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Mon, 21 Nov 2022 17:12:11 +0000 From: Vlastimil Babka To: Christoph Lameter , David Rientjes , Joonsoo Kim , Pekka Enberg Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>, Roman Gushchin , Andrew Morton , Linus Torvalds , Matthew Wilcox , patches@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka Subject: [PATCH 08/12] mm, slub: refactor free debug processing Date: Mon, 21 Nov 2022 18:11:58 +0100 Message-Id: <20221121171202.22080-9-vbabka@suse.cz> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221121171202.22080-1-vbabka@suse.cz> References: <20221121171202.22080-1-vbabka@suse.cz> MIME-Version: 1.0 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1669050733; a=rsa-sha256; cv=none; b=Iw9qs1QAdj1turff6JOAnA9q7eEKYTWNJBu6a0k31pHDiXdWOCK74PitP3VmwijnuFznhV y2Ds3H6MDOlaGxtr00xciQX42c2zb+/7+0VROOBdxf4RjIf25WN/VAQV+tKqhY/qf6jhs0 OgB/QnbTOmlVa2K8gzqLPl/aNvv8T5s= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=ZVaRYtFQ; 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spf=pass (imf21.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none X-Rspam-User: X-Stat-Signature: f9upsfaerhpmc5d4uegpyb15ew19rzph X-HE-Tag: 1669050733-898733 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Since commit c7323a5ad078 ("mm/slub: restrict sysfs validation to debug caches and make it safe"), caches with debugging enabled use the free_debug_processing() function to do both freeing checks and actual freeing to partial list under list_lock, bypassing the fast paths. We will want to use the same path for CONFIG_SLUB_TINY, but without the debugging checks, so refactor the code so that free_debug_processing() does only the checks, while the freeing is handled by a new function free_to_partial_list(). For consistency, change return parameter alloc_debug_processing() from int to bool and correct the !SLUB_DEBUG variant to return true and not false. This didn't matter until now, but will in the following changes. Signed-off-by: Vlastimil Babka Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> --- mm/slub.c | 154 +++++++++++++++++++++++++++++------------------------- 1 file changed, 83 insertions(+), 71 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index bf726dd00f7d..fd56d7cca9c2 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1368,7 +1368,7 @@ static inline int alloc_consistency_checks(struct kmem_cache *s, return 1; } -static noinline int alloc_debug_processing(struct kmem_cache *s, +static noinline bool alloc_debug_processing(struct kmem_cache *s, struct slab *slab, void *object, int orig_size) { if (s->flags & SLAB_CONSISTENCY_CHECKS) { @@ -1380,7 +1380,7 @@ static noinline int alloc_debug_processing(struct kmem_cache *s, trace(s, slab, object, 1); set_orig_size(s, object, orig_size); init_object(s, object, SLUB_RED_ACTIVE); - return 1; + return true; bad: if (folio_test_slab(slab_folio(slab))) { @@ -1393,7 +1393,7 @@ static noinline int alloc_debug_processing(struct kmem_cache *s, slab->inuse = slab->objects; slab->freelist = NULL; } - return 0; + return false; } static inline int free_consistency_checks(struct kmem_cache *s, @@ -1646,17 +1646,17 @@ static inline void setup_object_debug(struct kmem_cache *s, void *object) {} static inline void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {} -static inline int alloc_debug_processing(struct kmem_cache *s, - struct slab *slab, void *object, int orig_size) { return 0; } +static inline bool alloc_debug_processing(struct kmem_cache *s, + struct slab *slab, void *object, int orig_size) { return true; } -static inline void free_debug_processing( - struct kmem_cache *s, struct slab *slab, - void *head, void *tail, int bulk_cnt, - unsigned long addr) {} +static inline bool free_debug_processing(struct kmem_cache *s, + struct slab *slab, void *head, void *tail, int *bulk_cnt, + unsigned long addr, depot_stack_handle_t handle) { return true; } static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {} static inline int check_object(struct kmem_cache *s, struct slab *slab, void *object, u8 val) { return 1; } +static inline depot_stack_handle_t set_track_prepare(void) { return 0; } static inline void set_track(struct kmem_cache *s, void *object, enum track_item alloc, unsigned long addr) {} static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n, @@ -2833,38 +2833,28 @@ static inline unsigned long node_nr_objs(struct kmem_cache_node *n) } /* Supports checking bulk free of a constructed freelist */ -static noinline void free_debug_processing( - struct kmem_cache *s, struct slab *slab, - void *head, void *tail, int bulk_cnt, - unsigned long addr) +static inline bool free_debug_processing(struct kmem_cache *s, + struct slab *slab, void *head, void *tail, int *bulk_cnt, + unsigned long addr, depot_stack_handle_t handle) { - struct kmem_cache_node *n = get_node(s, slab_nid(slab)); - struct slab *slab_free = NULL; + bool checks_ok = false; void *object = head; int cnt = 0; - unsigned long flags; - bool checks_ok = false; - depot_stack_handle_t handle = 0; - - if (s->flags & SLAB_STORE_USER) - handle = set_track_prepare(); - - spin_lock_irqsave(&n->list_lock, flags); if (s->flags & SLAB_CONSISTENCY_CHECKS) { if (!check_slab(s, slab)) goto out; } - if (slab->inuse < bulk_cnt) { + if (slab->inuse < *bulk_cnt) { slab_err(s, slab, "Slab has %d allocated objects but %d are to be freed\n", - slab->inuse, bulk_cnt); + slab->inuse, *bulk_cnt); goto out; } next_object: - if (++cnt > bulk_cnt) + if (++cnt > *bulk_cnt) goto out_cnt; if (s->flags & SLAB_CONSISTENCY_CHECKS) { @@ -2886,57 +2876,18 @@ static noinline void free_debug_processing( checks_ok = true; out_cnt: - if (cnt != bulk_cnt) + if (cnt != *bulk_cnt) { slab_err(s, slab, "Bulk free expected %d objects but found %d\n", - bulk_cnt, cnt); - -out: - if (checks_ok) { - void *prior = slab->freelist; - - /* Perform the actual freeing while we still hold the locks */ - slab->inuse -= cnt; - set_freepointer(s, tail, prior); - slab->freelist = head; - - /* - * If the slab is empty, and node's partial list is full, - * it should be discarded anyway no matter it's on full or - * partial list. - */ - if (slab->inuse == 0 && n->nr_partial >= s->min_partial) - slab_free = slab; - - if (!prior) { - /* was on full list */ - remove_full(s, n, slab); - if (!slab_free) { - add_partial(n, slab, DEACTIVATE_TO_TAIL); - stat(s, FREE_ADD_PARTIAL); - } - } else if (slab_free) { - remove_partial(n, slab); - stat(s, FREE_REMOVE_PARTIAL); - } + *bulk_cnt, cnt); + *bulk_cnt = cnt; } - if (slab_free) { - /* - * Update the counters while still holding n->list_lock to - * prevent spurious validation warnings - */ - dec_slabs_node(s, slab_nid(slab_free), slab_free->objects); - } - - spin_unlock_irqrestore(&n->list_lock, flags); +out: if (!checks_ok) slab_fix(s, "Object at 0x%p not freed", object); - if (slab_free) { - stat(s, FREE_SLAB); - free_slab(s, slab_free); - } + return checks_ok; } #endif /* CONFIG_SLUB_DEBUG */ @@ -3453,6 +3404,67 @@ void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) } EXPORT_SYMBOL(kmem_cache_alloc_node); +static noinline void free_to_partial_list( + struct kmem_cache *s, struct slab *slab, + void *head, void *tail, int bulk_cnt, + unsigned long addr) +{ + struct kmem_cache_node *n = get_node(s, slab_nid(slab)); + struct slab *slab_free = NULL; + int cnt = bulk_cnt; + unsigned long flags; + depot_stack_handle_t handle = 0; + + if (s->flags & SLAB_STORE_USER) + handle = set_track_prepare(); + + spin_lock_irqsave(&n->list_lock, flags); + + if (free_debug_processing(s, slab, head, tail, &cnt, addr, handle)) { + void *prior = slab->freelist; + + /* Perform the actual freeing while we still hold the locks */ + slab->inuse -= cnt; + set_freepointer(s, tail, prior); + slab->freelist = head; + + /* + * If the slab is empty, and node's partial list is full, + * it should be discarded anyway no matter it's on full or + * partial list. + */ + if (slab->inuse == 0 && n->nr_partial >= s->min_partial) + slab_free = slab; + + if (!prior) { + /* was on full list */ + remove_full(s, n, slab); + if (!slab_free) { + add_partial(n, slab, DEACTIVATE_TO_TAIL); + stat(s, FREE_ADD_PARTIAL); + } + } else if (slab_free) { + remove_partial(n, slab); + stat(s, FREE_REMOVE_PARTIAL); + } + } + + if (slab_free) { + /* + * Update the counters while still holding n->list_lock to + * prevent spurious validation warnings + */ + dec_slabs_node(s, slab_nid(slab_free), slab_free->objects); + } + + spin_unlock_irqrestore(&n->list_lock, flags); + + if (slab_free) { + stat(s, FREE_SLAB); + free_slab(s, slab_free); + } +} + /* * Slow path handling. This may still be called frequently since objects * have a longer lifetime than the cpu slabs in most processing loads. @@ -3479,7 +3491,7 @@ static void __slab_free(struct kmem_cache *s, struct slab *slab, return; if (kmem_cache_debug(s)) { - free_debug_processing(s, slab, head, tail, cnt, addr); + free_to_partial_list(s, slab, head, tail, cnt, addr); return; }