From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:44720 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752434AbcJFWeR (ORCPT ); Thu, 6 Oct 2016 18:34:17 -0400 Date: Thu, 06 Oct 2016 15:34:16 -0700 From: akpm@linux-foundation.org To: iamjoonsoo.kim@lge.com, cl@linux.com, dsmythies@telus.net, penberg@kernel.org, rientjes@google.com, stable@vger.kernel.org, mm-commits@vger.kernel.org Subject: + mm-slab-fix-kmemcg-cache-creation-delayed-issue.patch added to -mm tree Message-ID: <57f6d168.V0C85KTHXxyvCdK4%akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: The patch titled Subject: mm/slab: fix kmemcg cache creation delayed issue has been added to the -mm tree. Its filename is mm-slab-fix-kmemcg-cache-creation-delayed-issue.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-slab-fix-kmemcg-cache-creation-delayed-issue.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-slab-fix-kmemcg-cache-creation-delayed-issue.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Joonsoo Kim Subject: mm/slab: fix kmemcg cache creation delayed issue There is a bug report that SLAB makes extreme load average due to over 2000 kworker thread. https://bugzilla.kernel.org/show_bug.cgi?id=172981 This issue is caused by kmemcg feature that try to create new set of kmem_caches for each memcg. Recently, kmem_cache creation is slowed by synchronize_sched() and futher kmem_cache creation is also delayed since kmem_cache creation is synchronized by a global slab_mutex lock. So, the number of kworker that try to create kmem_cache increases quitely. synchronize_sched() is for lockless access to node's shared array but it's not needed when a new kmem_cache is created. So, this patch rules out that case. Fixes: 801faf0db894 ("mm/slab: lockless decision to grow cache") Link: http://lkml.kernel.org/r/1475734855-4837-1-git-send-email-iamjoonsoo.kim@lge.com Reported-by: Doug Smythies Tested-by: Doug Smythies Signed-off-by: Joonsoo Kim Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Signed-off-by: Andrew Morton --- mm/slab.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN mm/slab.c~mm-slab-fix-kmemcg-cache-creation-delayed-issue mm/slab.c --- a/mm/slab.c~mm-slab-fix-kmemcg-cache-creation-delayed-issue +++ a/mm/slab.c @@ -966,7 +966,7 @@ static int setup_kmem_cache_node(struct * guaranteed to be valid until irq is re-enabled, because it will be * freed after synchronize_sched(). */ - if (force_change) + if (old_shared && force_change) synchronize_sched(); fail: _ Patches currently in -mm which might be from iamjoonsoo.kim@lge.com are mm-slab-fix-kmemcg-cache-creation-delayed-issue.patch mm-debug_pagealloc-clean-up-guard-page-handling-code.patch mm-debug_pagealloc-dont-allocate-page_ext-if-we-dont-use-guard-page.patch mm-page_owner-move-page_owner-specific-function-to-page_ownerc.patch mm-page_ext-rename-offset-to-index.patch mm-page_ext-support-extra-space-allocation-by-page_ext-user.patch mm-page_owner-dont-define-fields-on-struct-page_ext-by-hard-coding.patch