After "[RFC zsmalloc 0/4] meta diet" [1], the struct it close to be migrated. But the LRU is still used. And to use the migration frame in [2], need a way to get class through page struct. So this patch add a new struct zs_migration and store it in struct page.
[1] https://lkml.org/lkml/2015/8/10/90 [2] https://lkml.org/lkml/2015/7/7/21 Signed-off-by: Hui Zhu <zhu...@xiaomi.com> --- mm/zsmalloc.c | 178 ++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 104 insertions(+), 74 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 1b18144..57c91a5 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -17,10 +17,10 @@ * * Usage of struct page fields: * page->first_page: points to the first component (0-order) page - * page->index (union with page->freelist): offset of the first object - * starting in this page. - * page->lru: links together all component pages (except the first page) - * of a zspage + * ZS_MIGRATION(page)->index: offset of the first object starting in + * this page + * ZS_MIGRATION(page)->lru: links together all component pages (except + * the first page) of a zspage * * For _first_ page only: * @@ -28,9 +28,9 @@ * component page after the first page * If the page is first_page for huge object, it stores handle. * Look at size_class->huge. - * page->lru: links together first pages of various zspages. + * ZS_MIGRATION(page)->lru: links together first pages of various zspages. * Basically forming list of zspages in a fullness group. - * page->freelist: override by struct zs_meta + * ZS_MIGRATION(page)->index: override by struct zs_meta * * Usage of struct page flags: * PG_private: identifies the first component page @@ -136,7 +136,7 @@ #define INUSE_BITS 11 #define INUSE_MASK ((1 << INUSE_BITS) - 1) #define ETC_BITS ((sizeof(unsigned long) * 8) - FREE_OBJ_IDX_BITS - \ - CLASS_IDX_BITS - FULLNESS_BITS - INUSE_BITS) + FULLNESS_BITS - INUSE_BITS) /* * On systems with 4K page size, this gives 255 size classes! There is a * trader-off here: @@ -266,12 +266,21 @@ struct zs_pool { */ struct zs_meta { unsigned long free_idx:FREE_OBJ_IDX_BITS; - unsigned long class_idx:CLASS_IDX_BITS; unsigned long fullness:FULLNESS_BITS; unsigned long inuse:INUSE_BITS; unsigned long etc:ETC_BITS; }; +struct zs_migration { + unsigned long index; + struct size_class *class; + struct list_head lru; + struct page *page; +}; + +#define ZS_MIGRATION(p) ((struct zs_migration *)((p)->freelist)) +#define ZS_META(p) ((struct zs_meta *)&(ZS_MIGRATION(p)->index)) + struct mapping_area { #ifdef CONFIG_PGTABLE_MAPPING struct vm_struct *vm; /* vm area for mapping object that span pages */ @@ -311,6 +320,19 @@ static void record_obj(unsigned long handle, unsigned long obj) *(unsigned long *)handle = obj; } +struct kmem_cache *zs_migration_cachep; + +static struct migration *alloc_migration(gfp_t flags) +{ + return (struct migration *)kmem_cache_alloc(zs_migration_cachep, + flags & ~__GFP_HIGHMEM); +} + +static void free_migration(struct migration *migration) +{ + kmem_cache_free(zs_migration_cachep, (void *)migration); +} + /* zpool driver */ #ifdef CONFIG_ZPOOL @@ -414,7 +436,7 @@ static int get_inuse_obj(struct page *page) BUG_ON(!is_first_page(page)); - m = (struct zs_meta *)&page->freelist; + m = ZS_META(page); return m->inuse; } @@ -425,48 +447,22 @@ static void set_inuse_obj(struct page *page, int inc) BUG_ON(!is_first_page(page)); - m = (struct zs_meta *)&page->freelist; + m = ZS_META(page); m->inuse += inc; } static void set_free_obj_idx(struct page *first_page, int idx) { - struct zs_meta *m = (struct zs_meta *)&first_page->freelist; + struct zs_meta *m = ZS_META(first_page); m->free_idx = idx; } static unsigned long get_free_obj_idx(struct page *first_page) { - struct zs_meta *m = (struct zs_meta *)&first_page->freelist; + struct zs_meta *m = ZS_META(first_page); return m->free_idx; } -static void get_zspage_mapping(struct page *page, unsigned int *class_idx, - enum fullness_group *fullness) -{ - struct zs_meta *m; - BUG_ON(!is_first_page(page)); - - m = (struct zs_meta *)&page->freelist; - *fullness = m->fullness; - *class_idx = m->class_idx; -} - -static void set_zspage_mapping(struct page *page, unsigned int class_idx, - enum fullness_group fullness) -{ - struct zs_meta *m; - - BUG_ON(!is_first_page(page)); - - BUG_ON(class_idx >= (1 << CLASS_IDX_BITS)); - BUG_ON(fullness >= (1 << FULLNESS_BITS)); - - m = (struct zs_meta *)&page->freelist; - m->fullness = fullness; - m->class_idx = class_idx; -} - /* * zsmalloc divides the pool into various size classes where each * class maintains a list of zspages where each zspage is divided @@ -698,7 +694,7 @@ static void insert_zspage(struct page *page, struct size_class *class, * We want to see more ZS_FULL pages and less almost * empty/full. Put pages with higher inuse first. */ - list_add_tail(&page->lru, &(*head)->lru); + list_add_tail(&ZS_MIGRATION(page)->lru, &ZS_MIGRATION(*head)->lru); if (get_inuse_obj(page) >= get_inuse_obj(*head)) *head = page; } @@ -719,13 +715,18 @@ static void remove_zspage(struct page *page, struct size_class *class, head = &class->fullness_list[fullness]; BUG_ON(!*head); - if (list_empty(&(*head)->lru)) + if (list_empty(&ZS_MIGRATION(*head)->lru)) *head = NULL; - else if (*head == page) - *head = (struct page *)list_entry((*head)->lru.next, - struct page, lru); + else if (*head == page) { + struct zs_migration *m; - list_del_init(&page->lru); + m = (struct zs_migration *) + list_entry(ZS_MIGRATION(*head)->lru.next, + struct zs_migration, lru); + *head = m->page; + } + + list_del_init(&ZS_MIGRATION(page)->lru); zs_stat_dec(class, fullness == ZS_ALMOST_EMPTY ? CLASS_ALMOST_EMPTY : CLASS_ALMOST_FULL, 1); } @@ -742,19 +743,18 @@ static void remove_zspage(struct page *page, struct size_class *class, static enum fullness_group fix_fullness_group(struct size_class *class, struct page *page) { - int class_idx; enum fullness_group currfg, newfg; BUG_ON(!is_first_page(page)); - get_zspage_mapping(page, &class_idx, &currfg); + currfg = ZS_META(page)->fullness; newfg = get_fullness_group(class, page); if (newfg == currfg) goto out; remove_zspage(page, class, currfg); insert_zspage(page, class, newfg); - set_zspage_mapping(page, class_idx, newfg); + ZS_META(page)->fullness = newfg; out: return newfg; @@ -817,8 +817,14 @@ static struct page *get_next_page(struct page *page) next = NULL; else if (is_first_page(page)) next = (struct page *)page_private(page); - else - next = list_entry(page->lru.next, struct page, lru); + else { + struct zs_migration *m; + + m = (struct zs_migration *) + list_entry(ZS_MIGRATION(page)->lru.next, + struct zs_migration, lru); + next = m->page; + } return next; } @@ -908,13 +914,15 @@ static void reset_page(struct page *page) clear_bit(PG_private, &page->flags); clear_bit(PG_private_2, &page->flags); set_page_private(page, 0); + free_migration(page->freelist); page->freelist = NULL; page_mapcount_reset(page); } static void free_zspage(struct page *first_page) { - struct page *nextp, *tmp, *head_extra; + struct zs_migration *tmp, *nextm; + struct page *nextp, *head_extra; BUG_ON(!is_first_page(first_page)); BUG_ON(get_inuse_obj(first_page)); @@ -928,8 +936,10 @@ static void free_zspage(struct page *first_page) if (!head_extra) return; - list_for_each_entry_safe(nextp, tmp, &head_extra->lru, lru) { - list_del(&nextp->lru); + list_for_each_entry_safe(nextm, tmp, &ZS_MIGRATION(head_extra)->lru, + lru) { + nextp = nextm->page; + list_del(&ZS_MIGRATION(nextp)->lru); reset_page(nextp); __free_page(nextp); } @@ -951,15 +961,14 @@ static void init_zspage(struct page *first_page, struct size_class *class) void *vaddr; /* - * page->index stores offset of first object starting - * in the page. + * ZS_MIGRATION(page)->index stores offset of first object + * starting in the page. */ if (page != first_page) - page->index = off; + ZS_MIGRATION(page)->index = off; vaddr = kmap_atomic(page); link = (struct link_free *)vaddr + off / sizeof(*link); - while ((off += class->size) < PAGE_SIZE) { link->next = (obj_idx++ << OBJ_ALLOCATED_TAG); link += class->size / sizeof(*link); @@ -994,13 +1003,13 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags) /* * Allocate individual pages and link them together as: * 1. first page->private = first sub-page - * 2. all sub-pages are linked together using page->lru + * 2. all sub-pages are linked together using ZS_MIGRATION(page)->lru * 3. each sub-page is linked to the first page using page->first_page * * For each size class, First/Head pages are linked together using - * page->lru. Also, we set PG_private to identify the first page - * (i.e. no other sub-page has this flag set) and PG_private_2 to - * identify the last page. + * ZS_MIGRATION(page)->lru. Also, we set PG_private to identify the + * first page (i.e. no other sub-page has this flag set) and + * PG_private_2 to identify the last page. */ error = -ENOMEM; for (i = 0; i < class->pages_per_zspage; i++) { @@ -1009,8 +1018,17 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags) page = alloc_page(flags); if (!page) goto cleanup; + page->freelist = alloc_migration(flags); + if (!page->freelist) { + __free_page(page); + goto cleanup; + } INIT_LIST_HEAD(&page->lru); + INIT_LIST_HEAD(&ZS_MIGRATION(page)->lru); + ZS_MIGRATION(page)->index = 0; + ZS_MIGRATION(page)->page = page; + ZS_MIGRATION(page)->class = class; if (i == 0) { /* first page */ SetPagePrivate(page); set_page_private(page, 0); @@ -1022,7 +1040,8 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags) if (i >= 1) page->first_page = first_page; if (i >= 2) - list_add(&page->lru, &prev_page->lru); + list_add(&ZS_MIGRATION(page)->lru, + &ZS_MIGRATION(prev_page)->lru); if (i == class->pages_per_zspage - 1) /* last page */ SetPagePrivate2(page); prev_page = page; @@ -1292,7 +1311,6 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle, struct page *obj_page, *first_page; unsigned long obj, obj_idx, obj_ofs; - unsigned int class_idx; enum fullness_group fg; struct size_class *class; struct mapping_area *area; @@ -1315,9 +1333,10 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle, obj_to_obj_idx(obj, &obj_page, &obj_idx); first_page = get_first_page(obj_page); - get_zspage_mapping(first_page, &class_idx, &fg); - class = pool->size_class[class_idx]; + fg = ZS_META(first_page)->fullness; + class = ZS_MIGRATION(first_page)->class; + obj_ofs = (class->size * obj_idx) % PAGE_SIZE; area = &get_cpu_var(zs_map_area); @@ -1348,7 +1367,6 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle) struct page *obj_page, *first_page; unsigned long obj, obj_idx, obj_ofs; - unsigned int class_idx; enum fullness_group fg; struct size_class *class; struct mapping_area *area; @@ -1359,8 +1377,8 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle) obj_to_obj_idx(obj, &obj_page, &obj_idx); first_page = get_first_page(obj_page); - get_zspage_mapping(first_page, &class_idx, &fg); - class = pool->size_class[class_idx]; + fg = ZS_META(first_page)->fullness; + class = ZS_MIGRATION(first_page)->class; obj_ofs = (class->size * obj_idx) % PAGE_SIZE; area = this_cpu_ptr(&zs_map_area); @@ -1450,7 +1468,8 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size) return 0; } - set_zspage_mapping(first_page, class->index, ZS_EMPTY); + ZS_META(first_page)->fullness = ZS_EMPTY; + ZS_MIGRATION(first_page)->class = class; atomic_long_add(class->pages_per_zspage, &pool->pages_allocated); @@ -1501,7 +1520,6 @@ void zs_free(struct zs_pool *pool, unsigned long handle) { struct page *first_page, *obj_page; unsigned long obj, obj_idx; - int class_idx; struct size_class *class; enum fullness_group fullness; @@ -1513,8 +1531,8 @@ void zs_free(struct zs_pool *pool, unsigned long handle) obj_to_obj_idx(obj, &obj_page, &obj_idx); first_page = get_first_page(obj_page); - get_zspage_mapping(first_page, &class_idx, &fullness); - class = pool->size_class[class_idx]; + fullness = ZS_META(first_page)->fullness; + class = ZS_MIGRATION(first_page)->class; spin_lock(&class->lock); obj_free(pool, class, obj); @@ -1611,7 +1629,7 @@ static unsigned long find_alloced_obj(struct page *page, int index, void *addr = kmap_atomic(page); if (!is_first_page(page)) - offset = page->index; + offset = ZS_MIGRATION(page)->index; offset += class->size * index; while (offset < PAGE_SIZE) { @@ -1719,7 +1737,8 @@ static enum fullness_group putback_zspage(struct zs_pool *pool, fullness = get_fullness_group(class, first_page); insert_zspage(first_page, class, fullness); - set_zspage_mapping(first_page, class->index, fullness); + ZS_META(first_page)->fullness = fullness; + ZS_MIGRATION(first_page)->class = class; if (fullness == ZS_EMPTY) { zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage( @@ -2041,7 +2060,7 @@ static int __init zs_init(void) goto notifier_fail; BUILD_BUG_ON(sizeof(unsigned long) * 8 < (FREE_OBJ_IDX_BITS + \ - CLASS_IDX_BITS + FULLNESS_BITS + INUSE_BITS + ETC_BITS)); + FULLNESS_BITS + INUSE_BITS + ETC_BITS)); init_zs_size_classes(); @@ -2054,6 +2073,15 @@ static int __init zs_init(void) pr_err("zs stat initialization failed\n"); goto stat_fail; } + + zs_migration_cachep = kmem_cache_create("zs_migration", + sizeof(struct zs_migration), + 0, 0, NULL); + if (!zs_migration_cachep) { + pr_err("zs migration initialization failed\n"); + goto stat_fail; + } + return 0; stat_fail: @@ -2068,6 +2096,8 @@ notifier_fail: static void __exit zs_exit(void) { + kmem_cache_destroy(zs_migration_cachep); + #ifdef CONFIG_ZPOOL zpool_unregister_driver(&zs_zpool_driver); #endif -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
