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 9268BC433EF for ; Tue, 25 Jan 2022 18:35:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C5C2F6B0074; Tue, 25 Jan 2022 13:35:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C0B256B0075; Tue, 25 Jan 2022 13:35:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AD33C6B007B; Tue, 25 Jan 2022 13:35:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0001.hostedemail.com [216.40.44.1]) by kanga.kvack.org (Postfix) with ESMTP id 9AE976B0074 for ; Tue, 25 Jan 2022 13:35:45 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 5648190F59 for ; Tue, 25 Jan 2022 18:35:45 +0000 (UTC) X-FDA: 79069663050.21.57C890B Received: from mail-pl1-f179.google.com (mail-pl1-f179.google.com [209.85.214.179]) by imf12.hostedemail.com (Postfix) with ESMTP id 9B4094000B for ; Tue, 25 Jan 2022 18:35:44 +0000 (UTC) Received: by mail-pl1-f179.google.com with SMTP id u11so20187462plh.13 for ; Tue, 25 Jan 2022 10:35:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=l7lUxEYolU+vrePYlAdUz/HMspuBnKr+CPn2t+D6Als=; b=adDbN80v/yzdqXnlwhZG3lQu7WKIfcd43UuporRcdZ1YPGKtpqXMKQm5lPnUmkHfK9 GDpAht3amkKBrP7qYMMvXj6cTfUu2snK8ZAl5vys28r3PpApO27dZgnd1uhFDZvrZYWd QexX9WrZTVjkgnSNDCK1nC/5idOUOacS0EDbleqhmiADSHze5p6JHos9r+wHATkn8P6o ZtTAXy8dzcZrlEe9ykSCDmN1qm4e3G40XonL5l+3KsIO2VUzekWGAhs3Drs3vOTjAJpL QfIsGCOVrhvkw3YgHu/y9nmmha2rI2D2JW9juIGPKSJueKv1D/P9oMb72qj9iQjpCm+K J+ag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=l7lUxEYolU+vrePYlAdUz/HMspuBnKr+CPn2t+D6Als=; b=NxJEiBc+qWlxHvQFl/HwA/izusIdU3WrHRaNb0cgRuuG5CS9GnE8AAg4BAFhyl+Eb2 EigD47lSwNlqCdKMpEeh2AYnF8y5L8afgiZxeeZVmV5Bb9KJoGxlsOjhVxv5x9kKErNN b4I4VGGwFKQu3I9a31uS4ZCy4UYmxzdePzF+ckphIyp8xmSltJ3nB2GFavH/aIvA/nFt a1f0t+LmI9x4AtWVXlwx401FWrJwWZ9/CO2m915IMi1MqtIus42DxjrNDcZuM3bTQZ+/ 1gjEIoFFVxPTKebB+kf3QVnLwUGzFMnXBJkKbqOi6tyMtCYRweMPjz6oty9rngcBBppR ijWA== X-Gm-Message-State: AOAM533zxAYsOXUNgqMYHWP2gN/AaGhj5G3JfgbyahAVxBBoyjFV+P5s eqETBOzekHblA8yCt275aRVZ/g== X-Google-Smtp-Source: ABdhPJw2yz0Lh1lxSqIHUG23Q4Ja1K10CXmGKanA/NSaFg52LBMwChb0J9jkka0yAdXUSotlq4JdbQ== X-Received: by 2002:a17:902:8695:b0:149:cb5d:ddf1 with SMTP id g21-20020a170902869500b00149cb5dddf1mr20526862plo.103.1643135743371; Tue, 25 Jan 2022 10:35:43 -0800 (PST) Received: from [2620:15c:29:204:6f7a:fc02:d37c:a8b0] ([2620:15c:29:204:6f7a:fc02:d37c:a8b0]) by smtp.gmail.com with ESMTPSA id b9sm20373466pfm.154.2022.01.25.10.35.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Jan 2022 10:35:42 -0800 (PST) Date: Tue, 25 Jan 2022 10:35:42 -0800 (PST) From: David Rientjes To: Shakeel Butt cc: Jens Axboe , Pavel Begunkov , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, io-uring@vger.kernel.org Subject: Re: [PATCH] mm: io_uring: allow oom-killer from io_uring_setup In-Reply-To: <20220125051736.2981459-1-shakeelb@google.com> Message-ID: <2bec4db-1533-2d39-77f9-bf613fc262d9@google.com> References: <20220125051736.2981459-1-shakeelb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 9B4094000B X-Stat-Signature: sbwpkri1igq8hzc5uxm165rjw1en9ksi Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=adDbN80v; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf12.hostedemail.com: domain of rientjes@google.com designates 209.85.214.179 as permitted sender) smtp.mailfrom=rientjes@google.com X-Rspam-User: nil X-HE-Tag: 1643135744-187641 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 Mon, 24 Jan 2022, Shakeel Butt wrote: > On an overcommitted system which is running multiple workloads of > varying priorities, it is preferred to trigger an oom-killer to kill a > low priority workload than to let the high priority workload receiving > ENOMEMs. On our memory overcommitted systems, we are seeing a lot of > ENOMEMs instead of oom-kills because io_uring_setup callchain is using > __GFP_NORETRY gfp flag which avoids the oom-killer. Let's remove it and > allow the oom-killer to kill a lower priority job. > What is the size of the allocations that io_mem_alloc() is doing? If get_order(size) > PAGE_ALLOC_COSTLY_ORDER, then this will fail even without the __GFP_NORETRY. To make the guarantee that workloads are not receiving ENOMEM, it seems like we'd need to guarantee that allocations going through io_mem_alloc() are sufficiently small. (And if we're really serious about it, then even something like a BUILD_BUG_ON().) > Signed-off-by: Shakeel Butt > --- > fs/io_uring.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index e54c4127422e..d9eeb202363c 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -8928,10 +8928,9 @@ static void io_mem_free(void *ptr) > > static void *io_mem_alloc(size_t size) > { > - gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP | > - __GFP_NORETRY | __GFP_ACCOUNT; > + gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP; > > - return (void *) __get_free_pages(gfp_flags, get_order(size)); > + return (void *) __get_free_pages(gfp, get_order(size)); > } > > static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries, > -- > 2.35.0.rc0.227.g00780c9af4-goog > > >