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[18.210.29.142]) by smtp-relay.gmail.com with ESMTPS id i2sm1155195otk.4.2019.11.02.09.28.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 02 Nov 2019 09:28:22 -0700 (PDT) X-Relaying-Domain: familie-tometzki.de Received: from freebsd.familie-tometzki.de (localhost [127.0.0.1]) by freebsd.familie-tometzki.de (Postfix) with ESMTP id E4F00278CC; Sat, 2 Nov 2019 17:28:21 +0100 (CET) Date: Sat, 2 Nov 2019 17:28:21 +0100 From: Damian Tometzki To: Konstantin Khlebnikov Cc: linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Michal Hocko Subject: Re: [PATCH] mm/memcontrol: update documentation about invoking oom killer Message-ID: <20191102162821.GB19103@freebsd.familie-tometzki.de> Mail-Followup-To: Konstantin Khlebnikov , linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Michal Hocko References: <157270779336.1961.6528158720593572480.stgit@buzz> <20191102160252.GA19103@freebsd.familie-tometzki.de> <5c85a690-4ed7-91bb-30b5-c40174534a27@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5c85a690-4ed7-91bb-30b5-c40174534a27@yandex-team.ru> User-Agent: Mutt/1.11.4 (2019-03-13) 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: On Sat, 02. Nov 19:14, Konstantin Khlebnikov wrote: > > > On 02/11/2019 19.02, Damian Tometzki wrote: > > On Sat, 02. Nov 18:16, Konstantin Khlebnikov wrote: > >> Since commit 29ef680ae7c2 ("memcg, oom: move out_of_memory back to the > >> charge path") memcg invokes oom killer not only for user page-faults. > >> This means 0-order allocation will either succeed or task get killed. > >> > >> Fixes: 8e675f7af507 ("mm/oom_kill: count global and memory cgroup oom kills") > >> Signed-off-by: Konstantin Khlebnikov > >> --- > >> Documentation/admin-guide/cgroup-v2.rst | 9 +++++++-- > >> 1 file changed, 7 insertions(+), 2 deletions(-) > >> > >> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst > >> index 5361ebec3361..eb47815e137b 100644 > >> --- a/Documentation/admin-guide/cgroup-v2.rst > >> +++ b/Documentation/admin-guide/cgroup-v2.rst > >> @@ -1219,8 +1219,13 @@ PAGE_SIZE multiple when read back. > >> > >> Failed allocation in its turn could be returned into > >> userspace as -ENOMEM or silently ignored in cases like > >> - disk readahead. For now OOM in memory cgroup kills > >> - tasks iff shortage has happened inside page fault. > >> + disk readahead. > >> + > >> + Before 4.19 OOM in memory cgroup killed tasks iff > > Hello Konstantin, > > > > iff --> if :-) > > > > This "iff" is shortened "if and only if". > https://en.wikipedia.org/wiki/If_and_only_if good to know :-) > > > Best regards > > Damian > > > > > >> + shortage has happened inside page fault, random > >> + syscall may fail with ENOMEM or EFAULT. Since 4.19 > >> + failed memory cgroup allocation invokes oom killer and > >> + keeps retrying until it succeeds. > >> > >> This event is not raised if the OOM killer is not > >> considered as an option, e.g. for failed high-order > >>