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, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8051EC433DB for ; Thu, 28 Jan 2021 21:38:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 25E4764DD8 for ; Thu, 28 Jan 2021 21:38:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231378AbhA1ViR (ORCPT ); Thu, 28 Jan 2021 16:38:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:35880 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229677AbhA1ViP (ORCPT ); Thu, 28 Jan 2021 16:38:15 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C20F064DD8; Thu, 28 Jan 2021 21:37:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1611869854; bh=PduBNW8cMfaTTP3RvrDhtDpwFami5KR30wb6tkJcODI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=p7GDh/fK8k5tGcOJocJr1cWChrHNE8GeXPhRP6prTO+tLEBZviBoh4SEpKEu0lOeM cH4RFgVrc8J/fD7ukA+pDnIwi45bLagoKoeP72V7ldoACFGnX+cML3tD6l2+yGqIVQ FChBUSsQnf2c+bA8amD1up7bWwCK77zcweeOXDMU= Date: Thu, 28 Jan 2021 13:37:33 -0800 From: Andrew Morton To: Oscar Salvador Cc: Mike Kravetz , Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Naoya Horiguchi , Muchun Song , David Hildenbrand , Matthew Wilcox , Miaohe Lin Subject: Re: [PATCH v3 3/5] hugetlb: only set HPageMigratable for migratable hstates Message-Id: <20210128133733.ce1fb2eac98ab5696c08f288@linux-foundation.org> In-Reply-To: <20210128055221.GA3166@localhost.localdomain> References: <20210122195231.324857-1-mike.kravetz@oracle.com> <20210122195231.324857-4-mike.kravetz@oracle.com> <20210127103523.GI827@dhcp22.suse.cz> <2196d93e-f573-7163-183e-0ad2cec7555e@oracle.com> <20210128055221.GA3166@localhost.localdomain> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 28 Jan 2021 06:52:21 +0100 Oscar Salvador wrote: > On Wed, Jan 27, 2021 at 03:36:41PM -0800, Mike Kravetz wrote: > > Yes, this patch is somewhat optional. It should be a minor improvement > > in cases where we are dealing with hpages in a non-migratable hstate. > > Although, I do not believe this is the common case. > > > > The real reason for even looking into this was a comment by Oscar. With > > the name change to HPageMigratable, it implies that the page is migratable. > > However, this is not the case if the page's hstate does not support migration. > > So, if we check the hstate when setting the flag we can eliminate those > > cases where the page is certainly not migratable. > > > > I don't really love this patch. It has minimal functional value. > > > > Oscar, what do you think about dropping this? > > Yeah, I remember this topic arose during a discussion of patch#2 in the > early versions, about whether the renaming to HPageMigratable made > sense. > > Back then I thought that we could have this in one place at fault-path [1], > which should have made this prettier, but it is not the case. > True is that the optimization is little, so I am fine with dropping this > patch. I've dropped it. > unmap_and_move_huge_page() fences off pages belonging to non-migratable > hstates. > > [1] https://patchwork.kernel.org/project/linux-mm/patch/20210120013049.311822-3-mike.kravetz@oracle.com/#23914033