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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 B85E4C63697 for ; Thu, 26 Nov 2020 16:56:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4A0BB221EB for ; Thu, 26 Nov 2020 16:56:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4A0BB221EB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DC6AE6B0073; Thu, 26 Nov 2020 11:56:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D9C3B6B0074; Thu, 26 Nov 2020 11:56:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CDA786B0075; Thu, 26 Nov 2020 11:56:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0120.hostedemail.com [216.40.44.120]) by kanga.kvack.org (Postfix) with ESMTP id B7F586B0073 for ; Thu, 26 Nov 2020 11:56:49 -0500 (EST) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 7ED171EF1 for ; Thu, 26 Nov 2020 16:56:49 +0000 (UTC) X-FDA: 77527173738.14.wool71_051844b27380 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin14.hostedemail.com (Postfix) with ESMTP id 6300318229835 for ; Thu, 26 Nov 2020 16:56:49 +0000 (UTC) X-HE-Tag: wool71_051844b27380 X-Filterd-Recvd-Size: 2744 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf02.hostedemail.com (Postfix) with ESMTP for ; Thu, 26 Nov 2020 16:56:48 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C1125ACE0; Thu, 26 Nov 2020 16:56:47 +0000 (UTC) Subject: Re: [PATCH 1/3] mm,thp,shmem: limit shmem THP alloc gfp_mask To: Rik van Riel , hughd@google.com Cc: xuyu@linux.alibaba.com, akpm@linux-foundation.org, mgorman@suse.de, aarcange@redhat.com, willy@infradead.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, linux-mm@kvack.org, mhocko@suse.com References: <20201124194925.623931-1-riel@surriel.com> <20201124194925.623931-2-riel@surriel.com> From: Vlastimil Babka Message-ID: <18cea0b2-1037-3276-1d42-2a4adcc129e4@suse.cz> Date: Thu, 26 Nov 2020 17:56:47 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20201124194925.623931-2-riel@surriel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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 11/24/20 8:49 PM, Rik van Riel wrote: > The allocation flags of anonymous transparent huge pages can be controlled > through the files in /sys/kernel/mm/transparent_hugepage/defrag, which can > help the system from getting bogged down in the page reclaim and compaction > code when many THPs are getting allocated simultaneously. > > However, the gfp_mask for shmem THP allocations were not limited by those > configuration settings, and some workloads ended up with all CPUs stuck > on the LRU lock in the page reclaim code, trying to allocate dozens of > THPs simultaneously. > > This patch applies the same configurated limitation of THPs to shmem > hugepage allocations, to prevent that from happening. > > Controlling the gfp_mask of THP allocations through the knobs in > sysfs allows users to determine the balance between how aggressively > the system tries to allocate THPs at fault time, and how much the > application may end up stalling attempting those allocations. > > This way a THP defrag setting of "never" or "defer+madvise" will result > in quick allocation failures without direct reclaim when no 2MB free > pages are available. > > With this patch applied, THP allocations for tmpfs will be a little > more aggressive than today for files mmapped with MADV_HUGEPAGE, > and a little less aggressive for files that are not mmapped or > mapped without that flag. > > Signed-off-by: Rik van Riel Acked-by: Vlastimil Babka