diff options
Diffstat (limited to '')
| -rw-r--r-- | mm/zsmalloc.c | 810 |
1 files changed, 294 insertions, 516 deletions
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 22d17ecfe7df..d03941cace2c 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -17,10 +17,10 @@ * * Usage of struct page fields: * page->private: points to zspage - * page->freelist(index): links together all component pages of a zspage + * page->index: links together all component pages of a zspage * For the huge page, this is always 0, so we use this field * to store handle. - * page->units: first object offset in a subpage of zspage + * page->page_type: first object offset in a subpage of zspage * * Usage of struct page flags: * PG_private: identifies the first component page @@ -30,17 +30,24 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +/* + * lock ordering: + * page_lock + * pool->migrate_lock + * class->lock + * zspage->lock + */ + #include <linux/module.h> #include <linux/kernel.h> #include <linux/sched.h> -#include <linux/magic.h> #include <linux/bitops.h> #include <linux/errno.h> #include <linux/highmem.h> #include <linux/string.h> #include <linux/slab.h> +#include <linux/pgtable.h> #include <asm/tlbflush.h> -#include <asm/pgtable.h> #include <linux/cpumask.h> #include <linux/cpu.h> #include <linux/vmalloc.h> @@ -51,17 +58,16 @@ #include <linux/debugfs.h> #include <linux/zsmalloc.h> #include <linux/zpool.h> -#include <linux/mount.h> -#include <linux/pseudo_fs.h> #include <linux/migrate.h> #include <linux/wait.h> #include <linux/pagemap.h> #include <linux/fs.h> +#include <linux/local_lock.h> #define ZSPAGE_MAGIC 0x58 /* - * This must be power of 2 and greater than of equal to sizeof(link_free). + * This must be power of 2 and greater than or equal to sizeof(link_free). * These two conditions ensure that any 'struct link_free' itself doesn't * span more than 1 page which avoids complex case of mapping 2 pages simply * to restore link_free pointer values. @@ -79,7 +85,7 @@ /* * Object location (<PFN>, <obj_idx>) is encoded as - * as single (unsigned long) handle value. + * a single (unsigned long) handle value. * * Note that object index <obj_idx> starts from 0. * @@ -101,15 +107,6 @@ #define _PFN_BITS (MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT) /* - * Memory for allocating for handle keeps object position by - * encoding <page, obj_idx> and the encoded value has a room - * in least bit(ie, look at obj_to_location). - * We use the bit to synchronize between object access by - * user and migration. - */ -#define HANDLE_PIN_BIT 0 - -/* * Head in allocated object should have OBJ_ALLOCATED_TAG * to identify the object was allocated or not. * It's okay to add the status bit in the least bit because @@ -121,6 +118,7 @@ #define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS) #define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1) +#define HUGE_BITS 1 #define FULLNESS_BITS 2 #define CLASS_BITS 8 #define ISOLATED_BITS 3 @@ -158,7 +156,7 @@ enum fullness_group { NR_ZS_FULLNESS, }; -enum zs_stat_type { +enum class_stat_type { CLASS_EMPTY, CLASS_ALMOST_EMPTY, CLASS_ALMOST_FULL, @@ -176,10 +174,6 @@ struct zs_size_stat { static struct dentry *zs_stat_root; #endif -#ifdef CONFIG_COMPACTION -static struct vfsmount *zsmalloc_mnt; -#endif - /* * We assign a page to ZS_ALMOST_EMPTY fullness group when: * n <= N / f, where @@ -213,22 +207,6 @@ struct size_class { struct zs_size_stat stats; }; -/* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */ -static void SetPageHugeObject(struct page *page) -{ - SetPageOwnerPriv1(page); -} - -static void ClearPageHugeObject(struct page *page) -{ - ClearPageOwnerPriv1(page); -} - -static int PageHugeObject(struct page *page) -{ - return PageOwnerPriv1(page); -} - /* * Placed within free objects to form a singly linked list. * For every zspage, zspage->freeobj gives head of this list. @@ -267,17 +245,15 @@ struct zs_pool { struct dentry *stat_dentry; #endif #ifdef CONFIG_COMPACTION - struct inode *inode; struct work_struct free_work; - /* A wait queue for when migration races with async_free_zspage() */ - struct wait_queue_head migration_wait; - atomic_long_t isolated_pages; - bool destroying; #endif + /* protect page/zspage migration */ + rwlock_t migrate_lock; }; struct zspage { struct { + unsigned int huge:HUGE_BITS; unsigned int fullness:FULLNESS_BITS; unsigned int class:CLASS_BITS + 1; unsigned int isolated:ISOLATED_BITS; @@ -287,38 +263,47 @@ struct zspage { unsigned int freeobj; struct page *first_page; struct list_head list; /* fullness list */ + struct zs_pool *pool; #ifdef CONFIG_COMPACTION rwlock_t lock; #endif }; struct mapping_area { -#ifdef CONFIG_PGTABLE_MAPPING - struct vm_struct *vm; /* vm area for mapping object that span pages */ -#else + local_lock_t lock; char *vm_buf; /* copy buffer for objects that span pages */ -#endif char *vm_addr; /* address of kmap_atomic()'ed pages */ enum zs_mapmode vm_mm; /* mapping mode */ }; +/* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */ +static void SetZsHugePage(struct zspage *zspage) +{ + zspage->huge = 1; +} + +static bool ZsHugePage(struct zspage *zspage) +{ + return zspage->huge; +} + #ifdef CONFIG_COMPACTION -static int zs_register_migration(struct zs_pool *pool); -static void zs_unregister_migration(struct zs_pool *pool); static void migrate_lock_init(struct zspage *zspage); static void migrate_read_lock(struct zspage *zspage); static void migrate_read_unlock(struct zspage *zspage); +static void migrate_write_lock(struct zspage *zspage); +static void migrate_write_lock_nested(struct zspage *zspage); +static void migrate_write_unlock(struct zspage *zspage); static void kick_deferred_free(struct zs_pool *pool); static void init_deferred_free(struct zs_pool *pool); static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage); #else -static int zsmalloc_mount(void) { return 0; } -static void zsmalloc_unmount(void) {} -static int zs_register_migration(struct zs_pool *pool) { return 0; } -static void zs_unregister_migration(struct zs_pool *pool) {} static void migrate_lock_init(struct zspage *zspage) {} static void migrate_read_lock(struct zspage *zspage) {} static void migrate_read_unlock(struct zspage *zspage) {} +static void migrate_write_lock(struct zspage *zspage) {} +static void migrate_write_lock_nested(struct zspage *zspage) {} +static void migrate_write_unlock(struct zspage *zspage) {} static void kick_deferred_free(struct zs_pool *pool) {} static void init_deferred_free(struct zs_pool *pool) {} static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {} @@ -361,7 +346,7 @@ static void cache_free_handle(struct zs_pool *pool, unsigned long handle) static struct zspage *cache_alloc_zspage(struct zs_pool *pool, gfp_t flags) { - return kmem_cache_alloc(pool->zspage_cachep, + return kmem_cache_zalloc(pool->zspage_cachep, flags & ~(__GFP_HIGHMEM|__GFP_MOVABLE)); } @@ -370,14 +355,10 @@ static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage) kmem_cache_free(pool->zspage_cachep, zspage); } +/* class->lock(which owns the handle) synchronizes races */ static void record_obj(unsigned long handle, unsigned long obj) { - /* - * lsb of @obj represents handle lock while other bits - * represent object value the handle is pointing so - * updating shouldn't do store tearing. - */ - WRITE_ONCE(*(unsigned long *)handle, obj); + *(unsigned long *)handle = obj; } /* zpool driver */ @@ -405,7 +386,10 @@ static int zs_zpool_malloc(void *pool, size_t size, gfp_t gfp, unsigned long *handle) { *handle = zs_malloc(pool, size, gfp); - return *handle ? 0 : -1; + + if (IS_ERR((void *)(*handle))) + return PTR_ERR((void *)*handle); + return 0; } static void zs_zpool_free(void *pool, unsigned long handle) { @@ -424,7 +408,7 @@ static void *zs_zpool_map(void *pool, unsigned long handle, case ZPOOL_MM_WO: zs_mm = ZS_MM_WO; break; - case ZPOOL_MM_RW: /* fall through */ + case ZPOOL_MM_RW: default: zs_mm = ZS_MM_RW; break; @@ -459,12 +443,9 @@ MODULE_ALIAS("zpool-zsmalloc"); #endif /* CONFIG_ZPOOL */ /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */ -static DEFINE_PER_CPU(struct mapping_area, zs_map_area); - -static bool is_zspage_isolated(struct zspage *zspage) -{ - return zspage->isolated; -} +static DEFINE_PER_CPU(struct mapping_area, zs_map_area) = { + .lock = INIT_LOCAL_LOCK(lock), +}; static __maybe_unused int is_first_page(struct page *page) { @@ -491,14 +472,14 @@ static inline struct page *get_first_page(struct zspage *zspage) return first_page; } -static inline int get_first_obj_offset(struct page *page) +static inline unsigned int get_first_obj_offset(struct page *page) { - return page->units; + return page->page_type; } -static inline void set_first_obj_offset(struct page *page, int offset) +static inline void set_first_obj_offset(struct page *page, unsigned int offset) { - page->units = offset; + page->page_type = offset; } static inline unsigned int get_freeobj(struct zspage *zspage) @@ -521,6 +502,12 @@ static void get_zspage_mapping(struct zspage *zspage, *class_idx = zspage->class; } +static struct size_class *zspage_class(struct zs_pool *pool, + struct zspage *zspage) +{ + return pool->size_class[zspage->class]; +} + static void set_zspage_mapping(struct zspage *zspage, unsigned int class_idx, enum fullness_group fullness) @@ -534,7 +521,7 @@ static void set_zspage_mapping(struct zspage *zspage, * class maintains a list of zspages where each zspage is divided * into equal sized chunks. Each allocation falls into one of these * classes depending on its size. This function returns index of the - * size class which has chunk size big enough to hold the give size. + * size class which has chunk size big enough to hold the given size. */ static int get_size_class_index(int size) { @@ -547,21 +534,21 @@ static int get_size_class_index(int size) return min_t(int, ZS_SIZE_CLASSES - 1, idx); } -/* type can be of enum type zs_stat_type or fullness_group */ -static inline void zs_stat_inc(struct size_class *class, +/* type can be of enum type class_stat_type or fullness_group */ +static inline void class_stat_inc(struct size_class *class, int type, unsigned long cnt) { class->stats.objs[type] += cnt; } -/* type can be of enum type zs_stat_type or fullness_group */ -static inline void zs_stat_dec(struct size_class *class, +/* type can be of enum type class_stat_type or fullness_group */ +static inline void class_stat_dec(struct size_class *class, int type, unsigned long cnt) { class->stats.objs[type] -= cnt; } -/* type can be of enum type zs_stat_type or fullness_group */ +/* type can be of enum type class_stat_type or fullness_group */ static inline unsigned long zs_stat_get(struct size_class *class, int type) { @@ -723,20 +710,17 @@ static void insert_zspage(struct size_class *class, { struct zspage *head; - zs_stat_inc(class, fullness, 1); + class_stat_inc(class, fullness, 1); head = list_first_entry_or_null(&class->fullness_list[fullness], struct zspage, list); /* * We want to see more ZS_FULL pages and less almost empty/full. * Put pages with higher ->inuse first. */ - if (head) { - if (get_zspage_inuse(zspage) < get_zspage_inuse(head)) { - list_add(&zspage->list, &head->list); - return; - } - } - list_add(&zspage->list, &class->fullness_list[fullness]); + if (head && get_zspage_inuse(zspage) < get_zspage_inuse(head)) + list_add(&zspage->list, &head->list); + else + list_add(&zspage->list, &class->fullness_list[fullness]); } /* @@ -748,10 +732,9 @@ static void remove_zspage(struct size_class *class, enum fullness_group fullness) { VM_BUG_ON(list_empty(&class->fullness_list[fullness])); - VM_BUG_ON(is_zspage_isolated(zspage)); list_del_init(&zspage->list); - zs_stat_dec(class, fullness, 1); + class_stat_dec(class, fullness, 1); } /* @@ -774,13 +757,9 @@ static enum fullness_group fix_fullness_group(struct size_class *class, if (newfg == currfg) goto out; - if (!is_zspage_isolated(zspage)) { - remove_zspage(class, zspage, currfg); - insert_zspage(class, zspage, newfg); - } - + remove_zspage(class, zspage, currfg); + insert_zspage(class, zspage, newfg); set_zspage_mapping(zspage, class_idx, newfg); - out: return newfg; } @@ -823,7 +802,7 @@ static int get_pages_per_zspage(int class_size) static struct zspage *get_zspage(struct page *page) { - struct zspage *zspage = (struct zspage *)page->private; + struct zspage *zspage = (struct zspage *)page_private(page); BUG_ON(zspage->magic != ZSPAGE_MAGIC); return zspage; @@ -831,10 +810,12 @@ static struct zspage *get_zspage(struct page *page) static struct page *get_next_page(struct page *page) { - if (unlikely(PageHugeObject(page))) + struct zspage *zspage = get_zspage(page); + + if (unlikely(ZsHugePage(zspage))) return NULL; - return page->freelist; + return (struct page *)page->index; } /** @@ -851,6 +832,12 @@ static void obj_to_location(unsigned long obj, struct page **page, *obj_idx = (obj & OBJ_INDEX_MASK); } +static void obj_to_page(unsigned long obj, struct page **page) +{ + obj >>= OBJ_TAG_BITS; + *page = pfn_to_page(obj >> OBJ_INDEX_BITS); +} + /** * location_to_obj - get obj value encoded from (<page>, <obj_idx>) * @page: page object resides in zspage @@ -872,33 +859,22 @@ static unsigned long handle_to_obj(unsigned long handle) return *(unsigned long *)handle; } -static unsigned long obj_to_head(struct page *page, void *obj) +static bool obj_allocated(struct page *page, void *obj, unsigned long *phandle) { - if (unlikely(PageHugeObject(page))) { + unsigned long handle; + struct zspage *zspage = get_zspage(page); + + if (unlikely(ZsHugePage(zspage))) { VM_BUG_ON_PAGE(!is_first_page(page), page); - return page->index; + handle = page->index; } else - return *(unsigned long *)obj; -} + handle = *(unsigned long *)obj; -static inline int testpin_tag(unsigned long handle) -{ - return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle); -} - -static inline int trypin_tag(unsigned long handle) -{ - return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle); -} - -static void pin_tag(unsigned long handle) -{ - bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle); -} + if (!(handle & OBJ_ALLOCATED_TAG)) + return false; -static void unpin_tag(unsigned long handle) -{ - bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle); + *phandle = handle & ~OBJ_ALLOCATED_TAG; + return true; } static void reset_page(struct page *page) @@ -907,8 +883,7 @@ static void reset_page(struct page *page) ClearPagePrivate(page); set_page_private(page, 0); page_mapcount_reset(page); - ClearPageHugeObject(page); - page->freelist = NULL; + page->index = 0; } static int trylock_zspage(struct zspage *zspage) @@ -959,7 +934,7 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class, cache_free_zspage(pool, zspage); - zs_stat_dec(class, OBJ_ALLOCATED, class->objs_per_zspage); + class_stat_dec(class, OBJ_ALLOCATED, class->objs_per_zspage); atomic_long_sub(class->pages_per_zspage, &pool->pages_allocated); } @@ -970,6 +945,11 @@ static void free_zspage(struct zs_pool *pool, struct size_class *class, VM_BUG_ON(get_zspage_inuse(zspage)); VM_BUG_ON(list_empty(&zspage->list)); + /* + * Since zs_free couldn't be sleepable, this function cannot call + * lock_page. The page locks trylock_zspage got will be released + * by __free_zspage. + */ if (!trylock_zspage(zspage)) { kick_deferred_free(pool); return; @@ -1034,7 +1014,7 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage, /* * Allocate individual pages and link them together as: - * 1. all pages are linked together using page->freelist + * 1. all pages are linked together using page->index * 2. each sub-page point to zspage using page->private * * we set PG_private to identify the first page (i.e. no other sub-page @@ -1043,15 +1023,15 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage, for (i = 0; i < nr_pages; i++) { page = pages[i]; set_page_private(page, (unsigned long)zspage); - page->freelist = NULL; + page->index = 0; if (i == 0) { zspage->first_page = page; SetPagePrivate(page); if (unlikely(class->objs_per_zspage == 1 && class->pages_per_zspage == 1)) - SetPageHugeObject(page); + SetZsHugePage(zspage); } else { - prev_page->freelist = page; + prev_page->index = (unsigned long)page; } prev_page = page; } @@ -1071,7 +1051,6 @@ static struct zspage *alloc_zspage(struct zs_pool *pool, if (!zspage) return NULL; - memset(zspage, 0, sizeof(struct zspage)); zspage->magic = ZSPAGE_MAGIC; migrate_lock_init(zspage); @@ -1094,6 +1073,7 @@ static struct zspage *alloc_zspage(struct zs_pool *pool, create_page_chain(class, zspage, pages); init_zspage(class, zspage); + zspage->pool = pool; return zspage; } @@ -1113,46 +1093,6 @@ static struct zspage *find_get_zspage(struct size_class *class) return zspage; } -#ifdef CONFIG_PGTABLE_MAPPING -static inline int __zs_cpu_up(struct mapping_area *area) -{ - /* - * Make sure we don't leak memory if a cpu UP notification - * and zs_init() race and both call zs_cpu_up() on the same cpu - */ - if (area->vm) - return 0; - area->vm = alloc_vm_area(PAGE_SIZE * 2, NULL); - if (!area->vm) - return -ENOMEM; - return 0; -} - -static inline void __zs_cpu_down(struct mapping_area *area) -{ - if (area->vm) - free_vm_area(area->vm); - area->vm = NULL; -} - -static inline void *__zs_map_object(struct mapping_area *area, - struct page *pages[2], int off, int size) -{ - BUG_ON(map_vm_area(area->vm, PAGE_KERNEL, pages)); - area->vm_addr = area->vm->addr; - return area->vm_addr + off; -} - -static inline void __zs_unmap_object(struct mapping_area *area, - struct page *pages[2], int off, int size) -{ - unsigned long addr = (unsigned long)area->vm_addr; - - unmap_kernel_range(addr, PAGE_SIZE * 2); -} - -#else /* CONFIG_PGTABLE_MAPPING */ - static inline int __zs_cpu_up(struct mapping_area *area) { /* @@ -1233,8 +1173,6 @@ out: pagefault_enable(); } -#endif /* CONFIG_PGTABLE_MAPPING */ - static int zs_cpu_prepare(unsigned int cpu) { struct mapping_area *area; @@ -1277,7 +1215,7 @@ EXPORT_SYMBOL_GPL(zs_get_total_pages); * zs_map_object - get address of allocated object from handle. * @pool: pool from which the object was allocated * @handle: handle returned from zs_malloc - * @mm: maping mode to use + * @mm: mapping mode to use * * Before using an object allocated from zs_malloc, it must be mapped using * this function. When done with the object, it must be unmapped using @@ -1296,8 +1234,6 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle, unsigned long obj, off; unsigned int obj_idx; - unsigned int class_idx; - enum fullness_group fg; struct size_class *class; struct mapping_area *area; struct page *pages[2]; @@ -1310,21 +1246,26 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle, */ BUG_ON(in_interrupt()); - /* From now on, migration cannot move the object */ - pin_tag(handle); - + /* It guarantees it can get zspage from handle safely */ + read_lock(&pool->migrate_lock); obj = handle_to_obj(handle); obj_to_location(obj, &page, &obj_idx); zspage = get_zspage(page); - /* migration cannot move any subpage in this zspage */ + /* + * migration cannot move any zpages in this zspage. Here, class->lock + * is too heavy since callers would take some time until they calls + * zs_unmap_object API so delegate the locking from class to zspage + * which is smaller granularity. + */ migrate_read_lock(zspage); + read_unlock(&pool->migrate_lock); - get_zspage_mapping(zspage, &class_idx, &fg); - class = pool->size_class[class_idx]; + class = zspage_class(pool, zspage); off = (class->size * obj_idx) & ~PAGE_MASK; - area = &get_cpu_var(zs_map_area); + local_lock(&zs_map_area.lock); + area = this_cpu_ptr(&zs_map_area); area->vm_mm = mm; if (off + class->size <= PAGE_SIZE) { /* this object is contained entirely within a page */ @@ -1340,7 +1281,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle, ret = __zs_map_object(area, pages, off, class->size); out: - if (likely(!PageHugeObject(page))) + if (likely(!ZsHugePage(zspage))) ret += ZS_HANDLE_SIZE; return ret; @@ -1354,16 +1295,13 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle) unsigned long obj, off; unsigned int obj_idx; - unsigned int class_idx; - enum fullness_group fg; struct size_class *class; struct mapping_area *area; obj = handle_to_obj(handle); obj_to_location(obj, &page, &obj_idx); zspage = get_zspage(page); - get_zspage_mapping(zspage, &class_idx, &fg); - class = pool->size_class[class_idx]; + class = zspage_class(pool, zspage); off = (class->size * obj_idx) & ~PAGE_MASK; area = this_cpu_ptr(&zs_map_area); @@ -1378,10 +1316,9 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle) __zs_unmap_object(area, pages, off, class->size); } - put_cpu_var(zs_map_area); + local_unlock(&zs_map_area.lock); migrate_read_unlock(zspage); - unpin_tag(handle); } EXPORT_SYMBOL_GPL(zs_unmap_object); @@ -1404,17 +1341,19 @@ size_t zs_huge_class_size(struct zs_pool *pool) } EXPORT_SYMBOL_GPL(zs_huge_class_size); -static unsigned long obj_malloc(struct size_class *class, +static unsigned long obj_malloc(struct zs_pool *pool, struct zspage *zspage, unsigned long handle) { int i, nr_page, offset; unsigned long obj; struct link_free *link; + struct size_class *class; struct page *m_page; unsigned long m_offset; void *vaddr; + class = pool->size_class[zspage->class]; handle |= OBJ_ALLOCATED_TAG; obj = get_freeobj(zspage); @@ -1429,7 +1368,7 @@ static unsigned long obj_malloc(struct size_class *class, vaddr = kmap_atomic(m_page); link = (struct link_free *)vaddr + m_offset / sizeof(*link); set_freeobj(zspage, link->next >> OBJ_TAG_BITS); - if (likely(!PageHugeObject(m_page))) + if (likely(!ZsHugePage(zspage))) /* record handle in the header of allocated chunk */ link->handle = handle; else @@ -1438,7 +1377,6 @@ static unsigned long obj_malloc(struct size_class *class, kunmap_atomic(vaddr); mod_zspage_inuse(zspage, 1); - zs_stat_inc(class, OBJ_USED, 1); obj = location_to_obj(m_page, obj); @@ -1453,7 +1391,7 @@ static unsigned long obj_malloc(struct size_class *class, * @gfp: gfp flags when allocating object * * On success, handle to the allocated object is returned, - * otherwise 0. + * otherwise an ERR_PTR(). * Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail. */ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp) @@ -1464,23 +1402,25 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp) struct zspage *zspage; if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE)) - return 0; + return (unsigned long)ERR_PTR(-EINVAL); handle = cache_alloc_handle(pool, gfp); if (!handle) - return 0; + return (unsigned long)ERR_PTR(-ENOMEM); /* extra space in chunk to keep the handle */ size += ZS_HANDLE_SIZE; class = pool->size_class[get_size_class_index(size)]; + /* class->lock effectively protects the zpage migration */ spin_lock(&class->lock); zspage = find_get_zspage(class); if (likely(zspage)) { - obj = obj_malloc(class, zspage, handle); + obj = obj_malloc(pool, zspage, handle); /* Now move the zspage to another fullness group, if required */ fix_fullness_group(class, zspage); record_obj(handle, obj); + class_stat_inc(class, OBJ_USED, 1); spin_unlock(&class->lock); return handle; @@ -1491,18 +1431,19 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp) zspage = alloc_zspage(pool, class, gfp); if (!zspage) { cache_free_handle(pool, handle); - return 0; + return (unsigned long)ERR_PTR(-ENOMEM); } spin_lock(&class->lock); - obj = obj_malloc(class, zspage, handle); + obj = obj_malloc(pool, zspage, handle); newfg = get_fullness_group(class, zspage); insert_zspage(class, zspage, newfg); set_zspage_mapping(zspage, class->index, newfg); record_obj(handle, obj); atomic_long_add(class->pages_per_zspage, &pool->pages_allocated); - zs_stat_inc(class, OBJ_ALLOCATED, class->objs_per_zspage); + class_stat_inc(class, OBJ_ALLOCATED, class->objs_per_zspage); + class_stat_inc(class, OBJ_USED, 1); /* We completely set up zspage so mark them as movable */ SetZsPageMovable(pool, zspage); @@ -1512,7 +1453,7 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp) } EXPORT_SYMBOL_GPL(zs_malloc); -static void obj_free(struct size_class *class, unsigned long obj) +static void obj_free(int class_size, unsigned long obj) { struct link_free *link; struct zspage *zspage; @@ -1521,20 +1462,21 @@ static void obj_free(struct size_class *class, unsigned long obj) unsigned int f_objidx; void *vaddr; - obj &= ~OBJ_ALLOCATED_TAG; obj_to_location(obj, &f_page, &f_objidx); - f_offset = (class->size * f_objidx) & ~PAGE_MASK; + f_offset = (class_size * f_objidx) & ~PAGE_MASK; zspage = get_zspage(f_page); vaddr = kmap_atomic(f_page); /* Insert this object in containing zspage's freelist */ link = (struct link_free *)(vaddr + f_offset); - link->next = get_freeobj(zspage) << OBJ_TAG_BITS; + if (likely(!ZsHugePage(zspage))) + link->next = get_freeobj(zspage) << OBJ_TAG_BITS; + else + f_page->index = 0; kunmap_atomic(vaddr); set_freeobj(zspage, f_objidx); mod_zspage_inuse(zspage, -1); - zs_stat_dec(class, OBJ_USED, 1); } void zs_free(struct zs_pool *pool, unsigned long handle) @@ -1542,42 +1484,33 @@ void zs_free(struct zs_pool *pool, unsigned long handle) struct zspage *zspage; struct page *f_page; unsigned long obj; - unsigned int f_objidx; - int class_idx; struct size_class *class; enum fullness_group fullness; - bool isolated; - if (unlikely(!handle)) + if (IS_ERR_OR_NULL((void *)handle)) return; - pin_tag(handle); + /* + * The pool->migrate_lock protects the race with zpage's migration + * so it's safe to get the page from handle. + */ + read_lock(&pool->migrate_lock); obj = handle_to_obj(handle); - obj_to_location(obj, &f_page, &f_objidx); + obj_to_page(obj, &f_page); zspage = get_zspage(f_page); - - migrate_read_lock(zspage); - - get_zspage_mapping(zspage, &class_idx, &fullness); - class = pool->size_class[class_idx]; - + class = zspage_class(pool, zspage); spin_lock(&class->lock); - obj_free(class, obj); + read_unlock(&pool->migrate_lock); + + obj_free(class->size, obj); + class_stat_dec(class, OBJ_USED, 1); fullness = fix_fullness_group(class, zspage); - if (fullness != ZS_EMPTY) { - migrate_read_unlock(zspage); + if (fullness != ZS_EMPTY) goto out; - } - isolated = is_zspage_isolated(zspage); - migrate_read_unlock(zspage); - /* If zspage is isolated, zs_page_putback will free the zspage */ - if (likely(!isolated)) - free_zspage(pool, class, zspage); + free_zspage(pool, class, zspage); out: - spin_unlock(&class->lock); - unpin_tag(handle); cache_free_handle(pool, handle); } EXPORT_SYMBOL_GPL(zs_free); @@ -1622,6 +1555,13 @@ static void zs_object_copy(struct size_class *class, unsigned long dst, d_off += size; d_size -= size; + /* + * Calling kunmap_atomic(d_addr) is necessary. kunmap_atomic() + * calls must occurs in reverse order of calls to kmap_atomic(). + * So, to call kunmap_atomic(s_addr) we should first call + * kunmap_atomic(d_addr). For more details see + * Documentation/mm/highmem.rst. + */ if (s_off >= PAGE_SIZE) { kunmap_atomic(d_addr); kunmap_atomic(s_addr); @@ -1652,8 +1592,7 @@ static void zs_object_copy(struct size_class *class, unsigned long dst, static unsigned long find_alloced_obj(struct size_class *class, struct page *page, int *obj_idx) { - unsigned long head; - int offset = 0; + unsigned int offset; int index = *obj_idx; unsigned long handle = 0; void *addr = kmap_atomic(page); @@ -1662,13 +1601,8 @@ static unsigned long find_alloced_obj(struct size_class *class, offset += class->size * index; while (offset < PAGE_SIZE) { - head = obj_to_head(page, addr + offset); - if (head & OBJ_ALLOCATED_TAG) { - handle = head & ~OBJ_ALLOCATED_TAG; - if (trypin_tag(handle)) - break; - handle = 0; - } + if (obj_allocated(page, addr + offset, &handle)) + break; offset += class->size; index++; @@ -1714,25 +1648,16 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class, /* Stop if there is no more space */ if (zspage_full(class, get_zspage(d_page))) { - unpin_tag(handle); ret = -ENOMEM; break; } used_obj = handle_to_obj(handle); - free_obj = obj_malloc(class, get_zspage(d_page), handle); + free_obj = obj_malloc(pool, get_zspage(d_page), handle); zs_object_copy(class, free_obj, used_obj); obj_idx++; - /* - * record_obj updates handle's value to free_obj and it will - * invalidate lock bit(ie, HANDLE_PIN_BIT) of handle, which - * breaks synchronization using pin_tag(e,g, zs_free) so - * let's keep the lock bit. - */ - free_obj |= BIT(HANDLE_PIN_BIT); record_obj(handle, free_obj); - unpin_tag(handle); - obj_free(class, used_obj); + obj_free(class->size, used_obj); } /* Remember last position in this iteration */ @@ -1757,7 +1682,6 @@ static struct zspage *isolate_zspage(struct size_class *class, bool source) zspage = list_first_entry_or_null(&class->fullness_list[fg[i]], struct zspage, list); if (zspage) { - VM_BUG_ON(is_zspage_isolated(zspage)); remove_zspage(class, zspage, fg[i]); return zspage; } @@ -1778,8 +1702,6 @@ static enum fullness_group putback_zspage(struct size_class *class, { enum fullness_group fullness; - VM_BUG_ON(is_zspage_isolated(zspage)); - fullness = get_fullness_group(class, zspage); insert_zspage(class, zspage, fullness); set_zspage_mapping(zspage, class->index, fullness); @@ -1794,38 +1716,40 @@ static enum fullness_group putback_zspage(struct size_class *class, */ static void lock_zspage(struct zspage *zspage) { - struct page *page = get_first_page(zspage); - - do { - lock_page(page); - } while ((page = get_next_page(page)) != NULL); -} - -static int zs_init_fs_context(struct fs_context *fc) -{ - return init_pseudo(fc, ZSMALLOC_MAGIC) ? 0 : -ENOMEM; -} + struct page *curr_page, *page; -static struct file_system_type zsmalloc_fs = { - .name = "zsmalloc", - .init_fs_context = zs_init_fs_context, - .kill_sb = kill_anon_super, -}; - -static int zsmalloc_mount(void) -{ - int ret = 0; - - zsmalloc_mnt = kern_mount(&zsmalloc_fs); - if (IS_ERR(zsmalloc_mnt)) - ret = PTR_ERR(zsmalloc_mnt); - - return ret; -} + /* + * Pages we haven't locked yet can be migrated off the list while we're + * trying to lock them, so we need to be careful and only attempt to + * lock each page under migrate_read_lock(). Otherwise, the page we lock + * may no longer belong to the zspage. This means that we may wait for + * the wrong page to unlock, so we must take a reference to the page + * prior to waiting for it to unlock outside migrate_read_lock(). + */ + while (1) { + migrate_read_lock(zspage); + page = get_first_page(zspage); + if (trylock_page(page)) + break; + get_page(page); + migrate_read_unlock(zspage); + wait_on_page_locked(page); + put_page(page); + } -static void zsmalloc_unmount(void) -{ - kern_unmount(zsmalloc_mnt); + curr_page = page; + while ((page = get_next_page(curr_page))) { + if (trylock_page(page)) { + curr_page = page; + } else { + get_page(page); + migrate_read_unlock(zspage); + wait_on_page_locked(page); + put_page(page); + migrate_read_lock(zspage); + } + } + migrate_read_unlock(zspage); } static void migrate_lock_init(struct zspage *zspage) @@ -1833,12 +1757,12 @@ static void migrate_lock_init(struct zspage *zspage) rwlock_init(&zspage->lock); } -static void migrate_read_lock(struct zspage *zspage) +static void migrate_read_lock(struct zspage *zspage) __acquires(&zspage->lock) { read_lock(&zspage->lock); } -static void migrate_read_unlock(struct zspage *zspage) +static void migrate_read_unlock(struct zspage *zspage) __releases(&zspage->lock) { read_unlock(&zspage->lock); } @@ -1848,6 +1772,11 @@ static void migrate_write_lock(struct zspage *zspage) write_lock(&zspage->lock); } +static void migrate_write_lock_nested(struct zspage *zspage) +{ + write_lock_nested(&zspage->lock, SINGLE_DEPTH_NESTING); +} + static void migrate_write_unlock(struct zspage *zspage) { write_unlock(&zspage->lock); @@ -1861,33 +1790,11 @@ static void inc_zspage_isolation(struct zspage *zspage) static void dec_zspage_isolation(struct zspage *zspage) { + VM_BUG_ON(zspage->isolated == 0); zspage->isolated--; } -static void putback_zspage_deferred(struct zs_pool *pool, - struct size_class *class, - struct zspage *zspage) -{ - enum fullness_group fg; - - fg = putback_zspage(class, zspage); - if (fg == ZS_EMPTY) - schedule_work(&pool->free_work); - -} - -static inline void zs_pool_dec_isolated(struct zs_pool *pool) -{ - VM_BUG_ON(atomic_long_read(&pool->isolated_pages) <= 0); - atomic_long_dec(&pool->isolated_pages); - /* - * There's no possibility of racing, since wait_for_isolated_drain() - * checks the isolated count under &class->lock after enqueuing - * on migration_wait. - */ - if (atomic_long_read(&pool->isolated_pages) == 0 && pool->destroying) - wake_up_all(&pool->migration_wait); -} +static const struct movable_operations zsmalloc_mops; static void replace_sub_page(struct size_class *class, struct zspage *zspage, struct page *newpage, struct page *oldpage) @@ -1907,19 +1814,14 @@ static void replace_sub_page(struct size_class *class, struct zspage *zspage, create_page_chain(class, zspage, pages); set_first_obj_offset(newpage, get_first_obj_offset(oldpage)); - if (unlikely(PageHugeObject(oldpage))) + if (unlikely(ZsHugePage(zspage))) newpage->index = oldpage->index; - __SetPageMovable(newpage, page_mapping(oldpage)); + __SetPageMovable(newpage, &zsmalloc_mops); } static bool zs_page_isolate(struct page *page, isolate_mode_t mode) { - struct zs_pool *pool; - struct size_class *class; - int class_idx; - enum fullness_group fullness; struct zspage *zspage; - struct address_space *mapping; /* * Page is locked so zspage couldn't be destroyed. For detail, look at @@ -1929,60 +1831,25 @@ static bool zs_page_isolate(struct page *page, isolate_mode_t mode) VM_BUG_ON_PAGE(PageIsolated(page), page); zspage = get_zspage(page); - - /* - * Without class lock, fullness could be stale while class_idx is okay - * because class_idx is constant unless page is freed so we should get - * fullness again under class lock. - */ - get_zspage_mapping(zspage, &class_idx, &fullness); - mapping = page_mapping(page); - pool = mapping->private_data; - class = pool->size_class[class_idx]; - - spin_lock(&class->lock); - if (get_zspage_inuse(zspage) == 0) { - spin_unlock(&class->lock); - return false; - } - - /* zspage is isolated for object migration */ - if (list_empty(&zspage->list) && !is_zspage_isolated(zspage)) { - spin_unlock(&class->lock); - return false; - } - - /* - * If this is first time isolation for the zspage, isolate zspage from - * size_class to prevent further object allocation from the zspage. - */ - if (!list_empty(&zspage->list) && !is_zspage_isolated(zspage)) { - get_zspage_mapping(zspage, &class_idx, &fullness); - atomic_long_inc(&pool->isolated_pages); - remove_zspage(class, zspage, fullness); - } - + migrate_write_lock(zspage); inc_zspage_isolation(zspage); - spin_unlock(&class->lock); + migrate_write_unlock(zspage); return true; } -static int zs_page_migrate(struct address_space *mapping, struct page *newpage, - struct page *page, enum migrate_mode mode) +static int zs_page_migrate(struct page *newpage, struct page *page, + enum migrate_mode mode) { struct zs_pool *pool; struct size_class *class; - int class_idx; - enum fullness_group fullness; struct zspage *zspage; struct page *dummy; void *s_addr, *d_addr, *addr; - int offset, pos; - unsigned long handle, head; + unsigned int offset; + unsigned long handle; unsigned long old_obj, new_obj; unsigned int obj_idx; - int ret = -EAGAIN; /* * We cannot support the _NO_COPY case here, because copy needs to @@ -1995,35 +1862,26 @@ static int zs_page_migrate(struct address_space *mapping, struct page *newpage, VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(!PageIsolated(page), page); + /* The page is locked, so this pointer must remain valid */ zspage = get_zspage(page); + pool = zspage->pool; - /* Concurrent compactor cannot migrate any subpage in zspage */ - migrate_write_lock(zspage); - get_zspage_mapping(zspage, &class_idx, &fullness); - pool = mapping->private_data; - class = pool->size_class[class_idx]; - offset = get_first_obj_offset(page); + /* + * The pool migrate_lock protects the race between zpage migration + * and zs_free. + */ + write_lock(&pool->migrate_lock); + class = zspage_class(pool, zspage); + /* + * the class lock protects zpage alloc/free in the zspage. + */ spin_lock(&class->lock); - if (!get_zspage_inuse(zspage)) { - /* - * Set "offset" to end of the page so that every loops - * skips unnecessary object scanning. - */ - offset = PAGE_SIZE; - } + /* the migrate_write_lock protects zpage access via zs_map_object */ + migrate_write_lock(zspage); - pos = offset; + offset = get_first_obj_offset(page); s_addr = kmap_atomic(page); - while (pos < PAGE_SIZE) { - head = obj_to_head(page, s_addr + pos); - if (head & OBJ_ALLOCATED_TAG) { - handle = head & ~OBJ_ALLOCATED_TAG; - if (!trypin_tag(handle)) - goto unpin_objects; - } - pos += class->size; - } /* * Here, any user cannot access all objects in the zspage so let's move. @@ -2032,43 +1890,30 @@ static int zs_page_migrate(struct address_space *mapping, struct page *newpage, memcpy(d_addr, s_addr, PAGE_SIZE); kunmap_atomic(d_addr); - for (addr = s_addr + offset; addr < s_addr + pos; + for (addr = s_addr + offset; addr < s_addr + PAGE_SIZE; addr += class->size) { - head = obj_to_head(page, addr); - if (head & OBJ_ALLOCATED_TAG) { - handle = head & ~OBJ_ALLOCATED_TAG; - if (!testpin_tag(handle)) - BUG(); + if (obj_allocated(page, addr, &handle)) { old_obj = handle_to_obj(handle); obj_to_location(old_obj, &dummy, &obj_idx); new_obj = (unsigned long)location_to_obj(newpage, obj_idx); - new_obj |= BIT(HANDLE_PIN_BIT); record_obj(handle, new_obj); } } + kunmap_atomic(s_addr); replace_sub_page(class, zspage, newpage, page); - get_page(newpage); - - dec_zspage_isolation(zspage); - /* - * Page migration is done so let's putback isolated zspage to - * the list if @page is final isolated subpage in the zspage. + * Since we complete the data copy and set up new zspage structure, + * it's okay to release migration_lock. */ - if (!is_zspage_isolated(zspage)) { - /* - * We cannot race with zs_destroy_pool() here because we wait - * for isolation to hit zero before we start destroying. - * Also, we ensure that everyone can see pool->destroying before - * we start waiting. - */ - putback_zspage_deferred(pool, class, zspage); - zs_pool_dec_isolated(pool); - } + write_unlock(&pool->migrate_lock); + spin_unlock(&class->lock); + dec_zspage_isolation(zspage); + migrate_write_unlock(zspage); + get_page(newpage); if (page_zone(newpage) != page_zone(page)) { dec_zone_page_state(page, NR_ZSPAGES); inc_zone_page_state(newpage, NR_ZSPAGES); @@ -2076,111 +1921,29 @@ static int zs_page_migrate(struct address_space *mapping, struct page *newpage, reset_page(page); put_page(page); - page = newpage; - - ret = MIGRATEPAGE_SUCCESS; -unpin_objects: - for (addr = s_addr + offset; addr < s_addr + pos; - addr += class->size) { - head = obj_to_head(page, addr); - if (head & OBJ_ALLOCATED_TAG) { - handle = head & ~OBJ_ALLOCATED_TAG; - if (!testpin_tag(handle)) - BUG(); - unpin_tag(handle); - } - } - kunmap_atomic(s_addr); - spin_unlock(&class->lock); - migrate_write_unlock(zspage); - return ret; + return MIGRATEPAGE_SUCCESS; } static void zs_page_putback(struct page *page) { - struct zs_pool *pool; - struct size_class *class; - int class_idx; - enum fullness_group fg; - struct address_space *mapping; struct zspage *zspage; VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(!PageIsolated(page), page); zspage = get_zspage(page); - get_zspage_mapping(zspage, &class_idx, &fg); - mapping = page_mapping(page); - pool = mapping->private_data; - class = pool->size_class[class_idx]; - - spin_lock(&class->lock); + migrate_write_lock(zspage); dec_zspage_isolation(zspage); - if (!is_zspage_isolated(zspage)) { - /* - * Due to page_lock, we cannot free zspage immediately - * so let's defer. - */ - putback_zspage_deferred(pool, class, zspage); - zs_pool_dec_isolated(pool); - } - spin_unlock(&class->lock); + migrate_write_unlock(zspage); } -static const struct address_space_operations zsmalloc_aops = { +static const struct movable_operations zsmalloc_mops = { .isolate_page = zs_page_isolate, - .migratepage = zs_page_migrate, + .migrate_page = zs_page_migrate, .putback_page = zs_page_putback, }; -static int zs_register_migration(struct zs_pool *pool) -{ - pool->inode = alloc_anon_inode(zsmalloc_mnt->mnt_sb); - if (IS_ERR(pool->inode)) { - pool->inode = NULL; - return 1; - } - - pool->inode->i_mapping->private_data = pool; - pool->inode->i_mapping->a_ops = &zsmalloc_aops; - return 0; -} - -static bool pool_isolated_are_drained(struct zs_pool *pool) -{ - return atomic_long_read(&pool->isolated_pages) == 0; -} - -/* Function for resolving migration */ -static void wait_for_isolated_drain(struct zs_pool *pool) -{ - - /* - * We're in the process of destroying the pool, so there are no - * active allocations. zs_page_isolate() fails for completely free - * zspages, so we need only wait for the zs_pool's isolated - * count to hit zero. - */ - wait_event(pool->migration_wait, - pool_isolated_are_drained(pool)); -} - -static void zs_unregister_migration(struct zs_pool *pool) -{ - pool->destroying = true; - /* - * We need a memory barrier here to ensure global visibility of - * pool->destroying. Thus pool->isolated pages will either be 0 in which - * case we don't care, or it will be > 0 and pool->destroying will - * ensure that we wake up once isolation hits 0. - */ - smp_mb(); - wait_for_isolated_drain(pool); /* This can block */ - flush_work(&pool->free_work); - iput(pool->inode); -} - /* * Caller should hold page_lock of all pages in the zspage * In here, we cannot use zspage meta data. @@ -2206,7 +1969,6 @@ static void async_free_zspage(struct work_struct *work) spin_unlock(&class->lock); } - list_for_each_entry_safe(zspage, tmp, &free_pages, list) { list_del(&zspage->list); lock_zspage(zspage); @@ -2215,7 +1977,7 @@ static void async_free_zspage(struct work_struct *work) VM_BUG_ON(fullness != ZS_EMPTY); class = pool->size_class[class_idx]; spin_lock(&class->lock); - __free_zspage(pool, pool->size_class[class_idx], zspage); + __free_zspage(pool, class, zspage); spin_unlock(&class->lock); } }; @@ -2225,6 +1987,11 @@ static void kick_deferred_free(struct zs_pool *pool) schedule_work(&pool->free_work); } +static void zs_flush_migration(struct zs_pool *pool) +{ + flush_work(&pool->free_work); +} + static void init_deferred_free(struct zs_pool *pool) { INIT_WORK(&pool->free_work, async_free_zspage); @@ -2236,10 +2003,12 @@ static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) do { WARN_ON(!trylock_page(page)); - __SetPageMovable(page, pool->inode->i_mapping); + __SetPageMovable(page, &zsmalloc_mops); unlock_page(page); } while ((page = get_next_page(page)) != NULL); } +#else +static inline void zs_flush_migration(struct zs_pool *pool) { } #endif /* @@ -2262,14 +2031,21 @@ static unsigned long zs_can_compact(struct size_class *class) return obj_wasted * class->pages_per_zspage; } -static void __zs_compact(struct zs_pool *pool, struct size_class *class) +static unsigned long __zs_compact(struct zs_pool *pool, + struct size_class *class) { struct zs_compact_control cc; struct zspage *src_zspage; struct zspage *dst_zspage = NULL; + unsigned long pages_freed = 0; + /* protect the race between zpage migration and zs_free */ + write_lock(&pool->migrate_lock); + /* protect zpage allocation/free */ spin_lock(&class->lock); while ((src_zspage = isolate_zspage(class, true))) { + /* protect someone accessing the zspage(i.e., zs_map_object) */ + migrate_write_lock(src_zspage); if (!zs_can_compact(class)) break; @@ -2278,6 +2054,8 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class) cc.s_page = get_first_page(src_zspage); while ((dst_zspage = isolate_zspage(class, false))) { + migrate_write_lock_nested(dst_zspage); + cc.d_page = get_first_page(dst_zspage); /* * If there is no more space in dst_page, resched @@ -2287,6 +2065,10 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class) break; putback_zspage(class, dst_zspage); + migrate_write_unlock(dst_zspage); + dst_zspage = NULL; + if (rwlock_is_contended(&pool->migrate_lock)) + break; } /* Stop if we couldn't find slot */ @@ -2294,36 +2076,47 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class) break; putback_zspage(class, dst_zspage); + migrate_write_unlock(dst_zspage); + if (putback_zspage(class, src_zspage) == ZS_EMPTY) { + migrate_write_unlock(src_zspage); free_zspage(pool, class, src_zspage); - pool->stats.pages_compacted += class->pages_per_zspage; - } + pages_freed += class->pages_per_zspage; + } else + migrate_write_unlock(src_zspage); spin_unlock(&class->lock); + write_unlock(&pool->migrate_lock); cond_resched(); + write_lock(&pool->migrate_lock); spin_lock(&class->lock); } - if (src_zspage) + if (src_zspage) { putback_zspage(class, src_zspage); + migrate_write_unlock(src_zspage); + } spin_unlock(&class->lock); + write_unlock(&pool->migrate_lock); + + return pages_freed; } unsigned long zs_compact(struct zs_pool *pool) { int i; struct size_class *class; + unsigned long pages_freed = 0; for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) { class = pool->size_class[i]; - if (!class) - continue; if (class->index != i) continue; - __zs_compact(pool, class); + pages_freed += __zs_compact(pool, class); } + atomic_long_add(pages_freed, &pool->stats.pages_compacted); - return pool->stats.pages_compacted; + return pages_freed; } EXPORT_SYMBOL_GPL(zs_compact); @@ -2340,13 +2133,12 @@ static unsigned long zs_shrinker_scan(struct shrinker *shrinker, struct zs_pool *pool = container_of(shrinker, struct zs_pool, shrinker); - pages_freed = pool->stats.pages_compacted; /* * Compact classes and calculate compaction delta. * Can run concurrently with a manually triggered * (by user) compaction. */ - pages_freed = zs_compact(pool) - pages_freed; + pages_freed = zs_compact(pool); return pages_freed ? pages_freed : SHRINK_STOP; } @@ -2362,8 +2154,6 @@ static unsigned long zs_shrinker_count(struct shrinker *shrinker, for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) { class = pool->size_class[i]; - if (!class) - continue; if (class->index != i) continue; @@ -2385,7 +2175,8 @@ static int zs_register_shrinker(struct zs_pool *pool) pool->shrinker.batch = 0; pool->shrinker.seeks = DEFAULT_SEEKS; - return register_shrinker(&pool->shrinker); + return register_shrinker(&pool->shrinker, "mm-zspool:%s", + pool->name); } /** @@ -2409,15 +2200,12 @@ struct zs_pool *zs_create_pool(const char *name) return NULL; init_deferred_free(pool); + rwlock_init(&pool->migrate_lock); pool->name = kstrdup(name, GFP_KERNEL); if (!pool->name) goto err; -#ifdef CONFIG_COMPACTION - init_waitqueue_head(&pool->migration_wait); -#endif - if (create_cache(pool)) goto err; @@ -2495,9 +2283,6 @@ struct zs_pool *zs_create_pool(const char *name) /* debug only, don't abort if it fails */ zs_pool_stat_create(pool, name); - if (zs_register_migration(pool)) - goto err; - /* * Not critical since shrinker is only used to trigger internal * defragmentation of the pool which is pretty optional thing. If @@ -2519,7 +2304,7 @@ void zs_destroy_pool(struct zs_pool *pool) int i; zs_unregister_shrinker(pool); - zs_unregister_migration(pool); + zs_flush_migration(pool); zs_pool_stat_destroy(pool); for (i = 0; i < ZS_SIZE_CLASSES; i++) { @@ -2551,14 +2336,10 @@ static int __init zs_init(void) { int ret; - ret = zsmalloc_mount(); - if (ret) - goto out; - ret = cpuhp_setup_state(CPUHP_MM_ZS_PREPARE, "mm/zsmalloc:prepare", zs_cpu_prepare, zs_cpu_dead); if (ret) - goto hp_setup_fail; + goto out; #ifdef CONFIG_ZPOOL zpool_register_driver(&zs_zpool_driver); @@ -2568,8 +2349,6 @@ static int __init zs_init(void) return 0; -hp_setup_fail: - zsmalloc_unmount(); out: return ret; } @@ -2579,7 +2358,6 @@ static void __exit zs_exit(void) #ifdef CONFIG_ZPOOL zpool_unregister_driver(&zs_zpool_driver); #endif - zsmalloc_unmount(); cpuhp_remove_state(CPUHP_MM_ZS_PREPARE); zs_stat_exit(); |