109c434b8SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 29a001fc1SVitaly Wool /* 39a001fc1SVitaly Wool * z3fold.c 49a001fc1SVitaly Wool * 59a001fc1SVitaly Wool * Author: Vitaly Wool <vitaly.wool@konsulko.com> 69a001fc1SVitaly Wool * Copyright (C) 2016, Sony Mobile Communications Inc. 79a001fc1SVitaly Wool * 89a001fc1SVitaly Wool * This implementation is based on zbud written by Seth Jennings. 99a001fc1SVitaly Wool * 109a001fc1SVitaly Wool * z3fold is an special purpose allocator for storing compressed pages. It 119a001fc1SVitaly Wool * can store up to three compressed pages per page which improves the 129a001fc1SVitaly Wool * compression ratio of zbud while retaining its main concepts (e. g. always 139a001fc1SVitaly Wool * storing an integral number of objects per page) and simplicity. 149a001fc1SVitaly Wool * It still has simple and deterministic reclaim properties that make it 159a001fc1SVitaly Wool * preferable to a higher density approach (with no requirement on integral 169a001fc1SVitaly Wool * number of object per page) when reclaim is used. 179a001fc1SVitaly Wool * 189a001fc1SVitaly Wool * As in zbud, pages are divided into "chunks". The size of the chunks is 199a001fc1SVitaly Wool * fixed at compile time and is determined by NCHUNKS_ORDER below. 209a001fc1SVitaly Wool * 219a001fc1SVitaly Wool * z3fold doesn't export any API and is meant to be used via zpool API. 229a001fc1SVitaly Wool */ 239a001fc1SVitaly Wool 249a001fc1SVitaly Wool #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 259a001fc1SVitaly Wool 269a001fc1SVitaly Wool #include <linux/atomic.h> 27d30561c5SVitaly Wool #include <linux/sched.h> 281f862989SVitaly Wool #include <linux/cpumask.h> 299a001fc1SVitaly Wool #include <linux/list.h> 309a001fc1SVitaly Wool #include <linux/mm.h> 319a001fc1SVitaly Wool #include <linux/module.h> 321f862989SVitaly Wool #include <linux/page-flags.h> 331f862989SVitaly Wool #include <linux/migrate.h> 341f862989SVitaly Wool #include <linux/node.h> 351f862989SVitaly Wool #include <linux/compaction.h> 36d30561c5SVitaly Wool #include <linux/percpu.h> 371f862989SVitaly Wool #include <linux/mount.h> 38ea8157abSDavid Howells #include <linux/pseudo_fs.h> 391f862989SVitaly Wool #include <linux/fs.h> 409a001fc1SVitaly Wool #include <linux/preempt.h> 41d30561c5SVitaly Wool #include <linux/workqueue.h> 429a001fc1SVitaly Wool #include <linux/slab.h> 439a001fc1SVitaly Wool #include <linux/spinlock.h> 449a001fc1SVitaly Wool #include <linux/zpool.h> 45ea8157abSDavid Howells #include <linux/magic.h> 46af4798a5SQian Cai #include <linux/kmemleak.h> 479a001fc1SVitaly Wool 489a001fc1SVitaly Wool /* 499a001fc1SVitaly Wool * NCHUNKS_ORDER determines the internal allocation granularity, effectively 509a001fc1SVitaly Wool * adjusting internal fragmentation. It also determines the number of 519a001fc1SVitaly Wool * freelists maintained in each pool. NCHUNKS_ORDER of 6 means that the 52ede93213SVitaly Wool * allocation granularity will be in chunks of size PAGE_SIZE/64. Some chunks 53ede93213SVitaly Wool * in the beginning of an allocated page are occupied by z3fold header, so 54ede93213SVitaly Wool * NCHUNKS will be calculated to 63 (or 62 in case CONFIG_DEBUG_SPINLOCK=y), 55ede93213SVitaly Wool * which shows the max number of free chunks in z3fold page, also there will 56ede93213SVitaly Wool * be 63, or 62, respectively, freelists per pool. 579a001fc1SVitaly Wool */ 589a001fc1SVitaly Wool #define NCHUNKS_ORDER 6 599a001fc1SVitaly Wool 609a001fc1SVitaly Wool #define CHUNK_SHIFT (PAGE_SHIFT - NCHUNKS_ORDER) 619a001fc1SVitaly Wool #define CHUNK_SIZE (1 << CHUNK_SHIFT) 62ede93213SVitaly Wool #define ZHDR_SIZE_ALIGNED round_up(sizeof(struct z3fold_header), CHUNK_SIZE) 63ede93213SVitaly Wool #define ZHDR_CHUNKS (ZHDR_SIZE_ALIGNED >> CHUNK_SHIFT) 64ede93213SVitaly Wool #define TOTAL_CHUNKS (PAGE_SIZE >> CHUNK_SHIFT) 65e3c0db4fSMiaohe Lin #define NCHUNKS (TOTAL_CHUNKS - ZHDR_CHUNKS) 669a001fc1SVitaly Wool 67f201ebd8Szhong jiang #define BUDDY_MASK (0x3) 68ca0246bbSVitaly Wool #define BUDDY_SHIFT 2 697c2b8baaSVitaly Wool #define SLOTS_ALIGN (0x40) 707c2b8baaSVitaly Wool 717c2b8baaSVitaly Wool /***************** 727c2b8baaSVitaly Wool * Structures 737c2b8baaSVitaly Wool *****************/ 747c2b8baaSVitaly Wool struct z3fold_pool; 757c2b8baaSVitaly Wool struct z3fold_ops { 767c2b8baaSVitaly Wool int (*evict)(struct z3fold_pool *pool, unsigned long handle); 777c2b8baaSVitaly Wool }; 787c2b8baaSVitaly Wool 797c2b8baaSVitaly Wool enum buddy { 807c2b8baaSVitaly Wool HEADLESS = 0, 817c2b8baaSVitaly Wool FIRST, 827c2b8baaSVitaly Wool MIDDLE, 837c2b8baaSVitaly Wool LAST, 847c2b8baaSVitaly Wool BUDDIES_MAX = LAST 857c2b8baaSVitaly Wool }; 867c2b8baaSVitaly Wool 877c2b8baaSVitaly Wool struct z3fold_buddy_slots { 887c2b8baaSVitaly Wool /* 897c2b8baaSVitaly Wool * we are using BUDDY_MASK in handle_to_buddy etc. so there should 907c2b8baaSVitaly Wool * be enough slots to hold all possible variants 917c2b8baaSVitaly Wool */ 927c2b8baaSVitaly Wool unsigned long slot[BUDDY_MASK + 1]; 93fc548865SVitaly Wool unsigned long pool; /* back link */ 944a3ac931SVitaly Wool rwlock_t lock; 957c2b8baaSVitaly Wool }; 967c2b8baaSVitaly Wool #define HANDLE_FLAG_MASK (0x03) 977c2b8baaSVitaly Wool 987c2b8baaSVitaly Wool /* 997c2b8baaSVitaly Wool * struct z3fold_header - z3fold page metadata occupying first chunks of each 1007c2b8baaSVitaly Wool * z3fold page, except for HEADLESS pages 1017c2b8baaSVitaly Wool * @buddy: links the z3fold page into the relevant list in the 1027c2b8baaSVitaly Wool * pool 1037c2b8baaSVitaly Wool * @page_lock: per-page lock 1047c2b8baaSVitaly Wool * @refcount: reference count for the z3fold page 1057c2b8baaSVitaly Wool * @work: work_struct for page layout optimization 1067c2b8baaSVitaly Wool * @slots: pointer to the structure holding buddy slots 107bb9a374dSVitaly Wool * @pool: pointer to the containing pool 1087c2b8baaSVitaly Wool * @cpu: CPU which this page "belongs" to 1097c2b8baaSVitaly Wool * @first_chunks: the size of the first buddy in chunks, 0 if free 1107c2b8baaSVitaly Wool * @middle_chunks: the size of the middle buddy in chunks, 0 if free 1117c2b8baaSVitaly Wool * @last_chunks: the size of the last buddy in chunks, 0 if free 1127c2b8baaSVitaly Wool * @first_num: the starting number (for the first handle) 1131f862989SVitaly Wool * @mapped_count: the number of objects currently mapped 1147c2b8baaSVitaly Wool */ 1157c2b8baaSVitaly Wool struct z3fold_header { 1167c2b8baaSVitaly Wool struct list_head buddy; 1177c2b8baaSVitaly Wool spinlock_t page_lock; 1187c2b8baaSVitaly Wool struct kref refcount; 1197c2b8baaSVitaly Wool struct work_struct work; 1207c2b8baaSVitaly Wool struct z3fold_buddy_slots *slots; 121bb9a374dSVitaly Wool struct z3fold_pool *pool; 1227c2b8baaSVitaly Wool short cpu; 1237c2b8baaSVitaly Wool unsigned short first_chunks; 1247c2b8baaSVitaly Wool unsigned short middle_chunks; 1257c2b8baaSVitaly Wool unsigned short last_chunks; 1267c2b8baaSVitaly Wool unsigned short start_middle; 1277c2b8baaSVitaly Wool unsigned short first_num:2; 1281f862989SVitaly Wool unsigned short mapped_count:2; 1294a3ac931SVitaly Wool unsigned short foreign_handles:2; 1307c2b8baaSVitaly Wool }; 1319a001fc1SVitaly Wool 1329a001fc1SVitaly Wool /** 1339a001fc1SVitaly Wool * struct z3fold_pool - stores metadata for each z3fold pool 134d30561c5SVitaly Wool * @name: pool name 135d30561c5SVitaly Wool * @lock: protects pool unbuddied/lru lists 136d30561c5SVitaly Wool * @stale_lock: protects pool stale page list 137d30561c5SVitaly Wool * @unbuddied: per-cpu array of lists tracking z3fold pages that contain 2- 138d30561c5SVitaly Wool * buddies; the list each z3fold page is added to depends on 139d30561c5SVitaly Wool * the size of its free region. 1409a001fc1SVitaly Wool * @lru: list tracking the z3fold pages in LRU order by most recently 1419a001fc1SVitaly Wool * added buddy. 142d30561c5SVitaly Wool * @stale: list of pages marked for freeing 1439a001fc1SVitaly Wool * @pages_nr: number of z3fold pages in the pool. 1447c2b8baaSVitaly Wool * @c_handle: cache for z3fold_buddy_slots allocation 1459a001fc1SVitaly Wool * @ops: pointer to a structure of user defined operations specified at 1469a001fc1SVitaly Wool * pool creation time. 14730522175SMel Gorman * @zpool: zpool driver 14830522175SMel Gorman * @zpool_ops: zpool operations structure with an evict callback 149d30561c5SVitaly Wool * @compact_wq: workqueue for page layout background optimization 150d30561c5SVitaly Wool * @release_wq: workqueue for safe page release 151d30561c5SVitaly Wool * @work: work_struct for safe page release 1521f862989SVitaly Wool * @inode: inode for z3fold pseudo filesystem 1539a001fc1SVitaly Wool * 1549a001fc1SVitaly Wool * This structure is allocated at pool creation time and maintains metadata 1559a001fc1SVitaly Wool * pertaining to a particular z3fold pool. 1569a001fc1SVitaly Wool */ 1579a001fc1SVitaly Wool struct z3fold_pool { 158d30561c5SVitaly Wool const char *name; 1599a001fc1SVitaly Wool spinlock_t lock; 160d30561c5SVitaly Wool spinlock_t stale_lock; 161d30561c5SVitaly Wool struct list_head *unbuddied; 1629a001fc1SVitaly Wool struct list_head lru; 163d30561c5SVitaly Wool struct list_head stale; 16412d59ae6SVitaly Wool atomic64_t pages_nr; 1657c2b8baaSVitaly Wool struct kmem_cache *c_handle; 1669a001fc1SVitaly Wool const struct z3fold_ops *ops; 1679a001fc1SVitaly Wool struct zpool *zpool; 1689a001fc1SVitaly Wool const struct zpool_ops *zpool_ops; 169d30561c5SVitaly Wool struct workqueue_struct *compact_wq; 170d30561c5SVitaly Wool struct workqueue_struct *release_wq; 171d30561c5SVitaly Wool struct work_struct work; 1721f862989SVitaly Wool struct inode *inode; 1739a001fc1SVitaly Wool }; 1749a001fc1SVitaly Wool 1759a001fc1SVitaly Wool /* 1769a001fc1SVitaly Wool * Internal z3fold page flags 1779a001fc1SVitaly Wool */ 1789a001fc1SVitaly Wool enum z3fold_page_flags { 1795a27aa82SVitaly Wool PAGE_HEADLESS = 0, 1809a001fc1SVitaly Wool MIDDLE_CHUNK_MAPPED, 181d30561c5SVitaly Wool NEEDS_COMPACTING, 1826098d7e1SVitaly Wool PAGE_STALE, 183ca0246bbSVitaly Wool PAGE_CLAIMED, /* by either reclaim or free */ 184*943fb61dSMiaohe Lin PAGE_MIGRATED, /* page is migrated and soon to be released */ 1859a001fc1SVitaly Wool }; 1869a001fc1SVitaly Wool 1874a3ac931SVitaly Wool /* 188dcf5aedbSVitaly Wool * handle flags, go under HANDLE_FLAG_MASK 189dcf5aedbSVitaly Wool */ 190dcf5aedbSVitaly Wool enum z3fold_handle_flags { 191dcf5aedbSVitaly Wool HANDLES_NOFREE = 0, 192dcf5aedbSVitaly Wool }; 193dcf5aedbSVitaly Wool 194dcf5aedbSVitaly Wool /* 1954a3ac931SVitaly Wool * Forward declarations 1964a3ac931SVitaly Wool */ 1974a3ac931SVitaly Wool static struct z3fold_header *__z3fold_alloc(struct z3fold_pool *, size_t, bool); 1984a3ac931SVitaly Wool static void compact_page_work(struct work_struct *w); 1994a3ac931SVitaly Wool 2009a001fc1SVitaly Wool /***************** 2019a001fc1SVitaly Wool * Helpers 2029a001fc1SVitaly Wool *****************/ 2039a001fc1SVitaly Wool 2049a001fc1SVitaly Wool /* Converts an allocation size in bytes to size in z3fold chunks */ 2059a001fc1SVitaly Wool static int size_to_chunks(size_t size) 2069a001fc1SVitaly Wool { 2079a001fc1SVitaly Wool return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT; 2089a001fc1SVitaly Wool } 2099a001fc1SVitaly Wool 2109a001fc1SVitaly Wool #define for_each_unbuddied_list(_iter, _begin) \ 2119a001fc1SVitaly Wool for ((_iter) = (_begin); (_iter) < NCHUNKS; (_iter)++) 2129a001fc1SVitaly Wool 213bb9f6f63SVitaly Wool static inline struct z3fold_buddy_slots *alloc_slots(struct z3fold_pool *pool, 214bb9f6f63SVitaly Wool gfp_t gfp) 2157c2b8baaSVitaly Wool { 216f4bad643SMiaohe Lin struct z3fold_buddy_slots *slots = kmem_cache_zalloc(pool->c_handle, 217f4bad643SMiaohe Lin gfp); 2187c2b8baaSVitaly Wool 2197c2b8baaSVitaly Wool if (slots) { 220af4798a5SQian Cai /* It will be freed separately in free_handle(). */ 221af4798a5SQian Cai kmemleak_not_leak(slots); 2227c2b8baaSVitaly Wool slots->pool = (unsigned long)pool; 2234a3ac931SVitaly Wool rwlock_init(&slots->lock); 2247c2b8baaSVitaly Wool } 2257c2b8baaSVitaly Wool 2267c2b8baaSVitaly Wool return slots; 2277c2b8baaSVitaly Wool } 2287c2b8baaSVitaly Wool 2297c2b8baaSVitaly Wool static inline struct z3fold_pool *slots_to_pool(struct z3fold_buddy_slots *s) 2307c2b8baaSVitaly Wool { 2317c2b8baaSVitaly Wool return (struct z3fold_pool *)(s->pool & ~HANDLE_FLAG_MASK); 2327c2b8baaSVitaly Wool } 2337c2b8baaSVitaly Wool 2347c2b8baaSVitaly Wool static inline struct z3fold_buddy_slots *handle_to_slots(unsigned long handle) 2357c2b8baaSVitaly Wool { 2367c2b8baaSVitaly Wool return (struct z3fold_buddy_slots *)(handle & ~(SLOTS_ALIGN - 1)); 2377c2b8baaSVitaly Wool } 2387c2b8baaSVitaly Wool 2394a3ac931SVitaly Wool /* Lock a z3fold page */ 2404a3ac931SVitaly Wool static inline void z3fold_page_lock(struct z3fold_header *zhdr) 2414a3ac931SVitaly Wool { 2424a3ac931SVitaly Wool spin_lock(&zhdr->page_lock); 2434a3ac931SVitaly Wool } 2444a3ac931SVitaly Wool 2454a3ac931SVitaly Wool /* Try to lock a z3fold page */ 2464a3ac931SVitaly Wool static inline int z3fold_page_trylock(struct z3fold_header *zhdr) 2474a3ac931SVitaly Wool { 2484a3ac931SVitaly Wool return spin_trylock(&zhdr->page_lock); 2494a3ac931SVitaly Wool } 2504a3ac931SVitaly Wool 2514a3ac931SVitaly Wool /* Unlock a z3fold page */ 2524a3ac931SVitaly Wool static inline void z3fold_page_unlock(struct z3fold_header *zhdr) 2534a3ac931SVitaly Wool { 2544a3ac931SVitaly Wool spin_unlock(&zhdr->page_lock); 2554a3ac931SVitaly Wool } 2564a3ac931SVitaly Wool 257767cc6c5SMiaohe Lin /* return locked z3fold page if it's not headless */ 258767cc6c5SMiaohe Lin static inline struct z3fold_header *get_z3fold_header(unsigned long handle) 2594a3ac931SVitaly Wool { 2604a3ac931SVitaly Wool struct z3fold_buddy_slots *slots; 2614a3ac931SVitaly Wool struct z3fold_header *zhdr; 2624a3ac931SVitaly Wool int locked = 0; 2634a3ac931SVitaly Wool 2644a3ac931SVitaly Wool if (!(handle & (1 << PAGE_HEADLESS))) { 2654a3ac931SVitaly Wool slots = handle_to_slots(handle); 2664a3ac931SVitaly Wool do { 2674a3ac931SVitaly Wool unsigned long addr; 2684a3ac931SVitaly Wool 2694a3ac931SVitaly Wool read_lock(&slots->lock); 2704a3ac931SVitaly Wool addr = *(unsigned long *)handle; 2714a3ac931SVitaly Wool zhdr = (struct z3fold_header *)(addr & PAGE_MASK); 2724a3ac931SVitaly Wool locked = z3fold_page_trylock(zhdr); 2734a3ac931SVitaly Wool read_unlock(&slots->lock); 274*943fb61dSMiaohe Lin if (locked) { 275*943fb61dSMiaohe Lin struct page *page = virt_to_page(zhdr); 276*943fb61dSMiaohe Lin 277*943fb61dSMiaohe Lin if (!test_bit(PAGE_MIGRATED, &page->private)) 2784a3ac931SVitaly Wool break; 279*943fb61dSMiaohe Lin z3fold_page_unlock(zhdr); 280*943fb61dSMiaohe Lin } 2814a3ac931SVitaly Wool cpu_relax(); 282767cc6c5SMiaohe Lin } while (true); 2834a3ac931SVitaly Wool } else { 2844a3ac931SVitaly Wool zhdr = (struct z3fold_header *)(handle & PAGE_MASK); 2854a3ac931SVitaly Wool } 2864a3ac931SVitaly Wool 2874a3ac931SVitaly Wool return zhdr; 2884a3ac931SVitaly Wool } 2894a3ac931SVitaly Wool 2904a3ac931SVitaly Wool static inline void put_z3fold_header(struct z3fold_header *zhdr) 2914a3ac931SVitaly Wool { 2924a3ac931SVitaly Wool struct page *page = virt_to_page(zhdr); 2934a3ac931SVitaly Wool 2944a3ac931SVitaly Wool if (!test_bit(PAGE_HEADLESS, &page->private)) 2954a3ac931SVitaly Wool z3fold_page_unlock(zhdr); 2964a3ac931SVitaly Wool } 2974a3ac931SVitaly Wool 298fc548865SVitaly Wool static inline void free_handle(unsigned long handle, struct z3fold_header *zhdr) 2997c2b8baaSVitaly Wool { 3007c2b8baaSVitaly Wool struct z3fold_buddy_slots *slots; 3017c2b8baaSVitaly Wool int i; 3027c2b8baaSVitaly Wool bool is_free; 3037c2b8baaSVitaly Wool 3044a3ac931SVitaly Wool if (WARN_ON(*(unsigned long *)handle == 0)) 3054a3ac931SVitaly Wool return; 3064a3ac931SVitaly Wool 3077c2b8baaSVitaly Wool slots = handle_to_slots(handle); 3084a3ac931SVitaly Wool write_lock(&slots->lock); 3094a3ac931SVitaly Wool *(unsigned long *)handle = 0; 310dcf5aedbSVitaly Wool 311dcf5aedbSVitaly Wool if (test_bit(HANDLES_NOFREE, &slots->pool)) { 312dcf5aedbSVitaly Wool write_unlock(&slots->lock); 313dcf5aedbSVitaly Wool return; /* simple case, nothing else to do */ 314dcf5aedbSVitaly Wool } 315dcf5aedbSVitaly Wool 316fc548865SVitaly Wool if (zhdr->slots != slots) 3174a3ac931SVitaly Wool zhdr->foreign_handles--; 318fc548865SVitaly Wool 3197c2b8baaSVitaly Wool is_free = true; 3207c2b8baaSVitaly Wool for (i = 0; i <= BUDDY_MASK; i++) { 3217c2b8baaSVitaly Wool if (slots->slot[i]) { 3227c2b8baaSVitaly Wool is_free = false; 3237c2b8baaSVitaly Wool break; 3247c2b8baaSVitaly Wool } 3257c2b8baaSVitaly Wool } 326d8f117abSUladzislau Rezki write_unlock(&slots->lock); 3277c2b8baaSVitaly Wool 3287c2b8baaSVitaly Wool if (is_free) { 3297c2b8baaSVitaly Wool struct z3fold_pool *pool = slots_to_pool(slots); 3307c2b8baaSVitaly Wool 331fc548865SVitaly Wool if (zhdr->slots == slots) 332fc548865SVitaly Wool zhdr->slots = NULL; 3337c2b8baaSVitaly Wool kmem_cache_free(pool->c_handle, slots); 3347c2b8baaSVitaly Wool } 3357c2b8baaSVitaly Wool } 3367c2b8baaSVitaly Wool 337ea8157abSDavid Howells static int z3fold_init_fs_context(struct fs_context *fc) 3381f862989SVitaly Wool { 339ea8157abSDavid Howells return init_pseudo(fc, Z3FOLD_MAGIC) ? 0 : -ENOMEM; 3401f862989SVitaly Wool } 3411f862989SVitaly Wool 3421f862989SVitaly Wool static struct file_system_type z3fold_fs = { 3431f862989SVitaly Wool .name = "z3fold", 344ea8157abSDavid Howells .init_fs_context = z3fold_init_fs_context, 3451f862989SVitaly Wool .kill_sb = kill_anon_super, 3461f862989SVitaly Wool }; 3471f862989SVitaly Wool 3481f862989SVitaly Wool static struct vfsmount *z3fold_mnt; 349dc3a1f30SMiaohe Lin static int __init z3fold_mount(void) 3501f862989SVitaly Wool { 3511f862989SVitaly Wool int ret = 0; 3521f862989SVitaly Wool 3531f862989SVitaly Wool z3fold_mnt = kern_mount(&z3fold_fs); 3541f862989SVitaly Wool if (IS_ERR(z3fold_mnt)) 3551f862989SVitaly Wool ret = PTR_ERR(z3fold_mnt); 3561f862989SVitaly Wool 3571f862989SVitaly Wool return ret; 3581f862989SVitaly Wool } 3591f862989SVitaly Wool 3601f862989SVitaly Wool static void z3fold_unmount(void) 3611f862989SVitaly Wool { 3621f862989SVitaly Wool kern_unmount(z3fold_mnt); 3631f862989SVitaly Wool } 3641f862989SVitaly Wool 3651f862989SVitaly Wool static const struct address_space_operations z3fold_aops; 3661f862989SVitaly Wool static int z3fold_register_migration(struct z3fold_pool *pool) 3671f862989SVitaly Wool { 3681f862989SVitaly Wool pool->inode = alloc_anon_inode(z3fold_mnt->mnt_sb); 3691f862989SVitaly Wool if (IS_ERR(pool->inode)) { 3701f862989SVitaly Wool pool->inode = NULL; 3711f862989SVitaly Wool return 1; 3721f862989SVitaly Wool } 3731f862989SVitaly Wool 3741f862989SVitaly Wool pool->inode->i_mapping->private_data = pool; 3751f862989SVitaly Wool pool->inode->i_mapping->a_ops = &z3fold_aops; 3761f862989SVitaly Wool return 0; 3771f862989SVitaly Wool } 3781f862989SVitaly Wool 3791f862989SVitaly Wool static void z3fold_unregister_migration(struct z3fold_pool *pool) 3801f862989SVitaly Wool { 3811f862989SVitaly Wool if (pool->inode) 3821f862989SVitaly Wool iput(pool->inode); 3831f862989SVitaly Wool } 3841f862989SVitaly Wool 3859a001fc1SVitaly Wool /* Initializes the z3fold header of a newly allocated z3fold page */ 38663398413SVitaly Wool static struct z3fold_header *init_z3fold_page(struct page *page, bool headless, 387bb9f6f63SVitaly Wool struct z3fold_pool *pool, gfp_t gfp) 3889a001fc1SVitaly Wool { 3899a001fc1SVitaly Wool struct z3fold_header *zhdr = page_address(page); 39063398413SVitaly Wool struct z3fold_buddy_slots *slots; 3919a001fc1SVitaly Wool 3929a001fc1SVitaly Wool INIT_LIST_HEAD(&page->lru); 3939a001fc1SVitaly Wool clear_bit(PAGE_HEADLESS, &page->private); 3949a001fc1SVitaly Wool clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); 395d30561c5SVitaly Wool clear_bit(NEEDS_COMPACTING, &page->private); 396d30561c5SVitaly Wool clear_bit(PAGE_STALE, &page->private); 397ca0246bbSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 398*943fb61dSMiaohe Lin clear_bit(PAGE_MIGRATED, &page->private); 39963398413SVitaly Wool if (headless) 40063398413SVitaly Wool return zhdr; 40163398413SVitaly Wool 40263398413SVitaly Wool slots = alloc_slots(pool, gfp); 40363398413SVitaly Wool if (!slots) 40463398413SVitaly Wool return NULL; 4059a001fc1SVitaly Wool 406c457cd96SMiaohe Lin memset(zhdr, 0, sizeof(*zhdr)); 4072f1e5e4dSVitaly Wool spin_lock_init(&zhdr->page_lock); 4085a27aa82SVitaly Wool kref_init(&zhdr->refcount); 409d30561c5SVitaly Wool zhdr->cpu = -1; 4107c2b8baaSVitaly Wool zhdr->slots = slots; 411bb9a374dSVitaly Wool zhdr->pool = pool; 4129a001fc1SVitaly Wool INIT_LIST_HEAD(&zhdr->buddy); 413d30561c5SVitaly Wool INIT_WORK(&zhdr->work, compact_page_work); 4149a001fc1SVitaly Wool return zhdr; 4159a001fc1SVitaly Wool } 4169a001fc1SVitaly Wool 4179a001fc1SVitaly Wool /* Resets the struct page fields and frees the page */ 4181f862989SVitaly Wool static void free_z3fold_page(struct page *page, bool headless) 4199a001fc1SVitaly Wool { 4201f862989SVitaly Wool if (!headless) { 4211f862989SVitaly Wool lock_page(page); 4221f862989SVitaly Wool __ClearPageMovable(page); 4231f862989SVitaly Wool unlock_page(page); 4241f862989SVitaly Wool } 4255a27aa82SVitaly Wool __free_page(page); 4265a27aa82SVitaly Wool } 4275a27aa82SVitaly Wool 4287c2b8baaSVitaly Wool /* Helper function to build the index */ 4297c2b8baaSVitaly Wool static inline int __idx(struct z3fold_header *zhdr, enum buddy bud) 4307c2b8baaSVitaly Wool { 4317c2b8baaSVitaly Wool return (bud + zhdr->first_num) & BUDDY_MASK; 4327c2b8baaSVitaly Wool } 4337c2b8baaSVitaly Wool 4349a001fc1SVitaly Wool /* 4359a001fc1SVitaly Wool * Encodes the handle of a particular buddy within a z3fold page 4369a001fc1SVitaly Wool * Pool lock should be held as this function accesses first_num 4379a001fc1SVitaly Wool */ 4383f9d2b57SVitaly Wool static unsigned long __encode_handle(struct z3fold_header *zhdr, 4393f9d2b57SVitaly Wool struct z3fold_buddy_slots *slots, 4403f9d2b57SVitaly Wool enum buddy bud) 4419a001fc1SVitaly Wool { 4427c2b8baaSVitaly Wool unsigned long h = (unsigned long)zhdr; 4437c2b8baaSVitaly Wool int idx = 0; 4449a001fc1SVitaly Wool 4457c2b8baaSVitaly Wool /* 4467c2b8baaSVitaly Wool * For a headless page, its handle is its pointer with the extra 4477c2b8baaSVitaly Wool * PAGE_HEADLESS bit set 4487c2b8baaSVitaly Wool */ 4497c2b8baaSVitaly Wool if (bud == HEADLESS) 4507c2b8baaSVitaly Wool return h | (1 << PAGE_HEADLESS); 4517c2b8baaSVitaly Wool 4527c2b8baaSVitaly Wool /* otherwise, return pointer to encoded handle */ 4537c2b8baaSVitaly Wool idx = __idx(zhdr, bud); 4547c2b8baaSVitaly Wool h += idx; 455ca0246bbSVitaly Wool if (bud == LAST) 4567c2b8baaSVitaly Wool h |= (zhdr->last_chunks << BUDDY_SHIFT); 4577c2b8baaSVitaly Wool 4584a3ac931SVitaly Wool write_lock(&slots->lock); 4597c2b8baaSVitaly Wool slots->slot[idx] = h; 4604a3ac931SVitaly Wool write_unlock(&slots->lock); 4617c2b8baaSVitaly Wool return (unsigned long)&slots->slot[idx]; 4629a001fc1SVitaly Wool } 4639a001fc1SVitaly Wool 4643f9d2b57SVitaly Wool static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) 4653f9d2b57SVitaly Wool { 4663f9d2b57SVitaly Wool return __encode_handle(zhdr, zhdr->slots, bud); 4673f9d2b57SVitaly Wool } 4683f9d2b57SVitaly Wool 469ca0246bbSVitaly Wool /* only for LAST bud, returns zero otherwise */ 470ca0246bbSVitaly Wool static unsigned short handle_to_chunks(unsigned long handle) 471ca0246bbSVitaly Wool { 4724a3ac931SVitaly Wool struct z3fold_buddy_slots *slots = handle_to_slots(handle); 4734a3ac931SVitaly Wool unsigned long addr; 4747c2b8baaSVitaly Wool 4754a3ac931SVitaly Wool read_lock(&slots->lock); 4764a3ac931SVitaly Wool addr = *(unsigned long *)handle; 4774a3ac931SVitaly Wool read_unlock(&slots->lock); 4787c2b8baaSVitaly Wool return (addr & ~PAGE_MASK) >> BUDDY_SHIFT; 479ca0246bbSVitaly Wool } 480ca0246bbSVitaly Wool 481f201ebd8Szhong jiang /* 482f201ebd8Szhong jiang * (handle & BUDDY_MASK) < zhdr->first_num is possible in encode_handle 483f201ebd8Szhong jiang * but that doesn't matter. because the masking will result in the 484f201ebd8Szhong jiang * correct buddy number. 485f201ebd8Szhong jiang */ 4869a001fc1SVitaly Wool static enum buddy handle_to_buddy(unsigned long handle) 4879a001fc1SVitaly Wool { 4887c2b8baaSVitaly Wool struct z3fold_header *zhdr; 4894a3ac931SVitaly Wool struct z3fold_buddy_slots *slots = handle_to_slots(handle); 4907c2b8baaSVitaly Wool unsigned long addr; 4917c2b8baaSVitaly Wool 4924a3ac931SVitaly Wool read_lock(&slots->lock); 4937c2b8baaSVitaly Wool WARN_ON(handle & (1 << PAGE_HEADLESS)); 4947c2b8baaSVitaly Wool addr = *(unsigned long *)handle; 4954a3ac931SVitaly Wool read_unlock(&slots->lock); 4967c2b8baaSVitaly Wool zhdr = (struct z3fold_header *)(addr & PAGE_MASK); 4977c2b8baaSVitaly Wool return (addr - zhdr->first_num) & BUDDY_MASK; 4989a001fc1SVitaly Wool } 4999a001fc1SVitaly Wool 5009050cce1SVitaly Wool static inline struct z3fold_pool *zhdr_to_pool(struct z3fold_header *zhdr) 5019050cce1SVitaly Wool { 502bb9a374dSVitaly Wool return zhdr->pool; 5039050cce1SVitaly Wool } 5049050cce1SVitaly Wool 505d30561c5SVitaly Wool static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) 506d30561c5SVitaly Wool { 507d30561c5SVitaly Wool struct page *page = virt_to_page(zhdr); 5089050cce1SVitaly Wool struct z3fold_pool *pool = zhdr_to_pool(zhdr); 509d30561c5SVitaly Wool 510d30561c5SVitaly Wool WARN_ON(!list_empty(&zhdr->buddy)); 511d30561c5SVitaly Wool set_bit(PAGE_STALE, &page->private); 51235529357SVitaly Wool clear_bit(NEEDS_COMPACTING, &page->private); 513d30561c5SVitaly Wool spin_lock(&pool->lock); 514d30561c5SVitaly Wool if (!list_empty(&page->lru)) 5151f862989SVitaly Wool list_del_init(&page->lru); 516d30561c5SVitaly Wool spin_unlock(&pool->lock); 5174a3ac931SVitaly Wool 518d30561c5SVitaly Wool if (locked) 519d30561c5SVitaly Wool z3fold_page_unlock(zhdr); 5204a3ac931SVitaly Wool 521d30561c5SVitaly Wool spin_lock(&pool->stale_lock); 522d30561c5SVitaly Wool list_add(&zhdr->buddy, &pool->stale); 523d30561c5SVitaly Wool queue_work(pool->release_wq, &pool->work); 524d30561c5SVitaly Wool spin_unlock(&pool->stale_lock); 5255e36c25bSMiaohe Lin 5265e36c25bSMiaohe Lin atomic64_dec(&pool->pages_nr); 527d30561c5SVitaly Wool } 528d30561c5SVitaly Wool 529d30561c5SVitaly Wool static void release_z3fold_page_locked(struct kref *ref) 530d30561c5SVitaly Wool { 531d30561c5SVitaly Wool struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, 532d30561c5SVitaly Wool refcount); 533d30561c5SVitaly Wool WARN_ON(z3fold_page_trylock(zhdr)); 534d30561c5SVitaly Wool __release_z3fold_page(zhdr, true); 535d30561c5SVitaly Wool } 536d30561c5SVitaly Wool 537d30561c5SVitaly Wool static void release_z3fold_page_locked_list(struct kref *ref) 538d30561c5SVitaly Wool { 539d30561c5SVitaly Wool struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, 540d30561c5SVitaly Wool refcount); 5419050cce1SVitaly Wool struct z3fold_pool *pool = zhdr_to_pool(zhdr); 5424a3ac931SVitaly Wool 5439050cce1SVitaly Wool spin_lock(&pool->lock); 544d30561c5SVitaly Wool list_del_init(&zhdr->buddy); 5459050cce1SVitaly Wool spin_unlock(&pool->lock); 546d30561c5SVitaly Wool 547d30561c5SVitaly Wool WARN_ON(z3fold_page_trylock(zhdr)); 548d30561c5SVitaly Wool __release_z3fold_page(zhdr, true); 549d30561c5SVitaly Wool } 550d30561c5SVitaly Wool 551d30561c5SVitaly Wool static void free_pages_work(struct work_struct *w) 552d30561c5SVitaly Wool { 553d30561c5SVitaly Wool struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work); 554d30561c5SVitaly Wool 555d30561c5SVitaly Wool spin_lock(&pool->stale_lock); 556d30561c5SVitaly Wool while (!list_empty(&pool->stale)) { 557d30561c5SVitaly Wool struct z3fold_header *zhdr = list_first_entry(&pool->stale, 558d30561c5SVitaly Wool struct z3fold_header, buddy); 559d30561c5SVitaly Wool struct page *page = virt_to_page(zhdr); 560d30561c5SVitaly Wool 561d30561c5SVitaly Wool list_del(&zhdr->buddy); 562d30561c5SVitaly Wool if (WARN_ON(!test_bit(PAGE_STALE, &page->private))) 563d30561c5SVitaly Wool continue; 564d30561c5SVitaly Wool spin_unlock(&pool->stale_lock); 565d30561c5SVitaly Wool cancel_work_sync(&zhdr->work); 5661f862989SVitaly Wool free_z3fold_page(page, false); 567d30561c5SVitaly Wool cond_resched(); 568d30561c5SVitaly Wool spin_lock(&pool->stale_lock); 569d30561c5SVitaly Wool } 570d30561c5SVitaly Wool spin_unlock(&pool->stale_lock); 571d30561c5SVitaly Wool } 572d30561c5SVitaly Wool 5739a001fc1SVitaly Wool /* 5749a001fc1SVitaly Wool * Returns the number of free chunks in a z3fold page. 5759a001fc1SVitaly Wool * NB: can't be used with HEADLESS pages. 5769a001fc1SVitaly Wool */ 5779a001fc1SVitaly Wool static int num_free_chunks(struct z3fold_header *zhdr) 5789a001fc1SVitaly Wool { 5799a001fc1SVitaly Wool int nfree; 5809a001fc1SVitaly Wool /* 5819a001fc1SVitaly Wool * If there is a middle object, pick up the bigger free space 5829a001fc1SVitaly Wool * either before or after it. Otherwise just subtract the number 5839a001fc1SVitaly Wool * of chunks occupied by the first and the last objects. 5849a001fc1SVitaly Wool */ 5859a001fc1SVitaly Wool if (zhdr->middle_chunks != 0) { 5869a001fc1SVitaly Wool int nfree_before = zhdr->first_chunks ? 587ede93213SVitaly Wool 0 : zhdr->start_middle - ZHDR_CHUNKS; 5889a001fc1SVitaly Wool int nfree_after = zhdr->last_chunks ? 589ede93213SVitaly Wool 0 : TOTAL_CHUNKS - 590ede93213SVitaly Wool (zhdr->start_middle + zhdr->middle_chunks); 5919a001fc1SVitaly Wool nfree = max(nfree_before, nfree_after); 5929a001fc1SVitaly Wool } else 5939a001fc1SVitaly Wool nfree = NCHUNKS - zhdr->first_chunks - zhdr->last_chunks; 5949a001fc1SVitaly Wool return nfree; 5959a001fc1SVitaly Wool } 5969a001fc1SVitaly Wool 5979050cce1SVitaly Wool /* Add to the appropriate unbuddied list */ 5989050cce1SVitaly Wool static inline void add_to_unbuddied(struct z3fold_pool *pool, 5999050cce1SVitaly Wool struct z3fold_header *zhdr) 6009050cce1SVitaly Wool { 6019050cce1SVitaly Wool if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 || 6029050cce1SVitaly Wool zhdr->middle_chunks == 0) { 603135f97fdSVitaly Wool struct list_head *unbuddied; 6049050cce1SVitaly Wool int freechunks = num_free_chunks(zhdr); 605135f97fdSVitaly Wool 606135f97fdSVitaly Wool migrate_disable(); 607135f97fdSVitaly Wool unbuddied = this_cpu_ptr(pool->unbuddied); 6089050cce1SVitaly Wool spin_lock(&pool->lock); 6099050cce1SVitaly Wool list_add(&zhdr->buddy, &unbuddied[freechunks]); 6109050cce1SVitaly Wool spin_unlock(&pool->lock); 6119050cce1SVitaly Wool zhdr->cpu = smp_processor_id(); 612135f97fdSVitaly Wool migrate_enable(); 6139050cce1SVitaly Wool } 6149050cce1SVitaly Wool } 6159050cce1SVitaly Wool 616dcf5aedbSVitaly Wool static inline enum buddy get_free_buddy(struct z3fold_header *zhdr, int chunks) 617dcf5aedbSVitaly Wool { 618dcf5aedbSVitaly Wool enum buddy bud = HEADLESS; 619dcf5aedbSVitaly Wool 620dcf5aedbSVitaly Wool if (zhdr->middle_chunks) { 621dcf5aedbSVitaly Wool if (!zhdr->first_chunks && 622dcf5aedbSVitaly Wool chunks <= zhdr->start_middle - ZHDR_CHUNKS) 623dcf5aedbSVitaly Wool bud = FIRST; 624dcf5aedbSVitaly Wool else if (!zhdr->last_chunks) 625dcf5aedbSVitaly Wool bud = LAST; 626dcf5aedbSVitaly Wool } else { 627dcf5aedbSVitaly Wool if (!zhdr->first_chunks) 628dcf5aedbSVitaly Wool bud = FIRST; 629dcf5aedbSVitaly Wool else if (!zhdr->last_chunks) 630dcf5aedbSVitaly Wool bud = LAST; 631dcf5aedbSVitaly Wool else 632dcf5aedbSVitaly Wool bud = MIDDLE; 633dcf5aedbSVitaly Wool } 634dcf5aedbSVitaly Wool 635dcf5aedbSVitaly Wool return bud; 636dcf5aedbSVitaly Wool } 637dcf5aedbSVitaly Wool 638ede93213SVitaly Wool static inline void *mchunk_memmove(struct z3fold_header *zhdr, 639ede93213SVitaly Wool unsigned short dst_chunk) 640ede93213SVitaly Wool { 641ede93213SVitaly Wool void *beg = zhdr; 642ede93213SVitaly Wool return memmove(beg + (dst_chunk << CHUNK_SHIFT), 643ede93213SVitaly Wool beg + (zhdr->start_middle << CHUNK_SHIFT), 644ede93213SVitaly Wool zhdr->middle_chunks << CHUNK_SHIFT); 645ede93213SVitaly Wool } 646ede93213SVitaly Wool 6474a3ac931SVitaly Wool static inline bool buddy_single(struct z3fold_header *zhdr) 6484a3ac931SVitaly Wool { 6494a3ac931SVitaly Wool return !((zhdr->first_chunks && zhdr->middle_chunks) || 6504a3ac931SVitaly Wool (zhdr->first_chunks && zhdr->last_chunks) || 6514a3ac931SVitaly Wool (zhdr->middle_chunks && zhdr->last_chunks)); 6524a3ac931SVitaly Wool } 6534a3ac931SVitaly Wool 6544a3ac931SVitaly Wool static struct z3fold_header *compact_single_buddy(struct z3fold_header *zhdr) 6554a3ac931SVitaly Wool { 6564a3ac931SVitaly Wool struct z3fold_pool *pool = zhdr_to_pool(zhdr); 6574a3ac931SVitaly Wool void *p = zhdr; 6584a3ac931SVitaly Wool unsigned long old_handle = 0; 6594a3ac931SVitaly Wool size_t sz = 0; 6604a3ac931SVitaly Wool struct z3fold_header *new_zhdr = NULL; 6614a3ac931SVitaly Wool int first_idx = __idx(zhdr, FIRST); 6624a3ac931SVitaly Wool int middle_idx = __idx(zhdr, MIDDLE); 6634a3ac931SVitaly Wool int last_idx = __idx(zhdr, LAST); 6644a3ac931SVitaly Wool unsigned short *moved_chunks = NULL; 6654a3ac931SVitaly Wool 6664a3ac931SVitaly Wool /* 6674a3ac931SVitaly Wool * No need to protect slots here -- all the slots are "local" and 6684a3ac931SVitaly Wool * the page lock is already taken 6694a3ac931SVitaly Wool */ 6704a3ac931SVitaly Wool if (zhdr->first_chunks && zhdr->slots->slot[first_idx]) { 6714a3ac931SVitaly Wool p += ZHDR_SIZE_ALIGNED; 6724a3ac931SVitaly Wool sz = zhdr->first_chunks << CHUNK_SHIFT; 6734a3ac931SVitaly Wool old_handle = (unsigned long)&zhdr->slots->slot[first_idx]; 6744a3ac931SVitaly Wool moved_chunks = &zhdr->first_chunks; 6754a3ac931SVitaly Wool } else if (zhdr->middle_chunks && zhdr->slots->slot[middle_idx]) { 6764a3ac931SVitaly Wool p += zhdr->start_middle << CHUNK_SHIFT; 6774a3ac931SVitaly Wool sz = zhdr->middle_chunks << CHUNK_SHIFT; 6784a3ac931SVitaly Wool old_handle = (unsigned long)&zhdr->slots->slot[middle_idx]; 6794a3ac931SVitaly Wool moved_chunks = &zhdr->middle_chunks; 6804a3ac931SVitaly Wool } else if (zhdr->last_chunks && zhdr->slots->slot[last_idx]) { 6814a3ac931SVitaly Wool p += PAGE_SIZE - (zhdr->last_chunks << CHUNK_SHIFT); 6824a3ac931SVitaly Wool sz = zhdr->last_chunks << CHUNK_SHIFT; 6834a3ac931SVitaly Wool old_handle = (unsigned long)&zhdr->slots->slot[last_idx]; 6844a3ac931SVitaly Wool moved_chunks = &zhdr->last_chunks; 6854a3ac931SVitaly Wool } 6864a3ac931SVitaly Wool 6874a3ac931SVitaly Wool if (sz > 0) { 6884a3ac931SVitaly Wool enum buddy new_bud = HEADLESS; 6894a3ac931SVitaly Wool short chunks = size_to_chunks(sz); 6904a3ac931SVitaly Wool void *q; 6914a3ac931SVitaly Wool 6924a3ac931SVitaly Wool new_zhdr = __z3fold_alloc(pool, sz, false); 6934a3ac931SVitaly Wool if (!new_zhdr) 6944a3ac931SVitaly Wool return NULL; 6954a3ac931SVitaly Wool 6964a3ac931SVitaly Wool if (WARN_ON(new_zhdr == zhdr)) 6974a3ac931SVitaly Wool goto out_fail; 6984a3ac931SVitaly Wool 699dcf5aedbSVitaly Wool new_bud = get_free_buddy(new_zhdr, chunks); 7004a3ac931SVitaly Wool q = new_zhdr; 7014a3ac931SVitaly Wool switch (new_bud) { 7024a3ac931SVitaly Wool case FIRST: 7034a3ac931SVitaly Wool new_zhdr->first_chunks = chunks; 7044a3ac931SVitaly Wool q += ZHDR_SIZE_ALIGNED; 7054a3ac931SVitaly Wool break; 7064a3ac931SVitaly Wool case MIDDLE: 7074a3ac931SVitaly Wool new_zhdr->middle_chunks = chunks; 7084a3ac931SVitaly Wool new_zhdr->start_middle = 7094a3ac931SVitaly Wool new_zhdr->first_chunks + ZHDR_CHUNKS; 7104a3ac931SVitaly Wool q += new_zhdr->start_middle << CHUNK_SHIFT; 7114a3ac931SVitaly Wool break; 7124a3ac931SVitaly Wool case LAST: 7134a3ac931SVitaly Wool new_zhdr->last_chunks = chunks; 7144a3ac931SVitaly Wool q += PAGE_SIZE - (new_zhdr->last_chunks << CHUNK_SHIFT); 7154a3ac931SVitaly Wool break; 7164a3ac931SVitaly Wool default: 7174a3ac931SVitaly Wool goto out_fail; 7184a3ac931SVitaly Wool } 7194a3ac931SVitaly Wool new_zhdr->foreign_handles++; 7204a3ac931SVitaly Wool memcpy(q, p, sz); 7214a3ac931SVitaly Wool write_lock(&zhdr->slots->lock); 7224a3ac931SVitaly Wool *(unsigned long *)old_handle = (unsigned long)new_zhdr + 7234a3ac931SVitaly Wool __idx(new_zhdr, new_bud); 7244a3ac931SVitaly Wool if (new_bud == LAST) 7254a3ac931SVitaly Wool *(unsigned long *)old_handle |= 7264a3ac931SVitaly Wool (new_zhdr->last_chunks << BUDDY_SHIFT); 7274a3ac931SVitaly Wool write_unlock(&zhdr->slots->lock); 7284a3ac931SVitaly Wool add_to_unbuddied(pool, new_zhdr); 7294a3ac931SVitaly Wool z3fold_page_unlock(new_zhdr); 7304a3ac931SVitaly Wool 7314a3ac931SVitaly Wool *moved_chunks = 0; 7324a3ac931SVitaly Wool } 7334a3ac931SVitaly Wool 7344a3ac931SVitaly Wool return new_zhdr; 7354a3ac931SVitaly Wool 7364a3ac931SVitaly Wool out_fail: 7375e36c25bSMiaohe Lin if (new_zhdr && !kref_put(&new_zhdr->refcount, release_z3fold_page_locked)) { 7384a3ac931SVitaly Wool add_to_unbuddied(pool, new_zhdr); 7394a3ac931SVitaly Wool z3fold_page_unlock(new_zhdr); 7404a3ac931SVitaly Wool } 7414a3ac931SVitaly Wool return NULL; 7424a3ac931SVitaly Wool 7434a3ac931SVitaly Wool } 7444a3ac931SVitaly Wool 7451b096e5aSVitaly Wool #define BIG_CHUNK_GAP 3 7469a001fc1SVitaly Wool /* Has to be called with lock held */ 7479a001fc1SVitaly Wool static int z3fold_compact_page(struct z3fold_header *zhdr) 7489a001fc1SVitaly Wool { 7499a001fc1SVitaly Wool struct page *page = virt_to_page(zhdr); 7509a001fc1SVitaly Wool 751ede93213SVitaly Wool if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private)) 752ede93213SVitaly Wool return 0; /* can't move middle chunk, it's used */ 7539a001fc1SVitaly Wool 7541f862989SVitaly Wool if (unlikely(PageIsolated(page))) 7551f862989SVitaly Wool return 0; 7561f862989SVitaly Wool 757ede93213SVitaly Wool if (zhdr->middle_chunks == 0) 758ede93213SVitaly Wool return 0; /* nothing to compact */ 759ede93213SVitaly Wool 760ede93213SVitaly Wool if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) { 761ede93213SVitaly Wool /* move to the beginning */ 762ede93213SVitaly Wool mchunk_memmove(zhdr, ZHDR_CHUNKS); 7639a001fc1SVitaly Wool zhdr->first_chunks = zhdr->middle_chunks; 7649a001fc1SVitaly Wool zhdr->middle_chunks = 0; 7659a001fc1SVitaly Wool zhdr->start_middle = 0; 7669a001fc1SVitaly Wool zhdr->first_num++; 767ede93213SVitaly Wool return 1; 7689a001fc1SVitaly Wool } 7699a001fc1SVitaly Wool 7701b096e5aSVitaly Wool /* 7711b096e5aSVitaly Wool * moving data is expensive, so let's only do that if 7721b096e5aSVitaly Wool * there's substantial gain (at least BIG_CHUNK_GAP chunks) 7731b096e5aSVitaly Wool */ 7741b096e5aSVitaly Wool if (zhdr->first_chunks != 0 && zhdr->last_chunks == 0 && 7751b096e5aSVitaly Wool zhdr->start_middle - (zhdr->first_chunks + ZHDR_CHUNKS) >= 7761b096e5aSVitaly Wool BIG_CHUNK_GAP) { 7771b096e5aSVitaly Wool mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS); 7781b096e5aSVitaly Wool zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; 7791b096e5aSVitaly Wool return 1; 7801b096e5aSVitaly Wool } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 && 7811b096e5aSVitaly Wool TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle 7821b096e5aSVitaly Wool + zhdr->middle_chunks) >= 7831b096e5aSVitaly Wool BIG_CHUNK_GAP) { 7841b096e5aSVitaly Wool unsigned short new_start = TOTAL_CHUNKS - zhdr->last_chunks - 7851b096e5aSVitaly Wool zhdr->middle_chunks; 7861b096e5aSVitaly Wool mchunk_memmove(zhdr, new_start); 7871b096e5aSVitaly Wool zhdr->start_middle = new_start; 7881b096e5aSVitaly Wool return 1; 7891b096e5aSVitaly Wool } 7901b096e5aSVitaly Wool 7911b096e5aSVitaly Wool return 0; 7921b096e5aSVitaly Wool } 7931b096e5aSVitaly Wool 794d30561c5SVitaly Wool static void do_compact_page(struct z3fold_header *zhdr, bool locked) 795d30561c5SVitaly Wool { 7969050cce1SVitaly Wool struct z3fold_pool *pool = zhdr_to_pool(zhdr); 797d30561c5SVitaly Wool struct page *page; 798d30561c5SVitaly Wool 799d30561c5SVitaly Wool page = virt_to_page(zhdr); 800d30561c5SVitaly Wool if (locked) 801d30561c5SVitaly Wool WARN_ON(z3fold_page_trylock(zhdr)); 802d30561c5SVitaly Wool else 803d30561c5SVitaly Wool z3fold_page_lock(zhdr); 8045d03a661SVitaly Wool if (WARN_ON(!test_and_clear_bit(NEEDS_COMPACTING, &page->private))) { 805d30561c5SVitaly Wool z3fold_page_unlock(zhdr); 806d30561c5SVitaly Wool return; 807d30561c5SVitaly Wool } 808d30561c5SVitaly Wool spin_lock(&pool->lock); 809d30561c5SVitaly Wool list_del_init(&zhdr->buddy); 810d30561c5SVitaly Wool spin_unlock(&pool->lock); 811d30561c5SVitaly Wool 8125e36c25bSMiaohe Lin if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) 8135d03a661SVitaly Wool return; 8145d03a661SVitaly Wool 815dcf5aedbSVitaly Wool if (test_bit(PAGE_STALE, &page->private) || 816dcf5aedbSVitaly Wool test_and_set_bit(PAGE_CLAIMED, &page->private)) { 8171f862989SVitaly Wool z3fold_page_unlock(zhdr); 8181f862989SVitaly Wool return; 8191f862989SVitaly Wool } 8201f862989SVitaly Wool 8214a3ac931SVitaly Wool if (!zhdr->foreign_handles && buddy_single(zhdr) && 8224a3ac931SVitaly Wool zhdr->mapped_count == 0 && compact_single_buddy(zhdr)) { 8235e36c25bSMiaohe Lin if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) { 824dcf5aedbSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 8254a3ac931SVitaly Wool z3fold_page_unlock(zhdr); 826dcf5aedbSVitaly Wool } 8274a3ac931SVitaly Wool return; 8284a3ac931SVitaly Wool } 8294a3ac931SVitaly Wool 830d30561c5SVitaly Wool z3fold_compact_page(zhdr); 8319050cce1SVitaly Wool add_to_unbuddied(pool, zhdr); 832dcf5aedbSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 833d30561c5SVitaly Wool z3fold_page_unlock(zhdr); 834d30561c5SVitaly Wool } 835d30561c5SVitaly Wool 836d30561c5SVitaly Wool static void compact_page_work(struct work_struct *w) 837d30561c5SVitaly Wool { 838d30561c5SVitaly Wool struct z3fold_header *zhdr = container_of(w, struct z3fold_header, 839d30561c5SVitaly Wool work); 840d30561c5SVitaly Wool 841d30561c5SVitaly Wool do_compact_page(zhdr, false); 842d30561c5SVitaly Wool } 843d30561c5SVitaly Wool 8449050cce1SVitaly Wool /* returns _locked_ z3fold page header or NULL */ 8459050cce1SVitaly Wool static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool, 8469050cce1SVitaly Wool size_t size, bool can_sleep) 8479050cce1SVitaly Wool { 8489050cce1SVitaly Wool struct z3fold_header *zhdr = NULL; 8499050cce1SVitaly Wool struct page *page; 8509050cce1SVitaly Wool struct list_head *unbuddied; 8519050cce1SVitaly Wool int chunks = size_to_chunks(size), i; 8529050cce1SVitaly Wool 8539050cce1SVitaly Wool lookup: 854135f97fdSVitaly Wool migrate_disable(); 8559050cce1SVitaly Wool /* First, try to find an unbuddied z3fold page. */ 856135f97fdSVitaly Wool unbuddied = this_cpu_ptr(pool->unbuddied); 8579050cce1SVitaly Wool for_each_unbuddied_list(i, chunks) { 8589050cce1SVitaly Wool struct list_head *l = &unbuddied[i]; 8599050cce1SVitaly Wool 8609050cce1SVitaly Wool zhdr = list_first_entry_or_null(READ_ONCE(l), 8619050cce1SVitaly Wool struct z3fold_header, buddy); 8629050cce1SVitaly Wool 8639050cce1SVitaly Wool if (!zhdr) 8649050cce1SVitaly Wool continue; 8659050cce1SVitaly Wool 8669050cce1SVitaly Wool /* Re-check under lock. */ 8679050cce1SVitaly Wool spin_lock(&pool->lock); 8689050cce1SVitaly Wool if (unlikely(zhdr != list_first_entry(READ_ONCE(l), 8699050cce1SVitaly Wool struct z3fold_header, buddy)) || 8709050cce1SVitaly Wool !z3fold_page_trylock(zhdr)) { 8719050cce1SVitaly Wool spin_unlock(&pool->lock); 8729050cce1SVitaly Wool zhdr = NULL; 873135f97fdSVitaly Wool migrate_enable(); 8749050cce1SVitaly Wool if (can_sleep) 8759050cce1SVitaly Wool cond_resched(); 8769050cce1SVitaly Wool goto lookup; 8779050cce1SVitaly Wool } 8789050cce1SVitaly Wool list_del_init(&zhdr->buddy); 8799050cce1SVitaly Wool zhdr->cpu = -1; 8809050cce1SVitaly Wool spin_unlock(&pool->lock); 8819050cce1SVitaly Wool 8829050cce1SVitaly Wool page = virt_to_page(zhdr); 8834a3ac931SVitaly Wool if (test_bit(NEEDS_COMPACTING, &page->private) || 8844a3ac931SVitaly Wool test_bit(PAGE_CLAIMED, &page->private)) { 8859050cce1SVitaly Wool z3fold_page_unlock(zhdr); 8869050cce1SVitaly Wool zhdr = NULL; 887135f97fdSVitaly Wool migrate_enable(); 8889050cce1SVitaly Wool if (can_sleep) 8899050cce1SVitaly Wool cond_resched(); 8909050cce1SVitaly Wool goto lookup; 8919050cce1SVitaly Wool } 8929050cce1SVitaly Wool 8939050cce1SVitaly Wool /* 8949050cce1SVitaly Wool * this page could not be removed from its unbuddied 8959050cce1SVitaly Wool * list while pool lock was held, and then we've taken 8969050cce1SVitaly Wool * page lock so kref_put could not be called before 8979050cce1SVitaly Wool * we got here, so it's safe to just call kref_get() 8989050cce1SVitaly Wool */ 8999050cce1SVitaly Wool kref_get(&zhdr->refcount); 9009050cce1SVitaly Wool break; 9019050cce1SVitaly Wool } 902135f97fdSVitaly Wool migrate_enable(); 9039050cce1SVitaly Wool 904351618b2SVitaly Wool if (!zhdr) { 905351618b2SVitaly Wool int cpu; 906351618b2SVitaly Wool 907351618b2SVitaly Wool /* look for _exact_ match on other cpus' lists */ 908351618b2SVitaly Wool for_each_online_cpu(cpu) { 909351618b2SVitaly Wool struct list_head *l; 910351618b2SVitaly Wool 911351618b2SVitaly Wool unbuddied = per_cpu_ptr(pool->unbuddied, cpu); 912351618b2SVitaly Wool spin_lock(&pool->lock); 913351618b2SVitaly Wool l = &unbuddied[chunks]; 914351618b2SVitaly Wool 915351618b2SVitaly Wool zhdr = list_first_entry_or_null(READ_ONCE(l), 916351618b2SVitaly Wool struct z3fold_header, buddy); 917351618b2SVitaly Wool 918351618b2SVitaly Wool if (!zhdr || !z3fold_page_trylock(zhdr)) { 919351618b2SVitaly Wool spin_unlock(&pool->lock); 920351618b2SVitaly Wool zhdr = NULL; 921351618b2SVitaly Wool continue; 922351618b2SVitaly Wool } 923351618b2SVitaly Wool list_del_init(&zhdr->buddy); 924351618b2SVitaly Wool zhdr->cpu = -1; 925351618b2SVitaly Wool spin_unlock(&pool->lock); 926351618b2SVitaly Wool 927351618b2SVitaly Wool page = virt_to_page(zhdr); 9284a3ac931SVitaly Wool if (test_bit(NEEDS_COMPACTING, &page->private) || 9294a3ac931SVitaly Wool test_bit(PAGE_CLAIMED, &page->private)) { 930351618b2SVitaly Wool z3fold_page_unlock(zhdr); 931351618b2SVitaly Wool zhdr = NULL; 932351618b2SVitaly Wool if (can_sleep) 933351618b2SVitaly Wool cond_resched(); 934351618b2SVitaly Wool continue; 935351618b2SVitaly Wool } 936351618b2SVitaly Wool kref_get(&zhdr->refcount); 937351618b2SVitaly Wool break; 938351618b2SVitaly Wool } 939351618b2SVitaly Wool } 940351618b2SVitaly Wool 9417c61c35bSMiaohe Lin if (zhdr && !zhdr->slots) { 9424c6bdb36SMiaohe Lin zhdr->slots = alloc_slots(pool, GFP_ATOMIC); 9437c61c35bSMiaohe Lin if (!zhdr->slots) 9447c61c35bSMiaohe Lin goto out_fail; 9457c61c35bSMiaohe Lin } 9469050cce1SVitaly Wool return zhdr; 9477c61c35bSMiaohe Lin 9487c61c35bSMiaohe Lin out_fail: 9497c61c35bSMiaohe Lin if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) { 9507c61c35bSMiaohe Lin add_to_unbuddied(pool, zhdr); 9517c61c35bSMiaohe Lin z3fold_page_unlock(zhdr); 9527c61c35bSMiaohe Lin } 9537c61c35bSMiaohe Lin return NULL; 9549050cce1SVitaly Wool } 955d30561c5SVitaly Wool 956d30561c5SVitaly Wool /* 957d30561c5SVitaly Wool * API Functions 958d30561c5SVitaly Wool */ 959d30561c5SVitaly Wool 960d30561c5SVitaly Wool /** 961d30561c5SVitaly Wool * z3fold_create_pool() - create a new z3fold pool 962d30561c5SVitaly Wool * @name: pool name 963d30561c5SVitaly Wool * @gfp: gfp flags when allocating the z3fold pool structure 964d30561c5SVitaly Wool * @ops: user-defined operations for the z3fold pool 965d30561c5SVitaly Wool * 966d30561c5SVitaly Wool * Return: pointer to the new z3fold pool or NULL if the metadata allocation 967d30561c5SVitaly Wool * failed. 968d30561c5SVitaly Wool */ 969d30561c5SVitaly Wool static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp, 970d30561c5SVitaly Wool const struct z3fold_ops *ops) 971d30561c5SVitaly Wool { 972d30561c5SVitaly Wool struct z3fold_pool *pool = NULL; 973d30561c5SVitaly Wool int i, cpu; 974d30561c5SVitaly Wool 975d30561c5SVitaly Wool pool = kzalloc(sizeof(struct z3fold_pool), gfp); 976d30561c5SVitaly Wool if (!pool) 977d30561c5SVitaly Wool goto out; 9787c2b8baaSVitaly Wool pool->c_handle = kmem_cache_create("z3fold_handle", 9797c2b8baaSVitaly Wool sizeof(struct z3fold_buddy_slots), 9807c2b8baaSVitaly Wool SLOTS_ALIGN, 0, NULL); 9817c2b8baaSVitaly Wool if (!pool->c_handle) 9827c2b8baaSVitaly Wool goto out_c; 983d30561c5SVitaly Wool spin_lock_init(&pool->lock); 984d30561c5SVitaly Wool spin_lock_init(&pool->stale_lock); 985e891f60eSMiaohe Lin pool->unbuddied = __alloc_percpu(sizeof(struct list_head) * NCHUNKS, 986e891f60eSMiaohe Lin __alignof__(struct list_head)); 9871ec6995dSXidong Wang if (!pool->unbuddied) 9881ec6995dSXidong Wang goto out_pool; 989d30561c5SVitaly Wool for_each_possible_cpu(cpu) { 990d30561c5SVitaly Wool struct list_head *unbuddied = 991d30561c5SVitaly Wool per_cpu_ptr(pool->unbuddied, cpu); 992d30561c5SVitaly Wool for_each_unbuddied_list(i, 0) 993d30561c5SVitaly Wool INIT_LIST_HEAD(&unbuddied[i]); 994d30561c5SVitaly Wool } 995d30561c5SVitaly Wool INIT_LIST_HEAD(&pool->lru); 996d30561c5SVitaly Wool INIT_LIST_HEAD(&pool->stale); 997d30561c5SVitaly Wool atomic64_set(&pool->pages_nr, 0); 998d30561c5SVitaly Wool pool->name = name; 999d30561c5SVitaly Wool pool->compact_wq = create_singlethread_workqueue(pool->name); 1000d30561c5SVitaly Wool if (!pool->compact_wq) 10011ec6995dSXidong Wang goto out_unbuddied; 1002d30561c5SVitaly Wool pool->release_wq = create_singlethread_workqueue(pool->name); 1003d30561c5SVitaly Wool if (!pool->release_wq) 1004d30561c5SVitaly Wool goto out_wq; 10051f862989SVitaly Wool if (z3fold_register_migration(pool)) 10061f862989SVitaly Wool goto out_rwq; 1007d30561c5SVitaly Wool INIT_WORK(&pool->work, free_pages_work); 1008d30561c5SVitaly Wool pool->ops = ops; 1009d30561c5SVitaly Wool return pool; 1010d30561c5SVitaly Wool 10111f862989SVitaly Wool out_rwq: 10121f862989SVitaly Wool destroy_workqueue(pool->release_wq); 1013d30561c5SVitaly Wool out_wq: 1014d30561c5SVitaly Wool destroy_workqueue(pool->compact_wq); 10151ec6995dSXidong Wang out_unbuddied: 10161ec6995dSXidong Wang free_percpu(pool->unbuddied); 10171ec6995dSXidong Wang out_pool: 10187c2b8baaSVitaly Wool kmem_cache_destroy(pool->c_handle); 10197c2b8baaSVitaly Wool out_c: 1020d30561c5SVitaly Wool kfree(pool); 10211ec6995dSXidong Wang out: 1022d30561c5SVitaly Wool return NULL; 1023d30561c5SVitaly Wool } 1024d30561c5SVitaly Wool 1025d30561c5SVitaly Wool /** 1026d30561c5SVitaly Wool * z3fold_destroy_pool() - destroys an existing z3fold pool 1027d30561c5SVitaly Wool * @pool: the z3fold pool to be destroyed 1028d30561c5SVitaly Wool * 1029d30561c5SVitaly Wool * The pool should be emptied before this function is called. 1030d30561c5SVitaly Wool */ 1031d30561c5SVitaly Wool static void z3fold_destroy_pool(struct z3fold_pool *pool) 1032d30561c5SVitaly Wool { 10337c2b8baaSVitaly Wool kmem_cache_destroy(pool->c_handle); 10346051d3bdSHenry Burns 10356051d3bdSHenry Burns /* 10366051d3bdSHenry Burns * We need to destroy pool->compact_wq before pool->release_wq, 10376051d3bdSHenry Burns * as any pending work on pool->compact_wq will call 10386051d3bdSHenry Burns * queue_work(pool->release_wq, &pool->work). 1039b997052bSHenry Burns * 1040b997052bSHenry Burns * There are still outstanding pages until both workqueues are drained, 1041b997052bSHenry Burns * so we cannot unregister migration until then. 10426051d3bdSHenry Burns */ 10436051d3bdSHenry Burns 1044d30561c5SVitaly Wool destroy_workqueue(pool->compact_wq); 10456051d3bdSHenry Burns destroy_workqueue(pool->release_wq); 1046b997052bSHenry Burns z3fold_unregister_migration(pool); 1047dac0d1cfSMiaohe Lin free_percpu(pool->unbuddied); 1048d30561c5SVitaly Wool kfree(pool); 1049d30561c5SVitaly Wool } 1050d30561c5SVitaly Wool 10519a001fc1SVitaly Wool /** 10529a001fc1SVitaly Wool * z3fold_alloc() - allocates a region of a given size 10539a001fc1SVitaly Wool * @pool: z3fold pool from which to allocate 10549a001fc1SVitaly Wool * @size: size in bytes of the desired allocation 10559a001fc1SVitaly Wool * @gfp: gfp flags used if the pool needs to grow 10569a001fc1SVitaly Wool * @handle: handle of the new allocation 10579a001fc1SVitaly Wool * 10589a001fc1SVitaly Wool * This function will attempt to find a free region in the pool large enough to 10599a001fc1SVitaly Wool * satisfy the allocation request. A search of the unbuddied lists is 10609a001fc1SVitaly Wool * performed first. If no suitable free region is found, then a new page is 10619a001fc1SVitaly Wool * allocated and added to the pool to satisfy the request. 10629a001fc1SVitaly Wool * 10639a001fc1SVitaly Wool * Return: 0 if success and handle is set, otherwise -EINVAL if the size or 10649a001fc1SVitaly Wool * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate 10659a001fc1SVitaly Wool * a new page. 10669a001fc1SVitaly Wool */ 10679a001fc1SVitaly Wool static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, 10689a001fc1SVitaly Wool unsigned long *handle) 10699a001fc1SVitaly Wool { 10709050cce1SVitaly Wool int chunks = size_to_chunks(size); 10719a001fc1SVitaly Wool struct z3fold_header *zhdr = NULL; 1072d30561c5SVitaly Wool struct page *page = NULL; 10739a001fc1SVitaly Wool enum buddy bud; 10748a97ea54SMatthew Wilcox bool can_sleep = gfpflags_allow_blocking(gfp); 10759a001fc1SVitaly Wool 1076f4bad643SMiaohe Lin if (!size || (gfp & __GFP_HIGHMEM)) 10779a001fc1SVitaly Wool return -EINVAL; 10789a001fc1SVitaly Wool 10799a001fc1SVitaly Wool if (size > PAGE_SIZE) 10809a001fc1SVitaly Wool return -ENOSPC; 10819a001fc1SVitaly Wool 10829a001fc1SVitaly Wool if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE) 10839a001fc1SVitaly Wool bud = HEADLESS; 10849a001fc1SVitaly Wool else { 10859050cce1SVitaly Wool retry: 10869050cce1SVitaly Wool zhdr = __z3fold_alloc(pool, size, can_sleep); 1087d30561c5SVitaly Wool if (zhdr) { 1088dcf5aedbSVitaly Wool bud = get_free_buddy(zhdr, chunks); 1089dcf5aedbSVitaly Wool if (bud == HEADLESS) { 10905e36c25bSMiaohe Lin if (!kref_put(&zhdr->refcount, 1091d30561c5SVitaly Wool release_z3fold_page_locked)) 1092d30561c5SVitaly Wool z3fold_page_unlock(zhdr); 10939a001fc1SVitaly Wool pr_err("No free chunks in unbuddied\n"); 10949a001fc1SVitaly Wool WARN_ON(1); 10959050cce1SVitaly Wool goto retry; 10969a001fc1SVitaly Wool } 10979050cce1SVitaly Wool page = virt_to_page(zhdr); 10989a001fc1SVitaly Wool goto found; 10999a001fc1SVitaly Wool } 11009a001fc1SVitaly Wool bud = FIRST; 11019a001fc1SVitaly Wool } 11029a001fc1SVitaly Wool 11035c9bab59SVitaly Wool page = alloc_page(gfp); 11049a001fc1SVitaly Wool if (!page) 11059a001fc1SVitaly Wool return -ENOMEM; 11062f1e5e4dSVitaly Wool 110763398413SVitaly Wool zhdr = init_z3fold_page(page, bud == HEADLESS, pool, gfp); 11089050cce1SVitaly Wool if (!zhdr) { 11099050cce1SVitaly Wool __free_page(page); 11109050cce1SVitaly Wool return -ENOMEM; 11119050cce1SVitaly Wool } 11129050cce1SVitaly Wool atomic64_inc(&pool->pages_nr); 11139a001fc1SVitaly Wool 11149a001fc1SVitaly Wool if (bud == HEADLESS) { 11159a001fc1SVitaly Wool set_bit(PAGE_HEADLESS, &page->private); 11169a001fc1SVitaly Wool goto headless; 11179a001fc1SVitaly Wool } 1118810481a2SHenry Burns if (can_sleep) { 1119810481a2SHenry Burns lock_page(page); 11201f862989SVitaly Wool __SetPageMovable(page, pool->inode->i_mapping); 1121810481a2SHenry Burns unlock_page(page); 1122810481a2SHenry Burns } else { 11232c0f3514SMiaohe Lin WARN_ON(!trylock_page(page)); 1124810481a2SHenry Burns __SetPageMovable(page, pool->inode->i_mapping); 1125810481a2SHenry Burns unlock_page(page); 1126810481a2SHenry Burns } 11272f1e5e4dSVitaly Wool z3fold_page_lock(zhdr); 11289a001fc1SVitaly Wool 11299a001fc1SVitaly Wool found: 11309a001fc1SVitaly Wool if (bud == FIRST) 11319a001fc1SVitaly Wool zhdr->first_chunks = chunks; 11329a001fc1SVitaly Wool else if (bud == LAST) 11339a001fc1SVitaly Wool zhdr->last_chunks = chunks; 11349a001fc1SVitaly Wool else { 11359a001fc1SVitaly Wool zhdr->middle_chunks = chunks; 1136ede93213SVitaly Wool zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; 11379a001fc1SVitaly Wool } 11389050cce1SVitaly Wool add_to_unbuddied(pool, zhdr); 11399a001fc1SVitaly Wool 11409a001fc1SVitaly Wool headless: 1141d30561c5SVitaly Wool spin_lock(&pool->lock); 11429a001fc1SVitaly Wool /* Add/move z3fold page to beginning of LRU */ 11439a001fc1SVitaly Wool if (!list_empty(&page->lru)) 11449a001fc1SVitaly Wool list_del(&page->lru); 11459a001fc1SVitaly Wool 11469a001fc1SVitaly Wool list_add(&page->lru, &pool->lru); 11479a001fc1SVitaly Wool 11489a001fc1SVitaly Wool *handle = encode_handle(zhdr, bud); 11499a001fc1SVitaly Wool spin_unlock(&pool->lock); 11502f1e5e4dSVitaly Wool if (bud != HEADLESS) 11512f1e5e4dSVitaly Wool z3fold_page_unlock(zhdr); 11529a001fc1SVitaly Wool 11539a001fc1SVitaly Wool return 0; 11549a001fc1SVitaly Wool } 11559a001fc1SVitaly Wool 11569a001fc1SVitaly Wool /** 11579a001fc1SVitaly Wool * z3fold_free() - frees the allocation associated with the given handle 11589a001fc1SVitaly Wool * @pool: pool in which the allocation resided 11599a001fc1SVitaly Wool * @handle: handle associated with the allocation returned by z3fold_alloc() 11609a001fc1SVitaly Wool * 11619a001fc1SVitaly Wool * In the case that the z3fold page in which the allocation resides is under 1162ed0e5dcaSMiaohe Lin * reclaim, as indicated by the PAGE_CLAIMED flag being set, this function 1163ed0e5dcaSMiaohe Lin * only sets the first|middle|last_chunks to 0. The page is actually freed 1164ed0e5dcaSMiaohe Lin * once all buddies are evicted (see z3fold_reclaim_page() below). 11659a001fc1SVitaly Wool */ 11669a001fc1SVitaly Wool static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) 11679a001fc1SVitaly Wool { 11689a001fc1SVitaly Wool struct z3fold_header *zhdr; 11699a001fc1SVitaly Wool struct page *page; 11709a001fc1SVitaly Wool enum buddy bud; 11715b6807deSVitaly Wool bool page_claimed; 11729a001fc1SVitaly Wool 11734a3ac931SVitaly Wool zhdr = get_z3fold_header(handle); 11749a001fc1SVitaly Wool page = virt_to_page(zhdr); 11755b6807deSVitaly Wool page_claimed = test_and_set_bit(PAGE_CLAIMED, &page->private); 11769a001fc1SVitaly Wool 11779a001fc1SVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) { 1178ca0246bbSVitaly Wool /* if a headless page is under reclaim, just leave. 1179ca0246bbSVitaly Wool * NB: we use test_and_set_bit for a reason: if the bit 1180ca0246bbSVitaly Wool * has not been set before, we release this page 1181ca0246bbSVitaly Wool * immediately so we don't care about its value any more. 1182ca0246bbSVitaly Wool */ 11835b6807deSVitaly Wool if (!page_claimed) { 1184ca0246bbSVitaly Wool spin_lock(&pool->lock); 1185ca0246bbSVitaly Wool list_del(&page->lru); 1186ca0246bbSVitaly Wool spin_unlock(&pool->lock); 11874a3ac931SVitaly Wool put_z3fold_header(zhdr); 11881f862989SVitaly Wool free_z3fold_page(page, true); 1189ca0246bbSVitaly Wool atomic64_dec(&pool->pages_nr); 1190ca0246bbSVitaly Wool } 1191ca0246bbSVitaly Wool return; 1192ca0246bbSVitaly Wool } 1193ca0246bbSVitaly Wool 1194ca0246bbSVitaly Wool /* Non-headless case */ 119543afc194SVitaly Wool bud = handle_to_buddy(handle); 11969a001fc1SVitaly Wool 11979a001fc1SVitaly Wool switch (bud) { 11989a001fc1SVitaly Wool case FIRST: 11999a001fc1SVitaly Wool zhdr->first_chunks = 0; 12009a001fc1SVitaly Wool break; 12019a001fc1SVitaly Wool case MIDDLE: 12029a001fc1SVitaly Wool zhdr->middle_chunks = 0; 12039a001fc1SVitaly Wool break; 12049a001fc1SVitaly Wool case LAST: 12059a001fc1SVitaly Wool zhdr->last_chunks = 0; 12069a001fc1SVitaly Wool break; 12079a001fc1SVitaly Wool default: 12089a001fc1SVitaly Wool pr_err("%s: unknown bud %d\n", __func__, bud); 12099a001fc1SVitaly Wool WARN_ON(1); 12104a3ac931SVitaly Wool put_z3fold_header(zhdr); 12119a001fc1SVitaly Wool return; 12129a001fc1SVitaly Wool } 12139a001fc1SVitaly Wool 12144a3ac931SVitaly Wool if (!page_claimed) 1215fc548865SVitaly Wool free_handle(handle, zhdr); 12165e36c25bSMiaohe Lin if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) 1217d30561c5SVitaly Wool return; 12185b6807deSVitaly Wool if (page_claimed) { 12195b6807deSVitaly Wool /* the page has not been claimed by us */ 1220ed0e5dcaSMiaohe Lin put_z3fold_header(zhdr); 12216098d7e1SVitaly Wool return; 12226098d7e1SVitaly Wool } 1223dcf5aedbSVitaly Wool if (test_and_set_bit(NEEDS_COMPACTING, &page->private)) { 12245b6807deSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 12254a1c3839SMiaohe Lin put_z3fold_header(zhdr); 1226d30561c5SVitaly Wool return; 1227d30561c5SVitaly Wool } 1228d30561c5SVitaly Wool if (zhdr->cpu < 0 || !cpu_online(zhdr->cpu)) { 1229d30561c5SVitaly Wool zhdr->cpu = -1; 12305d03a661SVitaly Wool kref_get(&zhdr->refcount); 12315b6807deSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 12324a3ac931SVitaly Wool do_compact_page(zhdr, true); 1233d30561c5SVitaly Wool return; 1234d30561c5SVitaly Wool } 12355d03a661SVitaly Wool kref_get(&zhdr->refcount); 12365b6807deSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 12374a3ac931SVitaly Wool queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work); 12384a3ac931SVitaly Wool put_z3fold_header(zhdr); 12399a001fc1SVitaly Wool } 12409a001fc1SVitaly Wool 12419a001fc1SVitaly Wool /** 12429a001fc1SVitaly Wool * z3fold_reclaim_page() - evicts allocations from a pool page and frees it 12439a001fc1SVitaly Wool * @pool: pool from which a page will attempt to be evicted 1244f144c390SMike Rapoport * @retries: number of pages on the LRU list for which eviction will 12459a001fc1SVitaly Wool * be attempted before failing 12469a001fc1SVitaly Wool * 12479a001fc1SVitaly Wool * z3fold reclaim is different from normal system reclaim in that it is done 12489a001fc1SVitaly Wool * from the bottom, up. This is because only the bottom layer, z3fold, has 12499a001fc1SVitaly Wool * information on how the allocations are organized within each z3fold page. 12509a001fc1SVitaly Wool * This has the potential to create interesting locking situations between 12519a001fc1SVitaly Wool * z3fold and the user, however. 12529a001fc1SVitaly Wool * 12539a001fc1SVitaly Wool * To avoid these, this is how z3fold_reclaim_page() should be called: 1254f144c390SMike Rapoport * 12559a001fc1SVitaly Wool * The user detects a page should be reclaimed and calls z3fold_reclaim_page(). 12569a001fc1SVitaly Wool * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and 12579a001fc1SVitaly Wool * call the user-defined eviction handler with the pool and handle as 12589a001fc1SVitaly Wool * arguments. 12599a001fc1SVitaly Wool * 12609a001fc1SVitaly Wool * If the handle can not be evicted, the eviction handler should return 12619a001fc1SVitaly Wool * non-zero. z3fold_reclaim_page() will add the z3fold page back to the 12629a001fc1SVitaly Wool * appropriate list and try the next z3fold page on the LRU up to 12639a001fc1SVitaly Wool * a user defined number of retries. 12649a001fc1SVitaly Wool * 12659a001fc1SVitaly Wool * If the handle is successfully evicted, the eviction handler should 12669a001fc1SVitaly Wool * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free() 12679a001fc1SVitaly Wool * contains logic to delay freeing the page if the page is under reclaim, 12689a001fc1SVitaly Wool * as indicated by the setting of the PG_reclaim flag on the underlying page. 12699a001fc1SVitaly Wool * 12709a001fc1SVitaly Wool * If all buddies in the z3fold page are successfully evicted, then the 12719a001fc1SVitaly Wool * z3fold page can be freed. 12729a001fc1SVitaly Wool * 12739a001fc1SVitaly Wool * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are 12749a001fc1SVitaly Wool * no pages to evict or an eviction handler is not registered, -EAGAIN if 12759a001fc1SVitaly Wool * the retry limit was hit. 12769a001fc1SVitaly Wool */ 12779a001fc1SVitaly Wool static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) 12789a001fc1SVitaly Wool { 12794a3ac931SVitaly Wool int i, ret = -1; 1280d30561c5SVitaly Wool struct z3fold_header *zhdr = NULL; 1281d30561c5SVitaly Wool struct page *page = NULL; 1282d30561c5SVitaly Wool struct list_head *pos; 12839a001fc1SVitaly Wool unsigned long first_handle = 0, middle_handle = 0, last_handle = 0; 1284dcf5aedbSVitaly Wool struct z3fold_buddy_slots slots __attribute__((aligned(SLOTS_ALIGN))); 1285dcf5aedbSVitaly Wool 1286dcf5aedbSVitaly Wool rwlock_init(&slots.lock); 1287dcf5aedbSVitaly Wool slots.pool = (unsigned long)pool | (1 << HANDLES_NOFREE); 12889a001fc1SVitaly Wool 12899a001fc1SVitaly Wool spin_lock(&pool->lock); 12902f1e5e4dSVitaly Wool if (!pool->ops || !pool->ops->evict || retries == 0) { 12919a001fc1SVitaly Wool spin_unlock(&pool->lock); 12929a001fc1SVitaly Wool return -EINVAL; 12939a001fc1SVitaly Wool } 12949a001fc1SVitaly Wool for (i = 0; i < retries; i++) { 12952f1e5e4dSVitaly Wool if (list_empty(&pool->lru)) { 12962f1e5e4dSVitaly Wool spin_unlock(&pool->lock); 12972f1e5e4dSVitaly Wool return -EINVAL; 12982f1e5e4dSVitaly Wool } 1299d30561c5SVitaly Wool list_for_each_prev(pos, &pool->lru) { 1300d30561c5SVitaly Wool page = list_entry(pos, struct page, lru); 1301ca0246bbSVitaly Wool 13023f9d2b57SVitaly Wool zhdr = page_address(page); 13036d679578SThomas Hebb if (test_bit(PAGE_HEADLESS, &page->private)) { 13046d679578SThomas Hebb /* 13056d679578SThomas Hebb * For non-headless pages, we wait to do this 13066d679578SThomas Hebb * until we have the page lock to avoid racing 13076d679578SThomas Hebb * with __z3fold_alloc(). Headless pages don't 13086d679578SThomas Hebb * have a lock (and __z3fold_alloc() will never 13096d679578SThomas Hebb * see them), but we still need to test and set 13106d679578SThomas Hebb * PAGE_CLAIMED to avoid racing with 13116d679578SThomas Hebb * z3fold_free(), so just do it now before 13126d679578SThomas Hebb * leaving the loop. 13136d679578SThomas Hebb */ 13146d679578SThomas Hebb if (test_and_set_bit(PAGE_CLAIMED, &page->private)) 13156d679578SThomas Hebb continue; 13166d679578SThomas Hebb 1317ca0246bbSVitaly Wool break; 13186d679578SThomas Hebb } 1319ca0246bbSVitaly Wool 1320ca0246bbSVitaly Wool if (!z3fold_page_trylock(zhdr)) { 1321ca0246bbSVitaly Wool zhdr = NULL; 1322d30561c5SVitaly Wool continue; /* can't evict at this point */ 1323ca0246bbSVitaly Wool } 1324dcf5aedbSVitaly Wool 1325dcf5aedbSVitaly Wool /* test_and_set_bit is of course atomic, but we still 1326dcf5aedbSVitaly Wool * need to do it under page lock, otherwise checking 1327dcf5aedbSVitaly Wool * that bit in __z3fold_alloc wouldn't make sense 1328dcf5aedbSVitaly Wool */ 1329dcf5aedbSVitaly Wool if (zhdr->foreign_handles || 1330dcf5aedbSVitaly Wool test_and_set_bit(PAGE_CLAIMED, &page->private)) { 13314a3ac931SVitaly Wool z3fold_page_unlock(zhdr); 13324a3ac931SVitaly Wool zhdr = NULL; 13334a3ac931SVitaly Wool continue; /* can't evict such page */ 13344a3ac931SVitaly Wool } 1335d30561c5SVitaly Wool list_del_init(&zhdr->buddy); 1336d30561c5SVitaly Wool zhdr->cpu = -1; 133704094226SMiaohe Lin /* See comment in __z3fold_alloc. */ 133804094226SMiaohe Lin kref_get(&zhdr->refcount); 13396098d7e1SVitaly Wool break; 1340d30561c5SVitaly Wool } 1341d30561c5SVitaly Wool 1342ca0246bbSVitaly Wool if (!zhdr) 1343ca0246bbSVitaly Wool break; 1344ca0246bbSVitaly Wool 1345d30561c5SVitaly Wool list_del_init(&page->lru); 13462f1e5e4dSVitaly Wool spin_unlock(&pool->lock); 1347d30561c5SVitaly Wool 1348d30561c5SVitaly Wool if (!test_bit(PAGE_HEADLESS, &page->private)) { 13499a001fc1SVitaly Wool /* 13503f9d2b57SVitaly Wool * We need encode the handles before unlocking, and 13513f9d2b57SVitaly Wool * use our local slots structure because z3fold_free 13523f9d2b57SVitaly Wool * can zero out zhdr->slots and we can't do much 13533f9d2b57SVitaly Wool * about that 13549a001fc1SVitaly Wool */ 13559a001fc1SVitaly Wool first_handle = 0; 13569a001fc1SVitaly Wool last_handle = 0; 13579a001fc1SVitaly Wool middle_handle = 0; 1358dcf5aedbSVitaly Wool memset(slots.slot, 0, sizeof(slots.slot)); 13599a001fc1SVitaly Wool if (zhdr->first_chunks) 1360dcf5aedbSVitaly Wool first_handle = __encode_handle(zhdr, &slots, 1361dcf5aedbSVitaly Wool FIRST); 13629a001fc1SVitaly Wool if (zhdr->middle_chunks) 1363dcf5aedbSVitaly Wool middle_handle = __encode_handle(zhdr, &slots, 1364dcf5aedbSVitaly Wool MIDDLE); 13659a001fc1SVitaly Wool if (zhdr->last_chunks) 1366dcf5aedbSVitaly Wool last_handle = __encode_handle(zhdr, &slots, 1367dcf5aedbSVitaly Wool LAST); 1368d30561c5SVitaly Wool /* 1369d30561c5SVitaly Wool * it's safe to unlock here because we hold a 1370d30561c5SVitaly Wool * reference to this page 1371d30561c5SVitaly Wool */ 13722f1e5e4dSVitaly Wool z3fold_page_unlock(zhdr); 13739a001fc1SVitaly Wool } else { 13744a3ac931SVitaly Wool first_handle = encode_handle(zhdr, HEADLESS); 13759a001fc1SVitaly Wool last_handle = middle_handle = 0; 13762f1e5e4dSVitaly Wool } 13779a001fc1SVitaly Wool /* Issue the eviction callback(s) */ 13789a001fc1SVitaly Wool if (middle_handle) { 13799a001fc1SVitaly Wool ret = pool->ops->evict(pool, middle_handle); 13809a001fc1SVitaly Wool if (ret) 13819a001fc1SVitaly Wool goto next; 13829a001fc1SVitaly Wool } 13839a001fc1SVitaly Wool if (first_handle) { 13849a001fc1SVitaly Wool ret = pool->ops->evict(pool, first_handle); 13859a001fc1SVitaly Wool if (ret) 13869a001fc1SVitaly Wool goto next; 13879a001fc1SVitaly Wool } 13889a001fc1SVitaly Wool if (last_handle) { 13899a001fc1SVitaly Wool ret = pool->ops->evict(pool, last_handle); 13909a001fc1SVitaly Wool if (ret) 13919a001fc1SVitaly Wool goto next; 13929a001fc1SVitaly Wool } 13939a001fc1SVitaly Wool next: 13945a27aa82SVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) { 13955a27aa82SVitaly Wool if (ret == 0) { 13961f862989SVitaly Wool free_z3fold_page(page, true); 1397ca0246bbSVitaly Wool atomic64_dec(&pool->pages_nr); 13989a001fc1SVitaly Wool return 0; 13995a27aa82SVitaly Wool } 14006098d7e1SVitaly Wool spin_lock(&pool->lock); 14016098d7e1SVitaly Wool list_add(&page->lru, &pool->lru); 1402d5567c9dSVitaly Wool spin_unlock(&pool->lock); 14033f9d2b57SVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 14046098d7e1SVitaly Wool } else { 1405dcf5aedbSVitaly Wool struct z3fold_buddy_slots *slots = zhdr->slots; 14066098d7e1SVitaly Wool z3fold_page_lock(zhdr); 14076098d7e1SVitaly Wool if (kref_put(&zhdr->refcount, 14086098d7e1SVitaly Wool release_z3fold_page_locked)) { 1409dcf5aedbSVitaly Wool kmem_cache_free(pool->c_handle, slots); 14105a27aa82SVitaly Wool return 0; 14115a27aa82SVitaly Wool } 14125a27aa82SVitaly Wool /* 14136098d7e1SVitaly Wool * if we are here, the page is still not completely 14146098d7e1SVitaly Wool * free. Take the global pool lock then to be able 14156098d7e1SVitaly Wool * to add it back to the lru list 14165a27aa82SVitaly Wool */ 14176098d7e1SVitaly Wool spin_lock(&pool->lock); 14189a001fc1SVitaly Wool list_add(&page->lru, &pool->lru); 14196098d7e1SVitaly Wool spin_unlock(&pool->lock); 14206cf9a349SMiaohe Lin if (list_empty(&zhdr->buddy)) 14216cf9a349SMiaohe Lin add_to_unbuddied(pool, zhdr); 14223f9d2b57SVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 14234a1c3839SMiaohe Lin z3fold_page_unlock(zhdr); 14246098d7e1SVitaly Wool } 14256098d7e1SVitaly Wool 14266098d7e1SVitaly Wool /* We started off locked to we need to lock the pool back */ 14276098d7e1SVitaly Wool spin_lock(&pool->lock); 14289a001fc1SVitaly Wool } 14299a001fc1SVitaly Wool spin_unlock(&pool->lock); 14309a001fc1SVitaly Wool return -EAGAIN; 14319a001fc1SVitaly Wool } 14329a001fc1SVitaly Wool 14339a001fc1SVitaly Wool /** 14349a001fc1SVitaly Wool * z3fold_map() - maps the allocation associated with the given handle 14359a001fc1SVitaly Wool * @pool: pool in which the allocation resides 14369a001fc1SVitaly Wool * @handle: handle associated with the allocation to be mapped 14379a001fc1SVitaly Wool * 14389a001fc1SVitaly Wool * Extracts the buddy number from handle and constructs the pointer to the 14399a001fc1SVitaly Wool * correct starting chunk within the page. 14409a001fc1SVitaly Wool * 14419a001fc1SVitaly Wool * Returns: a pointer to the mapped allocation 14429a001fc1SVitaly Wool */ 14439a001fc1SVitaly Wool static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle) 14449a001fc1SVitaly Wool { 14459a001fc1SVitaly Wool struct z3fold_header *zhdr; 14469a001fc1SVitaly Wool struct page *page; 14479a001fc1SVitaly Wool void *addr; 14489a001fc1SVitaly Wool enum buddy buddy; 14499a001fc1SVitaly Wool 14504a3ac931SVitaly Wool zhdr = get_z3fold_header(handle); 14519a001fc1SVitaly Wool addr = zhdr; 14529a001fc1SVitaly Wool page = virt_to_page(zhdr); 14539a001fc1SVitaly Wool 14549a001fc1SVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) 14559a001fc1SVitaly Wool goto out; 14569a001fc1SVitaly Wool 14579a001fc1SVitaly Wool buddy = handle_to_buddy(handle); 14589a001fc1SVitaly Wool switch (buddy) { 14599a001fc1SVitaly Wool case FIRST: 14609a001fc1SVitaly Wool addr += ZHDR_SIZE_ALIGNED; 14619a001fc1SVitaly Wool break; 14629a001fc1SVitaly Wool case MIDDLE: 14639a001fc1SVitaly Wool addr += zhdr->start_middle << CHUNK_SHIFT; 14649a001fc1SVitaly Wool set_bit(MIDDLE_CHUNK_MAPPED, &page->private); 14659a001fc1SVitaly Wool break; 14669a001fc1SVitaly Wool case LAST: 1467ca0246bbSVitaly Wool addr += PAGE_SIZE - (handle_to_chunks(handle) << CHUNK_SHIFT); 14689a001fc1SVitaly Wool break; 14699a001fc1SVitaly Wool default: 14709a001fc1SVitaly Wool pr_err("unknown buddy id %d\n", buddy); 14719a001fc1SVitaly Wool WARN_ON(1); 14729a001fc1SVitaly Wool addr = NULL; 14739a001fc1SVitaly Wool break; 14749a001fc1SVitaly Wool } 14752f1e5e4dSVitaly Wool 14761f862989SVitaly Wool if (addr) 14771f862989SVitaly Wool zhdr->mapped_count++; 14789a001fc1SVitaly Wool out: 14794a3ac931SVitaly Wool put_z3fold_header(zhdr); 14809a001fc1SVitaly Wool return addr; 14819a001fc1SVitaly Wool } 14829a001fc1SVitaly Wool 14839a001fc1SVitaly Wool /** 14849a001fc1SVitaly Wool * z3fold_unmap() - unmaps the allocation associated with the given handle 14859a001fc1SVitaly Wool * @pool: pool in which the allocation resides 14869a001fc1SVitaly Wool * @handle: handle associated with the allocation to be unmapped 14879a001fc1SVitaly Wool */ 14889a001fc1SVitaly Wool static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle) 14899a001fc1SVitaly Wool { 14909a001fc1SVitaly Wool struct z3fold_header *zhdr; 14919a001fc1SVitaly Wool struct page *page; 14929a001fc1SVitaly Wool enum buddy buddy; 14939a001fc1SVitaly Wool 14944a3ac931SVitaly Wool zhdr = get_z3fold_header(handle); 14959a001fc1SVitaly Wool page = virt_to_page(zhdr); 14969a001fc1SVitaly Wool 14972f1e5e4dSVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) 14989a001fc1SVitaly Wool return; 14999a001fc1SVitaly Wool 15009a001fc1SVitaly Wool buddy = handle_to_buddy(handle); 15019a001fc1SVitaly Wool if (buddy == MIDDLE) 15029a001fc1SVitaly Wool clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); 15031f862989SVitaly Wool zhdr->mapped_count--; 15044a3ac931SVitaly Wool put_z3fold_header(zhdr); 15059a001fc1SVitaly Wool } 15069a001fc1SVitaly Wool 15079a001fc1SVitaly Wool /** 15089a001fc1SVitaly Wool * z3fold_get_pool_size() - gets the z3fold pool size in pages 15099a001fc1SVitaly Wool * @pool: pool whose size is being queried 15109a001fc1SVitaly Wool * 151112d59ae6SVitaly Wool * Returns: size in pages of the given pool. 15129a001fc1SVitaly Wool */ 15139a001fc1SVitaly Wool static u64 z3fold_get_pool_size(struct z3fold_pool *pool) 15149a001fc1SVitaly Wool { 151512d59ae6SVitaly Wool return atomic64_read(&pool->pages_nr); 15169a001fc1SVitaly Wool } 15179a001fc1SVitaly Wool 15181f862989SVitaly Wool static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode) 15191f862989SVitaly Wool { 15201f862989SVitaly Wool struct z3fold_header *zhdr; 15211f862989SVitaly Wool struct z3fold_pool *pool; 15221f862989SVitaly Wool 15231f862989SVitaly Wool VM_BUG_ON_PAGE(!PageMovable(page), page); 15241f862989SVitaly Wool VM_BUG_ON_PAGE(PageIsolated(page), page); 15251f862989SVitaly Wool 1526dcf5aedbSVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) 15271f862989SVitaly Wool return false; 15281f862989SVitaly Wool 15291f862989SVitaly Wool zhdr = page_address(page); 15301f862989SVitaly Wool z3fold_page_lock(zhdr); 15311f862989SVitaly Wool if (test_bit(NEEDS_COMPACTING, &page->private) || 15321f862989SVitaly Wool test_bit(PAGE_STALE, &page->private)) 15331f862989SVitaly Wool goto out; 15341f862989SVitaly Wool 15354a3ac931SVitaly Wool if (zhdr->mapped_count != 0 || zhdr->foreign_handles != 0) 15364a3ac931SVitaly Wool goto out; 15371f862989SVitaly Wool 1538dcf5aedbSVitaly Wool if (test_and_set_bit(PAGE_CLAIMED, &page->private)) 1539dcf5aedbSVitaly Wool goto out; 15404a3ac931SVitaly Wool pool = zhdr_to_pool(zhdr); 15414a3ac931SVitaly Wool spin_lock(&pool->lock); 15421f862989SVitaly Wool if (!list_empty(&zhdr->buddy)) 15431f862989SVitaly Wool list_del_init(&zhdr->buddy); 15441f862989SVitaly Wool if (!list_empty(&page->lru)) 15454a3ac931SVitaly Wool list_del_init(&page->lru); 15461f862989SVitaly Wool spin_unlock(&pool->lock); 15474a3ac931SVitaly Wool 15484a3ac931SVitaly Wool kref_get(&zhdr->refcount); 15491f862989SVitaly Wool z3fold_page_unlock(zhdr); 15501f862989SVitaly Wool return true; 15514a3ac931SVitaly Wool 15521f862989SVitaly Wool out: 15531f862989SVitaly Wool z3fold_page_unlock(zhdr); 15541f862989SVitaly Wool return false; 15551f862989SVitaly Wool } 15561f862989SVitaly Wool 15571f862989SVitaly Wool static int z3fold_page_migrate(struct address_space *mapping, struct page *newpage, 15581f862989SVitaly Wool struct page *page, enum migrate_mode mode) 15591f862989SVitaly Wool { 15601f862989SVitaly Wool struct z3fold_header *zhdr, *new_zhdr; 15611f862989SVitaly Wool struct z3fold_pool *pool; 15621f862989SVitaly Wool struct address_space *new_mapping; 15631f862989SVitaly Wool 15641f862989SVitaly Wool VM_BUG_ON_PAGE(!PageMovable(page), page); 15651f862989SVitaly Wool VM_BUG_ON_PAGE(!PageIsolated(page), page); 1566dcf5aedbSVitaly Wool VM_BUG_ON_PAGE(!test_bit(PAGE_CLAIMED, &page->private), page); 1567810481a2SHenry Burns VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); 15681f862989SVitaly Wool 15691f862989SVitaly Wool zhdr = page_address(page); 15701f862989SVitaly Wool pool = zhdr_to_pool(zhdr); 15711f862989SVitaly Wool 1572dcf5aedbSVitaly Wool if (!z3fold_page_trylock(zhdr)) 15731f862989SVitaly Wool return -EAGAIN; 15744a3ac931SVitaly Wool if (zhdr->mapped_count != 0 || zhdr->foreign_handles != 0) { 1575dcf5aedbSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 15764a1c3839SMiaohe Lin z3fold_page_unlock(zhdr); 15771f862989SVitaly Wool return -EBUSY; 15781f862989SVitaly Wool } 1579c92d2f38SHenry Burns if (work_pending(&zhdr->work)) { 1580c92d2f38SHenry Burns z3fold_page_unlock(zhdr); 1581c92d2f38SHenry Burns return -EAGAIN; 1582c92d2f38SHenry Burns } 15831f862989SVitaly Wool new_zhdr = page_address(newpage); 15841f862989SVitaly Wool memcpy(new_zhdr, zhdr, PAGE_SIZE); 15851f862989SVitaly Wool newpage->private = page->private; 1586*943fb61dSMiaohe Lin set_bit(PAGE_MIGRATED, &page->private); 15871f862989SVitaly Wool z3fold_page_unlock(zhdr); 15881f862989SVitaly Wool spin_lock_init(&new_zhdr->page_lock); 1589c92d2f38SHenry Burns INIT_WORK(&new_zhdr->work, compact_page_work); 1590c92d2f38SHenry Burns /* 1591c92d2f38SHenry Burns * z3fold_page_isolate() ensures that new_zhdr->buddy is empty, 1592c92d2f38SHenry Burns * so we only have to reinitialize it. 1593c92d2f38SHenry Burns */ 1594c92d2f38SHenry Burns INIT_LIST_HEAD(&new_zhdr->buddy); 15951f862989SVitaly Wool new_mapping = page_mapping(page); 15961f862989SVitaly Wool __ClearPageMovable(page); 15971f862989SVitaly Wool 15981f862989SVitaly Wool get_page(newpage); 15991f862989SVitaly Wool z3fold_page_lock(new_zhdr); 16001f862989SVitaly Wool if (new_zhdr->first_chunks) 16011f862989SVitaly Wool encode_handle(new_zhdr, FIRST); 16021f862989SVitaly Wool if (new_zhdr->last_chunks) 16031f862989SVitaly Wool encode_handle(new_zhdr, LAST); 16041f862989SVitaly Wool if (new_zhdr->middle_chunks) 16051f862989SVitaly Wool encode_handle(new_zhdr, MIDDLE); 16061f862989SVitaly Wool set_bit(NEEDS_COMPACTING, &newpage->private); 16071f862989SVitaly Wool new_zhdr->cpu = smp_processor_id(); 16081f862989SVitaly Wool spin_lock(&pool->lock); 16091f862989SVitaly Wool list_add(&newpage->lru, &pool->lru); 16101f862989SVitaly Wool spin_unlock(&pool->lock); 16111f862989SVitaly Wool __SetPageMovable(newpage, new_mapping); 16121f862989SVitaly Wool z3fold_page_unlock(new_zhdr); 16131f862989SVitaly Wool 16141f862989SVitaly Wool queue_work_on(new_zhdr->cpu, pool->compact_wq, &new_zhdr->work); 16151f862989SVitaly Wool 1616*943fb61dSMiaohe Lin /* PAGE_CLAIMED and PAGE_MIGRATED are cleared now. */ 1617*943fb61dSMiaohe Lin page->private = 0; 16181f862989SVitaly Wool put_page(page); 16191f862989SVitaly Wool return 0; 16201f862989SVitaly Wool } 16211f862989SVitaly Wool 16221f862989SVitaly Wool static void z3fold_page_putback(struct page *page) 16231f862989SVitaly Wool { 16241f862989SVitaly Wool struct z3fold_header *zhdr; 16251f862989SVitaly Wool struct z3fold_pool *pool; 16261f862989SVitaly Wool 16271f862989SVitaly Wool zhdr = page_address(page); 16281f862989SVitaly Wool pool = zhdr_to_pool(zhdr); 16291f862989SVitaly Wool 16301f862989SVitaly Wool z3fold_page_lock(zhdr); 16311f862989SVitaly Wool if (!list_empty(&zhdr->buddy)) 16321f862989SVitaly Wool list_del_init(&zhdr->buddy); 16331f862989SVitaly Wool INIT_LIST_HEAD(&page->lru); 16345e36c25bSMiaohe Lin if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) 16351f862989SVitaly Wool return; 16361f862989SVitaly Wool spin_lock(&pool->lock); 16371f862989SVitaly Wool list_add(&page->lru, &pool->lru); 16381f862989SVitaly Wool spin_unlock(&pool->lock); 16396cf9a349SMiaohe Lin if (list_empty(&zhdr->buddy)) 16406cf9a349SMiaohe Lin add_to_unbuddied(pool, zhdr); 1641dcf5aedbSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 16421f862989SVitaly Wool z3fold_page_unlock(zhdr); 16431f862989SVitaly Wool } 16441f862989SVitaly Wool 16451f862989SVitaly Wool static const struct address_space_operations z3fold_aops = { 16461f862989SVitaly Wool .isolate_page = z3fold_page_isolate, 16471f862989SVitaly Wool .migratepage = z3fold_page_migrate, 16481f862989SVitaly Wool .putback_page = z3fold_page_putback, 16491f862989SVitaly Wool }; 16501f862989SVitaly Wool 16519a001fc1SVitaly Wool /***************** 16529a001fc1SVitaly Wool * zpool 16539a001fc1SVitaly Wool ****************/ 16549a001fc1SVitaly Wool 16559a001fc1SVitaly Wool static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle) 16569a001fc1SVitaly Wool { 16579a001fc1SVitaly Wool if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) 16589a001fc1SVitaly Wool return pool->zpool_ops->evict(pool->zpool, handle); 16599a001fc1SVitaly Wool else 16609a001fc1SVitaly Wool return -ENOENT; 16619a001fc1SVitaly Wool } 16629a001fc1SVitaly Wool 16639a001fc1SVitaly Wool static const struct z3fold_ops z3fold_zpool_ops = { 16649a001fc1SVitaly Wool .evict = z3fold_zpool_evict 16659a001fc1SVitaly Wool }; 16669a001fc1SVitaly Wool 16679a001fc1SVitaly Wool static void *z3fold_zpool_create(const char *name, gfp_t gfp, 16689a001fc1SVitaly Wool const struct zpool_ops *zpool_ops, 16699a001fc1SVitaly Wool struct zpool *zpool) 16709a001fc1SVitaly Wool { 16719a001fc1SVitaly Wool struct z3fold_pool *pool; 16729a001fc1SVitaly Wool 1673d30561c5SVitaly Wool pool = z3fold_create_pool(name, gfp, 1674d30561c5SVitaly Wool zpool_ops ? &z3fold_zpool_ops : NULL); 16759a001fc1SVitaly Wool if (pool) { 16769a001fc1SVitaly Wool pool->zpool = zpool; 16779a001fc1SVitaly Wool pool->zpool_ops = zpool_ops; 16789a001fc1SVitaly Wool } 16799a001fc1SVitaly Wool return pool; 16809a001fc1SVitaly Wool } 16819a001fc1SVitaly Wool 16829a001fc1SVitaly Wool static void z3fold_zpool_destroy(void *pool) 16839a001fc1SVitaly Wool { 16849a001fc1SVitaly Wool z3fold_destroy_pool(pool); 16859a001fc1SVitaly Wool } 16869a001fc1SVitaly Wool 16879a001fc1SVitaly Wool static int z3fold_zpool_malloc(void *pool, size_t size, gfp_t gfp, 16889a001fc1SVitaly Wool unsigned long *handle) 16899a001fc1SVitaly Wool { 16909a001fc1SVitaly Wool return z3fold_alloc(pool, size, gfp, handle); 16919a001fc1SVitaly Wool } 16929a001fc1SVitaly Wool static void z3fold_zpool_free(void *pool, unsigned long handle) 16939a001fc1SVitaly Wool { 16949a001fc1SVitaly Wool z3fold_free(pool, handle); 16959a001fc1SVitaly Wool } 16969a001fc1SVitaly Wool 16979a001fc1SVitaly Wool static int z3fold_zpool_shrink(void *pool, unsigned int pages, 16989a001fc1SVitaly Wool unsigned int *reclaimed) 16999a001fc1SVitaly Wool { 17009a001fc1SVitaly Wool unsigned int total = 0; 17019a001fc1SVitaly Wool int ret = -EINVAL; 17029a001fc1SVitaly Wool 17039a001fc1SVitaly Wool while (total < pages) { 17049a001fc1SVitaly Wool ret = z3fold_reclaim_page(pool, 8); 17059a001fc1SVitaly Wool if (ret < 0) 17069a001fc1SVitaly Wool break; 17079a001fc1SVitaly Wool total++; 17089a001fc1SVitaly Wool } 17099a001fc1SVitaly Wool 17109a001fc1SVitaly Wool if (reclaimed) 17119a001fc1SVitaly Wool *reclaimed = total; 17129a001fc1SVitaly Wool 17139a001fc1SVitaly Wool return ret; 17149a001fc1SVitaly Wool } 17159a001fc1SVitaly Wool 17169a001fc1SVitaly Wool static void *z3fold_zpool_map(void *pool, unsigned long handle, 17179a001fc1SVitaly Wool enum zpool_mapmode mm) 17189a001fc1SVitaly Wool { 17199a001fc1SVitaly Wool return z3fold_map(pool, handle); 17209a001fc1SVitaly Wool } 17219a001fc1SVitaly Wool static void z3fold_zpool_unmap(void *pool, unsigned long handle) 17229a001fc1SVitaly Wool { 17239a001fc1SVitaly Wool z3fold_unmap(pool, handle); 17249a001fc1SVitaly Wool } 17259a001fc1SVitaly Wool 17269a001fc1SVitaly Wool static u64 z3fold_zpool_total_size(void *pool) 17279a001fc1SVitaly Wool { 17289a001fc1SVitaly Wool return z3fold_get_pool_size(pool) * PAGE_SIZE; 17299a001fc1SVitaly Wool } 17309a001fc1SVitaly Wool 17319a001fc1SVitaly Wool static struct zpool_driver z3fold_zpool_driver = { 17329a001fc1SVitaly Wool .type = "z3fold", 1733e818e820STian Tao .sleep_mapped = true, 17349a001fc1SVitaly Wool .owner = THIS_MODULE, 17359a001fc1SVitaly Wool .create = z3fold_zpool_create, 17369a001fc1SVitaly Wool .destroy = z3fold_zpool_destroy, 17379a001fc1SVitaly Wool .malloc = z3fold_zpool_malloc, 17389a001fc1SVitaly Wool .free = z3fold_zpool_free, 17399a001fc1SVitaly Wool .shrink = z3fold_zpool_shrink, 17409a001fc1SVitaly Wool .map = z3fold_zpool_map, 17419a001fc1SVitaly Wool .unmap = z3fold_zpool_unmap, 17429a001fc1SVitaly Wool .total_size = z3fold_zpool_total_size, 17439a001fc1SVitaly Wool }; 17449a001fc1SVitaly Wool 17459a001fc1SVitaly Wool MODULE_ALIAS("zpool-z3fold"); 17469a001fc1SVitaly Wool 17479a001fc1SVitaly Wool static int __init init_z3fold(void) 17489a001fc1SVitaly Wool { 17491f862989SVitaly Wool int ret; 17501f862989SVitaly Wool 1751014284a0SMiaohe Lin /* 1752014284a0SMiaohe Lin * Make sure the z3fold header is not larger than the page size and 1753014284a0SMiaohe Lin * there has remaining spaces for its buddy. 1754014284a0SMiaohe Lin */ 1755014284a0SMiaohe Lin BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE_SIZE - CHUNK_SIZE); 17561f862989SVitaly Wool ret = z3fold_mount(); 17571f862989SVitaly Wool if (ret) 17581f862989SVitaly Wool return ret; 17591f862989SVitaly Wool 17609a001fc1SVitaly Wool zpool_register_driver(&z3fold_zpool_driver); 17619a001fc1SVitaly Wool 17629a001fc1SVitaly Wool return 0; 17639a001fc1SVitaly Wool } 17649a001fc1SVitaly Wool 17659a001fc1SVitaly Wool static void __exit exit_z3fold(void) 17669a001fc1SVitaly Wool { 17671f862989SVitaly Wool z3fold_unmount(); 17689a001fc1SVitaly Wool zpool_unregister_driver(&z3fold_zpool_driver); 17699a001fc1SVitaly Wool } 17709a001fc1SVitaly Wool 17719a001fc1SVitaly Wool module_init(init_z3fold); 17729a001fc1SVitaly Wool module_exit(exit_z3fold); 17739a001fc1SVitaly Wool 17749a001fc1SVitaly Wool MODULE_LICENSE("GPL"); 17759a001fc1SVitaly Wool MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail.com>"); 17769a001fc1SVitaly Wool MODULE_DESCRIPTION("3-Fold Allocator for Compressed Pages"); 1777