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 6583DC433E0 for ; Tue, 12 Jan 2021 14:23:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BF17E23122 for ; Tue, 12 Jan 2021 14:23:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF17E23122 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 B894F6B013D; Tue, 12 Jan 2021 09:23:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B39B76B016B; Tue, 12 Jan 2021 09:23:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A262A6B017A; Tue, 12 Jan 2021 09:23:42 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0147.hostedemail.com [216.40.44.147]) by kanga.kvack.org (Postfix) with ESMTP id 88AB86B013D for ; Tue, 12 Jan 2021 09:23:42 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 4BA21181AC1F5 for ; Tue, 12 Jan 2021 14:23:42 +0000 (UTC) X-FDA: 77697341484.26.smell10_3807f9f27516 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id 289FF1804B640 for ; Tue, 12 Jan 2021 14:23:42 +0000 (UTC) X-HE-Tag: smell10_3807f9f27516 X-Filterd-Recvd-Size: 2589 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf37.hostedemail.com (Postfix) with ESMTP for ; Tue, 12 Jan 2021 14:23:41 +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=1610461420; 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=Xq1aHA8mbrEMaD5Ve0Fl96EfFqk/5ogr68Z+fQaO8D0=; b=rUyrJvvcNbludVlUMXKtBj3FaVcKKFoarrUICH/TobbkfNZkK39iW75Q5mw6kJSYFlMv4C +y7k9AL7Bkw4C24ytYRjCo3wyfRfly53q4h6kkVvkpGMxSlAXrcVjXCX03QFH04c/Idxyc GaJB/Xwnvn1U5zgx6D/kdpigldIaG28= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 55864ABD6; Tue, 12 Jan 2021 14:23:40 +0000 (UTC) Date: Tue, 12 Jan 2021 15:23:37 +0100 From: Michal Hocko To: David Hildenbrand Cc: Muchun Song , mike.kravetz@oracle.com, akpm@linux-foundation.org, n-horiguchi@ah.jp.nec.com, ak@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yang Shi Subject: Re: [PATCH v3 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one Message-ID: <20210112142337.GR22493@dhcp22.suse.cz> References: <20210110124017.86750-1-songmuchun@bytedance.com> <20210110124017.86750-2-songmuchun@bytedance.com> <1b39d654-0b8c-de3a-55d1-6ab8c2b2e0ba@redhat.com> <20210112112709.GO22493@dhcp22.suse.cz> <20210112121643.GP22493@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210112121643.GP22493@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 Tue 12-01-21 13:16:45, Michal Hocko wrote: [...] > Well, currently pool pages are not migrateable but you are right that > this is likely something that we will need to look into in the future > and this optimization would stand in the way. After some more thinking I believe I was wrong in my last statement. This optimization shouldn't have any effect on pages on the pool as those stay at reference count 0 and they cannot be isolated either (clear_page_huge_active before it is enqueued). That being said, the migration code would still have to learn about about this pages but that is out of scope of this discussion. Sorry about the confusion from my side. -- Michal Hocko SUSE Labs