diff options
| -rw-r--r-- | mm/z3fold.c | 375 |
1 files changed, 303 insertions, 72 deletions
diff --git a/mm/z3fold.c b/mm/z3fold.c index 6d3d3f698ebb..43754d8ebce8 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -41,6 +41,7 @@ #include <linux/workqueue.h> #include <linux/slab.h> #include <linux/spinlock.h> +#include <linux/rwlock.h> #include <linux/zpool.h> #include <linux/magic.h> @@ -90,6 +91,7 @@ struct z3fold_buddy_slots { */ unsigned long slot[BUDDY_MASK + 1]; unsigned long pool; /* back link + flags */ + rwlock_t lock; }; #define HANDLE_FLAG_MASK (0x03) @@ -124,6 +126,7 @@ struct z3fold_header { unsigned short start_middle; unsigned short first_num:2; unsigned short mapped_count:2; + unsigned short foreign_handles:2; }; /** @@ -178,6 +181,19 @@ enum z3fold_page_flags { PAGE_CLAIMED, /* by either reclaim or free */ }; +/* + * handle flags, go under HANDLE_FLAG_MASK + */ +enum z3fold_handle_flags { + HANDLES_ORPHANED = 0, +}; + +/* + * Forward declarations + */ +static struct z3fold_header *__z3fold_alloc(struct z3fold_pool *, size_t, bool); +static void compact_page_work(struct work_struct *w); + /***************** * Helpers *****************/ @@ -191,8 +207,6 @@ static int size_to_chunks(size_t size) #define for_each_unbuddied_list(_iter, _begin) \ for ((_iter) = (_begin); (_iter) < NCHUNKS; (_iter)++) -static void compact_page_work(struct work_struct *w); - static inline struct z3fold_buddy_slots *alloc_slots(struct z3fold_pool *pool, gfp_t gfp) { @@ -204,6 +218,7 @@ static inline struct z3fold_buddy_slots *alloc_slots(struct z3fold_pool *pool, if (slots) { memset(slots->slot, 0, sizeof(slots->slot)); slots->pool = (unsigned long)pool; + rwlock_init(&slots->lock); } return slots; @@ -219,25 +234,110 @@ static inline struct z3fold_buddy_slots *handle_to_slots(unsigned long handle) return (struct z3fold_buddy_slots *)(handle & ~(SLOTS_ALIGN - 1)); } +/* Lock a z3fold page */ +static inline void z3fold_page_lock(struct z3fold_header *zhdr) +{ + spin_lock(&zhdr->page_lock); +} + +/* Try to lock a z3fold page */ +static inline int z3fold_page_trylock(struct z3fold_header *zhdr) +{ + return spin_trylock(&zhdr->page_lock); +} + +/* Unlock a z3fold page */ +static inline void z3fold_page_unlock(struct z3fold_header *zhdr) +{ + spin_unlock(&zhdr->page_lock); +} + + +static inline struct z3fold_header *__get_z3fold_header(unsigned long handle, + bool lock) +{ + struct z3fold_buddy_slots *slots; + struct z3fold_header *zhdr; + int locked = 0; + + if (!(handle & (1 << PAGE_HEADLESS))) { + slots = handle_to_slots(handle); + do { + unsigned long addr; + + read_lock(&slots->lock); + addr = *(unsigned long *)handle; + zhdr = (struct z3fold_header *)(addr & PAGE_MASK); + if (lock) + locked = z3fold_page_trylock(zhdr); + read_unlock(&slots->lock); + if (locked) + break; + cpu_relax(); + } while (lock); + } else { + zhdr = (struct z3fold_header *)(handle & PAGE_MASK); + } + + return zhdr; +} + +/* Returns the z3fold page where a given handle is stored */ +static inline struct z3fold_header *handle_to_z3fold_header(unsigned long h) +{ + return __get_z3fold_header(h, false); +} + +/* return locked z3fold page if it's not headless */ +static inline struct z3fold_header *get_z3fold_header(unsigned long h) +{ + return __get_z3fold_header(h, true); +} + +static inline void put_z3fold_header(struct z3fold_header *zhdr) +{ + struct page *page = virt_to_page(zhdr); + + if (!test_bit(PAGE_HEADLESS, &page->private)) + z3fold_page_unlock(zhdr); +} + static inline void free_handle(unsigned long handle) { struct z3fold_buddy_slots *slots; + struct z3fold_header *zhdr; int i; bool is_free; if (handle & (1 << PAGE_HEADLESS)) return; - WARN_ON(*(unsigned long *)handle == 0); - *(unsigned long *)handle = 0; + if (WARN_ON(*(unsigned long *)handle == 0)) + return; + + zhdr = handle_to_z3fold_header(handle); slots = handle_to_slots(handle); + write_lock(&slots->lock); + *(unsigned long *)handle = 0; + write_unlock(&slots->lock); + if (zhdr->slots == slots) + return; /* simple case, nothing else to do */ + + /* we are freeing a foreign handle if we are here */ + zhdr->foreign_handles--; is_free = true; + read_lock(&slots->lock); + if (!test_bit(HANDLES_ORPHANED, &slots->pool)) { + read_unlock(&slots->lock); + return; + } for (i = 0; i <= BUDDY_MASK; i++) { if (slots->slot[i]) { is_free = false; break; } } + read_unlock(&slots->lock); if (is_free) { struct z3fold_pool *pool = slots_to_pool(slots); @@ -322,6 +422,7 @@ static struct z3fold_header *init_z3fold_page(struct page *page, bool headless, zhdr->first_num = 0; zhdr->start_middle = 0; zhdr->cpu = -1; + zhdr->foreign_handles = 0; zhdr->slots = slots; zhdr->pool = pool; INIT_LIST_HEAD(&zhdr->buddy); @@ -341,24 +442,6 @@ static void free_z3fold_page(struct page *page, bool headless) __free_page(page); } -/* Lock a z3fold page */ -static inline void z3fold_page_lock(struct z3fold_header *zhdr) -{ - spin_lock(&zhdr->page_lock); -} - -/* Try to lock a z3fold page */ -static inline int z3fold_page_trylock(struct z3fold_header *zhdr) -{ - return spin_trylock(&zhdr->page_lock); -} - -/* Unlock a z3fold page */ -static inline void z3fold_page_unlock(struct z3fold_header *zhdr) -{ - spin_unlock(&zhdr->page_lock); -} - /* Helper function to build the index */ static inline int __idx(struct z3fold_header *zhdr, enum buddy bud) { @@ -389,7 +472,9 @@ static unsigned long __encode_handle(struct z3fold_header *zhdr, if (bud == LAST) h |= (zhdr->last_chunks << BUDDY_SHIFT); + write_lock(&slots->lock); slots->slot[idx] = h; + write_unlock(&slots->lock); return (unsigned long)&slots->slot[idx]; } @@ -398,22 +483,15 @@ static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) return __encode_handle(zhdr, zhdr->slots, bud); } -/* Returns the z3fold page where a given handle is stored */ -static inline struct z3fold_header *handle_to_z3fold_header(unsigned long h) -{ - unsigned long addr = h; - - if (!(addr & (1 << PAGE_HEADLESS))) - addr = *(unsigned long *)h; - - return (struct z3fold_header *)(addr & PAGE_MASK); -} - /* only for LAST bud, returns zero otherwise */ static unsigned short handle_to_chunks(unsigned long handle) { - unsigned long addr = *(unsigned long *)handle; + struct z3fold_buddy_slots *slots = handle_to_slots(handle); + unsigned long addr; + read_lock(&slots->lock); + addr = *(unsigned long *)handle; + read_unlock(&slots->lock); return (addr & ~PAGE_MASK) >> BUDDY_SHIFT; } @@ -425,10 +503,13 @@ static unsigned short handle_to_chunks(unsigned long handle) static enum buddy handle_to_buddy(unsigned long handle) { struct z3fold_header *zhdr; + struct z3fold_buddy_slots *slots = handle_to_slots(handle); unsigned long addr; + read_lock(&slots->lock); WARN_ON(handle & (1 << PAGE_HEADLESS)); addr = *(unsigned long *)handle; + read_unlock(&slots->lock); zhdr = (struct z3fold_header *)(addr & PAGE_MASK); return (addr - zhdr->first_num) & BUDDY_MASK; } @@ -442,6 +523,8 @@ static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) { struct page *page = virt_to_page(zhdr); struct z3fold_pool *pool = zhdr_to_pool(zhdr); + bool is_free = true; + int i; WARN_ON(!list_empty(&zhdr->buddy)); set_bit(PAGE_STALE, &page->private); @@ -450,8 +533,25 @@ static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) if (!list_empty(&page->lru)) list_del_init(&page->lru); spin_unlock(&pool->lock); + + /* If there are no foreign handles, free the handles array */ + read_lock(&zhdr->slots->lock); + for (i = 0; i <= BUDDY_MASK; i++) { + if (zhdr->slots->slot[i]) { + is_free = false; + break; + } + } + if (!is_free) + set_bit(HANDLES_ORPHANED, &zhdr->slots->pool); + read_unlock(&zhdr->slots->lock); + + if (is_free) + kmem_cache_free(pool->c_handle, zhdr->slots); + if (locked) z3fold_page_unlock(zhdr); + spin_lock(&pool->stale_lock); list_add(&zhdr->buddy, &pool->stale); queue_work(pool->release_wq, &pool->work); @@ -479,6 +579,7 @@ static void release_z3fold_page_locked_list(struct kref *ref) struct z3fold_header *zhdr = container_of(ref, struct z3fold_header, refcount); struct z3fold_pool *pool = zhdr_to_pool(zhdr); + spin_lock(&pool->lock); list_del_init(&zhdr->buddy); spin_unlock(&pool->lock); @@ -559,6 +660,119 @@ static inline void *mchunk_memmove(struct z3fold_header *zhdr, zhdr->middle_chunks << CHUNK_SHIFT); } +static inline bool buddy_single(struct z3fold_header *zhdr) +{ + return !((zhdr->first_chunks && zhdr->middle_chunks) || + (zhdr->first_chunks && zhdr->last_chunks) || + (zhdr->middle_chunks && zhdr->last_chunks)); +} + +static struct z3fold_header *compact_single_buddy(struct z3fold_header *zhdr) +{ + struct z3fold_pool *pool = zhdr_to_pool(zhdr); + void *p = zhdr; + unsigned long old_handle = 0; + size_t sz = 0; + struct z3fold_header *new_zhdr = NULL; + int first_idx = __idx(zhdr, FIRST); + int middle_idx = __idx(zhdr, MIDDLE); + int last_idx = __idx(zhdr, LAST); + unsigned short *moved_chunks = NULL; + + /* + * No need to protect slots here -- all the slots are "local" and + * the page lock is already taken + */ + if (zhdr->first_chunks && zhdr->slots->slot[first_idx]) { + p += ZHDR_SIZE_ALIGNED; + sz = zhdr->first_chunks << CHUNK_SHIFT; + old_handle = (unsigned long)&zhdr->slots->slot[first_idx]; + moved_chunks = &zhdr->first_chunks; + } else if (zhdr->middle_chunks && zhdr->slots->slot[middle_idx]) { + p += zhdr->start_middle << CHUNK_SHIFT; + sz = zhdr->middle_chunks << CHUNK_SHIFT; + old_handle = (unsigned long)&zhdr->slots->slot[middle_idx]; + moved_chunks = &zhdr->middle_chunks; + } else if (zhdr->last_chunks && zhdr->slots->slot[last_idx]) { + p += PAGE_SIZE - (zhdr->last_chunks << CHUNK_SHIFT); + sz = zhdr->last_chunks << CHUNK_SHIFT; + old_handle = (unsigned long)&zhdr->slots->slot[last_idx]; + moved_chunks = &zhdr->last_chunks; + } + + if (sz > 0) { + enum buddy new_bud = HEADLESS; + short chunks = size_to_chunks(sz); + void *q; + + new_zhdr = __z3fold_alloc(pool, sz, false); + if (!new_zhdr) + return NULL; + + if (WARN_ON(new_zhdr == zhdr)) + goto out_fail; + + if (new_zhdr->first_chunks == 0) { + if (new_zhdr->middle_chunks != 0 && + chunks >= new_zhdr->start_middle) { + new_bud = LAST; + } else { + new_bud = FIRST; + } + } else if (new_zhdr->last_chunks == 0) { + new_bud = LAST; + } else if (new_zhdr->middle_chunks == 0) { + new_bud = MIDDLE; + } + q = new_zhdr; + switch (new_bud) { + case FIRST: + new_zhdr->first_chunks = chunks; + q += ZHDR_SIZE_ALIGNED; + break; + case MIDDLE: + new_zhdr->middle_chunks = chunks; + new_zhdr->start_middle = + new_zhdr->first_chunks + ZHDR_CHUNKS; + q += new_zhdr->start_middle << CHUNK_SHIFT; + break; + case LAST: + new_zhdr->last_chunks = chunks; + q += PAGE_SIZE - (new_zhdr->last_chunks << CHUNK_SHIFT); + break; + default: + goto out_fail; + } + new_zhdr->foreign_handles++; + memcpy(q, p, sz); + write_lock(&zhdr->slots->lock); + *(unsigned long *)old_handle = (unsigned long)new_zhdr + + __idx(new_zhdr, new_bud); + if (new_bud == LAST) + *(unsigned long *)old_handle |= + (new_zhdr->last_chunks << BUDDY_SHIFT); + write_unlock(&zhdr->slots->lock); + add_to_unbuddied(pool, new_zhdr); + z3fold_page_unlock(new_zhdr); + + *moved_chunks = 0; + } + + return new_zhdr; + +out_fail: + if (new_zhdr) { + if (kref_put(&new_zhdr->refcount, release_z3fold_page_locked)) + atomic64_dec(&pool->pages_nr); + else { + add_to_unbuddied(pool, new_zhdr); + z3fold_page_unlock(new_zhdr); + } + } + return NULL; + +} + #define BIG_CHUNK_GAP 3 /* Has to be called with lock held */ static int z3fold_compact_page(struct z3fold_header *zhdr) @@ -638,6 +852,15 @@ static void do_compact_page(struct z3fold_header *zhdr, bool locked) return; } + if (!zhdr->foreign_handles && buddy_single(zhdr) && + zhdr->mapped_count == 0 && compact_single_buddy(zhdr)) { + if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) + atomic64_dec(&pool->pages_nr); + else + z3fold_page_unlock(zhdr); + return; + } + z3fold_compact_page(zhdr); add_to_unbuddied(pool, zhdr); z3fold_page_unlock(zhdr); @@ -690,7 +913,8 @@ lookup: spin_unlock(&pool->lock); page = virt_to_page(zhdr); - if (test_bit(NEEDS_COMPACTING, &page->private)) { + if (test_bit(NEEDS_COMPACTING, &page->private) || + test_bit(PAGE_CLAIMED, &page->private)) { z3fold_page_unlock(zhdr); zhdr = NULL; put_cpu_ptr(pool->unbuddied); @@ -734,7 +958,8 @@ lookup: spin_unlock(&pool->lock); page = virt_to_page(zhdr); - if (test_bit(NEEDS_COMPACTING, &page->private)) { + if (test_bit(NEEDS_COMPACTING, &page->private) || + test_bit(PAGE_CLAIMED, &page->private)) { z3fold_page_unlock(zhdr); zhdr = NULL; if (can_sleep) @@ -1000,7 +1225,7 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) enum buddy bud; bool page_claimed; - zhdr = handle_to_z3fold_header(handle); + zhdr = get_z3fold_header(handle); page = virt_to_page(zhdr); page_claimed = test_and_set_bit(PAGE_CLAIMED, &page->private); @@ -1014,6 +1239,7 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) spin_lock(&pool->lock); list_del(&page->lru); spin_unlock(&pool->lock); + put_z3fold_header(zhdr); free_z3fold_page(page, true); atomic64_dec(&pool->pages_nr); } @@ -1021,7 +1247,6 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) } /* Non-headless case */ - z3fold_page_lock(zhdr); bud = handle_to_buddy(handle); switch (bud) { @@ -1037,11 +1262,13 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) default: pr_err("%s: unknown bud %d\n", __func__, bud); WARN_ON(1); - z3fold_page_unlock(zhdr); + put_z3fold_header(zhdr); + clear_bit(PAGE_CLAIMED, &page->private); return; } - free_handle(handle); + if (!page_claimed) + free_handle(handle); if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) { atomic64_dec(&pool->pages_nr); return; @@ -1053,7 +1280,7 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) } if (unlikely(PageIsolated(page)) || test_and_set_bit(NEEDS_COMPACTING, &page->private)) { - z3fold_page_unlock(zhdr); + put_z3fold_header(zhdr); clear_bit(PAGE_CLAIMED, &page->private); return; } @@ -1063,14 +1290,14 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) spin_unlock(&pool->lock); zhdr->cpu = -1; kref_get(&zhdr->refcount); - do_compact_page(zhdr, true); clear_bit(PAGE_CLAIMED, &page->private); + do_compact_page(zhdr, true); return; } kref_get(&zhdr->refcount); - queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work); clear_bit(PAGE_CLAIMED, &page->private); - z3fold_page_unlock(zhdr); + queue_work_on(zhdr->cpu, pool->compact_wq, &zhdr->work); + put_z3fold_header(zhdr); } /** @@ -1111,11 +1338,10 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle) */ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) { - int i, ret = 0; + int i, ret = -1; struct z3fold_header *zhdr = NULL; struct page *page = NULL; struct list_head *pos; - struct z3fold_buddy_slots slots; unsigned long first_handle = 0, middle_handle = 0, last_handle = 0; spin_lock(&pool->lock); @@ -1153,6 +1379,12 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) zhdr = NULL; continue; /* can't evict at this point */ } + if (zhdr->foreign_handles) { + clear_bit(PAGE_CLAIMED, &page->private); + z3fold_page_unlock(zhdr); + zhdr = NULL; + continue; /* can't evict such page */ + } kref_get(&zhdr->refcount); list_del_init(&zhdr->buddy); zhdr->cpu = -1; @@ -1176,39 +1408,38 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries) last_handle = 0; middle_handle = 0; if (zhdr->first_chunks) - first_handle = __encode_handle(zhdr, &slots, - FIRST); + first_handle = encode_handle(zhdr, FIRST); if (zhdr->middle_chunks) - middle_handle = __encode_handle(zhdr, &slots, - MIDDLE); + middle_handle = encode_handle(zhdr, MIDDLE); if (zhdr->last_chunks) - last_handle = __encode_handle(zhdr, &slots, - LAST); + last_handle = encode_handle(zhdr, LAST); /* * it's safe to unlock here because we hold a * reference to this page */ z3fold_page_unlock(zhdr); } else { - first_handle = __encode_handle(zhdr, &slots, HEADLESS); + first_handle = encode_handle(zhdr, HEADLESS); last_handle = middle_handle = 0; } - /* Issue the eviction callback(s) */ if (middle_handle) { ret = pool->ops->evict(pool, middle_handle); if (ret) goto next; + free_handle(middle_handle); } if (first_handle) { ret = pool->ops->evict(pool, first_handle); if (ret) goto next; + free_handle(first_handle); } if (last_handle) { ret = pool->ops->evict(pool, last_handle); if (ret) goto next; + free_handle(last_handle); } next: if (test_bit(PAGE_HEADLESS, &page->private)) { @@ -1264,14 +1495,13 @@ static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle) void *addr; enum buddy buddy; - zhdr = handle_to_z3fold_header(handle); + zhdr = get_z3fold_header(handle); addr = zhdr; page = virt_to_page(zhdr); if (test_bit(PAGE_HEADLESS, &page->private)) goto out; - z3fold_page_lock(zhdr); buddy = handle_to_buddy(handle); switch (buddy) { case FIRST: @@ -1293,8 +1523,8 @@ static void *z3fold_map(struct z3fold_pool *pool, unsigned long handle) if (addr) zhdr->mapped_count++; - z3fold_page_unlock(zhdr); out: + put_z3fold_header(zhdr); return addr; } @@ -1309,18 +1539,17 @@ static void z3fold_unmap(struct z3fold_pool *pool, unsigned long handle) struct page *page; enum buddy buddy; - zhdr = handle_to_z3fold_header(handle); + zhdr = get_z3fold_header(handle); page = virt_to_page(zhdr); if (test_bit(PAGE_HEADLESS, &page->private)) return; - z3fold_page_lock(zhdr); buddy = handle_to_buddy(handle); if (buddy == MIDDLE) clear_bit(MIDDLE_CHUNK_MAPPED, &page->private); zhdr->mapped_count--; - z3fold_page_unlock(zhdr); + put_z3fold_header(zhdr); } /** @@ -1352,19 +1581,21 @@ static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode) test_bit(PAGE_STALE, &page->private)) goto out; + if (zhdr->mapped_count != 0 || zhdr->foreign_handles != 0) + goto out; + pool = zhdr_to_pool(zhdr); + spin_lock(&pool->lock); + if (!list_empty(&zhdr->buddy)) + list_del_init(&zhdr->buddy); + if (!list_empty(&page->lru)) + list_del_init(&page->lru); + spin_unlock(&pool->lock); + + kref_get(&zhdr->refcount); + z3fold_page_unlock(zhdr); + return true; - if (zhdr->mapped_count == 0) { - kref_get(&zhdr->refcount); - if (!list_empty(&zhdr->buddy)) - list_del_init(&zhdr->buddy); - spin_lock(&pool->lock); - if (!list_empty(&page->lru)) - list_del(&page->lru); - spin_unlock(&pool->lock); - z3fold_page_unlock(zhdr); - return true; - } out: z3fold_page_unlock(zhdr); return false; @@ -1387,7 +1618,7 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa if (!z3fold_page_trylock(zhdr)) { return -EAGAIN; } - if (zhdr->mapped_count != 0) { + if (zhdr->mapped_count != 0 || zhdr->foreign_handles != 0) { z3fold_page_unlock(zhdr); return -EBUSY; } |