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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B722CD1288 for ; Wed, 3 Apr 2024 18:02:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 574206B0083; Wed, 3 Apr 2024 14:02:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4FE3D6B0087; Wed, 3 Apr 2024 14:02:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 39D996B0088; Wed, 3 Apr 2024 14:02:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 197A26B0083 for ; Wed, 3 Apr 2024 14:02:31 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id A97261A0CBC for ; Wed, 3 Apr 2024 18:02:30 +0000 (UTC) X-FDA: 81968990460.21.72CEF69 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf04.hostedemail.com (Postfix) with ESMTP id 3B9484003A for ; Wed, 3 Apr 2024 18:02:22 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=none; spf=pass (imf04.hostedemail.com: domain of aishwarya.tcv@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=aishwarya.tcv@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1712167342; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zVsS4/McIZ2rFmGChCwH1Oum9JbWNRjCsuUljg3CrOI=; b=T9tJUVscBuFeFOhioDCndrFsFIsGfVs2M49kxstvKdDFUecfrsb0CMoJAb3fNB6t1dp8pj 36vymEDPkMFQLtnMSXBAZK/iX971AYneh41t+uTQuM9t91GGa3WGForhRTpRN51G9qNyp4 dF5TRutmAbJtIoeAktNyBqkwIxjRmMM= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1712167342; a=rsa-sha256; cv=none; b=ADfqGp17NtKdcxNsh6UMV3fKsSoR9vG+LUgdkDPl/qz4YRP9ib787ZZcqPLNxhm4WHHiNQ bZoR4TyCKmemy4mHsTW18BN0ZPI4uNdxSk1j05W1t42Yc1TIfgtPpJ0VeSW+9ovNjEzwDW tyRKLKN//nuSbBegrckT5EN5i7lZZMA= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=none; spf=pass (imf04.hostedemail.com: domain of aishwarya.tcv@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=aishwarya.tcv@arm.com; dmarc=pass (policy=none) header.from=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 20D441007; Wed, 3 Apr 2024 11:02:52 -0700 (PDT) Received: from [10.57.18.20] (unknown [10.57.18.20]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5F9333F766; Wed, 3 Apr 2024 11:02:17 -0700 (PDT) Message-ID: <2143378c-0d5b-4e68-9da4-cabc149cb84f@arm.com> Date: Wed, 3 Apr 2024 19:02:15 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/2] mm, slab: move memcg charging to post-alloc hook Content-Language: en-US To: Vlastimil Babka , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-fsdevel@vger.kernel.org, Chengming Zhou , Linus Torvalds , Josh Poimboeuf , Jeff Layton , Chuck Lever , Kees Cook , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Johannes Weiner , Michal Hocko , Muchun Song , Alexander Viro , Christian Brauner , Jan Kara , Shakeel Butt , Mark Brown References: <20240325-slab-memcg-v2-0-900a458233a6@suse.cz> <20240325-slab-memcg-v2-1-900a458233a6@suse.cz> <30df7730-1b37-420d-b661-e5316679246f@arm.com> <4af50be2-4109-45e5-8a36-2136252a635e@suse.cz> From: Aishwarya TCV In-Reply-To: <4af50be2-4109-45e5-8a36-2136252a635e@suse.cz> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 3B9484003A X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: jfjjqekw5i6xtd4r5n997j5wgoet5tk1 X-HE-Tag: 1712167342-320579 X-HE-Meta: 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 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: List-Subscribe: List-Unsubscribe: On 03/04/2024 16:48, Vlastimil Babka wrote: > On 4/3/24 1:39 PM, Aishwarya TCV wrote: >> >> >> On 25/03/2024 08:20, Vlastimil Babka wrote: >>> The MEMCG_KMEM integration with slab currently relies on two hooks >>> during allocation. memcg_slab_pre_alloc_hook() determines the objcg and >>> charges it, and memcg_slab_post_alloc_hook() assigns the objcg pointer >>> to the allocated object(s). >>> >>> As Linus pointed out, this is unnecessarily complex. Failing to charge >>> due to memcg limits should be rare, so we can optimistically allocate >>> the object(s) and do the charging together with assigning the objcg >>> pointer in a single post_alloc hook. In the rare case the charging >>> fails, we can free the object(s) back. >>> >>> This simplifies the code (no need to pass around the objcg pointer) and >>> potentially allows to separate charging from allocation in cases where >>> it's common that the allocation would be immediately freed, and the >>> memcg handling overhead could be saved. >>> >>> Suggested-by: Linus Torvalds >>> Link: https://lore.kernel.org/all/CAHk-=whYOOdM7jWy5jdrAm8LxcgCMFyk2bt8fYYvZzM4U-zAQA@mail.gmail.com/ >>> Reviewed-by: Roman Gushchin >>> Reviewed-by: Chengming Zhou >>> Signed-off-by: Vlastimil Babka >>> --- >>> mm/slub.c | 180 +++++++++++++++++++++++++++----------------------------------- >>> 1 file changed, 77 insertions(+), 103 deletions(-) >> >> Hi Vlastimil, >> >> When running the LTP test "memcg_limit_in_bytes" against next-master >> (next-20240402) kernel with Arm64 on JUNO, oops is observed in our CI. I >> can send the full logs if required. It is observed to work fine on >> softiron-overdrive-3000. >> >> A bisect identified 11bb2d9d91627935c63ea3e6a031fd238c846e1 as the first >> bad commit. Bisected it on the tag "next-20240402" at repo >> "https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git". >> >> This works fine on Linux version v6.9-rc2 > > Oops, sorry, can you verify that this fixes it? > Thanks. > > ----8<---- > From b0597c220624fef4f10e26079a3ff1c86f02a12b Mon Sep 17 00:00:00 2001 > From: Vlastimil Babka > Date: Wed, 3 Apr 2024 17:45:15 +0200 > Subject: [PATCH] fixup! mm, slab: move memcg charging to post-alloc hook > > The call to memcg_alloc_abort_single() is wrong, it expects a pointer to > single object, not an array. > > Reported-by: Aishwarya TCV > Signed-off-by: Vlastimil Babka > --- > mm/slub.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/slub.c b/mm/slub.c > index f5b151a58b7d..b32e79629ae7 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -2100,7 +2100,7 @@ bool memcg_slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru, > return true; > > if (likely(size == 1)) { > - memcg_alloc_abort_single(s, p); > + memcg_alloc_abort_single(s, *p); > *p = NULL; > } else { > kmem_cache_free_bulk(s, size, p); Tested the attached patch on next-20240302. Confirming that the test is running fine. Test run log is attached below. Test run log: -------------- memcg_limit_in_bytes 8 TPASS: process 614 is killed memcg_limit_in_bytes 9 TINFO: Test limit_in_bytes will be aligned to PAGESIZE memcg_limit_in_bytes 9 TPASS: echo 4095 > memory.limit_in_bytes passed as expected memcg_limit_in_bytes 9 TPASS: input=4095, limit_in_bytes=0 memcg_limit_in_bytes 10 TPASS: echo 4097 > memory.limit_in_bytes passed as expected memcg_limit_in_bytes 10 TPASS: input=4097, limit_in_bytes=4096 memcg_limit_in_bytes 11 TPASS: echo 1 > memory.limit_in_bytes passed as expected memcg_limit_in_bytes 11 TPASS: input=1, limit_in_bytes=0 memcg_limit_in_bytes 12 TINFO: Test invalid memory.limit_in_bytes memcg_limit_in_bytes 12 TPASS: echo -1 > memory.limit_in_bytes passed as expected memcg_limit_in_bytes 13 TPASS: echo 1.0 > memory.limit_in_bytes failed as expected memcg_limit_in_bytes 14 TPASS: echo 1xx > memory.limit_in_bytes failed as expected memcg_limit_in_bytes 15 TPASS: echo xx > memory.limit_in_bytes failed as expected Summary: passed 18 failed 0 broken 0 skipped 0 warnings 0 Thanks, Aishwarya