diff options
| -rw-r--r-- | mm/slab.c | 284 |
1 files changed, 116 insertions, 168 deletions
diff --git a/mm/slab.c b/mm/slab.c index 4f4e6472db5b..863c005a3d9c 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -169,12 +169,6 @@ typedef unsigned short freelist_idx_t; #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1) /* - * true if a page was allocated from pfmemalloc reserves for network-based - * swap - */ -static bool pfmemalloc_active __read_mostly; - -/* * struct array_cache * * Purpose: @@ -195,10 +189,6 @@ struct array_cache { * Must have this definition in here for the proper * alignment of array_cache. Also simplifies accessing * the entries. - * - * Entries should not be directly dereferenced as - * entries belonging to slabs marked pfmemalloc will - * have the lower bits set SLAB_OBJ_PFMEMALLOC */ }; @@ -207,23 +197,6 @@ struct alien_cache { struct array_cache ac; }; -#define SLAB_OBJ_PFMEMALLOC 1 -static inline bool is_obj_pfmemalloc(void *objp) -{ - return (unsigned long)objp & SLAB_OBJ_PFMEMALLOC; -} - -static inline void set_obj_pfmemalloc(void **objp) -{ - *objp = (void *)((unsigned long)*objp | SLAB_OBJ_PFMEMALLOC); - return; -} - -static inline void clear_obj_pfmemalloc(void **objp) -{ - *objp = (void *)((unsigned long)*objp & ~SLAB_OBJ_PFMEMALLOC); -} - /* * Need this for bootstrapping a per node allocator. */ @@ -623,120 +596,21 @@ static struct array_cache *alloc_arraycache(int node, int entries, return ac; } -static inline bool is_slab_pfmemalloc(struct page *page) -{ - return PageSlabPfmemalloc(page); -} - -/* Clears pfmemalloc_active if no slabs have pfmalloc set */ -static void recheck_pfmemalloc_active(struct kmem_cache *cachep, - struct array_cache *ac) -{ - struct kmem_cache_node *n = get_node(cachep, numa_mem_id()); - struct page *page; - unsigned long flags; - - if (!pfmemalloc_active) - return; - - spin_lock_irqsave(&n->list_lock, flags); - list_for_each_entry(page, &n->slabs_full, lru) - if (is_slab_pfmemalloc(page)) - goto out; - - list_for_each_entry(page, &n->slabs_partial, lru) - if (is_slab_pfmemalloc(page)) - goto out; - - list_for_each_entry(page, &n->slabs_free, lru) - if (is_slab_pfmemalloc(page)) - goto out; - - pfmemalloc_active = false; -out: - spin_unlock_irqrestore(&n->list_lock, flags); -} - -static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac, - gfp_t flags, bool force_refill) +static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep, + struct page *page, void *objp) { - int i; - void *objp = ac->entry[--ac->avail]; - - /* Ensure the caller is allowed to use objects from PFMEMALLOC slab */ - if (unlikely(is_obj_pfmemalloc(objp))) { - struct kmem_cache_node *n; - - if (gfp_pfmemalloc_allowed(flags)) { - clear_obj_pfmemalloc(&objp); - return objp; - } - - /* The caller cannot use PFMEMALLOC objects, find another one */ - for (i = 0; i < ac->avail; i++) { - /* If a !PFMEMALLOC object is found, swap them */ - if (!is_obj_pfmemalloc(ac->entry[i])) { - objp = ac->entry[i]; - ac->entry[i] = ac->entry[ac->avail]; - ac->entry[ac->avail] = objp; - return objp; - } - } - - /* - * If there are empty slabs on the slabs_free list and we are - * being forced to refill the cache, mark this one !pfmemalloc. - */ - n = get_node(cachep, numa_mem_id()); - if (!list_empty(&n->slabs_free) && force_refill) { - struct page *page = virt_to_head_page(objp); - ClearPageSlabPfmemalloc(page); - clear_obj_pfmemalloc(&objp); - recheck_pfmemalloc_active(cachep, ac); - return objp; - } - - /* No !PFMEMALLOC objects available */ - ac->avail++; - objp = NULL; - } - - return objp; -} - -static inline void *ac_get_obj(struct kmem_cache *cachep, - struct array_cache *ac, gfp_t flags, bool force_refill) -{ - void *objp; - - if (unlikely(sk_memalloc_socks())) - objp = __ac_get_obj(cachep, ac, flags, force_refill); - else - objp = ac->entry[--ac->avail]; - - return objp; -} - -static noinline void *__ac_put_obj(struct kmem_cache *cachep, - struct array_cache *ac, void *objp) -{ - if (unlikely(pfmemalloc_active)) { - /* Some pfmemalloc slabs exist, check if this is one */ - struct page *page = virt_to_head_page(objp); - if (PageSlabPfmemalloc(page)) - set_obj_pfmemalloc(&objp); - } + struct kmem_cache_node *n; + int page_node; + LIST_HEAD(list); - return objp; -} + page_node = page_to_nid(page); + n = get_node(cachep, page_node); -static inline void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac, - void *objp) -{ - if (unlikely(sk_memalloc_socks())) - objp = __ac_put_obj(cachep, ac, objp); + spin_lock(&n->list_lock); + free_block(cachep, &objp, 1, page_node, &list); + spin_unlock(&n->list_lock); - ac->entry[ac->avail++] = objp; + slabs_destroy(cachep, &list); } /* @@ -939,7 +813,7 @@ static int __cache_free_alien(struct kmem_cache *cachep, void *objp, STATS_INC_ACOVERFLOW(cachep); __drain_alien_cache(cachep, ac, page_node, &list); } - ac_put_obj(cachep, ac, objp); + ac->entry[ac->avail++] = objp; spin_unlock(&alien->lock); slabs_destroy(cachep, &list); } else { @@ -1540,10 +1414,6 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, return NULL; } - /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */ - if (page_is_pfmemalloc(page)) - pfmemalloc_active = true; - nr_pages = (1 << cachep->gfporder); if (cachep->flags & SLAB_RECLAIM_ACCOUNT) add_zone_page_state(page_zone(page), @@ -1551,8 +1421,10 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, else add_zone_page_state(page_zone(page), NR_SLAB_UNRECLAIMABLE, nr_pages); + __SetPageSlab(page); - if (page_is_pfmemalloc(page)) + /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */ + if (sk_memalloc_socks() && page_is_pfmemalloc(page)) SetPageSlabPfmemalloc(page); if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) { @@ -2823,7 +2695,46 @@ static inline void fixup_slab_list(struct kmem_cache *cachep, list_add(&page->lru, &n->slabs_partial); } -static struct page *get_first_slab(struct kmem_cache_node *n) +/* Try to find non-pfmemalloc slab if needed */ +static noinline struct page *get_valid_first_slab(struct kmem_cache_node *n, + struct page *page, bool pfmemalloc) +{ + if (!page) + return NULL; + + if (pfmemalloc) + return page; + + if (!PageSlabPfmemalloc(page)) + return page; + + /* No need to keep pfmemalloc slab if we have enough free objects */ + if (n->free_objects > n->free_limit) { + ClearPageSlabPfmemalloc(page); + return page; + } + + /* Move pfmemalloc slab to the end of list to speed up next search */ + list_del(&page->lru); + if (!page->active) + list_add_tail(&page->lru, &n->slabs_free); + else + list_add_tail(&page->lru, &n->slabs_partial); + + list_for_each_entry(page, &n->slabs_partial, lru) { + if (!PageSlabPfmemalloc(page)) + return page; + } + + list_for_each_entry(page, &n->slabs_free, lru) { + if (!PageSlabPfmemalloc(page)) + return page; + } + + return NULL; +} + +static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc) { struct page *page; @@ -2835,11 +2746,41 @@ static struct page *get_first_slab(struct kmem_cache_node *n) struct page, lru); } + if (sk_memalloc_socks()) + return get_valid_first_slab(n, page, pfmemalloc); + return page; } -static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags, - bool force_refill) +static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep, + struct kmem_cache_node *n, gfp_t flags) +{ + struct page *page; + void *obj; + void *list = NULL; + + if (!gfp_pfmemalloc_allowed(flags)) + return NULL; + + spin_lock(&n->list_lock); + page = get_first_slab(n, true); + if (!page) { + spin_unlock(&n->list_lock); + return NULL; + } + + obj = slab_get_obj(cachep, page); + n->free_objects--; + + fixup_slab_list(cachep, n, page, &list); + + spin_unlock(&n->list_lock); + fixup_objfreelist_debug(cachep, &list); + + return obj; +} + +static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) { int batchcount; struct kmem_cache_node *n; @@ -2849,8 +2790,7 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags, check_irq_off(); node = numa_mem_id(); - if (unlikely(force_refill)) - goto force_grow; + retry: ac = cpu_cache_get(cachep); batchcount = ac->batchcount; @@ -2876,7 +2816,7 @@ retry: while (batchcount > 0) { struct page *page; /* Get slab alloc is to come from. */ - page = get_first_slab(n); + page = get_first_slab(n, false); if (!page) goto must_grow; @@ -2894,7 +2834,7 @@ retry: STATS_INC_ACTIVE(cachep); STATS_SET_HIGH(cachep); - ac_put_obj(cachep, ac, slab_get_obj(cachep, page)); + ac->entry[ac->avail++] = slab_get_obj(cachep, page); } fixup_slab_list(cachep, n, page, &list); @@ -2908,7 +2848,15 @@ alloc_done: if (unlikely(!ac->avail)) { int x; -force_grow: + + /* Check if we can use obj in pfmemalloc slab */ + if (sk_memalloc_socks()) { + void *obj = cache_alloc_pfmemalloc(cachep, n, flags); + + if (obj) + return obj; + } + x = cache_grow(cachep, gfp_exact_node(flags), node, NULL); /* cache_grow can reenable interrupts, then ac could change. */ @@ -2916,7 +2864,7 @@ force_grow: node = numa_mem_id(); /* no objects in sight? abort */ - if (!x && (ac->avail == 0 || force_refill)) + if (!x && ac->avail == 0) return NULL; if (!ac->avail) /* objects refilled by interrupt? */ @@ -2924,7 +2872,7 @@ force_grow: } ac->touched = 1; - return ac_get_obj(cachep, ac, flags, force_refill); + return ac->entry[--ac->avail]; } static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep, @@ -2982,28 +2930,20 @@ static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) { void *objp; struct array_cache *ac; - bool force_refill = false; check_irq_off(); ac = cpu_cache_get(cachep); if (likely(ac->avail)) { ac->touched = 1; - objp = ac_get_obj(cachep, ac, flags, false); + objp = ac->entry[--ac->avail]; - /* - * Allow for the possibility all avail objects are not allowed - * by the current flags - */ - if (objp) { - STATS_INC_ALLOCHIT(cachep); - goto out; - } - force_refill = true; + STATS_INC_ALLOCHIT(cachep); + goto out; } STATS_INC_ALLOCMISS(cachep); - objp = cache_alloc_refill(cachep, flags, force_refill); + objp = cache_alloc_refill(cachep, flags); /* * the 'ac' may be updated by cache_alloc_refill(), * and kmemleak_erase() requires its correct value. @@ -3151,7 +3091,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, retry: check_irq_off(); spin_lock(&n->list_lock); - page = get_first_slab(n); + page = get_first_slab(n, false); if (!page) goto must_grow; @@ -3304,7 +3244,6 @@ static void free_block(struct kmem_cache *cachep, void **objpp, void *objp; struct page *page; - clear_obj_pfmemalloc(&objpp[i]); objp = objpp[i]; page = virt_to_head_page(objp); @@ -3410,7 +3349,16 @@ static inline void __cache_free(struct kmem_cache *cachep, void *objp, cache_flusharray(cachep, ac); } - ac_put_obj(cachep, ac, objp); + if (sk_memalloc_socks()) { + struct page *page = virt_to_head_page(objp); + + if (unlikely(PageSlabPfmemalloc(page))) { + cache_free_pfmemalloc(cachep, page, objp); + return; + } + } + + ac->entry[ac->avail++] = objp; } /** |