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> 46*af4798a5SQian 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) 659a001fc1SVitaly Wool #define NCHUNKS ((PAGE_SIZE - ZHDR_SIZE_ALIGNED) >> CHUNK_SHIFT) 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]; 937c2b8baaSVitaly Wool unsigned long pool; /* back link + flags */ 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. 147d30561c5SVitaly Wool * @compact_wq: workqueue for page layout background optimization 148d30561c5SVitaly Wool * @release_wq: workqueue for safe page release 149d30561c5SVitaly Wool * @work: work_struct for safe page release 1501f862989SVitaly Wool * @inode: inode for z3fold pseudo filesystem 1519a001fc1SVitaly Wool * 1529a001fc1SVitaly Wool * This structure is allocated at pool creation time and maintains metadata 1539a001fc1SVitaly Wool * pertaining to a particular z3fold pool. 1549a001fc1SVitaly Wool */ 1559a001fc1SVitaly Wool struct z3fold_pool { 156d30561c5SVitaly Wool const char *name; 1579a001fc1SVitaly Wool spinlock_t lock; 158d30561c5SVitaly Wool spinlock_t stale_lock; 159d30561c5SVitaly Wool struct list_head *unbuddied; 1609a001fc1SVitaly Wool struct list_head lru; 161d30561c5SVitaly Wool struct list_head stale; 16212d59ae6SVitaly Wool atomic64_t pages_nr; 1637c2b8baaSVitaly Wool struct kmem_cache *c_handle; 1649a001fc1SVitaly Wool const struct z3fold_ops *ops; 1659a001fc1SVitaly Wool struct zpool *zpool; 1669a001fc1SVitaly Wool const struct zpool_ops *zpool_ops; 167d30561c5SVitaly Wool struct workqueue_struct *compact_wq; 168d30561c5SVitaly Wool struct workqueue_struct *release_wq; 169d30561c5SVitaly Wool struct work_struct work; 1701f862989SVitaly Wool struct inode *inode; 1719a001fc1SVitaly Wool }; 1729a001fc1SVitaly Wool 1739a001fc1SVitaly Wool /* 1749a001fc1SVitaly Wool * Internal z3fold page flags 1759a001fc1SVitaly Wool */ 1769a001fc1SVitaly Wool enum z3fold_page_flags { 1775a27aa82SVitaly Wool PAGE_HEADLESS = 0, 1789a001fc1SVitaly Wool MIDDLE_CHUNK_MAPPED, 179d30561c5SVitaly Wool NEEDS_COMPACTING, 1806098d7e1SVitaly Wool PAGE_STALE, 181ca0246bbSVitaly Wool PAGE_CLAIMED, /* by either reclaim or free */ 1829a001fc1SVitaly Wool }; 1839a001fc1SVitaly Wool 1844a3ac931SVitaly Wool /* 1854a3ac931SVitaly Wool * handle flags, go under HANDLE_FLAG_MASK 1864a3ac931SVitaly Wool */ 1874a3ac931SVitaly Wool enum z3fold_handle_flags { 1884a3ac931SVitaly Wool HANDLES_ORPHANED = 0, 1894a3ac931SVitaly Wool }; 1904a3ac931SVitaly Wool 1914a3ac931SVitaly Wool /* 1924a3ac931SVitaly Wool * Forward declarations 1934a3ac931SVitaly Wool */ 1944a3ac931SVitaly Wool static struct z3fold_header *__z3fold_alloc(struct z3fold_pool *, size_t, bool); 1954a3ac931SVitaly Wool static void compact_page_work(struct work_struct *w); 1964a3ac931SVitaly Wool 1979a001fc1SVitaly Wool /***************** 1989a001fc1SVitaly Wool * Helpers 1999a001fc1SVitaly Wool *****************/ 2009a001fc1SVitaly Wool 2019a001fc1SVitaly Wool /* Converts an allocation size in bytes to size in z3fold chunks */ 2029a001fc1SVitaly Wool static int size_to_chunks(size_t size) 2039a001fc1SVitaly Wool { 2049a001fc1SVitaly Wool return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT; 2059a001fc1SVitaly Wool } 2069a001fc1SVitaly Wool 2079a001fc1SVitaly Wool #define for_each_unbuddied_list(_iter, _begin) \ 2089a001fc1SVitaly Wool for ((_iter) = (_begin); (_iter) < NCHUNKS; (_iter)++) 2099a001fc1SVitaly Wool 210bb9f6f63SVitaly Wool static inline struct z3fold_buddy_slots *alloc_slots(struct z3fold_pool *pool, 211bb9f6f63SVitaly Wool gfp_t gfp) 2127c2b8baaSVitaly Wool { 213f1549cb5SHenry Burns struct z3fold_buddy_slots *slots; 214f1549cb5SHenry Burns 215f1549cb5SHenry Burns slots = kmem_cache_alloc(pool->c_handle, 216f1549cb5SHenry Burns (gfp & ~(__GFP_HIGHMEM | __GFP_MOVABLE))); 2177c2b8baaSVitaly Wool 2187c2b8baaSVitaly Wool if (slots) { 219*af4798a5SQian Cai /* It will be freed separately in free_handle(). */ 220*af4798a5SQian Cai kmemleak_not_leak(slots); 2217c2b8baaSVitaly Wool memset(slots->slot, 0, sizeof(slots->slot)); 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 2574a3ac931SVitaly Wool 2584a3ac931SVitaly Wool static inline struct z3fold_header *__get_z3fold_header(unsigned long handle, 2594a3ac931SVitaly Wool bool lock) 2604a3ac931SVitaly Wool { 2614a3ac931SVitaly Wool struct z3fold_buddy_slots *slots; 2624a3ac931SVitaly Wool struct z3fold_header *zhdr; 2634a3ac931SVitaly Wool int locked = 0; 2644a3ac931SVitaly Wool 2654a3ac931SVitaly Wool if (!(handle & (1 << PAGE_HEADLESS))) { 2664a3ac931SVitaly Wool slots = handle_to_slots(handle); 2674a3ac931SVitaly Wool do { 2684a3ac931SVitaly Wool unsigned long addr; 2694a3ac931SVitaly Wool 2704a3ac931SVitaly Wool read_lock(&slots->lock); 2714a3ac931SVitaly Wool addr = *(unsigned long *)handle; 2724a3ac931SVitaly Wool zhdr = (struct z3fold_header *)(addr & PAGE_MASK); 2734a3ac931SVitaly Wool if (lock) 2744a3ac931SVitaly Wool locked = z3fold_page_trylock(zhdr); 2754a3ac931SVitaly Wool read_unlock(&slots->lock); 2764a3ac931SVitaly Wool if (locked) 2774a3ac931SVitaly Wool break; 2784a3ac931SVitaly Wool cpu_relax(); 2794a3ac931SVitaly Wool } while (lock); 2804a3ac931SVitaly Wool } else { 2814a3ac931SVitaly Wool zhdr = (struct z3fold_header *)(handle & PAGE_MASK); 2824a3ac931SVitaly Wool } 2834a3ac931SVitaly Wool 2844a3ac931SVitaly Wool return zhdr; 2854a3ac931SVitaly Wool } 2864a3ac931SVitaly Wool 2874a3ac931SVitaly Wool /* Returns the z3fold page where a given handle is stored */ 2884a3ac931SVitaly Wool static inline struct z3fold_header *handle_to_z3fold_header(unsigned long h) 2894a3ac931SVitaly Wool { 2904a3ac931SVitaly Wool return __get_z3fold_header(h, false); 2914a3ac931SVitaly Wool } 2924a3ac931SVitaly Wool 2934a3ac931SVitaly Wool /* return locked z3fold page if it's not headless */ 2944a3ac931SVitaly Wool static inline struct z3fold_header *get_z3fold_header(unsigned long h) 2954a3ac931SVitaly Wool { 2964a3ac931SVitaly Wool return __get_z3fold_header(h, true); 2974a3ac931SVitaly Wool } 2984a3ac931SVitaly Wool 2994a3ac931SVitaly Wool static inline void put_z3fold_header(struct z3fold_header *zhdr) 3004a3ac931SVitaly Wool { 3014a3ac931SVitaly Wool struct page *page = virt_to_page(zhdr); 3024a3ac931SVitaly Wool 3034a3ac931SVitaly Wool if (!test_bit(PAGE_HEADLESS, &page->private)) 3044a3ac931SVitaly Wool z3fold_page_unlock(zhdr); 3054a3ac931SVitaly Wool } 3064a3ac931SVitaly Wool 3077c2b8baaSVitaly Wool static inline void free_handle(unsigned long handle) 3087c2b8baaSVitaly Wool { 3097c2b8baaSVitaly Wool struct z3fold_buddy_slots *slots; 3104a3ac931SVitaly Wool struct z3fold_header *zhdr; 3117c2b8baaSVitaly Wool int i; 3127c2b8baaSVitaly Wool bool is_free; 3137c2b8baaSVitaly Wool 3147c2b8baaSVitaly Wool if (handle & (1 << PAGE_HEADLESS)) 3157c2b8baaSVitaly Wool return; 3167c2b8baaSVitaly Wool 3174a3ac931SVitaly Wool if (WARN_ON(*(unsigned long *)handle == 0)) 3184a3ac931SVitaly Wool return; 3194a3ac931SVitaly Wool 3204a3ac931SVitaly Wool zhdr = handle_to_z3fold_header(handle); 3217c2b8baaSVitaly Wool slots = handle_to_slots(handle); 3224a3ac931SVitaly Wool write_lock(&slots->lock); 3234a3ac931SVitaly Wool *(unsigned long *)handle = 0; 324d8f117abSUladzislau Rezki if (zhdr->slots == slots) { 3254a3ac931SVitaly Wool write_unlock(&slots->lock); 3264a3ac931SVitaly Wool return; /* simple case, nothing else to do */ 327d8f117abSUladzislau Rezki } 3284a3ac931SVitaly Wool 3294a3ac931SVitaly Wool /* we are freeing a foreign handle if we are here */ 3304a3ac931SVitaly Wool zhdr->foreign_handles--; 3317c2b8baaSVitaly Wool is_free = true; 3324a3ac931SVitaly Wool if (!test_bit(HANDLES_ORPHANED, &slots->pool)) { 333d8f117abSUladzislau Rezki write_unlock(&slots->lock); 3344a3ac931SVitaly Wool return; 3354a3ac931SVitaly Wool } 3367c2b8baaSVitaly Wool for (i = 0; i <= BUDDY_MASK; i++) { 3377c2b8baaSVitaly Wool if (slots->slot[i]) { 3387c2b8baaSVitaly Wool is_free = false; 3397c2b8baaSVitaly Wool break; 3407c2b8baaSVitaly Wool } 3417c2b8baaSVitaly Wool } 342d8f117abSUladzislau Rezki write_unlock(&slots->lock); 3437c2b8baaSVitaly Wool 3447c2b8baaSVitaly Wool if (is_free) { 3457c2b8baaSVitaly Wool struct z3fold_pool *pool = slots_to_pool(slots); 3467c2b8baaSVitaly Wool 3477c2b8baaSVitaly Wool kmem_cache_free(pool->c_handle, slots); 3487c2b8baaSVitaly Wool } 3497c2b8baaSVitaly Wool } 3507c2b8baaSVitaly Wool 351ea8157abSDavid Howells static int z3fold_init_fs_context(struct fs_context *fc) 3521f862989SVitaly Wool { 353ea8157abSDavid Howells return init_pseudo(fc, Z3FOLD_MAGIC) ? 0 : -ENOMEM; 3541f862989SVitaly Wool } 3551f862989SVitaly Wool 3561f862989SVitaly Wool static struct file_system_type z3fold_fs = { 3571f862989SVitaly Wool .name = "z3fold", 358ea8157abSDavid Howells .init_fs_context = z3fold_init_fs_context, 3591f862989SVitaly Wool .kill_sb = kill_anon_super, 3601f862989SVitaly Wool }; 3611f862989SVitaly Wool 3621f862989SVitaly Wool static struct vfsmount *z3fold_mnt; 3631f862989SVitaly Wool static int z3fold_mount(void) 3641f862989SVitaly Wool { 3651f862989SVitaly Wool int ret = 0; 3661f862989SVitaly Wool 3671f862989SVitaly Wool z3fold_mnt = kern_mount(&z3fold_fs); 3681f862989SVitaly Wool if (IS_ERR(z3fold_mnt)) 3691f862989SVitaly Wool ret = PTR_ERR(z3fold_mnt); 3701f862989SVitaly Wool 3711f862989SVitaly Wool return ret; 3721f862989SVitaly Wool } 3731f862989SVitaly Wool 3741f862989SVitaly Wool static void z3fold_unmount(void) 3751f862989SVitaly Wool { 3761f862989SVitaly Wool kern_unmount(z3fold_mnt); 3771f862989SVitaly Wool } 3781f862989SVitaly Wool 3791f862989SVitaly Wool static const struct address_space_operations z3fold_aops; 3801f862989SVitaly Wool static int z3fold_register_migration(struct z3fold_pool *pool) 3811f862989SVitaly Wool { 3821f862989SVitaly Wool pool->inode = alloc_anon_inode(z3fold_mnt->mnt_sb); 3831f862989SVitaly Wool if (IS_ERR(pool->inode)) { 3841f862989SVitaly Wool pool->inode = NULL; 3851f862989SVitaly Wool return 1; 3861f862989SVitaly Wool } 3871f862989SVitaly Wool 3881f862989SVitaly Wool pool->inode->i_mapping->private_data = pool; 3891f862989SVitaly Wool pool->inode->i_mapping->a_ops = &z3fold_aops; 3901f862989SVitaly Wool return 0; 3911f862989SVitaly Wool } 3921f862989SVitaly Wool 3931f862989SVitaly Wool static void z3fold_unregister_migration(struct z3fold_pool *pool) 3941f862989SVitaly Wool { 3951f862989SVitaly Wool if (pool->inode) 3961f862989SVitaly Wool iput(pool->inode); 3971f862989SVitaly Wool } 3981f862989SVitaly Wool 3999a001fc1SVitaly Wool /* Initializes the z3fold header of a newly allocated z3fold page */ 40063398413SVitaly Wool static struct z3fold_header *init_z3fold_page(struct page *page, bool headless, 401bb9f6f63SVitaly Wool struct z3fold_pool *pool, gfp_t gfp) 4029a001fc1SVitaly Wool { 4039a001fc1SVitaly Wool struct z3fold_header *zhdr = page_address(page); 40463398413SVitaly Wool struct z3fold_buddy_slots *slots; 4059a001fc1SVitaly Wool 4069a001fc1SVitaly Wool INIT_LIST_HEAD(&page->lru); 4079a001fc1SVitaly Wool clear_bit(PAGE_HEADLESS, &page->private); 4089a001fc1SVitaly Wool clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); 409d30561c5SVitaly Wool clear_bit(NEEDS_COMPACTING, &page->private); 410d30561c5SVitaly Wool clear_bit(PAGE_STALE, &page->private); 411ca0246bbSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 41263398413SVitaly Wool if (headless) 41363398413SVitaly Wool return zhdr; 41463398413SVitaly Wool 41563398413SVitaly Wool slots = alloc_slots(pool, gfp); 41663398413SVitaly Wool if (!slots) 41763398413SVitaly Wool return NULL; 4189a001fc1SVitaly Wool 4192f1e5e4dSVitaly Wool spin_lock_init(&zhdr->page_lock); 4205a27aa82SVitaly Wool kref_init(&zhdr->refcount); 4219a001fc1SVitaly Wool zhdr->first_chunks = 0; 4229a001fc1SVitaly Wool zhdr->middle_chunks = 0; 4239a001fc1SVitaly Wool zhdr->last_chunks = 0; 4249a001fc1SVitaly Wool zhdr->first_num = 0; 4259a001fc1SVitaly Wool zhdr->start_middle = 0; 426d30561c5SVitaly Wool zhdr->cpu = -1; 4274a3ac931SVitaly Wool zhdr->foreign_handles = 0; 428d8f117abSUladzislau Rezki zhdr->mapped_count = 0; 4297c2b8baaSVitaly Wool zhdr->slots = slots; 430bb9a374dSVitaly Wool zhdr->pool = pool; 4319a001fc1SVitaly Wool INIT_LIST_HEAD(&zhdr->buddy); 432d30561c5SVitaly Wool INIT_WORK(&zhdr->work, compact_page_work); 4339a001fc1SVitaly Wool return zhdr; 4349a001fc1SVitaly Wool } 4359a001fc1SVitaly Wool 4369a001fc1SVitaly Wool /* Resets the struct page fields and frees the page */ 4371f862989SVitaly Wool static void free_z3fold_page(struct page *page, bool headless) 4389a001fc1SVitaly Wool { 4391f862989SVitaly Wool if (!headless) { 4401f862989SVitaly Wool lock_page(page); 4411f862989SVitaly Wool __ClearPageMovable(page); 4421f862989SVitaly Wool unlock_page(page); 4431f862989SVitaly Wool } 4441f862989SVitaly Wool ClearPagePrivate(page); 4455a27aa82SVitaly Wool __free_page(page); 4465a27aa82SVitaly Wool } 4475a27aa82SVitaly Wool 4487c2b8baaSVitaly Wool /* Helper function to build the index */ 4497c2b8baaSVitaly Wool static inline int __idx(struct z3fold_header *zhdr, enum buddy bud) 4507c2b8baaSVitaly Wool { 4517c2b8baaSVitaly Wool return (bud + zhdr->first_num) & BUDDY_MASK; 4527c2b8baaSVitaly Wool } 4537c2b8baaSVitaly Wool 4549a001fc1SVitaly Wool /* 4559a001fc1SVitaly Wool * Encodes the handle of a particular buddy within a z3fold page 4569a001fc1SVitaly Wool * Pool lock should be held as this function accesses first_num 4579a001fc1SVitaly Wool */ 4583f9d2b57SVitaly Wool static unsigned long __encode_handle(struct z3fold_header *zhdr, 4593f9d2b57SVitaly Wool struct z3fold_buddy_slots *slots, 4603f9d2b57SVitaly Wool enum buddy bud) 4619a001fc1SVitaly Wool { 4627c2b8baaSVitaly Wool unsigned long h = (unsigned long)zhdr; 4637c2b8baaSVitaly Wool int idx = 0; 4649a001fc1SVitaly Wool 4657c2b8baaSVitaly Wool /* 4667c2b8baaSVitaly Wool * For a headless page, its handle is its pointer with the extra 4677c2b8baaSVitaly Wool * PAGE_HEADLESS bit set 4687c2b8baaSVitaly Wool */ 4697c2b8baaSVitaly Wool if (bud == HEADLESS) 4707c2b8baaSVitaly Wool return h | (1 << PAGE_HEADLESS); 4717c2b8baaSVitaly Wool 4727c2b8baaSVitaly Wool /* otherwise, return pointer to encoded handle */ 4737c2b8baaSVitaly Wool idx = __idx(zhdr, bud); 4747c2b8baaSVitaly Wool h += idx; 475ca0246bbSVitaly Wool if (bud == LAST) 4767c2b8baaSVitaly Wool h |= (zhdr->last_chunks << BUDDY_SHIFT); 4777c2b8baaSVitaly Wool 4784a3ac931SVitaly Wool write_lock(&slots->lock); 4797c2b8baaSVitaly Wool slots->slot[idx] = h; 4804a3ac931SVitaly Wool write_unlock(&slots->lock); 4817c2b8baaSVitaly Wool return (unsigned long)&slots->slot[idx]; 4829a001fc1SVitaly Wool } 4839a001fc1SVitaly Wool 4843f9d2b57SVitaly Wool static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) 4853f9d2b57SVitaly Wool { 4863f9d2b57SVitaly Wool return __encode_handle(zhdr, zhdr->slots, bud); 4873f9d2b57SVitaly Wool } 4883f9d2b57SVitaly Wool 489ca0246bbSVitaly Wool /* only for LAST bud, returns zero otherwise */ 490ca0246bbSVitaly Wool static unsigned short handle_to_chunks(unsigned long handle) 491ca0246bbSVitaly Wool { 4924a3ac931SVitaly Wool struct z3fold_buddy_slots *slots = handle_to_slots(handle); 4934a3ac931SVitaly Wool unsigned long addr; 4947c2b8baaSVitaly Wool 4954a3ac931SVitaly Wool read_lock(&slots->lock); 4964a3ac931SVitaly Wool addr = *(unsigned long *)handle; 4974a3ac931SVitaly Wool read_unlock(&slots->lock); 4987c2b8baaSVitaly Wool return (addr & ~PAGE_MASK) >> BUDDY_SHIFT; 499ca0246bbSVitaly Wool } 500ca0246bbSVitaly Wool 501f201ebd8Szhong jiang /* 502f201ebd8Szhong jiang * (handle & BUDDY_MASK) < zhdr->first_num is possible in encode_handle 503f201ebd8Szhong jiang * but that doesn't matter. because the masking will result in the 504f201ebd8Szhong jiang * correct buddy number. 505f201ebd8Szhong jiang */ 5069a001fc1SVitaly Wool static enum buddy handle_to_buddy(unsigned long handle) 5079a001fc1SVitaly Wool { 5087c2b8baaSVitaly Wool struct z3fold_header *zhdr; 5094a3ac931SVitaly Wool struct z3fold_buddy_slots *slots = handle_to_slots(handle); 5107c2b8baaSVitaly Wool unsigned long addr; 5117c2b8baaSVitaly Wool 5124a3ac931SVitaly Wool read_lock(&slots->lock); 5137c2b8baaSVitaly Wool WARN_ON(handle & (1 << PAGE_HEADLESS)); 5147c2b8baaSVitaly Wool addr = *(unsigned long *)handle; 5154a3ac931SVitaly Wool read_unlock(&slots->lock); 5167c2b8baaSVitaly Wool zhdr = (struct z3fold_header *)(addr & PAGE_MASK); 5177c2b8baaSVitaly Wool return (addr - zhdr->first_num) & BUDDY_MASK; 5189a001fc1SVitaly Wool } 5199a001fc1SVitaly Wool 5209050cce1SVitaly Wool static inline struct z3fold_pool *zhdr_to_pool(struct z3fold_header *zhdr) 5219050cce1SVitaly Wool { 522bb9a374dSVitaly Wool return zhdr->pool; 5239050cce1SVitaly Wool } 5249050cce1SVitaly Wool 525d30561c5SVitaly Wool static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) 526d30561c5SVitaly Wool { 527d30561c5SVitaly Wool struct page *page = virt_to_page(zhdr); 5289050cce1SVitaly Wool struct z3fold_pool *pool = zhdr_to_pool(zhdr); 5294a3ac931SVitaly Wool bool is_free = true; 5304a3ac931SVitaly Wool int i; 531d30561c5SVitaly Wool 532d30561c5SVitaly Wool WARN_ON(!list_empty(&zhdr->buddy)); 533d30561c5SVitaly Wool set_bit(PAGE_STALE, &page->private); 53435529357SVitaly Wool clear_bit(NEEDS_COMPACTING, &page->private); 535d30561c5SVitaly Wool spin_lock(&pool->lock); 536d30561c5SVitaly Wool if (!list_empty(&page->lru)) 5371f862989SVitaly Wool list_del_init(&page->lru); 538d30561c5SVitaly Wool spin_unlock(&pool->lock); 5394a3ac931SVitaly Wool 5404a3ac931SVitaly Wool /* If there are no foreign handles, free the handles array */ 5414a3ac931SVitaly Wool read_lock(&zhdr->slots->lock); 5424a3ac931SVitaly Wool for (i = 0; i <= BUDDY_MASK; i++) { 5434a3ac931SVitaly Wool if (zhdr->slots->slot[i]) { 5444a3ac931SVitaly Wool is_free = false; 5454a3ac931SVitaly Wool break; 5464a3ac931SVitaly Wool } 5474a3ac931SVitaly Wool } 5484a3ac931SVitaly Wool if (!is_free) 5494a3ac931SVitaly Wool set_bit(HANDLES_ORPHANED, &zhdr->slots->pool); 5504a3ac931SVitaly Wool read_unlock(&zhdr->slots->lock); 5514a3ac931SVitaly Wool 5524a3ac931SVitaly Wool if (is_free) 5534a3ac931SVitaly Wool kmem_cache_free(pool->c_handle, zhdr->slots); 5544a3ac931SVitaly Wool 555d30561c5SVitaly Wool if (locked) 556d30561c5SVitaly Wool z3fold_page_unlock(zhdr); 5574a3ac931SVitaly Wool 558d30561c5SVitaly Wool spin_lock(&pool->stale_lock); 559d30561c5SVitaly Wool list_add(&zhdr->buddy, &pool->stale); 560d30561c5SVitaly Wool queue_work(pool->release_wq, &pool->work); 561d30561c5SVitaly Wool spin_unlock(&pool->stale_lock); 562d30561c5SVitaly Wool } 563d30561c5SVitaly Wool 564d30561c5SVitaly Wool static void __attribute__((__unused__)) 565d30561c5SVitaly Wool release_z3fold_page(struct kref *ref) 566d30561c5SVitaly Wool { 567d30561c5SVitaly Wool struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, 568d30561c5SVitaly Wool refcount); 569d30561c5SVitaly Wool __release_z3fold_page(zhdr, false); 570d30561c5SVitaly Wool } 571d30561c5SVitaly Wool 572d30561c5SVitaly Wool static void release_z3fold_page_locked(struct kref *ref) 573d30561c5SVitaly Wool { 574d30561c5SVitaly Wool struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, 575d30561c5SVitaly Wool refcount); 576d30561c5SVitaly Wool WARN_ON(z3fold_page_trylock(zhdr)); 577d30561c5SVitaly Wool __release_z3fold_page(zhdr, true); 578d30561c5SVitaly Wool } 579d30561c5SVitaly Wool 580d30561c5SVitaly Wool static void release_z3fold_page_locked_list(struct kref *ref) 581d30561c5SVitaly Wool { 582d30561c5SVitaly Wool struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, 583d30561c5SVitaly Wool refcount); 5849050cce1SVitaly Wool struct z3fold_pool *pool = zhdr_to_pool(zhdr); 5854a3ac931SVitaly Wool 5869050cce1SVitaly Wool spin_lock(&pool->lock); 587d30561c5SVitaly Wool list_del_init(&zhdr->buddy); 5889050cce1SVitaly Wool spin_unlock(&pool->lock); 589d30561c5SVitaly Wool 590d30561c5SVitaly Wool WARN_ON(z3fold_page_trylock(zhdr)); 591d30561c5SVitaly Wool __release_z3fold_page(zhdr, true); 592d30561c5SVitaly Wool } 593d30561c5SVitaly Wool 594d30561c5SVitaly Wool static void free_pages_work(struct work_struct *w) 595d30561c5SVitaly Wool { 596d30561c5SVitaly Wool struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work); 597d30561c5SVitaly Wool 598d30561c5SVitaly Wool spin_lock(&pool->stale_lock); 599d30561c5SVitaly Wool while (!list_empty(&pool->stale)) { 600d30561c5SVitaly Wool struct z3fold_header *zhdr = list_first_entry(&pool->stale, 601d30561c5SVitaly Wool struct z3fold_header, buddy); 602d30561c5SVitaly Wool struct page *page = virt_to_page(zhdr); 603d30561c5SVitaly Wool 604d30561c5SVitaly Wool list_del(&zhdr->buddy); 605d30561c5SVitaly Wool if (WARN_ON(!test_bit(PAGE_STALE, &page->private))) 606d30561c5SVitaly Wool continue; 607d30561c5SVitaly Wool spin_unlock(&pool->stale_lock); 608d30561c5SVitaly Wool cancel_work_sync(&zhdr->work); 6091f862989SVitaly Wool free_z3fold_page(page, false); 610d30561c5SVitaly Wool cond_resched(); 611d30561c5SVitaly Wool spin_lock(&pool->stale_lock); 612d30561c5SVitaly Wool } 613d30561c5SVitaly Wool spin_unlock(&pool->stale_lock); 614d30561c5SVitaly Wool } 615d30561c5SVitaly Wool 6169a001fc1SVitaly Wool /* 6179a001fc1SVitaly Wool * Returns the number of free chunks in a z3fold page. 6189a001fc1SVitaly Wool * NB: can't be used with HEADLESS pages. 6199a001fc1SVitaly Wool */ 6209a001fc1SVitaly Wool static int num_free_chunks(struct z3fold_header *zhdr) 6219a001fc1SVitaly Wool { 6229a001fc1SVitaly Wool int nfree; 6239a001fc1SVitaly Wool /* 6249a001fc1SVitaly Wool * If there is a middle object, pick up the bigger free space 6259a001fc1SVitaly Wool * either before or after it. Otherwise just subtract the number 6269a001fc1SVitaly Wool * of chunks occupied by the first and the last objects. 6279a001fc1SVitaly Wool */ 6289a001fc1SVitaly Wool if (zhdr->middle_chunks != 0) { 6299a001fc1SVitaly Wool int nfree_before = zhdr->first_chunks ? 630ede93213SVitaly Wool 0 : zhdr->start_middle - ZHDR_CHUNKS; 6319a001fc1SVitaly Wool int nfree_after = zhdr->last_chunks ? 632ede93213SVitaly Wool 0 : TOTAL_CHUNKS - 633ede93213SVitaly Wool (zhdr->start_middle + zhdr->middle_chunks); 6349a001fc1SVitaly Wool nfree = max(nfree_before, nfree_after); 6359a001fc1SVitaly Wool } else 6369a001fc1SVitaly Wool nfree = NCHUNKS - zhdr->first_chunks - zhdr->last_chunks; 6379a001fc1SVitaly Wool return nfree; 6389a001fc1SVitaly Wool } 6399a001fc1SVitaly Wool 6409050cce1SVitaly Wool /* Add to the appropriate unbuddied list */ 6419050cce1SVitaly Wool static inline void add_to_unbuddied(struct z3fold_pool *pool, 6429050cce1SVitaly Wool struct z3fold_header *zhdr) 6439050cce1SVitaly Wool { 6449050cce1SVitaly Wool if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 || 6459050cce1SVitaly Wool zhdr->middle_chunks == 0) { 6469050cce1SVitaly Wool struct list_head *unbuddied = get_cpu_ptr(pool->unbuddied); 6479050cce1SVitaly Wool 6489050cce1SVitaly Wool int freechunks = num_free_chunks(zhdr); 6499050cce1SVitaly Wool spin_lock(&pool->lock); 6509050cce1SVitaly Wool list_add(&zhdr->buddy, &unbuddied[freechunks]); 6519050cce1SVitaly Wool spin_unlock(&pool->lock); 6529050cce1SVitaly Wool zhdr->cpu = smp_processor_id(); 6539050cce1SVitaly Wool put_cpu_ptr(pool->unbuddied); 6549050cce1SVitaly Wool } 6559050cce1SVitaly Wool } 6569050cce1SVitaly Wool 657ede93213SVitaly Wool static inline void *mchunk_memmove(struct z3fold_header *zhdr, 658ede93213SVitaly Wool unsigned short dst_chunk) 659ede93213SVitaly Wool { 660ede93213SVitaly Wool void *beg = zhdr; 661ede93213SVitaly Wool return memmove(beg + (dst_chunk << CHUNK_SHIFT), 662ede93213SVitaly Wool beg + (zhdr->start_middle << CHUNK_SHIFT), 663ede93213SVitaly Wool zhdr->middle_chunks << CHUNK_SHIFT); 664ede93213SVitaly Wool } 665ede93213SVitaly Wool 6664a3ac931SVitaly Wool static inline bool buddy_single(struct z3fold_header *zhdr) 6674a3ac931SVitaly Wool { 6684a3ac931SVitaly Wool return !((zhdr->first_chunks && zhdr->middle_chunks) || 6694a3ac931SVitaly Wool (zhdr->first_chunks && zhdr->last_chunks) || 6704a3ac931SVitaly Wool (zhdr->middle_chunks && zhdr->last_chunks)); 6714a3ac931SVitaly Wool } 6724a3ac931SVitaly Wool 6734a3ac931SVitaly Wool static struct z3fold_header *compact_single_buddy(struct z3fold_header *zhdr) 6744a3ac931SVitaly Wool { 6754a3ac931SVitaly Wool struct z3fold_pool *pool = zhdr_to_pool(zhdr); 6764a3ac931SVitaly Wool void *p = zhdr; 6774a3ac931SVitaly Wool unsigned long old_handle = 0; 6784a3ac931SVitaly Wool size_t sz = 0; 6794a3ac931SVitaly Wool struct z3fold_header *new_zhdr = NULL; 6804a3ac931SVitaly Wool int first_idx = __idx(zhdr, FIRST); 6814a3ac931SVitaly Wool int middle_idx = __idx(zhdr, MIDDLE); 6824a3ac931SVitaly Wool int last_idx = __idx(zhdr, LAST); 6834a3ac931SVitaly Wool unsigned short *moved_chunks = NULL; 6844a3ac931SVitaly Wool 6854a3ac931SVitaly Wool /* 6864a3ac931SVitaly Wool * No need to protect slots here -- all the slots are "local" and 6874a3ac931SVitaly Wool * the page lock is already taken 6884a3ac931SVitaly Wool */ 6894a3ac931SVitaly Wool if (zhdr->first_chunks && zhdr->slots->slot[first_idx]) { 6904a3ac931SVitaly Wool p += ZHDR_SIZE_ALIGNED; 6914a3ac931SVitaly Wool sz = zhdr->first_chunks << CHUNK_SHIFT; 6924a3ac931SVitaly Wool old_handle = (unsigned long)&zhdr->slots->slot[first_idx]; 6934a3ac931SVitaly Wool moved_chunks = &zhdr->first_chunks; 6944a3ac931SVitaly Wool } else if (zhdr->middle_chunks && zhdr->slots->slot[middle_idx]) { 6954a3ac931SVitaly Wool p += zhdr->start_middle << CHUNK_SHIFT; 6964a3ac931SVitaly Wool sz = zhdr->middle_chunks << CHUNK_SHIFT; 6974a3ac931SVitaly Wool old_handle = (unsigned long)&zhdr->slots->slot[middle_idx]; 6984a3ac931SVitaly Wool moved_chunks = &zhdr->middle_chunks; 6994a3ac931SVitaly Wool } else if (zhdr->last_chunks && zhdr->slots->slot[last_idx]) { 7004a3ac931SVitaly Wool p += PAGE_SIZE - (zhdr->last_chunks << CHUNK_SHIFT); 7014a3ac931SVitaly Wool sz = zhdr->last_chunks << CHUNK_SHIFT; 7024a3ac931SVitaly Wool old_handle = (unsigned long)&zhdr->slots->slot[last_idx]; 7034a3ac931SVitaly Wool moved_chunks = &zhdr->last_chunks; 7044a3ac931SVitaly Wool } 7054a3ac931SVitaly Wool 7064a3ac931SVitaly Wool if (sz > 0) { 7074a3ac931SVitaly Wool enum buddy new_bud = HEADLESS; 7084a3ac931SVitaly Wool short chunks = size_to_chunks(sz); 7094a3ac931SVitaly Wool void *q; 7104a3ac931SVitaly Wool 7114a3ac931SVitaly Wool new_zhdr = __z3fold_alloc(pool, sz, false); 7124a3ac931SVitaly Wool if (!new_zhdr) 7134a3ac931SVitaly Wool return NULL; 7144a3ac931SVitaly Wool 7154a3ac931SVitaly Wool if (WARN_ON(new_zhdr == zhdr)) 7164a3ac931SVitaly Wool goto out_fail; 7174a3ac931SVitaly Wool 7184a3ac931SVitaly Wool if (new_zhdr->first_chunks == 0) { 7194a3ac931SVitaly Wool if (new_zhdr->middle_chunks != 0 && 7204a3ac931SVitaly Wool chunks >= new_zhdr->start_middle) { 7214a3ac931SVitaly Wool new_bud = LAST; 7224a3ac931SVitaly Wool } else { 7234a3ac931SVitaly Wool new_bud = FIRST; 7244a3ac931SVitaly Wool } 7254a3ac931SVitaly Wool } else if (new_zhdr->last_chunks == 0) { 7264a3ac931SVitaly Wool new_bud = LAST; 7274a3ac931SVitaly Wool } else if (new_zhdr->middle_chunks == 0) { 7284a3ac931SVitaly Wool new_bud = MIDDLE; 7294a3ac931SVitaly Wool } 7304a3ac931SVitaly Wool q = new_zhdr; 7314a3ac931SVitaly Wool switch (new_bud) { 7324a3ac931SVitaly Wool case FIRST: 7334a3ac931SVitaly Wool new_zhdr->first_chunks = chunks; 7344a3ac931SVitaly Wool q += ZHDR_SIZE_ALIGNED; 7354a3ac931SVitaly Wool break; 7364a3ac931SVitaly Wool case MIDDLE: 7374a3ac931SVitaly Wool new_zhdr->middle_chunks = chunks; 7384a3ac931SVitaly Wool new_zhdr->start_middle = 7394a3ac931SVitaly Wool new_zhdr->first_chunks + ZHDR_CHUNKS; 7404a3ac931SVitaly Wool q += new_zhdr->start_middle << CHUNK_SHIFT; 7414a3ac931SVitaly Wool break; 7424a3ac931SVitaly Wool case LAST: 7434a3ac931SVitaly Wool new_zhdr->last_chunks = chunks; 7444a3ac931SVitaly Wool q += PAGE_SIZE - (new_zhdr->last_chunks << CHUNK_SHIFT); 7454a3ac931SVitaly Wool break; 7464a3ac931SVitaly Wool default: 7474a3ac931SVitaly Wool goto out_fail; 7484a3ac931SVitaly Wool } 7494a3ac931SVitaly Wool new_zhdr->foreign_handles++; 7504a3ac931SVitaly Wool memcpy(q, p, sz); 7514a3ac931SVitaly Wool write_lock(&zhdr->slots->lock); 7524a3ac931SVitaly Wool *(unsigned long *)old_handle = (unsigned long)new_zhdr + 7534a3ac931SVitaly Wool __idx(new_zhdr, new_bud); 7544a3ac931SVitaly Wool if (new_bud == LAST) 7554a3ac931SVitaly Wool *(unsigned long *)old_handle |= 7564a3ac931SVitaly Wool (new_zhdr->last_chunks << BUDDY_SHIFT); 7574a3ac931SVitaly Wool write_unlock(&zhdr->slots->lock); 7584a3ac931SVitaly Wool add_to_unbuddied(pool, new_zhdr); 7594a3ac931SVitaly Wool z3fold_page_unlock(new_zhdr); 7604a3ac931SVitaly Wool 7614a3ac931SVitaly Wool *moved_chunks = 0; 7624a3ac931SVitaly Wool } 7634a3ac931SVitaly Wool 7644a3ac931SVitaly Wool return new_zhdr; 7654a3ac931SVitaly Wool 7664a3ac931SVitaly Wool out_fail: 7674a3ac931SVitaly Wool if (new_zhdr) { 7684a3ac931SVitaly Wool if (kref_put(&new_zhdr->refcount, release_z3fold_page_locked)) 7694a3ac931SVitaly Wool atomic64_dec(&pool->pages_nr); 7704a3ac931SVitaly Wool else { 7714a3ac931SVitaly Wool add_to_unbuddied(pool, new_zhdr); 7724a3ac931SVitaly Wool z3fold_page_unlock(new_zhdr); 7734a3ac931SVitaly Wool } 7744a3ac931SVitaly Wool } 7754a3ac931SVitaly Wool return NULL; 7764a3ac931SVitaly Wool 7774a3ac931SVitaly Wool } 7784a3ac931SVitaly Wool 7791b096e5aSVitaly Wool #define BIG_CHUNK_GAP 3 7809a001fc1SVitaly Wool /* Has to be called with lock held */ 7819a001fc1SVitaly Wool static int z3fold_compact_page(struct z3fold_header *zhdr) 7829a001fc1SVitaly Wool { 7839a001fc1SVitaly Wool struct page *page = virt_to_page(zhdr); 7849a001fc1SVitaly Wool 785ede93213SVitaly Wool if (test_bit(MIDDLE_CHUNK_MAPPED, &page->private)) 786ede93213SVitaly Wool return 0; /* can't move middle chunk, it's used */ 7879a001fc1SVitaly Wool 7881f862989SVitaly Wool if (unlikely(PageIsolated(page))) 7891f862989SVitaly Wool return 0; 7901f862989SVitaly Wool 791ede93213SVitaly Wool if (zhdr->middle_chunks == 0) 792ede93213SVitaly Wool return 0; /* nothing to compact */ 793ede93213SVitaly Wool 794ede93213SVitaly Wool if (zhdr->first_chunks == 0 && zhdr->last_chunks == 0) { 795ede93213SVitaly Wool /* move to the beginning */ 796ede93213SVitaly Wool mchunk_memmove(zhdr, ZHDR_CHUNKS); 7979a001fc1SVitaly Wool zhdr->first_chunks = zhdr->middle_chunks; 7989a001fc1SVitaly Wool zhdr->middle_chunks = 0; 7999a001fc1SVitaly Wool zhdr->start_middle = 0; 8009a001fc1SVitaly Wool zhdr->first_num++; 801ede93213SVitaly Wool return 1; 8029a001fc1SVitaly Wool } 8039a001fc1SVitaly Wool 8041b096e5aSVitaly Wool /* 8051b096e5aSVitaly Wool * moving data is expensive, so let's only do that if 8061b096e5aSVitaly Wool * there's substantial gain (at least BIG_CHUNK_GAP chunks) 8071b096e5aSVitaly Wool */ 8081b096e5aSVitaly Wool if (zhdr->first_chunks != 0 && zhdr->last_chunks == 0 && 8091b096e5aSVitaly Wool zhdr->start_middle - (zhdr->first_chunks + ZHDR_CHUNKS) >= 8101b096e5aSVitaly Wool BIG_CHUNK_GAP) { 8111b096e5aSVitaly Wool mchunk_memmove(zhdr, zhdr->first_chunks + ZHDR_CHUNKS); 8121b096e5aSVitaly Wool zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; 8131b096e5aSVitaly Wool return 1; 8141b096e5aSVitaly Wool } else if (zhdr->last_chunks != 0 && zhdr->first_chunks == 0 && 8151b096e5aSVitaly Wool TOTAL_CHUNKS - (zhdr->last_chunks + zhdr->start_middle 8161b096e5aSVitaly Wool + zhdr->middle_chunks) >= 8171b096e5aSVitaly Wool BIG_CHUNK_GAP) { 8181b096e5aSVitaly Wool unsigned short new_start = TOTAL_CHUNKS - zhdr->last_chunks - 8191b096e5aSVitaly Wool zhdr->middle_chunks; 8201b096e5aSVitaly Wool mchunk_memmove(zhdr, new_start); 8211b096e5aSVitaly Wool zhdr->start_middle = new_start; 8221b096e5aSVitaly Wool return 1; 8231b096e5aSVitaly Wool } 8241b096e5aSVitaly Wool 8251b096e5aSVitaly Wool return 0; 8261b096e5aSVitaly Wool } 8271b096e5aSVitaly Wool 828d30561c5SVitaly Wool static void do_compact_page(struct z3fold_header *zhdr, bool locked) 829d30561c5SVitaly Wool { 8309050cce1SVitaly Wool struct z3fold_pool *pool = zhdr_to_pool(zhdr); 831d30561c5SVitaly Wool struct page *page; 832d30561c5SVitaly Wool 833d30561c5SVitaly Wool page = virt_to_page(zhdr); 834d30561c5SVitaly Wool if (locked) 835d30561c5SVitaly Wool WARN_ON(z3fold_page_trylock(zhdr)); 836d30561c5SVitaly Wool else 837d30561c5SVitaly Wool z3fold_page_lock(zhdr); 8385d03a661SVitaly Wool if (WARN_ON(!test_and_clear_bit(NEEDS_COMPACTING, &page->private))) { 839d30561c5SVitaly Wool z3fold_page_unlock(zhdr); 840d30561c5SVitaly Wool return; 841d30561c5SVitaly Wool } 842d30561c5SVitaly Wool spin_lock(&pool->lock); 843d30561c5SVitaly Wool list_del_init(&zhdr->buddy); 844d30561c5SVitaly Wool spin_unlock(&pool->lock); 845d30561c5SVitaly Wool 8465d03a661SVitaly Wool if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) { 8475d03a661SVitaly Wool atomic64_dec(&pool->pages_nr); 8485d03a661SVitaly Wool return; 8495d03a661SVitaly Wool } 8505d03a661SVitaly Wool 8511f862989SVitaly Wool if (unlikely(PageIsolated(page) || 8523f9d2b57SVitaly Wool test_bit(PAGE_CLAIMED, &page->private) || 8531f862989SVitaly Wool test_bit(PAGE_STALE, &page->private))) { 8541f862989SVitaly Wool z3fold_page_unlock(zhdr); 8551f862989SVitaly Wool return; 8561f862989SVitaly Wool } 8571f862989SVitaly Wool 8584a3ac931SVitaly Wool if (!zhdr->foreign_handles && buddy_single(zhdr) && 8594a3ac931SVitaly Wool zhdr->mapped_count == 0 && compact_single_buddy(zhdr)) { 8604a3ac931SVitaly Wool if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) 8614a3ac931SVitaly Wool atomic64_dec(&pool->pages_nr); 8624a3ac931SVitaly Wool else 8634a3ac931SVitaly Wool z3fold_page_unlock(zhdr); 8644a3ac931SVitaly Wool return; 8654a3ac931SVitaly Wool } 8664a3ac931SVitaly Wool 867d30561c5SVitaly Wool z3fold_compact_page(zhdr); 8689050cce1SVitaly Wool add_to_unbuddied(pool, zhdr); 869d30561c5SVitaly Wool z3fold_page_unlock(zhdr); 870d30561c5SVitaly Wool } 871d30561c5SVitaly Wool 872d30561c5SVitaly Wool static void compact_page_work(struct work_struct *w) 873d30561c5SVitaly Wool { 874d30561c5SVitaly Wool struct z3fold_header *zhdr = container_of(w, struct z3fold_header, 875d30561c5SVitaly Wool work); 876d30561c5SVitaly Wool 877d30561c5SVitaly Wool do_compact_page(zhdr, false); 878d30561c5SVitaly Wool } 879d30561c5SVitaly Wool 8809050cce1SVitaly Wool /* returns _locked_ z3fold page header or NULL */ 8819050cce1SVitaly Wool static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool, 8829050cce1SVitaly Wool size_t size, bool can_sleep) 8839050cce1SVitaly Wool { 8849050cce1SVitaly Wool struct z3fold_header *zhdr = NULL; 8859050cce1SVitaly Wool struct page *page; 8869050cce1SVitaly Wool struct list_head *unbuddied; 8879050cce1SVitaly Wool int chunks = size_to_chunks(size), i; 8889050cce1SVitaly Wool 8899050cce1SVitaly Wool lookup: 8909050cce1SVitaly Wool /* First, try to find an unbuddied z3fold page. */ 8919050cce1SVitaly Wool unbuddied = get_cpu_ptr(pool->unbuddied); 8929050cce1SVitaly Wool for_each_unbuddied_list(i, chunks) { 8939050cce1SVitaly Wool struct list_head *l = &unbuddied[i]; 8949050cce1SVitaly Wool 8959050cce1SVitaly Wool zhdr = list_first_entry_or_null(READ_ONCE(l), 8969050cce1SVitaly Wool struct z3fold_header, buddy); 8979050cce1SVitaly Wool 8989050cce1SVitaly Wool if (!zhdr) 8999050cce1SVitaly Wool continue; 9009050cce1SVitaly Wool 9019050cce1SVitaly Wool /* Re-check under lock. */ 9029050cce1SVitaly Wool spin_lock(&pool->lock); 9039050cce1SVitaly Wool l = &unbuddied[i]; 9049050cce1SVitaly Wool if (unlikely(zhdr != list_first_entry(READ_ONCE(l), 9059050cce1SVitaly Wool struct z3fold_header, buddy)) || 9069050cce1SVitaly Wool !z3fold_page_trylock(zhdr)) { 9079050cce1SVitaly Wool spin_unlock(&pool->lock); 9089050cce1SVitaly Wool zhdr = NULL; 9099050cce1SVitaly Wool put_cpu_ptr(pool->unbuddied); 9109050cce1SVitaly Wool if (can_sleep) 9119050cce1SVitaly Wool cond_resched(); 9129050cce1SVitaly Wool goto lookup; 9139050cce1SVitaly Wool } 9149050cce1SVitaly Wool list_del_init(&zhdr->buddy); 9159050cce1SVitaly Wool zhdr->cpu = -1; 9169050cce1SVitaly Wool spin_unlock(&pool->lock); 9179050cce1SVitaly Wool 9189050cce1SVitaly Wool page = virt_to_page(zhdr); 9194a3ac931SVitaly Wool if (test_bit(NEEDS_COMPACTING, &page->private) || 9204a3ac931SVitaly Wool test_bit(PAGE_CLAIMED, &page->private)) { 9219050cce1SVitaly Wool z3fold_page_unlock(zhdr); 9229050cce1SVitaly Wool zhdr = NULL; 9239050cce1SVitaly Wool put_cpu_ptr(pool->unbuddied); 9249050cce1SVitaly Wool if (can_sleep) 9259050cce1SVitaly Wool cond_resched(); 9269050cce1SVitaly Wool goto lookup; 9279050cce1SVitaly Wool } 9289050cce1SVitaly Wool 9299050cce1SVitaly Wool /* 9309050cce1SVitaly Wool * this page could not be removed from its unbuddied 9319050cce1SVitaly Wool * list while pool lock was held, and then we've taken 9329050cce1SVitaly Wool * page lock so kref_put could not be called before 9339050cce1SVitaly Wool * we got here, so it's safe to just call kref_get() 9349050cce1SVitaly Wool */ 9359050cce1SVitaly Wool kref_get(&zhdr->refcount); 9369050cce1SVitaly Wool break; 9379050cce1SVitaly Wool } 9389050cce1SVitaly Wool put_cpu_ptr(pool->unbuddied); 9399050cce1SVitaly Wool 940351618b2SVitaly Wool if (!zhdr) { 941351618b2SVitaly Wool int cpu; 942351618b2SVitaly Wool 943351618b2SVitaly Wool /* look for _exact_ match on other cpus' lists */ 944351618b2SVitaly Wool for_each_online_cpu(cpu) { 945351618b2SVitaly Wool struct list_head *l; 946351618b2SVitaly Wool 947351618b2SVitaly Wool unbuddied = per_cpu_ptr(pool->unbuddied, cpu); 948351618b2SVitaly Wool spin_lock(&pool->lock); 949351618b2SVitaly Wool l = &unbuddied[chunks]; 950351618b2SVitaly Wool 951351618b2SVitaly Wool zhdr = list_first_entry_or_null(READ_ONCE(l), 952351618b2SVitaly Wool struct z3fold_header, buddy); 953351618b2SVitaly Wool 954351618b2SVitaly Wool if (!zhdr || !z3fold_page_trylock(zhdr)) { 955351618b2SVitaly Wool spin_unlock(&pool->lock); 956351618b2SVitaly Wool zhdr = NULL; 957351618b2SVitaly Wool continue; 958351618b2SVitaly Wool } 959351618b2SVitaly Wool list_del_init(&zhdr->buddy); 960351618b2SVitaly Wool zhdr->cpu = -1; 961351618b2SVitaly Wool spin_unlock(&pool->lock); 962351618b2SVitaly Wool 963351618b2SVitaly Wool page = virt_to_page(zhdr); 9644a3ac931SVitaly Wool if (test_bit(NEEDS_COMPACTING, &page->private) || 9654a3ac931SVitaly Wool test_bit(PAGE_CLAIMED, &page->private)) { 966351618b2SVitaly Wool z3fold_page_unlock(zhdr); 967351618b2SVitaly Wool zhdr = NULL; 968351618b2SVitaly Wool if (can_sleep) 969351618b2SVitaly Wool cond_resched(); 970351618b2SVitaly Wool continue; 971351618b2SVitaly Wool } 972351618b2SVitaly Wool kref_get(&zhdr->refcount); 973351618b2SVitaly Wool break; 974351618b2SVitaly Wool } 975351618b2SVitaly Wool } 976351618b2SVitaly Wool 9779050cce1SVitaly Wool return zhdr; 9789050cce1SVitaly Wool } 979d30561c5SVitaly Wool 980d30561c5SVitaly Wool /* 981d30561c5SVitaly Wool * API Functions 982d30561c5SVitaly Wool */ 983d30561c5SVitaly Wool 984d30561c5SVitaly Wool /** 985d30561c5SVitaly Wool * z3fold_create_pool() - create a new z3fold pool 986d30561c5SVitaly Wool * @name: pool name 987d30561c5SVitaly Wool * @gfp: gfp flags when allocating the z3fold pool structure 988d30561c5SVitaly Wool * @ops: user-defined operations for the z3fold pool 989d30561c5SVitaly Wool * 990d30561c5SVitaly Wool * Return: pointer to the new z3fold pool or NULL if the metadata allocation 991d30561c5SVitaly Wool * failed. 992d30561c5SVitaly Wool */ 993d30561c5SVitaly Wool static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp, 994d30561c5SVitaly Wool const struct z3fold_ops *ops) 995d30561c5SVitaly Wool { 996d30561c5SVitaly Wool struct z3fold_pool *pool = NULL; 997d30561c5SVitaly Wool int i, cpu; 998d30561c5SVitaly Wool 999d30561c5SVitaly Wool pool = kzalloc(sizeof(struct z3fold_pool), gfp); 1000d30561c5SVitaly Wool if (!pool) 1001d30561c5SVitaly Wool goto out; 10027c2b8baaSVitaly Wool pool->c_handle = kmem_cache_create("z3fold_handle", 10037c2b8baaSVitaly Wool sizeof(struct z3fold_buddy_slots), 10047c2b8baaSVitaly Wool SLOTS_ALIGN, 0, NULL); 10057c2b8baaSVitaly Wool if (!pool->c_handle) 10067c2b8baaSVitaly Wool goto out_c; 1007d30561c5SVitaly Wool spin_lock_init(&pool->lock); 1008d30561c5SVitaly Wool spin_lock_init(&pool->stale_lock); 1009d30561c5SVitaly Wool pool->unbuddied = __alloc_percpu(sizeof(struct list_head)*NCHUNKS, 2); 10101ec6995dSXidong Wang if (!pool->unbuddied) 10111ec6995dSXidong Wang goto out_pool; 1012d30561c5SVitaly Wool for_each_possible_cpu(cpu) { 1013d30561c5SVitaly Wool struct list_head *unbuddied = 1014d30561c5SVitaly Wool per_cpu_ptr(pool->unbuddied, cpu); 1015d30561c5SVitaly Wool for_each_unbuddied_list(i, 0) 1016d30561c5SVitaly Wool INIT_LIST_HEAD(&unbuddied[i]); 1017d30561c5SVitaly Wool } 1018d30561c5SVitaly Wool INIT_LIST_HEAD(&pool->lru); 1019d30561c5SVitaly Wool INIT_LIST_HEAD(&pool->stale); 1020d30561c5SVitaly Wool atomic64_set(&pool->pages_nr, 0); 1021d30561c5SVitaly Wool pool->name = name; 1022d30561c5SVitaly Wool pool->compact_wq = create_singlethread_workqueue(pool->name); 1023d30561c5SVitaly Wool if (!pool->compact_wq) 10241ec6995dSXidong Wang goto out_unbuddied; 1025d30561c5SVitaly Wool pool->release_wq = create_singlethread_workqueue(pool->name); 1026d30561c5SVitaly Wool if (!pool->release_wq) 1027d30561c5SVitaly Wool goto out_wq; 10281f862989SVitaly Wool if (z3fold_register_migration(pool)) 10291f862989SVitaly Wool goto out_rwq; 1030d30561c5SVitaly Wool INIT_WORK(&pool->work, free_pages_work); 1031d30561c5SVitaly Wool pool->ops = ops; 1032d30561c5SVitaly Wool return pool; 1033d30561c5SVitaly Wool 10341f862989SVitaly Wool out_rwq: 10351f862989SVitaly Wool destroy_workqueue(pool->release_wq); 1036d30561c5SVitaly Wool out_wq: 1037d30561c5SVitaly Wool destroy_workqueue(pool->compact_wq); 10381ec6995dSXidong Wang out_unbuddied: 10391ec6995dSXidong Wang free_percpu(pool->unbuddied); 10401ec6995dSXidong Wang out_pool: 10417c2b8baaSVitaly Wool kmem_cache_destroy(pool->c_handle); 10427c2b8baaSVitaly Wool out_c: 1043d30561c5SVitaly Wool kfree(pool); 10441ec6995dSXidong Wang out: 1045d30561c5SVitaly Wool return NULL; 1046d30561c5SVitaly Wool } 1047d30561c5SVitaly Wool 1048d30561c5SVitaly Wool /** 1049d30561c5SVitaly Wool * z3fold_destroy_pool() - destroys an existing z3fold pool 1050d30561c5SVitaly Wool * @pool: the z3fold pool to be destroyed 1051d30561c5SVitaly Wool * 1052d30561c5SVitaly Wool * The pool should be emptied before this function is called. 1053d30561c5SVitaly Wool */ 1054d30561c5SVitaly Wool static void z3fold_destroy_pool(struct z3fold_pool *pool) 1055d30561c5SVitaly Wool { 10567c2b8baaSVitaly Wool kmem_cache_destroy(pool->c_handle); 10576051d3bdSHenry Burns 10586051d3bdSHenry Burns /* 10596051d3bdSHenry Burns * We need to destroy pool->compact_wq before pool->release_wq, 10606051d3bdSHenry Burns * as any pending work on pool->compact_wq will call 10616051d3bdSHenry Burns * queue_work(pool->release_wq, &pool->work). 1062b997052bSHenry Burns * 1063b997052bSHenry Burns * There are still outstanding pages until both workqueues are drained, 1064b997052bSHenry Burns * so we cannot unregister migration until then. 10656051d3bdSHenry Burns */ 10666051d3bdSHenry Burns 1067d30561c5SVitaly Wool destroy_workqueue(pool->compact_wq); 10686051d3bdSHenry Burns destroy_workqueue(pool->release_wq); 1069b997052bSHenry Burns z3fold_unregister_migration(pool); 1070d30561c5SVitaly Wool kfree(pool); 1071d30561c5SVitaly Wool } 1072d30561c5SVitaly Wool 10739a001fc1SVitaly Wool /** 10749a001fc1SVitaly Wool * z3fold_alloc() - allocates a region of a given size 10759a001fc1SVitaly Wool * @pool: z3fold pool from which to allocate 10769a001fc1SVitaly Wool * @size: size in bytes of the desired allocation 10779a001fc1SVitaly Wool * @gfp: gfp flags used if the pool needs to grow 10789a001fc1SVitaly Wool * @handle: handle of the new allocation 10799a001fc1SVitaly Wool * 10809a001fc1SVitaly Wool * This function will attempt to find a free region in the pool large enough to 10819a001fc1SVitaly Wool * satisfy the allocation request. A search of the unbuddied lists is 10829a001fc1SVitaly Wool * performed first. If no suitable free region is found, then a new page is 10839a001fc1SVitaly Wool * allocated and added to the pool to satisfy the request. 10849a001fc1SVitaly Wool * 10859a001fc1SVitaly Wool * gfp should not set __GFP_HIGHMEM as highmem pages cannot be used 10869a001fc1SVitaly Wool * as z3fold pool pages. 10879a001fc1SVitaly Wool * 10889a001fc1SVitaly Wool * Return: 0 if success and handle is set, otherwise -EINVAL if the size or 10899a001fc1SVitaly Wool * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate 10909a001fc1SVitaly Wool * a new page. 10919a001fc1SVitaly Wool */ 10929a001fc1SVitaly Wool static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, 10939a001fc1SVitaly Wool unsigned long *handle) 10949a001fc1SVitaly Wool { 10959050cce1SVitaly Wool int chunks = size_to_chunks(size); 10969a001fc1SVitaly Wool struct z3fold_header *zhdr = NULL; 1097d30561c5SVitaly Wool struct page *page = NULL; 10989a001fc1SVitaly Wool enum buddy bud; 10998a97ea54SMatthew Wilcox bool can_sleep = gfpflags_allow_blocking(gfp); 11009a001fc1SVitaly Wool 1101f1549cb5SHenry Burns if (!size) 11029a001fc1SVitaly Wool return -EINVAL; 11039a001fc1SVitaly Wool 11049a001fc1SVitaly Wool if (size > PAGE_SIZE) 11059a001fc1SVitaly Wool return -ENOSPC; 11069a001fc1SVitaly Wool 11079a001fc1SVitaly Wool if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE) 11089a001fc1SVitaly Wool bud = HEADLESS; 11099a001fc1SVitaly Wool else { 11109050cce1SVitaly Wool retry: 11119050cce1SVitaly Wool zhdr = __z3fold_alloc(pool, size, can_sleep); 1112d30561c5SVitaly Wool if (zhdr) { 11139a001fc1SVitaly Wool if (zhdr->first_chunks == 0) { 11149a001fc1SVitaly Wool if (zhdr->middle_chunks != 0 && 11159a001fc1SVitaly Wool chunks >= zhdr->start_middle) 11169a001fc1SVitaly Wool bud = LAST; 11179a001fc1SVitaly Wool else 11189a001fc1SVitaly Wool bud = FIRST; 11199a001fc1SVitaly Wool } else if (zhdr->last_chunks == 0) 11209a001fc1SVitaly Wool bud = LAST; 11219a001fc1SVitaly Wool else if (zhdr->middle_chunks == 0) 11229a001fc1SVitaly Wool bud = MIDDLE; 11239a001fc1SVitaly Wool else { 11245a27aa82SVitaly Wool if (kref_put(&zhdr->refcount, 1125d30561c5SVitaly Wool release_z3fold_page_locked)) 11265a27aa82SVitaly Wool atomic64_dec(&pool->pages_nr); 1127d30561c5SVitaly Wool else 1128d30561c5SVitaly Wool z3fold_page_unlock(zhdr); 11299a001fc1SVitaly Wool pr_err("No free chunks in unbuddied\n"); 11309a001fc1SVitaly Wool WARN_ON(1); 11319050cce1SVitaly Wool goto retry; 11329a001fc1SVitaly Wool } 11339050cce1SVitaly Wool page = virt_to_page(zhdr); 11349a001fc1SVitaly Wool goto found; 11359a001fc1SVitaly Wool } 11369a001fc1SVitaly Wool bud = FIRST; 11379a001fc1SVitaly Wool } 11389a001fc1SVitaly Wool 11395c9bab59SVitaly Wool page = NULL; 11405c9bab59SVitaly Wool if (can_sleep) { 1141d30561c5SVitaly Wool spin_lock(&pool->stale_lock); 1142d30561c5SVitaly Wool zhdr = list_first_entry_or_null(&pool->stale, 1143d30561c5SVitaly Wool struct z3fold_header, buddy); 1144d30561c5SVitaly Wool /* 11455c9bab59SVitaly Wool * Before allocating a page, let's see if we can take one from 11465c9bab59SVitaly Wool * the stale pages list. cancel_work_sync() can sleep so we 11475c9bab59SVitaly Wool * limit this case to the contexts where we can sleep 1148d30561c5SVitaly Wool */ 11495c9bab59SVitaly Wool if (zhdr) { 1150d30561c5SVitaly Wool list_del(&zhdr->buddy); 1151d30561c5SVitaly Wool spin_unlock(&pool->stale_lock); 1152d30561c5SVitaly Wool cancel_work_sync(&zhdr->work); 1153d30561c5SVitaly Wool page = virt_to_page(zhdr); 1154d30561c5SVitaly Wool } else { 1155d30561c5SVitaly Wool spin_unlock(&pool->stale_lock); 1156d30561c5SVitaly Wool } 11575c9bab59SVitaly Wool } 11585c9bab59SVitaly Wool if (!page) 11595c9bab59SVitaly Wool page = alloc_page(gfp); 1160d30561c5SVitaly Wool 11619a001fc1SVitaly Wool if (!page) 11629a001fc1SVitaly Wool return -ENOMEM; 11632f1e5e4dSVitaly Wool 116463398413SVitaly Wool zhdr = init_z3fold_page(page, bud == HEADLESS, pool, gfp); 11659050cce1SVitaly Wool if (!zhdr) { 11669050cce1SVitaly Wool __free_page(page); 11679050cce1SVitaly Wool return -ENOMEM; 11689050cce1SVitaly Wool } 11699050cce1SVitaly Wool atomic64_inc(&pool->pages_nr); 11709a001fc1SVitaly Wool 11719a001fc1SVitaly Wool if (bud == HEADLESS) { 11729a001fc1SVitaly Wool set_bit(PAGE_HEADLESS, &page->private); 11739a001fc1SVitaly Wool goto headless; 11749a001fc1SVitaly Wool } 1175810481a2SHenry Burns if (can_sleep) { 1176810481a2SHenry Burns lock_page(page); 11771f862989SVitaly Wool __SetPageMovable(page, pool->inode->i_mapping); 1178810481a2SHenry Burns unlock_page(page); 1179810481a2SHenry Burns } else { 1180810481a2SHenry Burns if (trylock_page(page)) { 1181810481a2SHenry Burns __SetPageMovable(page, pool->inode->i_mapping); 1182810481a2SHenry Burns unlock_page(page); 1183810481a2SHenry Burns } 1184810481a2SHenry Burns } 11852f1e5e4dSVitaly Wool z3fold_page_lock(zhdr); 11869a001fc1SVitaly Wool 11879a001fc1SVitaly Wool found: 11889a001fc1SVitaly Wool if (bud == FIRST) 11899a001fc1SVitaly Wool zhdr->first_chunks = chunks; 11909a001fc1SVitaly Wool else if (bud == LAST) 11919a001fc1SVitaly Wool zhdr->last_chunks = chunks; 11929a001fc1SVitaly Wool else { 11939a001fc1SVitaly Wool zhdr->middle_chunks = chunks; 1194ede93213SVitaly Wool zhdr->start_middle = zhdr->first_chunks + ZHDR_CHUNKS; 11959a001fc1SVitaly Wool } 11969050cce1SVitaly Wool add_to_unbuddied(pool, zhdr); 11979a001fc1SVitaly Wool 11989a001fc1SVitaly Wool headless: 1199d30561c5SVitaly Wool spin_lock(&pool->lock); 12009a001fc1SVitaly Wool /* Add/move z3fold page to beginning of LRU */ 12019a001fc1SVitaly Wool if (!list_empty(&page->lru)) 12029a001fc1SVitaly Wool list_del(&page->lru); 12039a001fc1SVitaly Wool 12049a001fc1SVitaly Wool list_add(&page->lru, &pool->lru); 12059a001fc1SVitaly Wool 12069a001fc1SVitaly Wool *handle = encode_handle(zhdr, bud); 12079a001fc1SVitaly Wool spin_unlock(&pool->lock); 12082f1e5e4dSVitaly Wool if (bud != HEADLESS) 12092f1e5e4dSVitaly Wool z3fold_page_unlock(zhdr); 12109a001fc1SVitaly Wool 12119a001fc1SVitaly Wool return 0; 12129a001fc1SVitaly Wool } 12139a001fc1SVitaly Wool 12149a001fc1SVitaly Wool /** 12159a001fc1SVitaly Wool * z3fold_free() - frees the allocation associated with the given handle 12169a001fc1SVitaly Wool * @pool: pool in which the allocation resided 12179a001fc1SVitaly Wool * @handle: handle associated with the allocation returned by z3fold_alloc() 12189a001fc1SVitaly Wool * 12199a001fc1SVitaly Wool * In the case that the z3fold page in which the allocation resides is under 12209a001fc1SVitaly Wool * reclaim, as indicated by the PG_reclaim flag being set, this function 12219a001fc1SVitaly Wool * only sets the first|last_chunks to 0. The page is actually freed 12229a001fc1SVitaly Wool * once both buddies are evicted (see z3fold_reclaim_page() below). 12239a001fc1SVitaly Wool */ 12249a001fc1SVitaly Wool static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) 12259a001fc1SVitaly Wool { 12269a001fc1SVitaly Wool struct z3fold_header *zhdr; 12279a001fc1SVitaly Wool struct page *page; 12289a001fc1SVitaly Wool enum buddy bud; 12295b6807deSVitaly Wool bool page_claimed; 12309a001fc1SVitaly Wool 12314a3ac931SVitaly Wool zhdr = get_z3fold_header(handle); 12329a001fc1SVitaly Wool page = virt_to_page(zhdr); 12335b6807deSVitaly Wool page_claimed = test_and_set_bit(PAGE_CLAIMED, &page->private); 12349a001fc1SVitaly Wool 12359a001fc1SVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) { 1236ca0246bbSVitaly Wool /* if a headless page is under reclaim, just leave. 1237ca0246bbSVitaly Wool * NB: we use test_and_set_bit for a reason: if the bit 1238ca0246bbSVitaly Wool * has not been set before, we release this page 1239ca0246bbSVitaly Wool * immediately so we don't care about its value any more. 1240ca0246bbSVitaly Wool */ 12415b6807deSVitaly Wool if (!page_claimed) { 1242ca0246bbSVitaly Wool spin_lock(&pool->lock); 1243ca0246bbSVitaly Wool list_del(&page->lru); 1244ca0246bbSVitaly Wool spin_unlock(&pool->lock); 12454a3ac931SVitaly Wool put_z3fold_header(zhdr); 12461f862989SVitaly Wool free_z3fold_page(page, true); 1247ca0246bbSVitaly Wool atomic64_dec(&pool->pages_nr); 1248ca0246bbSVitaly Wool } 1249ca0246bbSVitaly Wool return; 1250ca0246bbSVitaly Wool } 1251ca0246bbSVitaly Wool 1252ca0246bbSVitaly Wool /* Non-headless case */ 125343afc194SVitaly Wool bud = handle_to_buddy(handle); 12549a001fc1SVitaly Wool 12559a001fc1SVitaly Wool switch (bud) { 12569a001fc1SVitaly Wool case FIRST: 12579a001fc1SVitaly Wool zhdr->first_chunks = 0; 12589a001fc1SVitaly Wool break; 12599a001fc1SVitaly Wool case MIDDLE: 12609a001fc1SVitaly Wool zhdr->middle_chunks = 0; 12619a001fc1SVitaly Wool break; 12629a001fc1SVitaly Wool case LAST: 12639a001fc1SVitaly Wool zhdr->last_chunks = 0; 12649a001fc1SVitaly Wool break; 12659a001fc1SVitaly Wool default: 12669a001fc1SVitaly Wool pr_err("%s: unknown bud %d\n", __func__, bud); 12679a001fc1SVitaly Wool WARN_ON(1); 12684a3ac931SVitaly Wool put_z3fold_header(zhdr); 12694a3ac931SVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 12709a001fc1SVitaly Wool return; 12719a001fc1SVitaly Wool } 12729a001fc1SVitaly Wool 12734a3ac931SVitaly Wool if (!page_claimed) 12747c2b8baaSVitaly Wool free_handle(handle); 1275d30561c5SVitaly Wool if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) { 1276d30561c5SVitaly Wool atomic64_dec(&pool->pages_nr); 1277d30561c5SVitaly Wool return; 1278d30561c5SVitaly Wool } 12795b6807deSVitaly Wool if (page_claimed) { 12805b6807deSVitaly Wool /* the page has not been claimed by us */ 12816098d7e1SVitaly Wool z3fold_page_unlock(zhdr); 12826098d7e1SVitaly Wool return; 12836098d7e1SVitaly Wool } 12841f862989SVitaly Wool if (unlikely(PageIsolated(page)) || 12851f862989SVitaly Wool test_and_set_bit(NEEDS_COMPACTING, &page->private)) { 12864a3ac931SVitaly Wool put_z3fold_header(zhdr); 12875b6807deSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 1288d30561c5SVitaly Wool return; 1289d30561c5SVitaly Wool } 1290d30561c5SVitaly Wool if (zhdr->cpu < 0 || !cpu_online(zhdr->cpu)) { 1291d30561c5SVitaly Wool spin_lock(&pool->lock); 1292d30561c5SVitaly Wool list_del_init(&zhdr->buddy); 1293d30561c5SVitaly Wool spin_unlock(&pool->lock); 1294d30561c5SVitaly Wool zhdr->cpu = -1; 12955d03a661SVitaly Wool kref_get(&zhdr->refcount); 12965b6807deSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 12974a3ac931SVitaly Wool do_compact_page(zhdr, true); 1298d30561c5SVitaly Wool return; 1299d30561c5SVitaly Wool } 13005d03a661SVitaly Wool kref_get(&zhdr->refcount); 13015b6807deSVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 13024a3ac931SVitaly Wool queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work); 13034a3ac931SVitaly Wool put_z3fold_header(zhdr); 13049a001fc1SVitaly Wool } 13059a001fc1SVitaly Wool 13069a001fc1SVitaly Wool /** 13079a001fc1SVitaly Wool * z3fold_reclaim_page() - evicts allocations from a pool page and frees it 13089a001fc1SVitaly Wool * @pool: pool from which a page will attempt to be evicted 1309f144c390SMike Rapoport * @retries: number of pages on the LRU list for which eviction will 13109a001fc1SVitaly Wool * be attempted before failing 13119a001fc1SVitaly Wool * 13129a001fc1SVitaly Wool * z3fold reclaim is different from normal system reclaim in that it is done 13139a001fc1SVitaly Wool * from the bottom, up. This is because only the bottom layer, z3fold, has 13149a001fc1SVitaly Wool * information on how the allocations are organized within each z3fold page. 13159a001fc1SVitaly Wool * This has the potential to create interesting locking situations between 13169a001fc1SVitaly Wool * z3fold and the user, however. 13179a001fc1SVitaly Wool * 13189a001fc1SVitaly Wool * To avoid these, this is how z3fold_reclaim_page() should be called: 1319f144c390SMike Rapoport * 13209a001fc1SVitaly Wool * The user detects a page should be reclaimed and calls z3fold_reclaim_page(). 13219a001fc1SVitaly Wool * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and 13229a001fc1SVitaly Wool * call the user-defined eviction handler with the pool and handle as 13239a001fc1SVitaly Wool * arguments. 13249a001fc1SVitaly Wool * 13259a001fc1SVitaly Wool * If the handle can not be evicted, the eviction handler should return 13269a001fc1SVitaly Wool * non-zero. z3fold_reclaim_page() will add the z3fold page back to the 13279a001fc1SVitaly Wool * appropriate list and try the next z3fold page on the LRU up to 13289a001fc1SVitaly Wool * a user defined number of retries. 13299a001fc1SVitaly Wool * 13309a001fc1SVitaly Wool * If the handle is successfully evicted, the eviction handler should 13319a001fc1SVitaly Wool * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free() 13329a001fc1SVitaly Wool * contains logic to delay freeing the page if the page is under reclaim, 13339a001fc1SVitaly Wool * as indicated by the setting of the PG_reclaim flag on the underlying page. 13349a001fc1SVitaly Wool * 13359a001fc1SVitaly Wool * If all buddies in the z3fold page are successfully evicted, then the 13369a001fc1SVitaly Wool * z3fold page can be freed. 13379a001fc1SVitaly Wool * 13389a001fc1SVitaly Wool * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are 13399a001fc1SVitaly Wool * no pages to evict or an eviction handler is not registered, -EAGAIN if 13409a001fc1SVitaly Wool * the retry limit was hit. 13419a001fc1SVitaly Wool */ 13429a001fc1SVitaly Wool static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) 13439a001fc1SVitaly Wool { 13444a3ac931SVitaly Wool int i, ret = -1; 1345d30561c5SVitaly Wool struct z3fold_header *zhdr = NULL; 1346d30561c5SVitaly Wool struct page *page = NULL; 1347d30561c5SVitaly Wool struct list_head *pos; 13489a001fc1SVitaly Wool unsigned long first_handle = 0, middle_handle = 0, last_handle = 0; 13499a001fc1SVitaly Wool 13509a001fc1SVitaly Wool spin_lock(&pool->lock); 13512f1e5e4dSVitaly Wool if (!pool->ops || !pool->ops->evict || retries == 0) { 13529a001fc1SVitaly Wool spin_unlock(&pool->lock); 13539a001fc1SVitaly Wool return -EINVAL; 13549a001fc1SVitaly Wool } 13559a001fc1SVitaly Wool for (i = 0; i < retries; i++) { 13562f1e5e4dSVitaly Wool if (list_empty(&pool->lru)) { 13572f1e5e4dSVitaly Wool spin_unlock(&pool->lock); 13582f1e5e4dSVitaly Wool return -EINVAL; 13592f1e5e4dSVitaly Wool } 1360d30561c5SVitaly Wool list_for_each_prev(pos, &pool->lru) { 1361d30561c5SVitaly Wool page = list_entry(pos, struct page, lru); 1362ca0246bbSVitaly Wool 1363ca0246bbSVitaly Wool /* this bit could have been set by free, in which case 1364ca0246bbSVitaly Wool * we pass over to the next page in the pool. 1365ca0246bbSVitaly Wool */ 13663f9d2b57SVitaly Wool if (test_and_set_bit(PAGE_CLAIMED, &page->private)) { 13673f9d2b57SVitaly Wool page = NULL; 1368ca0246bbSVitaly Wool continue; 13693f9d2b57SVitaly Wool } 13709a001fc1SVitaly Wool 13713f9d2b57SVitaly Wool if (unlikely(PageIsolated(page))) { 13723f9d2b57SVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 13733f9d2b57SVitaly Wool page = NULL; 13741f862989SVitaly Wool continue; 13753f9d2b57SVitaly Wool } 13763f9d2b57SVitaly Wool zhdr = page_address(page); 1377ca0246bbSVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) 1378ca0246bbSVitaly Wool break; 1379ca0246bbSVitaly Wool 1380ca0246bbSVitaly Wool if (!z3fold_page_trylock(zhdr)) { 13813f9d2b57SVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 1382ca0246bbSVitaly Wool zhdr = NULL; 1383d30561c5SVitaly Wool continue; /* can't evict at this point */ 1384ca0246bbSVitaly Wool } 13854a3ac931SVitaly Wool if (zhdr->foreign_handles) { 13864a3ac931SVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 13874a3ac931SVitaly Wool z3fold_page_unlock(zhdr); 13884a3ac931SVitaly Wool zhdr = NULL; 13894a3ac931SVitaly Wool continue; /* can't evict such page */ 13904a3ac931SVitaly Wool } 13915a27aa82SVitaly Wool kref_get(&zhdr->refcount); 1392d30561c5SVitaly Wool list_del_init(&zhdr->buddy); 1393d30561c5SVitaly Wool zhdr->cpu = -1; 13946098d7e1SVitaly Wool break; 1395d30561c5SVitaly Wool } 1396d30561c5SVitaly Wool 1397ca0246bbSVitaly Wool if (!zhdr) 1398ca0246bbSVitaly Wool break; 1399ca0246bbSVitaly Wool 1400d30561c5SVitaly Wool list_del_init(&page->lru); 14012f1e5e4dSVitaly Wool spin_unlock(&pool->lock); 1402d30561c5SVitaly Wool 1403d30561c5SVitaly Wool if (!test_bit(PAGE_HEADLESS, &page->private)) { 14049a001fc1SVitaly Wool /* 14053f9d2b57SVitaly Wool * We need encode the handles before unlocking, and 14063f9d2b57SVitaly Wool * use our local slots structure because z3fold_free 14073f9d2b57SVitaly Wool * can zero out zhdr->slots and we can't do much 14083f9d2b57SVitaly Wool * about that 14099a001fc1SVitaly Wool */ 14109a001fc1SVitaly Wool first_handle = 0; 14119a001fc1SVitaly Wool last_handle = 0; 14129a001fc1SVitaly Wool middle_handle = 0; 14139a001fc1SVitaly Wool if (zhdr->first_chunks) 14144a3ac931SVitaly Wool first_handle = encode_handle(zhdr, FIRST); 14159a001fc1SVitaly Wool if (zhdr->middle_chunks) 14164a3ac931SVitaly Wool middle_handle = encode_handle(zhdr, MIDDLE); 14179a001fc1SVitaly Wool if (zhdr->last_chunks) 14184a3ac931SVitaly Wool last_handle = encode_handle(zhdr, LAST); 1419d30561c5SVitaly Wool /* 1420d30561c5SVitaly Wool * it's safe to unlock here because we hold a 1421d30561c5SVitaly Wool * reference to this page 1422d30561c5SVitaly Wool */ 14232f1e5e4dSVitaly Wool z3fold_page_unlock(zhdr); 14249a001fc1SVitaly Wool } else { 14254a3ac931SVitaly Wool first_handle = encode_handle(zhdr, HEADLESS); 14269a001fc1SVitaly Wool last_handle = middle_handle = 0; 14272f1e5e4dSVitaly Wool } 14289a001fc1SVitaly Wool /* Issue the eviction callback(s) */ 14299a001fc1SVitaly Wool if (middle_handle) { 14309a001fc1SVitaly Wool ret = pool->ops->evict(pool, middle_handle); 14319a001fc1SVitaly Wool if (ret) 14329a001fc1SVitaly Wool goto next; 14334a3ac931SVitaly Wool free_handle(middle_handle); 14349a001fc1SVitaly Wool } 14359a001fc1SVitaly Wool if (first_handle) { 14369a001fc1SVitaly Wool ret = pool->ops->evict(pool, first_handle); 14379a001fc1SVitaly Wool if (ret) 14389a001fc1SVitaly Wool goto next; 14394a3ac931SVitaly Wool free_handle(first_handle); 14409a001fc1SVitaly Wool } 14419a001fc1SVitaly Wool if (last_handle) { 14429a001fc1SVitaly Wool ret = pool->ops->evict(pool, last_handle); 14439a001fc1SVitaly Wool if (ret) 14449a001fc1SVitaly Wool goto next; 14454a3ac931SVitaly Wool free_handle(last_handle); 14469a001fc1SVitaly Wool } 14479a001fc1SVitaly Wool next: 14485a27aa82SVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) { 14495a27aa82SVitaly Wool if (ret == 0) { 14501f862989SVitaly Wool free_z3fold_page(page, true); 1451ca0246bbSVitaly Wool atomic64_dec(&pool->pages_nr); 14529a001fc1SVitaly Wool return 0; 14535a27aa82SVitaly Wool } 14546098d7e1SVitaly Wool spin_lock(&pool->lock); 14556098d7e1SVitaly Wool list_add(&page->lru, &pool->lru); 1456d5567c9dSVitaly Wool spin_unlock(&pool->lock); 14573f9d2b57SVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 14586098d7e1SVitaly Wool } else { 14596098d7e1SVitaly Wool z3fold_page_lock(zhdr); 14606098d7e1SVitaly Wool if (kref_put(&zhdr->refcount, 14616098d7e1SVitaly Wool release_z3fold_page_locked)) { 14626098d7e1SVitaly Wool atomic64_dec(&pool->pages_nr); 14635a27aa82SVitaly Wool return 0; 14645a27aa82SVitaly Wool } 14655a27aa82SVitaly Wool /* 14666098d7e1SVitaly Wool * if we are here, the page is still not completely 14676098d7e1SVitaly Wool * free. Take the global pool lock then to be able 14686098d7e1SVitaly Wool * to add it back to the lru list 14695a27aa82SVitaly Wool */ 14706098d7e1SVitaly Wool spin_lock(&pool->lock); 14719a001fc1SVitaly Wool list_add(&page->lru, &pool->lru); 14726098d7e1SVitaly Wool spin_unlock(&pool->lock); 14736098d7e1SVitaly Wool z3fold_page_unlock(zhdr); 14743f9d2b57SVitaly Wool clear_bit(PAGE_CLAIMED, &page->private); 14756098d7e1SVitaly Wool } 14766098d7e1SVitaly Wool 14776098d7e1SVitaly Wool /* We started off locked to we need to lock the pool back */ 14786098d7e1SVitaly Wool spin_lock(&pool->lock); 14799a001fc1SVitaly Wool } 14809a001fc1SVitaly Wool spin_unlock(&pool->lock); 14819a001fc1SVitaly Wool return -EAGAIN; 14829a001fc1SVitaly Wool } 14839a001fc1SVitaly Wool 14849a001fc1SVitaly Wool /** 14859a001fc1SVitaly Wool * z3fold_map() - maps the allocation associated with the given handle 14869a001fc1SVitaly Wool * @pool: pool in which the allocation resides 14879a001fc1SVitaly Wool * @handle: handle associated with the allocation to be mapped 14889a001fc1SVitaly Wool * 14899a001fc1SVitaly Wool * Extracts the buddy number from handle and constructs the pointer to the 14909a001fc1SVitaly Wool * correct starting chunk within the page. 14919a001fc1SVitaly Wool * 14929a001fc1SVitaly Wool * Returns: a pointer to the mapped allocation 14939a001fc1SVitaly Wool */ 14949a001fc1SVitaly Wool static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle) 14959a001fc1SVitaly Wool { 14969a001fc1SVitaly Wool struct z3fold_header *zhdr; 14979a001fc1SVitaly Wool struct page *page; 14989a001fc1SVitaly Wool void *addr; 14999a001fc1SVitaly Wool enum buddy buddy; 15009a001fc1SVitaly Wool 15014a3ac931SVitaly Wool zhdr = get_z3fold_header(handle); 15029a001fc1SVitaly Wool addr = zhdr; 15039a001fc1SVitaly Wool page = virt_to_page(zhdr); 15049a001fc1SVitaly Wool 15059a001fc1SVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) 15069a001fc1SVitaly Wool goto out; 15079a001fc1SVitaly Wool 15089a001fc1SVitaly Wool buddy = handle_to_buddy(handle); 15099a001fc1SVitaly Wool switch (buddy) { 15109a001fc1SVitaly Wool case FIRST: 15119a001fc1SVitaly Wool addr += ZHDR_SIZE_ALIGNED; 15129a001fc1SVitaly Wool break; 15139a001fc1SVitaly Wool case MIDDLE: 15149a001fc1SVitaly Wool addr += zhdr->start_middle << CHUNK_SHIFT; 15159a001fc1SVitaly Wool set_bit(MIDDLE_CHUNK_MAPPED, &page->private); 15169a001fc1SVitaly Wool break; 15179a001fc1SVitaly Wool case LAST: 1518ca0246bbSVitaly Wool addr += PAGE_SIZE - (handle_to_chunks(handle) << CHUNK_SHIFT); 15199a001fc1SVitaly Wool break; 15209a001fc1SVitaly Wool default: 15219a001fc1SVitaly Wool pr_err("unknown buddy id %d\n", buddy); 15229a001fc1SVitaly Wool WARN_ON(1); 15239a001fc1SVitaly Wool addr = NULL; 15249a001fc1SVitaly Wool break; 15259a001fc1SVitaly Wool } 15262f1e5e4dSVitaly Wool 15271f862989SVitaly Wool if (addr) 15281f862989SVitaly Wool zhdr->mapped_count++; 15299a001fc1SVitaly Wool out: 15304a3ac931SVitaly Wool put_z3fold_header(zhdr); 15319a001fc1SVitaly Wool return addr; 15329a001fc1SVitaly Wool } 15339a001fc1SVitaly Wool 15349a001fc1SVitaly Wool /** 15359a001fc1SVitaly Wool * z3fold_unmap() - unmaps the allocation associated with the given handle 15369a001fc1SVitaly Wool * @pool: pool in which the allocation resides 15379a001fc1SVitaly Wool * @handle: handle associated with the allocation to be unmapped 15389a001fc1SVitaly Wool */ 15399a001fc1SVitaly Wool static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle) 15409a001fc1SVitaly Wool { 15419a001fc1SVitaly Wool struct z3fold_header *zhdr; 15429a001fc1SVitaly Wool struct page *page; 15439a001fc1SVitaly Wool enum buddy buddy; 15449a001fc1SVitaly Wool 15454a3ac931SVitaly Wool zhdr = get_z3fold_header(handle); 15469a001fc1SVitaly Wool page = virt_to_page(zhdr); 15479a001fc1SVitaly Wool 15482f1e5e4dSVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private)) 15499a001fc1SVitaly Wool return; 15509a001fc1SVitaly Wool 15519a001fc1SVitaly Wool buddy = handle_to_buddy(handle); 15529a001fc1SVitaly Wool if (buddy == MIDDLE) 15539a001fc1SVitaly Wool clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); 15541f862989SVitaly Wool zhdr->mapped_count--; 15554a3ac931SVitaly Wool put_z3fold_header(zhdr); 15569a001fc1SVitaly Wool } 15579a001fc1SVitaly Wool 15589a001fc1SVitaly Wool /** 15599a001fc1SVitaly Wool * z3fold_get_pool_size() - gets the z3fold pool size in pages 15609a001fc1SVitaly Wool * @pool: pool whose size is being queried 15619a001fc1SVitaly Wool * 156212d59ae6SVitaly Wool * Returns: size in pages of the given pool. 15639a001fc1SVitaly Wool */ 15649a001fc1SVitaly Wool static u64 z3fold_get_pool_size(struct z3fold_pool *pool) 15659a001fc1SVitaly Wool { 156612d59ae6SVitaly Wool return atomic64_read(&pool->pages_nr); 15679a001fc1SVitaly Wool } 15689a001fc1SVitaly Wool 15691f862989SVitaly Wool static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode) 15701f862989SVitaly Wool { 15711f862989SVitaly Wool struct z3fold_header *zhdr; 15721f862989SVitaly Wool struct z3fold_pool *pool; 15731f862989SVitaly Wool 15741f862989SVitaly Wool VM_BUG_ON_PAGE(!PageMovable(page), page); 15751f862989SVitaly Wool VM_BUG_ON_PAGE(PageIsolated(page), page); 15761f862989SVitaly Wool 15773f9d2b57SVitaly Wool if (test_bit(PAGE_HEADLESS, &page->private) || 15783f9d2b57SVitaly Wool test_bit(PAGE_CLAIMED, &page->private)) 15791f862989SVitaly Wool return false; 15801f862989SVitaly Wool 15811f862989SVitaly Wool zhdr = page_address(page); 15821f862989SVitaly Wool z3fold_page_lock(zhdr); 15831f862989SVitaly Wool if (test_bit(NEEDS_COMPACTING, &page->private) || 15841f862989SVitaly Wool test_bit(PAGE_STALE, &page->private)) 15851f862989SVitaly Wool goto out; 15861f862989SVitaly Wool 15874a3ac931SVitaly Wool if (zhdr->mapped_count != 0 || zhdr->foreign_handles != 0) 15884a3ac931SVitaly Wool goto out; 15891f862989SVitaly Wool 15904a3ac931SVitaly Wool pool = zhdr_to_pool(zhdr); 15914a3ac931SVitaly Wool spin_lock(&pool->lock); 15921f862989SVitaly Wool if (!list_empty(&zhdr->buddy)) 15931f862989SVitaly Wool list_del_init(&zhdr->buddy); 15941f862989SVitaly Wool if (!list_empty(&page->lru)) 15954a3ac931SVitaly Wool list_del_init(&page->lru); 15961f862989SVitaly Wool spin_unlock(&pool->lock); 15974a3ac931SVitaly Wool 15984a3ac931SVitaly Wool kref_get(&zhdr->refcount); 15991f862989SVitaly Wool z3fold_page_unlock(zhdr); 16001f862989SVitaly Wool return true; 16014a3ac931SVitaly Wool 16021f862989SVitaly Wool out: 16031f862989SVitaly Wool z3fold_page_unlock(zhdr); 16041f862989SVitaly Wool return false; 16051f862989SVitaly Wool } 16061f862989SVitaly Wool 16071f862989SVitaly Wool static int z3fold_page_migrate(struct address_space *mapping, struct page *newpage, 16081f862989SVitaly Wool struct page *page, enum migrate_mode mode) 16091f862989SVitaly Wool { 16101f862989SVitaly Wool struct z3fold_header *zhdr, *new_zhdr; 16111f862989SVitaly Wool struct z3fold_pool *pool; 16121f862989SVitaly Wool struct address_space *new_mapping; 16131f862989SVitaly Wool 16141f862989SVitaly Wool VM_BUG_ON_PAGE(!PageMovable(page), page); 16151f862989SVitaly Wool VM_BUG_ON_PAGE(!PageIsolated(page), page); 1616810481a2SHenry Burns VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); 16171f862989SVitaly Wool 16181f862989SVitaly Wool zhdr = page_address(page); 16191f862989SVitaly Wool pool = zhdr_to_pool(zhdr); 16201f862989SVitaly Wool 16211f862989SVitaly Wool if (!z3fold_page_trylock(zhdr)) { 16221f862989SVitaly Wool return -EAGAIN; 16231f862989SVitaly Wool } 16244a3ac931SVitaly Wool if (zhdr->mapped_count != 0 || zhdr->foreign_handles != 0) { 16251f862989SVitaly Wool z3fold_page_unlock(zhdr); 16261f862989SVitaly Wool return -EBUSY; 16271f862989SVitaly Wool } 1628c92d2f38SHenry Burns if (work_pending(&zhdr->work)) { 1629c92d2f38SHenry Burns z3fold_page_unlock(zhdr); 1630c92d2f38SHenry Burns return -EAGAIN; 1631c92d2f38SHenry Burns } 16321f862989SVitaly Wool new_zhdr = page_address(newpage); 16331f862989SVitaly Wool memcpy(new_zhdr, zhdr, PAGE_SIZE); 16341f862989SVitaly Wool newpage->private = page->private; 16351f862989SVitaly Wool page->private = 0; 16361f862989SVitaly Wool z3fold_page_unlock(zhdr); 16371f862989SVitaly Wool spin_lock_init(&new_zhdr->page_lock); 1638c92d2f38SHenry Burns INIT_WORK(&new_zhdr->work, compact_page_work); 1639c92d2f38SHenry Burns /* 1640c92d2f38SHenry Burns * z3fold_page_isolate() ensures that new_zhdr->buddy is empty, 1641c92d2f38SHenry Burns * so we only have to reinitialize it. 1642c92d2f38SHenry Burns */ 1643c92d2f38SHenry Burns INIT_LIST_HEAD(&new_zhdr->buddy); 16441f862989SVitaly Wool new_mapping = page_mapping(page); 16451f862989SVitaly Wool __ClearPageMovable(page); 16461f862989SVitaly Wool ClearPagePrivate(page); 16471f862989SVitaly Wool 16481f862989SVitaly Wool get_page(newpage); 16491f862989SVitaly Wool z3fold_page_lock(new_zhdr); 16501f862989SVitaly Wool if (new_zhdr->first_chunks) 16511f862989SVitaly Wool encode_handle(new_zhdr, FIRST); 16521f862989SVitaly Wool if (new_zhdr->last_chunks) 16531f862989SVitaly Wool encode_handle(new_zhdr, LAST); 16541f862989SVitaly Wool if (new_zhdr->middle_chunks) 16551f862989SVitaly Wool encode_handle(new_zhdr, MIDDLE); 16561f862989SVitaly Wool set_bit(NEEDS_COMPACTING, &newpage->private); 16571f862989SVitaly Wool new_zhdr->cpu = smp_processor_id(); 16581f862989SVitaly Wool spin_lock(&pool->lock); 16591f862989SVitaly Wool list_add(&newpage->lru, &pool->lru); 16601f862989SVitaly Wool spin_unlock(&pool->lock); 16611f862989SVitaly Wool __SetPageMovable(newpage, new_mapping); 16621f862989SVitaly Wool z3fold_page_unlock(new_zhdr); 16631f862989SVitaly Wool 16641f862989SVitaly Wool queue_work_on(new_zhdr->cpu, pool->compact_wq, &new_zhdr->work); 16651f862989SVitaly Wool 16661f862989SVitaly Wool page_mapcount_reset(page); 16671f862989SVitaly Wool put_page(page); 16681f862989SVitaly Wool return 0; 16691f862989SVitaly Wool } 16701f862989SVitaly Wool 16711f862989SVitaly Wool static void z3fold_page_putback(struct page *page) 16721f862989SVitaly Wool { 16731f862989SVitaly Wool struct z3fold_header *zhdr; 16741f862989SVitaly Wool struct z3fold_pool *pool; 16751f862989SVitaly Wool 16761f862989SVitaly Wool zhdr = page_address(page); 16771f862989SVitaly Wool pool = zhdr_to_pool(zhdr); 16781f862989SVitaly Wool 16791f862989SVitaly Wool z3fold_page_lock(zhdr); 16801f862989SVitaly Wool if (!list_empty(&zhdr->buddy)) 16811f862989SVitaly Wool list_del_init(&zhdr->buddy); 16821f862989SVitaly Wool INIT_LIST_HEAD(&page->lru); 16831f862989SVitaly Wool if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) { 16841f862989SVitaly Wool atomic64_dec(&pool->pages_nr); 16851f862989SVitaly Wool return; 16861f862989SVitaly Wool } 16871f862989SVitaly Wool spin_lock(&pool->lock); 16881f862989SVitaly Wool list_add(&page->lru, &pool->lru); 16891f862989SVitaly Wool spin_unlock(&pool->lock); 16901f862989SVitaly Wool z3fold_page_unlock(zhdr); 16911f862989SVitaly Wool } 16921f862989SVitaly Wool 16931f862989SVitaly Wool static const struct address_space_operations z3fold_aops = { 16941f862989SVitaly Wool .isolate_page = z3fold_page_isolate, 16951f862989SVitaly Wool .migratepage = z3fold_page_migrate, 16961f862989SVitaly Wool .putback_page = z3fold_page_putback, 16971f862989SVitaly Wool }; 16981f862989SVitaly Wool 16999a001fc1SVitaly Wool /***************** 17009a001fc1SVitaly Wool * zpool 17019a001fc1SVitaly Wool ****************/ 17029a001fc1SVitaly Wool 17039a001fc1SVitaly Wool static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle) 17049a001fc1SVitaly Wool { 17059a001fc1SVitaly Wool if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict) 17069a001fc1SVitaly Wool return pool->zpool_ops->evict(pool->zpool, handle); 17079a001fc1SVitaly Wool else 17089a001fc1SVitaly Wool return -ENOENT; 17099a001fc1SVitaly Wool } 17109a001fc1SVitaly Wool 17119a001fc1SVitaly Wool static const struct z3fold_ops z3fold_zpool_ops = { 17129a001fc1SVitaly Wool .evict = z3fold_zpool_evict 17139a001fc1SVitaly Wool }; 17149a001fc1SVitaly Wool 17159a001fc1SVitaly Wool static void *z3fold_zpool_create(const char *name, gfp_t gfp, 17169a001fc1SVitaly Wool const struct zpool_ops *zpool_ops, 17179a001fc1SVitaly Wool struct zpool *zpool) 17189a001fc1SVitaly Wool { 17199a001fc1SVitaly Wool struct z3fold_pool *pool; 17209a001fc1SVitaly Wool 1721d30561c5SVitaly Wool pool = z3fold_create_pool(name, gfp, 1722d30561c5SVitaly Wool zpool_ops ? &z3fold_zpool_ops : NULL); 17239a001fc1SVitaly Wool if (pool) { 17249a001fc1SVitaly Wool pool->zpool = zpool; 17259a001fc1SVitaly Wool pool->zpool_ops = zpool_ops; 17269a001fc1SVitaly Wool } 17279a001fc1SVitaly Wool return pool; 17289a001fc1SVitaly Wool } 17299a001fc1SVitaly Wool 17309a001fc1SVitaly Wool static void z3fold_zpool_destroy(void *pool) 17319a001fc1SVitaly Wool { 17329a001fc1SVitaly Wool z3fold_destroy_pool(pool); 17339a001fc1SVitaly Wool } 17349a001fc1SVitaly Wool 17359a001fc1SVitaly Wool static int z3fold_zpool_malloc(void *pool, size_t size, gfp_t gfp, 17369a001fc1SVitaly Wool unsigned long *handle) 17379a001fc1SVitaly Wool { 17389a001fc1SVitaly Wool return z3fold_alloc(pool, size, gfp, handle); 17399a001fc1SVitaly Wool } 17409a001fc1SVitaly Wool static void z3fold_zpool_free(void *pool, unsigned long handle) 17419a001fc1SVitaly Wool { 17429a001fc1SVitaly Wool z3fold_free(pool, handle); 17439a001fc1SVitaly Wool } 17449a001fc1SVitaly Wool 17459a001fc1SVitaly Wool static int z3fold_zpool_shrink(void *pool, unsigned int pages, 17469a001fc1SVitaly Wool unsigned int *reclaimed) 17479a001fc1SVitaly Wool { 17489a001fc1SVitaly Wool unsigned int total = 0; 17499a001fc1SVitaly Wool int ret = -EINVAL; 17509a001fc1SVitaly Wool 17519a001fc1SVitaly Wool while (total < pages) { 17529a001fc1SVitaly Wool ret = z3fold_reclaim_page(pool, 8); 17539a001fc1SVitaly Wool if (ret < 0) 17549a001fc1SVitaly Wool break; 17559a001fc1SVitaly Wool total++; 17569a001fc1SVitaly Wool } 17579a001fc1SVitaly Wool 17589a001fc1SVitaly Wool if (reclaimed) 17599a001fc1SVitaly Wool *reclaimed = total; 17609a001fc1SVitaly Wool 17619a001fc1SVitaly Wool return ret; 17629a001fc1SVitaly Wool } 17639a001fc1SVitaly Wool 17649a001fc1SVitaly Wool static void *z3fold_zpool_map(void *pool, unsigned long handle, 17659a001fc1SVitaly Wool enum zpool_mapmode mm) 17669a001fc1SVitaly Wool { 17679a001fc1SVitaly Wool return z3fold_map(pool, handle); 17689a001fc1SVitaly Wool } 17699a001fc1SVitaly Wool static void z3fold_zpool_unmap(void *pool, unsigned long handle) 17709a001fc1SVitaly Wool { 17719a001fc1SVitaly Wool z3fold_unmap(pool, handle); 17729a001fc1SVitaly Wool } 17739a001fc1SVitaly Wool 17749a001fc1SVitaly Wool static u64 z3fold_zpool_total_size(void *pool) 17759a001fc1SVitaly Wool { 17769a001fc1SVitaly Wool return z3fold_get_pool_size(pool) * PAGE_SIZE; 17779a001fc1SVitaly Wool } 17789a001fc1SVitaly Wool 17799a001fc1SVitaly Wool static struct zpool_driver z3fold_zpool_driver = { 17809a001fc1SVitaly Wool .type = "z3fold", 17819a001fc1SVitaly Wool .owner = THIS_MODULE, 17829a001fc1SVitaly Wool .create = z3fold_zpool_create, 17839a001fc1SVitaly Wool .destroy = z3fold_zpool_destroy, 17849a001fc1SVitaly Wool .malloc = z3fold_zpool_malloc, 17859a001fc1SVitaly Wool .free = z3fold_zpool_free, 17869a001fc1SVitaly Wool .shrink = z3fold_zpool_shrink, 17879a001fc1SVitaly Wool .map = z3fold_zpool_map, 17889a001fc1SVitaly Wool .unmap = z3fold_zpool_unmap, 17899a001fc1SVitaly Wool .total_size = z3fold_zpool_total_size, 17909a001fc1SVitaly Wool }; 17919a001fc1SVitaly Wool 17929a001fc1SVitaly Wool MODULE_ALIAS("zpool-z3fold"); 17939a001fc1SVitaly Wool 17949a001fc1SVitaly Wool static int __init init_z3fold(void) 17959a001fc1SVitaly Wool { 17961f862989SVitaly Wool int ret; 17971f862989SVitaly Wool 1798ede93213SVitaly Wool /* Make sure the z3fold header is not larger than the page size */ 1799ede93213SVitaly Wool BUILD_BUG_ON(ZHDR_SIZE_ALIGNED > PAGE_SIZE); 18001f862989SVitaly Wool ret = z3fold_mount(); 18011f862989SVitaly Wool if (ret) 18021f862989SVitaly Wool return ret; 18031f862989SVitaly Wool 18049a001fc1SVitaly Wool zpool_register_driver(&z3fold_zpool_driver); 18059a001fc1SVitaly Wool 18069a001fc1SVitaly Wool return 0; 18079a001fc1SVitaly Wool } 18089a001fc1SVitaly Wool 18099a001fc1SVitaly Wool static void __exit exit_z3fold(void) 18109a001fc1SVitaly Wool { 18111f862989SVitaly Wool z3fold_unmount(); 18129a001fc1SVitaly Wool zpool_unregister_driver(&z3fold_zpool_driver); 18139a001fc1SVitaly Wool } 18149a001fc1SVitaly Wool 18159a001fc1SVitaly Wool module_init(init_z3fold); 18169a001fc1SVitaly Wool module_exit(exit_z3fold); 18179a001fc1SVitaly Wool 18189a001fc1SVitaly Wool MODULE_LICENSE("GPL"); 18199a001fc1SVitaly Wool MODULE_AUTHOR("Vitaly Wool <vitalywool@gmail.com>"); 18209a001fc1SVitaly Wool MODULE_DESCRIPTION("3-Fold Allocator for Compressed Pages"); 1821