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 X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1490C433E0 for ; Wed, 24 Feb 2021 20:39:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 833C864E7A for ; Wed, 24 Feb 2021 20:39:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235825AbhBXUix (ORCPT ); Wed, 24 Feb 2021 15:38:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235808AbhBXUir (ORCPT ); Wed, 24 Feb 2021 15:38:47 -0500 Received: from mail-qk1-x72a.google.com (mail-qk1-x72a.google.com [IPv6:2607:f8b0:4864:20::72a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A33EDC061786 for ; Wed, 24 Feb 2021 12:38:07 -0800 (PST) Received: by mail-qk1-x72a.google.com with SMTP id b14so3613451qkk.0 for ; Wed, 24 Feb 2021 12:38:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=k+Ml1eYPwjOONJLtwcZvZvyigCe2sKPobwXhkk2LCr8=; b=o683AocjgiZ8dTsfbgOPsZ0aNJ93D7mHTzh53sWfdoei5j0GUCUom8CTWS2haEcrTz Etc0lxlpqsu/wejXMugE69CVKPANUh9/hPseekOUrWhEMhp+HxppQ7M5KMfPNpi+8uv6 Pz2E9Ft44GezYCi1smMUl2sf/q2/uIT6JFHyb6POyQmgE90TJJO+qvx9OvOLjRQKQrPP 98KVonZFM0YhzjL/p4lSzkDV2hP53C4rZNzuKz6HucLSusO72qjeKVfWwXEzBL94NV7/ wCsvay/o2YDZeBYyR/5tRu7x7EKdsyXlFM45IJLzvzrmNl71lG8xorzEwLULc3Ys92bd 6NaQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=k+Ml1eYPwjOONJLtwcZvZvyigCe2sKPobwXhkk2LCr8=; b=peieYB+tupDfxH73bps6zUSurL4TGrh7wEct2yUjj1Kmrj2p9AgztR/j5vaX7inN7c R2uXPfr7TqhhUDSAJLcs5ikavaGHCAFVkPYFrGEkTkn83JWxuTcas6CNvnh4CFJTFY1/ bmRT9m3plHTeWniuJkaZrBLbRTdkiOLi2bd1nQRQLnWIyEbhwzUmNjxMxKH7E59PA9n+ t10wunEB7kkUapMt9g/tXGLguUsPqlOHRY/QZnxsEwLuIbimwGFXpsjlArr7lr9WbsYx 6ZkS7W1R7M84tJTxql5GRJW43GmqDZVrp6jgjC254wxQKQSF6WMifYRZIFQVMOiQXTRp ad0Q== X-Gm-Message-State: AOAM5315GT1SgWuBfJ6HNIyYXg4PFerTOLjuJrKQrHsSjZKZGCzaXl5u D1a6XgLMXhjbM94P1DEBAThzAg== X-Google-Smtp-Source: ABdhPJxE7Kk7WVegfW0dA3yem37nnEyNTOTba6gF7TKuZQhgqeiPc6vBrRVVN2Z1PlsTot+hhmq9cA== X-Received: by 2002:ae9:e50c:: with SMTP id w12mr32981266qkf.42.1614199086632; Wed, 24 Feb 2021 12:38:06 -0800 (PST) Received: from localhost (70.44.39.90.res-cmts.bus.ptd.net. [70.44.39.90]) by smtp.gmail.com with ESMTPSA id j20sm2399834qtl.36.2021.02.24.12.38.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Feb 2021 12:38:06 -0800 (PST) Date: Wed, 24 Feb 2021 15:38:05 -0500 From: Johannes Weiner To: Shakeel Butt Cc: David Rientjes , Roman Gushchin , Michal Hocko , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] memcg: enable memcg oom-kill for __GFP_NOFAIL Message-ID: References: <20210223204337.2785120-1-shakeelb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210223204337.2785120-1-shakeelb@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 23, 2021 at 12:43:37PM -0800, Shakeel Butt wrote: > In the era of async memcg oom-killer, the commit a0d8b00a3381 ("mm: > memcg: do not declare OOM from __GFP_NOFAIL allocations") added the code > to skip memcg oom-killer for __GFP_NOFAIL allocations. The reason was > that the __GFP_NOFAIL callers will not enter aync oom synchronization > path and will keep the task marked as in memcg oom. At that time the > tasks marked in memcg oom can bypass the memcg limits and the oom > synchronization would have happened later in the later userspace > triggered page fault. Thus letting the task marked as under memcg oom > bypass the memcg limit for arbitrary time. > > With the synchronous memcg oom-killer (commit 29ef680ae7c21 ("memcg, > oom: move out_of_memory back to the charge path")) and not letting the > task marked under memcg oom to bypass the memcg limits (commit > 1f14c1ac19aa4 ("mm: memcg: do not allow task about to OOM kill to bypass > the limit")), we can again allow __GFP_NOFAIL allocations to trigger > memcg oom-kill. This will make memcg oom behavior closer to page > allocator oom behavior. > > Signed-off-by: Shakeel Butt Acked-by: Johannes Weiner