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 4663FC433E0 for ; Tue, 26 Jan 2021 06:36:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1DBDA206F7 for ; Tue, 26 Jan 2021 06:36:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388571AbhAZGgk (ORCPT ); Tue, 26 Jan 2021 01:36:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729456AbhAYO3m (ORCPT ); Mon, 25 Jan 2021 09:29:42 -0500 Received: from mail-qt1-x832.google.com (mail-qt1-x832.google.com [IPv6:2607:f8b0:4864:20::832]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F505C0617A7 for ; Mon, 25 Jan 2021 06:28:21 -0800 (PST) Received: by mail-qt1-x832.google.com with SMTP id z9so9750948qtv.6 for ; Mon, 25 Jan 2021 06:28:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=gqrob1newlkQ15lRtU6auZ3RzaABmYXA8xpX2IglXFQ=; b=dGX57SKqFdpXq5Em8dpxESukUDK+OYiiN20VisCm8Wi+VFYCGEzLwzJQYwF1wsuX7r WjZJwHEvgvYAc4oAicLOOCAwPegzkAoCSLgLXVDWCGsrbRKY+vMoGhqIDIm/qcF3wyoX b+hwihpHfWpDuJsB4/bB0oipat6DwE7Oql4xR1XMqYNVs6VvbUXm35h4WKvxzkvcdadX kUDDTyr/b3yOo8C+AyPndWjFIf3sK4ivPmbG2qSZvbKM6s6BdVRmMkx02qk4qz5cKkBh 0E5bdtMqcDbzuKXs/tLLt3dvNzJfdlDzLp1x5LEheVzj+HrgZHJimVBItPJDW19vNXXO 8y2w== 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=gqrob1newlkQ15lRtU6auZ3RzaABmYXA8xpX2IglXFQ=; b=g2ecFhJq9hh+KNWQaTzkip0QvRJZvhMdQ8N93NBUkTZK/HtT/DMBuKOylq6EvBuVdD dpIBvi/Sks9SH6eeALdu0j2D9WB2QAuC9ErEBPbJVNkcWh3Lywyp65CopH+8hVeFIri3 M0wkLrXTxzJL01Aw2oq2H/q3pxQQ8G3EBiAdtgWDpHgtsUbJcEbpTMlqM4YXzrvQ6Cr0 71I/WmlDqpeacNHZwS4Ylu9Sxxf/forHRPaSpwEAlCqQM2/RrDlnkmMzWnCiNRhBlBGH 7qsp00uxnYCSMaHScTXVMeRA9I86gC67ZDFtHsbjLCGjbpStheFpkk64IB+ym8vxF8N/ B3jw== X-Gm-Message-State: AOAM5303jFZXcAKAfgQiZZZbRqmWiLC2nWyB+w6MHwmwgly6eTus4UR+ 9jkAAZxG8r3pS/rFPPqnlHdfEw== X-Google-Smtp-Source: ABdhPJzF2m7RRft4yyKJebF8jzkPIF+Jv8HIYEWXVMaMo2dw3cdqZZG9ubwMIkYD4CRazbEmFlt1hg== X-Received: by 2002:ac8:6edd:: with SMTP id f29mr654427qtv.213.1611584900594; Mon, 25 Jan 2021 06:28:20 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-115-133.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.115.133]) by smtp.gmail.com with ESMTPSA id m64sm12086816qkb.90.2021.01.25.06.28.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Jan 2021 06:28:20 -0800 (PST) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1l42qp-006Vxe-HI; Mon, 25 Jan 2021 10:28:19 -0400 Date: Mon, 25 Jan 2021 10:28:19 -0400 From: Jason Gunthorpe To: Pavel Tatashin Cc: LKML , linux-mm , Andrew Morton , Vlastimil Babka , Michal Hocko , David Hildenbrand , Oscar Salvador , Dan Williams , Sasha Levin , Tyler Hicks , Joonsoo Kim , mike.kravetz@oracle.com, Steven Rostedt , Ingo Molnar , Peter Zijlstra , Mel Gorman , Matthew Wilcox , David Rientjes , John Hubbard , Linux Doc Mailing List , Ira Weiny , linux-kselftest@vger.kernel.org Subject: Re: [PATCH v6 08/14] mm/gup: do not migrate zero page Message-ID: <20210125142819.GU4605@ziepe.ca> References: <20210120014333.222547-1-pasha.tatashin@soleen.com> <20210120014333.222547-9-pasha.tatashin@soleen.com> <20210120131400.GF4605@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 20, 2021 at 09:26:41AM -0500, Pavel Tatashin wrote: > I thought about this, and it would code a little cleaner. But, the > reason I did not is because zero_page is perfectly pinnable, it is not > pinnable only when it is in a movable zone (and it should not be in a > movable zones for other reasons as well), but that is another bug that > needs to be resolved, and once that bug is resolved this condition can > be removed from gup migration. My point is you've defined the zero page to be pinnable no matter what zone it is in, so is_pinnable(zero_page) == true Jason