From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65181CCA481 for ; Tue, 12 Jul 2022 02:28:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229667AbiGLC2U (ORCPT ); Mon, 11 Jul 2022 22:28:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229840AbiGLC2R (ORCPT ); Mon, 11 Jul 2022 22:28:17 -0400 Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E05447E016 for ; Mon, 11 Jul 2022 19:28:14 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046049;MF=rongwei.wang@linux.alibaba.com;NM=1;PH=DS;RN=10;SR=0;TI=SMTPD_---0VJ6Ep2a_1657592890; Received: from localhost.localdomain(mailfrom:rongwei.wang@linux.alibaba.com fp:SMTPD_---0VJ6Ep2a_1657592890) by smtp.aliyun-inc.com; Tue, 12 Jul 2022 10:28:11 +0800 From: Rongwei Wang To: akpm@linux-foundation.org, vbabka@suse.cz, 42.hyeyoo@gmail.com, roman.gushchin@linux.dev, iamjoonsoo.kim@lge.com, rientjes@google.com, penberg@kernel.org, cl@gentwo.de Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/3] mm/slub: improve consistency of nr_slabs count Date: Tue, 12 Jul 2022 10:28:06 +0800 Message-Id: <20220712022807.44113-2-rongwei.wang@linux.alibaba.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220712022807.44113-1-rongwei.wang@linux.alibaba.com> References: <20220712022807.44113-1-rongwei.wang@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, discard_slab() can change nr_slabs count without holding node's list_lock. This will lead some error messages print when scanning node's partial or full list, e.g. validate all slabs. Literally, it affects the consistency of nr_slabs count. Here, discard_slab() is abandoned, And dec_slabs_node() is called before releasing node's list_lock. dec_slabs_nodes() and free_slab() can be called separately to ensure consistency of nr_slabs count. Signed-off-by: Rongwei Wang --- mm/slub.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index e950d8df8380..587416e39292 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2065,12 +2065,6 @@ static void free_slab(struct kmem_cache *s, struct slab *slab) __free_slab(s, slab); } -static void discard_slab(struct kmem_cache *s, struct slab *slab) -{ - dec_slabs_node(s, slab_nid(slab), slab->objects); - free_slab(s, slab); -} - /* * Management of partially allocated slabs. */ @@ -2439,6 +2433,7 @@ static void deactivate_slab(struct kmem_cache *s, struct slab *slab, if (!new.inuse && n->nr_partial >= s->min_partial) { mode = M_FREE; + spin_lock_irqsave(&n->list_lock, flags); } else if (new.freelist) { mode = M_PARTIAL; /* @@ -2463,7 +2458,7 @@ static void deactivate_slab(struct kmem_cache *s, struct slab *slab, old.freelist, old.counters, new.freelist, new.counters, "unfreezing slab")) { - if (mode == M_PARTIAL || mode == M_FULL) + if (mode != M_FULL_NOLIST) spin_unlock_irqrestore(&n->list_lock, flags); goto redo; } @@ -2475,7 +2470,10 @@ static void deactivate_slab(struct kmem_cache *s, struct slab *slab, stat(s, tail); } else if (mode == M_FREE) { stat(s, DEACTIVATE_EMPTY); - discard_slab(s, slab); + dec_slabs_node(s, slab_nid(slab), slab->objects); + spin_unlock_irqrestore(&n->list_lock, flags); + + free_slab(s, slab); stat(s, FREE_SLAB); } else if (mode == M_FULL) { add_full(s, n, slab); @@ -2528,6 +2526,7 @@ static void __unfreeze_partials(struct kmem_cache *s, struct slab *partial_slab) if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) { slab->next = slab_to_discard; slab_to_discard = slab; + dec_slabs_node(s, slab_nid(slab), slab->objects); } else { add_partial(n, slab, DEACTIVATE_TO_TAIL); stat(s, FREE_ADD_PARTIAL); @@ -2542,7 +2541,7 @@ static void __unfreeze_partials(struct kmem_cache *s, struct slab *partial_slab) slab_to_discard = slab_to_discard->next; stat(s, DEACTIVATE_EMPTY); - discard_slab(s, slab); + free_slab(s, slab); stat(s, FREE_SLAB); } } @@ -3443,9 +3442,10 @@ static void __slab_free(struct kmem_cache *s, struct slab *slab, remove_full(s, n, slab); } + dec_slabs_node(s, slab_nid(slab), slab->objects); spin_unlock_irqrestore(&n->list_lock, flags); stat(s, FREE_SLAB); - discard_slab(s, slab); + free_slab(s, slab); } /* @@ -4302,6 +4302,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) if (!slab->inuse) { remove_partial(n, slab); list_add(&slab->slab_list, &discard); + dec_slabs_node(s, slab_nid(slab), slab->objects); } else { list_slab_objects(s, slab, "Objects remaining in %s on __kmem_cache_shutdown()"); @@ -4310,7 +4311,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) spin_unlock_irq(&n->list_lock); list_for_each_entry_safe(slab, h, &discard, slab_list) - discard_slab(s, slab); + free_slab(s, slab); } bool __kmem_cache_empty(struct kmem_cache *s) @@ -4640,6 +4641,7 @@ static int __kmem_cache_do_shrink(struct kmem_cache *s) if (free == slab->objects) { list_move(&slab->slab_list, &discard); n->nr_partial--; + dec_slabs_node(s, slab_nid(slab), slab->objects); } else if (free <= SHRINK_PROMOTE_MAX) list_move(&slab->slab_list, promote + free - 1); } @@ -4655,7 +4657,7 @@ static int __kmem_cache_do_shrink(struct kmem_cache *s) /* Release empty slabs */ list_for_each_entry_safe(slab, t, &discard, slab_list) - discard_slab(s, slab); + free_slab(s, slab); if (slabs_node(s, node)) ret = 1; -- 2.27.0