) 403 if (locked)
742 WARN_ON(z3fold_page_trylock(zh 404 WARN_ON(z3fold_page_trylock(zhdr));
743 else 405 else
744 z3fold_page_lock(zhdr); 406 z3fold_page_lock(zhdr);
745 if (WARN_ON(!test_and_clear_bit(NEEDS_ 407 if (WARN_ON(!test_and_clear_bit(NEEDS_COMPACTING, &page->private))) {
746 z3fold_page_unlock(zhdr); 408 z3fold_page_unlock(zhdr);
747 return; 409 return;
748 } 410 }
749 spin_lock(&pool->lock); 411 spin_lock(&pool->lock);
750 list_del_init(&zhdr->buddy); 412 list_del_init(&zhdr->buddy);
751 spin_unlock(&pool->lock); 413 spin_unlock(&pool->lock);
752 414
753 if (put_z3fold_locked(zhdr)) !! 415 if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
754 return; !! 416 atomic64_dec(&pool->pages_nr);
755 <<
756 if (test_bit(PAGE_STALE, &page->privat <<
757 test_and_set_bit(PAGE_CLAIMED, &pa <<
758 z3fold_page_unlock(zhdr); <<
759 return; <<
760 } <<
761 <<
762 if (!zhdr->foreign_handles && buddy_si <<
763 zhdr->mapped_count == 0 && compact <<
764 if (!put_z3fold_locked(zhdr)) <<
765 clear_bit(PAGE_CLAIMED <<
766 z3fold_page_unlock(zhd <<
767 } <<
768 return; 417 return;
769 } 418 }
770 419
771 z3fold_compact_page(zhdr); 420 z3fold_compact_page(zhdr);
772 add_to_unbuddied(pool, zhdr); !! 421 unbuddied = get_cpu_ptr(pool->unbuddied);
773 clear_bit(PAGE_CLAIMED, &page->private !! 422 fchunks = num_free_chunks(zhdr);
>> 423 if (fchunks < NCHUNKS &&
>> 424 (!zhdr->first_chunks || !zhdr->middle_chunks ||
>> 425 !zhdr->last_chunks)) {
>> 426 /* the page's not completely free and it's unbuddied */
>> 427 spin_lock(&pool->lock);
>> 428 list_add(&zhdr->buddy, &unbuddied[fchunks]);
>> 429 spin_unlock(&pool->lock);
>> 430 zhdr->cpu = smp_processor_id();
>> 431 }
>> 432 put_cpu_ptr(pool->unbuddied);
774 z3fold_page_unlock(zhdr); 433 z3fold_page_unlock(zhdr);
775 } 434 }
776 435
777 static void compact_page_work(struct work_stru 436 static void compact_page_work(struct work_struct *w)
778 { 437 {
779 struct z3fold_header *zhdr = container 438 struct z3fold_header *zhdr = container_of(w, struct z3fold_header,
780 439 work);
781 440
782 do_compact_page(zhdr, false); 441 do_compact_page(zhdr, false);
783 } 442 }
784 443
785 /* returns _locked_ z3fold page header or NULL <<
786 static inline struct z3fold_header *__z3fold_a <<
787 <<
788 { <<
789 struct z3fold_header *zhdr = NULL; <<
790 struct page *page; <<
791 struct list_head *unbuddied; <<
792 int chunks = size_to_chunks(size), i; <<
793 <<
794 lookup: <<
795 migrate_disable(); <<
796 /* First, try to find an unbuddied z3f <<
797 unbuddied = this_cpu_ptr(pool->unbuddi <<
798 for_each_unbuddied_list(i, chunks) { <<
799 struct list_head *l = &unbuddi <<
800 <<
801 zhdr = list_first_entry_or_nul <<
802 struct <<
803 <<
804 if (!zhdr) <<
805 continue; <<
806 <<
807 /* Re-check under lock. */ <<
808 spin_lock(&pool->lock); <<
809 if (unlikely(zhdr != list_firs <<
810 <<
811 !z3fold_page_trylock(zhdr) <<
812 spin_unlock(&pool->loc <<
813 zhdr = NULL; <<
814 migrate_enable(); <<
815 if (can_sleep) <<
816 cond_resched() <<
817 goto lookup; <<
818 } <<
819 list_del_init(&zhdr->buddy); <<
820 zhdr->cpu = -1; <<
821 spin_unlock(&pool->lock); <<
822 <<
823 page = virt_to_page(zhdr); <<
824 if (test_bit(NEEDS_COMPACTING, <<
825 test_bit(PAGE_CLAIMED, &pa <<
826 z3fold_page_unlock(zhd <<
827 zhdr = NULL; <<
828 migrate_enable(); <<
829 if (can_sleep) <<
830 cond_resched() <<
831 goto lookup; <<
832 } <<
833 <<
834 /* <<
835 * this page could not be remo <<
836 * list while pool lock was he <<
837 * page lock so kref_put could <<
838 * we got here, so it's safe t <<
839 */ <<
840 kref_get(&zhdr->refcount); <<
841 break; <<
842 } <<
843 migrate_enable(); <<
844 <<
845 if (!zhdr) { <<
846 int cpu; <<
847 <<
848 /* look for _exact_ match on o <<
849 for_each_online_cpu(cpu) { <<
850 struct list_head *l; <<
851 <<
852 unbuddied = per_cpu_pt <<
853 spin_lock(&pool->lock) <<
854 l = &unbuddied[chunks] <<
855 <<
856 zhdr = list_first_entr <<
857 <<
858 <<
859 if (!zhdr || !z3fold_p <<
860 spin_unlock(&p <<
861 zhdr = NULL; <<
862 continue; <<
863 } <<
864 list_del_init(&zhdr->b <<
865 zhdr->cpu = -1; <<
866 spin_unlock(&pool->loc <<
867 <<
868 page = virt_to_page(zh <<
869 if (test_bit(NEEDS_COM <<
870 test_bit(PAGE_CLAI <<
871 z3fold_page_un <<
872 zhdr = NULL; <<
873 if (can_sleep) <<
874 cond_r <<
875 continue; <<
876 } <<
877 kref_get(&zhdr->refcou <<
878 break; <<
879 } <<
880 } <<
881 <<
882 if (zhdr && !zhdr->slots) { <<
883 zhdr->slots = alloc_slots(pool <<
884 if (!zhdr->slots) <<
885 goto out_fail; <<
886 } <<
887 return zhdr; <<
888 <<
889 out_fail: <<
890 if (!put_z3fold_locked(zhdr)) { <<
891 add_to_unbuddied(pool, zhdr); <<
892 z3fold_page_unlock(zhdr); <<
893 } <<
894 return NULL; <<
895 } <<
896 444
897 /* 445 /*
898 * API Functions 446 * API Functions
899 */ 447 */
900 448
901 /** 449 /**
902 * z3fold_create_pool() - create a new z3fold 450 * z3fold_create_pool() - create a new z3fold pool
903 * @name: pool name 451 * @name: pool name
904 * @gfp: gfp flags when allocating the 452 * @gfp: gfp flags when allocating the z3fold pool structure
>> 453 * @ops: user-defined operations for the z3fold pool
905 * 454 *
906 * Return: pointer to the new z3fold pool or N 455 * Return: pointer to the new z3fold pool or NULL if the metadata allocation
907 * failed. 456 * failed.
908 */ 457 */
909 static struct z3fold_pool *z3fold_create_pool( !! 458 static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
>> 459 const struct z3fold_ops *ops)
910 { 460 {
911 struct z3fold_pool *pool = NULL; 461 struct z3fold_pool *pool = NULL;
912 int i, cpu; 462 int i, cpu;
913 463
914 pool = kzalloc(sizeof(struct z3fold_po 464 pool = kzalloc(sizeof(struct z3fold_pool), gfp);
915 if (!pool) 465 if (!pool)
916 goto out; 466 goto out;
917 pool->c_handle = kmem_cache_create("z3 <<
918 sizeof(struct <<
919 SLOTS_ALIGN, 0 <<
920 if (!pool->c_handle) <<
921 goto out_c; <<
922 spin_lock_init(&pool->lock); 467 spin_lock_init(&pool->lock);
923 spin_lock_init(&pool->stale_lock); 468 spin_lock_init(&pool->stale_lock);
924 pool->unbuddied = __alloc_percpu(sizeo !! 469 pool->unbuddied = __alloc_percpu(sizeof(struct list_head)*NCHUNKS, 2);
925 __ali <<
926 if (!pool->unbuddied) <<
927 goto out_pool; <<
928 for_each_possible_cpu(cpu) { 470 for_each_possible_cpu(cpu) {
929 struct list_head *unbuddied = 471 struct list_head *unbuddied =
930 per_cpu_ptr(po 472 per_cpu_ptr(pool->unbuddied, cpu);
931 for_each_unbuddied_list(i, 0) 473 for_each_unbuddied_list(i, 0)
932 INIT_LIST_HEAD(&unbudd 474 INIT_LIST_HEAD(&unbuddied[i]);
933 } 475 }
>> 476 INIT_LIST_HEAD(&pool->lru);
934 INIT_LIST_HEAD(&pool->stale); 477 INIT_LIST_HEAD(&pool->stale);
935 atomic64_set(&pool->pages_nr, 0); 478 atomic64_set(&pool->pages_nr, 0);
936 pool->name = name; 479 pool->name = name;
937 pool->compact_wq = create_singlethread 480 pool->compact_wq = create_singlethread_workqueue(pool->name);
938 if (!pool->compact_wq) 481 if (!pool->compact_wq)
939 goto out_unbuddied; !! 482 goto out;
940 pool->release_wq = create_singlethread 483 pool->release_wq = create_singlethread_workqueue(pool->name);
941 if (!pool->release_wq) 484 if (!pool->release_wq)
942 goto out_wq; 485 goto out_wq;
943 INIT_WORK(&pool->work, free_pages_work 486 INIT_WORK(&pool->work, free_pages_work);
>> 487 pool->ops = ops;
944 return pool; 488 return pool;
945 489
946 out_wq: 490 out_wq:
947 destroy_workqueue(pool->compact_wq); 491 destroy_workqueue(pool->compact_wq);
948 out_unbuddied: <<
949 free_percpu(pool->unbuddied); <<
950 out_pool: <<
951 kmem_cache_destroy(pool->c_handle); <<
952 out_c: <<
953 kfree(pool); <<
954 out: 492 out:
>> 493 kfree(pool);
955 return NULL; 494 return NULL;
956 } 495 }
957 496
958 /** 497 /**
959 * z3fold_destroy_pool() - destroys an existin 498 * z3fold_destroy_pool() - destroys an existing z3fold pool
960 * @pool: the z3fold pool to be destroye 499 * @pool: the z3fold pool to be destroyed
961 * 500 *
962 * The pool should be emptied before this func 501 * The pool should be emptied before this function is called.
963 */ 502 */
964 static void z3fold_destroy_pool(struct z3fold_ 503 static void z3fold_destroy_pool(struct z3fold_pool *pool)
965 { 504 {
966 kmem_cache_destroy(pool->c_handle); <<
967 <<
968 /* <<
969 * We need to destroy pool->compact_wq <<
970 * as any pending work on pool->compac <<
971 * queue_work(pool->release_wq, &pool- <<
972 * <<
973 * There are still outstanding pages u <<
974 * so we cannot unregister migration u <<
975 */ <<
976 <<
977 destroy_workqueue(pool->compact_wq); <<
978 destroy_workqueue(pool->release_wq); 505 destroy_workqueue(pool->release_wq);
979 free_percpu(pool->unbuddied); !! 506 destroy_workqueue(pool->compact_wq);
980 kfree(pool); 507 kfree(pool);
981 } 508 }
982 509
983 static const struct movable_operations z3fold_ <<
984 <<
985 /** 510 /**
986 * z3fold_alloc() - allocates a region of a gi 511 * z3fold_alloc() - allocates a region of a given size
987 * @pool: z3fold pool from which to allo 512 * @pool: z3fold pool from which to allocate
988 * @size: size in bytes of the desired a 513 * @size: size in bytes of the desired allocation
989 * @gfp: gfp flags used if the pool nee 514 * @gfp: gfp flags used if the pool needs to grow
990 * @handle: handle of the new allocation 515 * @handle: handle of the new allocation
991 * 516 *
992 * This function will attempt to find a free r 517 * This function will attempt to find a free region in the pool large enough to
993 * satisfy the allocation request. A search o 518 * satisfy the allocation request. A search of the unbuddied lists is
994 * performed first. If no suitable free region 519 * performed first. If no suitable free region is found, then a new page is
995 * allocated and added to the pool to satisfy 520 * allocated and added to the pool to satisfy the request.
996 * 521 *
>> 522 * gfp should not set __GFP_HIGHMEM as highmem pages cannot be used
>> 523 * as z3fold pool pages.
>> 524 *
997 * Return: 0 if success and handle is set, oth 525 * Return: 0 if success and handle is set, otherwise -EINVAL if the size or
998 * gfp arguments are invalid or -ENOMEM if the 526 * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate
999 * a new page. 527 * a new page.
1000 */ 528 */
1001 static int z3fold_alloc(struct z3fold_pool *p 529 static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
1002 unsigned long *handle 530 unsigned long *handle)
1003 { 531 {
1004 int chunks = size_to_chunks(size); !! 532 int chunks = 0, i, freechunks;
1005 struct z3fold_header *zhdr = NULL; 533 struct z3fold_header *zhdr = NULL;
1006 struct page *page = NULL; 534 struct page *page = NULL;
1007 enum buddy bud; 535 enum buddy bud;
1008 bool can_sleep = gfpflags_allow_block !! 536 bool can_sleep = (gfp & __GFP_RECLAIM) == __GFP_RECLAIM;
1009 537
1010 if (!size || (gfp & __GFP_HIGHMEM)) 538 if (!size || (gfp & __GFP_HIGHMEM))
1011 return -EINVAL; 539 return -EINVAL;
1012 540
1013 if (size > PAGE_SIZE) 541 if (size > PAGE_SIZE)
1014 return -ENOSPC; 542 return -ENOSPC;
1015 543
1016 if (size > PAGE_SIZE - ZHDR_SIZE_ALIG 544 if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE)
1017 bud = HEADLESS; 545 bud = HEADLESS;
1018 else { 546 else {
1019 retry: !! 547 struct list_head *unbuddied;
1020 zhdr = __z3fold_alloc(pool, s !! 548 chunks = size_to_chunks(size);
>> 549
>> 550 lookup:
>> 551 /* First, try to find an unbuddied z3fold page. */
>> 552 unbuddied = get_cpu_ptr(pool->unbuddied);
>> 553 for_each_unbuddied_list(i, chunks) {
>> 554 struct list_head *l = &unbuddied[i];
>> 555
>> 556 zhdr = list_first_entry_or_null(READ_ONCE(l),
>> 557 struct z3fold_header, buddy);
>> 558
>> 559 if (!zhdr)
>> 560 continue;
>> 561
>> 562 /* Re-check under lock. */
>> 563 spin_lock(&pool->lock);
>> 564 l = &unbuddied[i];
>> 565 if (unlikely(zhdr != list_first_entry(READ_ONCE(l),
>> 566 struct z3fold_header, buddy)) ||
>> 567 !z3fold_page_trylock(zhdr)) {
>> 568 spin_unlock(&pool->lock);
>> 569 put_cpu_ptr(pool->unbuddied);
>> 570 goto lookup;
>> 571 }
>> 572 list_del_init(&zhdr->buddy);
>> 573 zhdr->cpu = -1;
>> 574 spin_unlock(&pool->lock);
>> 575
>> 576 page = virt_to_page(zhdr);
>> 577 if (test_bit(NEEDS_COMPACTING, &page->private)) {
>> 578 z3fold_page_unlock(zhdr);
>> 579 zhdr = NULL;
>> 580 put_cpu_ptr(pool->unbuddied);
>> 581 if (can_sleep)
>> 582 cond_resched();
>> 583 goto lookup;
>> 584 }
>> 585
>> 586 /*
>> 587 * this page could not be removed from its unbuddied
>> 588 * list while pool lock was held, and then we've taken
>> 589 * page lock so kref_put could not be called before
>> 590 * we got here, so it's safe to just call kref_get()
>> 591 */
>> 592 kref_get(&zhdr->refcount);
>> 593 break;
>> 594 }
>> 595 put_cpu_ptr(pool->unbuddied);
>> 596
1021 if (zhdr) { 597 if (zhdr) {
1022 bud = get_free_buddy( !! 598 if (zhdr->first_chunks == 0) {
1023 if (bud == HEADLESS) !! 599 if (zhdr->middle_chunks != 0 &&
1024 if (!put_z3fo !! 600 chunks >= zhdr->start_middle)
>> 601 bud = LAST;
>> 602 else
>> 603 bud = FIRST;
>> 604 } else if (zhdr->last_chunks == 0)
>> 605 bud = LAST;
>> 606 else if (zhdr->middle_chunks == 0)
>> 607 bud = MIDDLE;
>> 608 else {
>> 609 if (kref_put(&zhdr->refcount,
>> 610 release_z3fold_page_locked))
>> 611 atomic64_dec(&pool->pages_nr);
>> 612 else
1025 z3fol 613 z3fold_page_unlock(zhdr);
1026 pr_err("No fr 614 pr_err("No free chunks in unbuddied\n");
1027 WARN_ON(1); 615 WARN_ON(1);
1028 goto retry; !! 616 goto lookup;
1029 } 617 }
1030 page = virt_to_page(z <<
1031 goto found; 618 goto found;
1032 } 619 }
1033 bud = FIRST; 620 bud = FIRST;
1034 } 621 }
1035 622
1036 page = alloc_page(gfp); !! 623 spin_lock(&pool->stale_lock);
>> 624 zhdr = list_first_entry_or_null(&pool->stale,
>> 625 struct z3fold_header, buddy);
>> 626 /*
>> 627 * Before allocating a page, let's see if we can take one from the
>> 628 * stale pages list. cancel_work_sync() can sleep so we must make
>> 629 * sure it won't be called in case we're in atomic context.
>> 630 */
>> 631 if (zhdr && (can_sleep || !work_pending(&zhdr->work))) {
>> 632 list_del(&zhdr->buddy);
>> 633 spin_unlock(&pool->stale_lock);
>> 634 if (can_sleep)
>> 635 cancel_work_sync(&zhdr->work);
>> 636 page = virt_to_page(zhdr);
>> 637 } else {
>> 638 spin_unlock(&pool->stale_lock);
>> 639 page = alloc_page(gfp);
>> 640 }
>> 641
1037 if (!page) 642 if (!page)
1038 return -ENOMEM; 643 return -ENOMEM;
1039 644
1040 zhdr = init_z3fold_page(page, bud == <<
1041 if (!zhdr) { <<
1042 __free_page(page); <<
1043 return -ENOMEM; <<
1044 } <<
1045 atomic64_inc(&pool->pages_nr); 645 atomic64_inc(&pool->pages_nr);
>> 646 zhdr = init_z3fold_page(page, pool);
1046 647
1047 if (bud == HEADLESS) { 648 if (bud == HEADLESS) {
1048 set_bit(PAGE_HEADLESS, &page- 649 set_bit(PAGE_HEADLESS, &page->private);
1049 goto headless; 650 goto headless;
1050 } 651 }
1051 if (can_sleep) { <<
1052 lock_page(page); <<
1053 __SetPageMovable(page, &z3fol <<
1054 unlock_page(page); <<
1055 } else { <<
1056 WARN_ON(!trylock_page(page)); <<
1057 __SetPageMovable(page, &z3fol <<
1058 unlock_page(page); <<
1059 } <<
1060 z3fold_page_lock(zhdr); 652 z3fold_page_lock(zhdr);
1061 653
1062 found: 654 found:
1063 if (bud == FIRST) 655 if (bud == FIRST)
1064 zhdr->first_chunks = chunks; 656 zhdr->first_chunks = chunks;
1065 else if (bud == LAST) 657 else if (bud == LAST)
1066 zhdr->last_chunks = chunks; 658 zhdr->last_chunks = chunks;
1067 else { 659 else {
1068 zhdr->middle_chunks = chunks; 660 zhdr->middle_chunks = chunks;
1069 zhdr->start_middle = zhdr->fi 661 zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS;
1070 } 662 }
1071 add_to_unbuddied(pool, zhdr); !! 663
>> 664 if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 ||
>> 665 zhdr->middle_chunks == 0) {
>> 666 struct list_head *unbuddied = get_cpu_ptr(pool->unbuddied);
>> 667
>> 668 /* Add to unbuddied list */
>> 669 freechunks = num_free_chunks(zhdr);
>> 670 spin_lock(&pool->lock);
>> 671 list_add(&zhdr->buddy, &unbuddied[freechunks]);
>> 672 spin_unlock(&pool->lock);
>> 673 zhdr->cpu = smp_processor_id();
>> 674 put_cpu_ptr(pool->unbuddied);
>> 675 }
1072 676
1073 headless: 677 headless:
1074 spin_lock(&pool->lock); 678 spin_lock(&pool->lock);
>> 679 /* Add/move z3fold page to beginning of LRU */
>> 680 if (!list_empty(&page->lru))
>> 681 list_del(&page->lru);
>> 682
>> 683 list_add(&page->lru, &pool->lru);
>> 684
1075 *handle = encode_handle(zhdr, bud); 685 *handle = encode_handle(zhdr, bud);
1076 spin_unlock(&pool->lock); 686 spin_unlock(&pool->lock);
1077 if (bud != HEADLESS) 687 if (bud != HEADLESS)
1078 z3fold_page_unlock(zhdr); 688 z3fold_page_unlock(zhdr);
1079 689
1080 return 0; 690 return 0;
1081 } 691 }
1082 692
1083 /** 693 /**
1084 * z3fold_free() - frees the allocation assoc 694 * z3fold_free() - frees the allocation associated with the given handle
1085 * @pool: pool in which the allocation 695 * @pool: pool in which the allocation resided
1086 * @handle: handle associated with the al 696 * @handle: handle associated with the allocation returned by z3fold_alloc()
1087 * 697 *
1088 * In the case that the z3fold page in which 698 * In the case that the z3fold page in which the allocation resides is under
1089 * reclaim, as indicated by the PAGE_CLAIMED !! 699 * reclaim, as indicated by the PG_reclaim flag being set, this function
1090 * only sets the first|middle|last_chunks to !! 700 * only sets the first|last_chunks to 0. The page is actually freed
1091 * once all buddies are evicted (see z3fold_r !! 701 * once both buddies are evicted (see z3fold_reclaim_page() below).
1092 */ 702 */
1093 static void z3fold_free(struct z3fold_pool *p 703 static void z3fold_free(struct z3fold_pool *pool, unsigned long handle)
1094 { 704 {
1095 struct z3fold_header *zhdr; 705 struct z3fold_header *zhdr;
1096 struct page *page; 706 struct page *page;
1097 enum buddy bud; 707 enum buddy bud;
1098 bool page_claimed; <<
1099 708
1100 zhdr = get_z3fold_header(handle); !! 709 zhdr = handle_to_z3fold_header(handle);
1101 page = virt_to_page(zhdr); 710 page = virt_to_page(zhdr);
1102 page_claimed = test_and_set_bit(PAGE_ <<
1103 711
1104 if (test_bit(PAGE_HEADLESS, &page->pr 712 if (test_bit(PAGE_HEADLESS, &page->private)) {
1105 /* if a headless page is unde !! 713 /* HEADLESS page stored */
1106 * NB: we use test_and_set_bi !! 714 bud = HEADLESS;
1107 * has not been set before, w !! 715 } else {
1108 * immediately so we don't ca !! 716 z3fold_page_lock(zhdr);
1109 */ !! 717 bud = handle_to_buddy(handle);
1110 if (!page_claimed) { !! 718
1111 put_z3fold_header(zhd !! 719 switch (bud) {
1112 free_z3fold_page(page !! 720 case FIRST:
1113 atomic64_dec(&pool->p !! 721 zhdr->first_chunks = 0;
>> 722 break;
>> 723 case MIDDLE:
>> 724 zhdr->middle_chunks = 0;
>> 725 zhdr->start_middle = 0;
>> 726 break;
>> 727 case LAST:
>> 728 zhdr->last_chunks = 0;
>> 729 break;
>> 730 default:
>> 731 pr_err("%s: unknown bud %d\n", __func__, bud);
>> 732 WARN_ON(1);
>> 733 z3fold_page_unlock(zhdr);
>> 734 return;
1114 } 735 }
1115 return; <<
1116 } 736 }
1117 737
1118 /* Non-headless case */ !! 738 if (bud == HEADLESS) {
1119 bud = handle_to_buddy(handle); !! 739 spin_lock(&pool->lock);
1120 !! 740 list_del(&page->lru);
1121 switch (bud) { !! 741 spin_unlock(&pool->lock);
1122 case FIRST: !! 742 free_z3fold_page(page);
1123 zhdr->first_chunks = 0; !! 743 atomic64_dec(&pool->pages_nr);
1124 break; <<
1125 case MIDDLE: <<
1126 zhdr->middle_chunks = 0; <<
1127 break; <<
1128 case LAST: <<
1129 zhdr->last_chunks = 0; <<
1130 break; <<
1131 default: <<
1132 pr_err("%s: unknown bud %d\n" <<
1133 WARN_ON(1); <<
1134 put_z3fold_header(zhdr); <<
1135 return; 744 return;
1136 } 745 }
1137 746
1138 if (!page_claimed) !! 747 if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) {
1139 free_handle(handle, zhdr); !! 748 atomic64_dec(&pool->pages_nr);
1140 if (put_z3fold_locked_list(zhdr)) <<
1141 return; <<
1142 if (page_claimed) { <<
1143 /* the page has not been clai <<
1144 put_z3fold_header(zhdr); <<
1145 return; 749 return;
1146 } 750 }
1147 if (test_and_set_bit(NEEDS_COMPACTING 751 if (test_and_set_bit(NEEDS_COMPACTING, &page->private)) {
1148 clear_bit(PAGE_CLAIMED, &page !! 752 z3fold_page_unlock(zhdr);
1149 put_z3fold_header(zhdr); <<
1150 return; 753 return;
1151 } 754 }
1152 if (zhdr->cpu < 0 || !cpu_online(zhdr 755 if (zhdr->cpu < 0 || !cpu_online(zhdr->cpu)) {
>> 756 spin_lock(&pool->lock);
>> 757 list_del_init(&zhdr->buddy);
>> 758 spin_unlock(&pool->lock);
1153 zhdr->cpu = -1; 759 zhdr->cpu = -1;
1154 kref_get(&zhdr->refcount); 760 kref_get(&zhdr->refcount);
1155 clear_bit(PAGE_CLAIMED, &page <<
1156 do_compact_page(zhdr, true); 761 do_compact_page(zhdr, true);
1157 return; 762 return;
1158 } 763 }
1159 kref_get(&zhdr->refcount); 764 kref_get(&zhdr->refcount);
1160 clear_bit(PAGE_CLAIMED, &page->privat <<
1161 queue_work_on(zhdr->cpu, pool->compac 765 queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work);
1162 put_z3fold_header(zhdr); !! 766 z3fold_page_unlock(zhdr);
>> 767 }
>> 768
>> 769 /**
>> 770 * z3fold_reclaim_page() - evicts allocations from a pool page and frees it
>> 771 * @pool: pool from which a page will attempt to be evicted
>> 772 * @retires: number of pages on the LRU list for which eviction will
>> 773 * be attempted before failing
>> 774 *
>> 775 * z3fold reclaim is different from normal system reclaim in that it is done
>> 776 * from the bottom, up. This is because only the bottom layer, z3fold, has
>> 777 * information on how the allocations are organized within each z3fold page.
>> 778 * This has the potential to create interesting locking situations between
>> 779 * z3fold and the user, however.
>> 780 *
>> 781 * To avoid these, this is how z3fold_reclaim_page() should be called:
>> 782
>> 783 * The user detects a page should be reclaimed and calls z3fold_reclaim_page().
>> 784 * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and
>> 785 * call the user-defined eviction handler with the pool and handle as
>> 786 * arguments.
>> 787 *
>> 788 * If the handle can not be evicted, the eviction handler should return
>> 789 * non-zero. z3fold_reclaim_page() will add the z3fold page back to the
>> 790 * appropriate list and try the next z3fold page on the LRU up to
>> 791 * a user defined number of retries.
>> 792 *
>> 793 * If the handle is successfully evicted, the eviction handler should
>> 794 * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free()
>> 795 * contains logic to delay freeing the page if the page is under reclaim,
>> 796 * as indicated by the setting of the PG_reclaim flag on the underlying page.
>> 797 *
>> 798 * If all buddies in the z3fold page are successfully evicted, then the
>> 799 * z3fold page can be freed.
>> 800 *
>> 801 * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are
>> 802 * no pages to evict or an eviction handler is not registered, -EAGAIN if
>> 803 * the retry limit was hit.
>> 804 */
>> 805 static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
>> 806 {
>> 807 int i, ret = 0;
>> 808 struct z3fold_header *zhdr = NULL;
>> 809 struct page *page = NULL;
>> 810 struct list_head *pos;
>> 811 unsigned long first_handle = 0, middle_handle = 0, last_handle = 0;
>> 812
>> 813 spin_lock(&pool->lock);
>> 814 if (!pool->ops || !pool->ops->evict || retries == 0) {
>> 815 spin_unlock(&pool->lock);
>> 816 return -EINVAL;
>> 817 }
>> 818 for (i = 0; i < retries; i++) {
>> 819 if (list_empty(&pool->lru)) {
>> 820 spin_unlock(&pool->lock);
>> 821 return -EINVAL;
>> 822 }
>> 823 list_for_each_prev(pos, &pool->lru) {
>> 824 page = list_entry(pos, struct page, lru);
>> 825 if (test_bit(PAGE_HEADLESS, &page->private))
>> 826 /* candidate found */
>> 827 break;
>> 828
>> 829 zhdr = page_address(page);
>> 830 if (!z3fold_page_trylock(zhdr))
>> 831 continue; /* can't evict at this point */
>> 832 kref_get(&zhdr->refcount);
>> 833 list_del_init(&zhdr->buddy);
>> 834 zhdr->cpu = -1;
>> 835 }
>> 836
>> 837 list_del_init(&page->lru);
>> 838 spin_unlock(&pool->lock);
>> 839
>> 840 if (!test_bit(PAGE_HEADLESS, &page->private)) {
>> 841 /*
>> 842 * We need encode the handles before unlocking, since
>> 843 * we can race with free that will set
>> 844 * (first|last)_chunks to 0
>> 845 */
>> 846 first_handle = 0;
>> 847 last_handle = 0;
>> 848 middle_handle = 0;
>> 849 if (zhdr->first_chunks)
>> 850 first_handle = encode_handle(zhdr, FIRST);
>> 851 if (zhdr->middle_chunks)
>> 852 middle_handle = encode_handle(zhdr, MIDDLE);
>> 853 if (zhdr->last_chunks)
>> 854 last_handle = encode_handle(zhdr, LAST);
>> 855 /*
>> 856 * it's safe to unlock here because we hold a
>> 857 * reference to this page
>> 858 */
>> 859 z3fold_page_unlock(zhdr);
>> 860 } else {
>> 861 first_handle = encode_handle(zhdr, HEADLESS);
>> 862 last_handle = middle_handle = 0;
>> 863 }
>> 864
>> 865 /* Issue the eviction callback(s) */
>> 866 if (middle_handle) {
>> 867 ret = pool->ops->evict(pool, middle_handle);
>> 868 if (ret)
>> 869 goto next;
>> 870 }
>> 871 if (first_handle) {
>> 872 ret = pool->ops->evict(pool, first_handle);
>> 873 if (ret)
>> 874 goto next;
>> 875 }
>> 876 if (last_handle) {
>> 877 ret = pool->ops->evict(pool, last_handle);
>> 878 if (ret)
>> 879 goto next;
>> 880 }
>> 881 next:
>> 882 spin_lock(&pool->lock);
>> 883 if (test_bit(PAGE_HEADLESS, &page->private)) {
>> 884 if (ret == 0) {
>> 885 spin_unlock(&pool->lock);
>> 886 free_z3fold_page(page);
>> 887 return 0;
>> 888 }
>> 889 } else if (kref_put(&zhdr->refcount, release_z3fold_page)) {
>> 890 atomic64_dec(&pool->pages_nr);
>> 891 spin_unlock(&pool->lock);
>> 892 return 0;
>> 893 }
>> 894
>> 895 /*
>> 896 * Add to the beginning of LRU.
>> 897 * Pool lock has to be kept here to ensure the page has
>> 898 * not already been released
>> 899 */
>> 900 list_add(&page->lru, &pool->lru);
>> 901 }
>> 902 spin_unlock(&pool->lock);
>> 903 return -EAGAIN;
1163 } 904 }
1164 905
1165 /** 906 /**
1166 * z3fold_map() - maps the allocation associa 907 * z3fold_map() - maps the allocation associated with the given handle
1167 * @pool: pool in which the allocation 908 * @pool: pool in which the allocation resides
1168 * @handle: handle associated with the al 909 * @handle: handle associated with the allocation to be mapped
1169 * 910 *
1170 * Extracts the buddy number from handle and 911 * Extracts the buddy number from handle and constructs the pointer to the
1171 * correct starting chunk within the page. 912 * correct starting chunk within the page.
1172 * 913 *
1173 * Returns: a pointer to the mapped allocatio 914 * Returns: a pointer to the mapped allocation
1174 */ 915 */
1175 static void *z3fold_map(struct z3fold_pool *p 916 static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle)
1176 { 917 {
1177 struct z3fold_header *zhdr; 918 struct z3fold_header *zhdr;
1178 struct page *page; 919 struct page *page;
1179 void *addr; 920 void *addr;
1180 enum buddy buddy; 921 enum buddy buddy;
1181 922
1182 zhdr = get_z3fold_header(handle); !! 923 zhdr = handle_to_z3fold_header(handle);
1183 addr = zhdr; 924 addr = zhdr;
1184 page = virt_to_page(zhdr); 925 page = virt_to_page(zhdr);
1185 926
1186 if (test_bit(PAGE_HEADLESS, &page->pr 927 if (test_bit(PAGE_HEADLESS, &page->private))
1187 goto out; 928 goto out;
1188 929
>> 930 z3fold_page_lock(zhdr);
1189 buddy = handle_to_buddy(handle); 931 buddy = handle_to_buddy(handle);
1190 switch (buddy) { 932 switch (buddy) {
1191 case FIRST: 933 case FIRST:
1192 addr += ZHDR_SIZE_ALIGNED; 934 addr += ZHDR_SIZE_ALIGNED;
1193 break; 935 break;
1194 case MIDDLE: 936 case MIDDLE:
1195 addr += zhdr->start_middle << 937 addr += zhdr->start_middle << CHUNK_SHIFT;
1196 set_bit(MIDDLE_CHUNK_MAPPED, 938 set_bit(MIDDLE_CHUNK_MAPPED, &page->private);
1197 break; 939 break;
1198 case LAST: 940 case LAST:
1199 addr += PAGE_SIZE - (handle_t !! 941 addr += PAGE_SIZE - (zhdr->last_chunks << CHUNK_SHIFT);
1200 break; 942 break;
1201 default: 943 default:
1202 pr_err("unknown buddy id %d\n 944 pr_err("unknown buddy id %d\n", buddy);
1203 WARN_ON(1); 945 WARN_ON(1);
1204 addr = NULL; 946 addr = NULL;
1205 break; 947 break;
1206 } 948 }
1207 949
1208 if (addr) !! 950 z3fold_page_unlock(zhdr);
1209 zhdr->mapped_count++; <<
1210 out: 951 out:
1211 put_z3fold_header(zhdr); <<
1212 return addr; 952 return addr;
1213 } 953 }
1214 954
1215 /** 955 /**
1216 * z3fold_unmap() - unmaps the allocation ass 956 * z3fold_unmap() - unmaps the allocation associated with the given handle
1217 * @pool: pool in which the allocation 957 * @pool: pool in which the allocation resides
1218 * @handle: handle associated with the al 958 * @handle: handle associated with the allocation to be unmapped
1219 */ 959 */
1220 static void z3fold_unmap(struct z3fold_pool * 960 static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle)
1221 { 961 {
1222 struct z3fold_header *zhdr; 962 struct z3fold_header *zhdr;
1223 struct page *page; 963 struct page *page;
1224 enum buddy buddy; 964 enum buddy buddy;
1225 965
1226 zhdr = get_z3fold_header(handle); !! 966 zhdr = handle_to_z3fold_header(handle);
1227 page = virt_to_page(zhdr); 967 page = virt_to_page(zhdr);
1228 968
1229 if (test_bit(PAGE_HEADLESS, &page->pr 969 if (test_bit(PAGE_HEADLESS, &page->private))
1230 return; 970 return;
1231 971
>> 972 z3fold_page_lock(zhdr);
1232 buddy = handle_to_buddy(handle); 973 buddy = handle_to_buddy(handle);
1233 if (buddy == MIDDLE) 974 if (buddy == MIDDLE)
1234 clear_bit(MIDDLE_CHUNK_MAPPED 975 clear_bit(MIDDLE_CHUNK_MAPPED, &page->private);
1235 zhdr->mapped_count--; !! 976 z3fold_page_unlock(zhdr);
1236 put_z3fold_header(zhdr); <<
1237 } 977 }
1238 978
1239 /** 979 /**
1240 * z3fold_get_pool_pages() - gets the z3fold !! 980 * z3fold_get_pool_size() - gets the z3fold pool size in pages
1241 * @pool: pool whose size is being quer 981 * @pool: pool whose size is being queried
1242 * 982 *
1243 * Returns: size in pages of the given pool. 983 * Returns: size in pages of the given pool.
1244 */ 984 */
1245 static u64 z3fold_get_pool_pages(struct z3fol !! 985 static u64 z3fold_get_pool_size(struct z3fold_pool *pool)
1246 { 986 {
1247 return atomic64_read(&pool->pages_nr) 987 return atomic64_read(&pool->pages_nr);
1248 } 988 }
1249 989
1250 static bool z3fold_page_isolate(struct page * !! 990 /*****************
1251 { !! 991 * zpool
1252 struct z3fold_header *zhdr; !! 992 ****************/
1253 struct z3fold_pool *pool; <<
1254 <<
1255 VM_BUG_ON_PAGE(PageIsolated(page), pa <<
1256 <<
1257 if (test_bit(PAGE_HEADLESS, &page->pr <<
1258 return false; <<
1259 <<
1260 zhdr = page_address(page); <<
1261 z3fold_page_lock(zhdr); <<
1262 if (test_bit(NEEDS_COMPACTING, &page- <<
1263 test_bit(PAGE_STALE, &page->priva <<
1264 goto out; <<
1265 <<
1266 if (zhdr->mapped_count != 0 || zhdr-> <<
1267 goto out; <<
1268 <<
1269 if (test_and_set_bit(PAGE_CLAIMED, &p <<
1270 goto out; <<
1271 pool = zhdr_to_pool(zhdr); <<
1272 spin_lock(&pool->lock); <<
1273 if (!list_empty(&zhdr->buddy)) <<
1274 list_del_init(&zhdr->buddy); <<
1275 spin_unlock(&pool->lock); <<
1276 <<
1277 kref_get(&zhdr->refcount); <<
1278 z3fold_page_unlock(zhdr); <<
1279 return true; <<
1280 <<
1281 out: <<
1282 z3fold_page_unlock(zhdr); <<
1283 return false; <<
1284 } <<
1285 <<
1286 static int z3fold_page_migrate(struct page *n <<
1287 enum migrate_mode mode) <<
1288 { <<
1289 struct z3fold_header *zhdr, *new_zhdr <<
1290 struct z3fold_pool *pool; <<
1291 <<
1292 VM_BUG_ON_PAGE(!PageIsolated(page), p <<
1293 VM_BUG_ON_PAGE(!test_bit(PAGE_CLAIMED <<
1294 VM_BUG_ON_PAGE(!PageLocked(newpage), <<
1295 <<
1296 zhdr = page_address(page); <<
1297 pool = zhdr_to_pool(zhdr); <<
1298 <<
1299 if (!z3fold_page_trylock(zhdr)) <<
1300 return -EAGAIN; <<
1301 if (zhdr->mapped_count != 0 || zhdr-> <<
1302 clear_bit(PAGE_CLAIMED, &page <<
1303 z3fold_page_unlock(zhdr); <<
1304 return -EBUSY; <<
1305 } <<
1306 if (work_pending(&zhdr->work)) { <<
1307 z3fold_page_unlock(zhdr); <<
1308 return -EAGAIN; <<
1309 } <<
1310 new_zhdr = page_address(newpage); <<
1311 memcpy(new_zhdr, zhdr, PAGE_SIZE); <<
1312 newpage->private = page->private; <<
1313 set_bit(PAGE_MIGRATED, &page->private <<
1314 z3fold_page_unlock(zhdr); <<
1315 spin_lock_init(&new_zhdr->page_lock); <<
1316 INIT_WORK(&new_zhdr->work, compact_pa <<
1317 /* <<
1318 * z3fold_page_isolate() ensures that <<
1319 * so we only have to reinitialize it <<
1320 */ <<
1321 INIT_LIST_HEAD(&new_zhdr->buddy); <<
1322 __ClearPageMovable(page); <<
1323 <<
1324 get_page(newpage); <<
1325 z3fold_page_lock(new_zhdr); <<
1326 if (new_zhdr->first_chunks) <<
1327 encode_handle(new_zhdr, FIRST <<
1328 if (new_zhdr->last_chunks) <<
1329 encode_handle(new_zhdr, LAST) <<
1330 if (new_zhdr->middle_chunks) <<
1331 encode_handle(new_zhdr, MIDDL <<
1332 set_bit(NEEDS_COMPACTING, &newpage->p <<
1333 new_zhdr->cpu = smp_processor_id(); <<
1334 __SetPageMovable(newpage, &z3fold_mop <<
1335 z3fold_page_unlock(new_zhdr); <<
1336 <<
1337 queue_work_on(new_zhdr->cpu, pool->co <<
1338 <<
1339 /* PAGE_CLAIMED and PAGE_MIGRATED are <<
1340 page->private = 0; <<
1341 put_page(page); <<
1342 return 0; <<
1343 } <<
1344 993
1345 static void z3fold_page_putback(struct page * !! 994 static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle)
1346 { 995 {
1347 struct z3fold_header *zhdr; !! 996 if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
1348 struct z3fold_pool *pool; !! 997 return pool->zpool_ops->evict(pool->zpool, handle);
1349 !! 998 else
1350 zhdr = page_address(page); !! 999 return -ENOENT;
1351 pool = zhdr_to_pool(zhdr); <<
1352 <<
1353 z3fold_page_lock(zhdr); <<
1354 if (!list_empty(&zhdr->buddy)) <<
1355 list_del_init(&zhdr->buddy); <<
1356 INIT_LIST_HEAD(&page->lru); <<
1357 if (put_z3fold_locked(zhdr)) <<
1358 return; <<
1359 if (list_empty(&zhdr->buddy)) <<
1360 add_to_unbuddied(pool, zhdr); <<
1361 clear_bit(PAGE_CLAIMED, &page->privat <<
1362 z3fold_page_unlock(zhdr); <<
1363 } 1000 }
1364 1001
1365 static const struct movable_operations z3fold !! 1002 static const struct z3fold_ops z3fold_zpool_ops = {
1366 .isolate_page = z3fold_page_isolate, !! 1003 .evict = z3fold_zpool_evict
1367 .migrate_page = z3fold_page_migrate, <<
1368 .putback_page = z3fold_page_putback, <<
1369 }; 1004 };
1370 1005
1371 /***************** !! 1006 static void *z3fold_zpool_create(const char *name, gfp_t gfp,
1372 * zpool !! 1007 const struct zpool_ops *zpool_ops,
1373 ****************/ !! 1008 struct zpool *zpool)
1374 <<
1375 static void *z3fold_zpool_create(const char * <<
1376 { 1009 {
1377 return z3fold_create_pool(name, gfp); !! 1010 struct z3fold_pool *pool;
>> 1011
>> 1012 pool = z3fold_create_pool(name, gfp,
>> 1013 zpool_ops ? &z3fold_zpool_ops : NULL);
>> 1014 if (pool) {
>> 1015 pool->zpool = zpool;
>> 1016 pool->zpool_ops = zpool_ops;
>> 1017 }
>> 1018 return pool;
1378 } 1019 }
1379 1020
1380 static void z3fold_zpool_destroy(void *pool) 1021 static void z3fold_zpool_destroy(void *pool)
1381 { 1022 {
1382 z3fold_destroy_pool(pool); 1023 z3fold_destroy_pool(pool);
1383 } 1024 }
1384 1025
1385 static int z3fold_zpool_malloc(void *pool, si 1026 static int z3fold_zpool_malloc(void *pool, size_t size, gfp_t gfp,
1386 unsigned long *handle 1027 unsigned long *handle)
1387 { 1028 {
1388 return z3fold_alloc(pool, size, gfp, 1029 return z3fold_alloc(pool, size, gfp, handle);
1389 } 1030 }
1390 static void z3fold_zpool_free(void *pool, uns 1031 static void z3fold_zpool_free(void *pool, unsigned long handle)
1391 { 1032 {
1392 z3fold_free(pool, handle); 1033 z3fold_free(pool, handle);
1393 } 1034 }
1394 1035
>> 1036 static int z3fold_zpool_shrink(void *pool, unsigned int pages,
>> 1037 unsigned int *reclaimed)
>> 1038 {
>> 1039 unsigned int total = 0;
>> 1040 int ret = -EINVAL;
>> 1041
>> 1042 while (total < pages) {
>> 1043 ret = z3fold_reclaim_page(pool, 8);
>> 1044 if (ret < 0)
>> 1045 break;
>> 1046 total++;
>> 1047 }
>> 1048
>> 1049 if (reclaimed)
>> 1050 *reclaimed = total;
>> 1051
>> 1052 return ret;
>> 1053 }
>> 1054
1395 static void *z3fold_zpool_map(void *pool, uns 1055 static void *z3fold_zpool_map(void *pool, unsigned long handle,
1396 enum zpool_mapmode mm 1056 enum zpool_mapmode mm)
1397 { 1057 {
1398 return z3fold_map(pool, handle); 1058 return z3fold_map(pool, handle);
1399 } 1059 }
1400 static void z3fold_zpool_unmap(void *pool, un 1060 static void z3fold_zpool_unmap(void *pool, unsigned long handle)
1401 { 1061 {
1402 z3fold_unmap(pool, handle); 1062 z3fold_unmap(pool, handle);
1403 } 1063 }
1404 1064
1405 static u64 z3fold_zpool_total_pages(void *poo !! 1065 static u64 z3fold_zpool_total_size(void *pool)
1406 { 1066 {
1407 return z3fold_get_pool_pages(pool); !! 1067 return z3fold_get_pool_size(pool) * PAGE_SIZE;
1408 } 1068 }
1409 1069
1410 static struct zpool_driver z3fold_zpool_drive 1070 static struct zpool_driver z3fold_zpool_driver = {
1411 .type = "z3fold", 1071 .type = "z3fold",
1412 .sleep_mapped = true, <<
1413 .owner = THIS_MODULE, 1072 .owner = THIS_MODULE,
1414 .create = z3fold_zpool_create, 1073 .create = z3fold_zpool_create,
1415 .destroy = z3fold_zpool_destroy, 1074 .destroy = z3fold_zpool_destroy,
1416 .malloc = z3fold_zpool_malloc, 1075 .malloc = z3fold_zpool_malloc,
1417 .free = z3fold_zpool_free, 1076 .free = z3fold_zpool_free,
>> 1077 .shrink = z3fold_zpool_shrink,
1418 .map = z3fold_zpool_map, 1078 .map = z3fold_zpool_map,
1419 .unmap = z3fold_zpool_unmap, 1079 .unmap = z3fold_zpool_unmap,
1420 .total_pages = z3fold_zpool_total_pa !! 1080 .total_size = z3fold_zpool_total_size,
1421 }; 1081 };
1422 1082
1423 MODULE_ALIAS("zpool-z3fold"); 1083 MODULE_ALIAS("zpool-z3fold");
1424 1084
1425 static int __init init_z3fold(void) 1085 static int __init init_z3fold(void)
1426 { 1086 {
1427 /* !! 1087 /* Make sure the z3fold header is not larger than the page size */
1428 * Make sure the z3fold header is not !! 1088 BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE_SIZE);
1429 * there has remaining spaces for its <<
1430 */ <<
1431 BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE <<
1432 zpool_register_driver(&z3fold_zpool_d 1089 zpool_register_driver(&z3fold_zpool_driver);
1433 1090
1434 return 0; 1091 return 0;
1435 } 1092 }
1436 1093
1437 static void __exit exit_z3fold(void) 1094 static void __exit exit_z3fold(void)
1438 { 1095 {
1439 zpool_unregister_driver(&z3fold_zpool 1096 zpool_unregister_driver(&z3fold_zpool_driver);
1440 } 1097 }
1441 1098
1442 module_init(init_z3fold); 1099 module_init(init_z3fold);
1443 module_exit(exit_z3fold); 1100 module_exit(exit_z3fold);
1444 1101
1445 MODULE_LICENSE("GPL"); 1102 MODULE_LICENSE("GPL");
1446 MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail. 1103 MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail.com>");
1447 MODULE_DESCRIPTION("3-Fold Allocator for Comp 1104 MODULE_DESCRIPTION("3-Fold Allocator for Compressed Pages");
1448 1105
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