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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 442EBC433EF for ; Wed, 20 Oct 2021 14:22:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 94B466136F for ; Wed, 20 Oct 2021 14:22:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 94B466136F Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id CD09E6B0071; Wed, 20 Oct 2021 10:22:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C810C6B0072; Wed, 20 Oct 2021 10:22:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B6F296B0073; Wed, 20 Oct 2021 10:22:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0099.hostedemail.com [216.40.44.99]) by kanga.kvack.org (Postfix) with ESMTP id A786A6B0071 for ; Wed, 20 Oct 2021 10:22:01 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 66DD325F24 for ; Wed, 20 Oct 2021 14:22:01 +0000 (UTC) X-FDA: 78717030042.25.3F72411 Received: from relay.sw.ru (relay.sw.ru [185.231.240.75]) by imf27.hostedemail.com (Postfix) with ESMTP id 69C8370000A2 for ; Wed, 20 Oct 2021 14:21:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=Content-Type:MIME-Version:Date:Message-ID:From: Subject; bh=ggO+FpcKH1wkkXlq2EYHdQ27UcwvObsXNymYB1kX5vo=; b=qICVdC1lEfiKYzFU0 8K47Lgduio85XZ6eCdSooKhVX2NtJObrUJsfhOgPRI1/7qkO7qepJK0z71tuX3axsSQsNHaPSDFiO YQxBeX7rWzBQlrSjhah3Y+4HBc3kWbSLYmtHP5nEt0pcUMUyUUPdH3GRLUO+mhlIXrBHEJUdf0+X8 =; Received: from [172.29.1.17] by relay.sw.ru with esmtp (Exim 4.94.2) (envelope-from ) id 1mdCTb-006bzD-13; Wed, 20 Oct 2021 17:21:55 +0300 Subject: Re: [PATCH memcg 2/3] memcg: remove charge forcinig for dying tasks To: Michal Hocko Cc: Johannes Weiner , Vladimir Davydov , Andrew Morton , Roman Gushchin , Uladzislau Rezki , Vlastimil Babka , Shakeel Butt , Mel Gorman , Tetsuo Handa , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel@openvz.org References: <56180e53-b705-b1be-9b60-75e141c8560c@virtuozzo.com> From: Vasily Averin Message-ID: Date: Wed, 20 Oct 2021 17:21:33 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 69C8370000A2 X-Stat-Signature: 64imsyfh56xqpruzn5o1gz6cg98z1jy1 Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=virtuozzo.com header.s=relay header.b=qICVdC1l; spf=pass (imf27.hostedemail.com: domain of vvs@virtuozzo.com designates 185.231.240.75 as permitted sender) smtp.mailfrom=vvs@virtuozzo.com; dmarc=pass (policy=quarantine) header.from=virtuozzo.com X-HE-Tag: 1634739719-760355 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 20.10.2021 15:41, Michal Hocko wrote: > On Wed 20-10-21 15:13:46, Vasily Averin wrote: >> ToDo: should we keep task_is_dying() in mem_cgroup_out_of_memory() ? >> >> Signed-off-by: Vasily Averin >> --- >> mm/memcontrol.c | 20 +++++++------------- >> 1 file changed, 7 insertions(+), 13 deletions(-) >> >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> index 6da5020a8656..74a7379dbac1 100644 >> --- a/mm/memcontrol.c >> +++ b/mm/memcontrol.c >> @@ -239,7 +239,7 @@ enum res_type { >> iter != NULL; \ >> iter = mem_cgroup_iter(NULL, iter, NULL)) >> >> -static inline bool should_force_charge(void) >> +static inline bool task_is_dying(void) >> { >> return tsk_is_oom_victim(current) || fatal_signal_pending(current) || >> (current->flags & PF_EXITING); >> @@ -1575,7 +1575,7 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, >> * A few threads which were not waiting at mutex_lock_killable() can >> * fail to bail out. Therefore, check again after holding oom_lock. >> */ >> - ret = should_force_charge() || out_of_memory(&oc); >> + ret = task_is_dying() || out_of_memory(&oc); > > Why are you keeping the task_is_dying check here? IIRC I have already > pointed out that out_of_memory already has some means to do a bypass > when needed. It was a misunderstanding. I've been waiting for your final decision. I have no good arguments "pro" or strong objection "contra". However, I prefer to keep task_is_dying() so as not to touch other tasks unnecessarily. I can't justify why its removal is necessary, but on the other hand, it shouldn't break anything. I can drop it if you think it's necessary. Thank you, Vasily Averin