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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 65E2FC433E0 for ; Wed, 6 Jan 2021 16:12:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F36302312F for ; Wed, 6 Jan 2021 16:12:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F36302312F Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 74CB56B0298; Wed, 6 Jan 2021 11:12:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6FB0D6B029A; Wed, 6 Jan 2021 11:12:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 638716B029B; Wed, 6 Jan 2021 11:12:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0116.hostedemail.com [216.40.44.116]) by kanga.kvack.org (Postfix) with ESMTP id 4A5C96B0298 for ; Wed, 6 Jan 2021 11:12:39 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id C294A180AD811 for ; Wed, 6 Jan 2021 16:12:38 +0000 (UTC) X-FDA: 77675843196.23.moon38_54180d2274e2 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id 9D05337608 for ; Wed, 6 Jan 2021 16:12:38 +0000 (UTC) X-HE-Tag: moon38_54180d2274e2 X-Filterd-Recvd-Size: 2056 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Wed, 6 Jan 2021 16:12:38 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1609949557; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=kKJzb3MOlxSvTvPOfZX83INGa5Pu51ElYOXk9ozMlRg=; b=MtZFWdUlsz4yMYA5uDGxEGeY+iUWLavAZM/D9x6JcWwOoou5yBW3TKZP5ncctO/ExLqR05 9oEXeegkHPs8LyYhsI5JmnF1flIk+uw/8cf23P3x8hjGeFC9wcXx9LzGUWtVsD71KgMuWv 2gpOUQvXFHFWuTOTGKkMuwFe60U7qls= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id D4E31AD75; Wed, 6 Jan 2021 16:12:36 +0000 (UTC) Date: Wed, 6 Jan 2021 17:12:36 +0100 From: Michal Hocko To: Muchun Song Cc: mike.kravetz@oracle.com, akpm@linux-foundation.org, hillf.zj@alibaba-inc.com, n-horiguchi@ah.jp.nec.com, ak@linux.intel.com, yongjun_wei@trendmicro.com.cn, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one Message-ID: <20210106161236.GQ13207@dhcp22.suse.cz> References: <20210104065843.5658-1-songmuchun@bytedance.com> <20210106161135.GP13207@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210106161135.GP13207@dhcp22.suse.cz> 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 Wed 06-01-21 17:11:39, Michal Hocko wrote: > On Mon 04-01-21 14:58:38, Muchun Song wrote: > > If the refcount is one when it is migrated, it means that the page > > was freed from under us. So we are done and do not need to migrate. > > Is this common enough that it would warrant the explicit check for each > migration? Ups, just noticed that you have posted a newer version. I will follow up there. -- Michal Hocko SUSE Labs