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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4C5EFC433F5 for ; Tue, 3 May 2022 15:26:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B035B6B007D; Tue, 3 May 2022 11:26:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AB2086B0093; Tue, 3 May 2022 11:26:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9529A6B0095; Tue, 3 May 2022 11:26:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id 8632A6B007D for ; Tue, 3 May 2022 11:26:46 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 422772BA8B for ; Tue, 3 May 2022 15:26:46 +0000 (UTC) X-FDA: 79424809212.05.225C52E Received: from mail-pl1-f174.google.com (mail-pl1-f174.google.com [209.85.214.174]) by imf09.hostedemail.com (Postfix) with ESMTP id 33EC4140072 for ; Tue, 3 May 2022 15:26:40 +0000 (UTC) Received: by mail-pl1-f174.google.com with SMTP id d15so15261294plh.2 for ; Tue, 03 May 2022 08:26:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=B6qlSDLxLCXUGUr/KLSuzX/SdSd4Bh+SQDNoC/TYzmE=; b=a9V1c+m8xen4XNysutPq9ZRoIjmYYTYB9zba7iFQsLjRQ5MiUhT5H1qYIaKTKEow5g g9zhI4udB18LnnSUbJC5H1ywxlNfBz4X7yaZ8BADGRV+iRcj0JZq3Fm/qBAO6m68Qut/ AsJU2WGQtlHRz7VNCx51AWV6y2nJwJmwinUnui4K7TiD0ENxQJzmmZjbbVHUjMITpxZT PCeKS+fagLNIbu8JPK0wy/eJA8AJFD7CaTgVx/EbTbJ8xEFAke8CSHQ2Vu1NHxhErYrH VPvsy6+1CXi21U2hs3zBJz6FSetzVDDUjj+SNc5Gp7V9EaORt0dxjzkzNv0W+UQ9i0kd JIvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=B6qlSDLxLCXUGUr/KLSuzX/SdSd4Bh+SQDNoC/TYzmE=; b=Br+UGP08z+4arGMFtOx5eDJl/4E1zV2umg01lnsp7g/LA635GzQGs4v4bv3tAuPxGK oJI1/4Jwxgj/aoYjFlgx7mNkVuK67/wTWuGRw6xDV/DvWbU3pDXm8WPdqXSTDZCXxU7S Mso8G17THrxNy4hpZ8IvYYjTRdrbb6mETkuWK2I32Q+nAuDqWCvveBhlNNKCFD9rdn0r Tk4VhFQe1rufjUbtRxCUk/XXq7pIHvxIDAou03SejMKv1Ps9YL3qIB6LKUp+NN9pZa5D DOlUFIfmvEtUI8gi2XOK2u9jH1GKdFvDeUqbXd161CqetTHFxz7FZi5vXvt7jncbix71 w+Wg== X-Gm-Message-State: AOAM533kCYjymQuUyNIyvlf+Qn8Bpskhs7k9DPSMr50TZZ4NhMaglUJE xVOvz/916HSIZnuSKluJN6o= X-Google-Smtp-Source: ABdhPJwtiCZaJcqzn0puTvFvsxn7j4SOqY0XuNO5Zm+mP9J/jRiQPjvKxr56epNb5EBBYr132XSONQ== X-Received: by 2002:a17:90a:7e94:b0:1da:3b47:b00e with SMTP id j20-20020a17090a7e9400b001da3b47b00emr5365604pjl.222.1651591604398; Tue, 03 May 2022 08:26:44 -0700 (PDT) Received: from google.com ([2620:15c:211:201:8998:54e:9def:1e7c]) by smtp.gmail.com with ESMTPSA id m19-20020a17090a7f9300b001cd60246575sm1489865pjl.17.2022.05.03.08.26.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 May 2022 08:26:43 -0700 (PDT) Date: Tue, 3 May 2022 08:26:42 -0700 From: Minchan Kim To: David Hildenbrand Cc: Andrew Morton , linux-mm , LKML , John Hubbard , John Dias Subject: Re: [PATCH] mm: fix is_pinnable_page against on cma page Message-ID: References: <20220502173558.2510641-1-minchan@kernel.org> <29d0c1c3-a44e-4573-7e7e-32be07544dbe@redhat.com> <08e9855c-395d-f40c-de3d-1ec8b644bfe8@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <08e9855c-395d-f40c-de3d-1ec8b644bfe8@redhat.com> Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=a9V1c+m8; spf=pass (imf09.hostedemail.com: domain of minchan.kim@gmail.com designates 209.85.214.174 as permitted sender) smtp.mailfrom=minchan.kim@gmail.com; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none) X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 33EC4140072 X-Stat-Signature: 6s7fm17ae1qxtkggy8p3cnfx1nxuprc7 X-HE-Tag: 1651591600-92273 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000038, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, May 03, 2022 at 03:15:24AM +0200, David Hildenbrand wrote: > > >>>> However, I assume we have the same issue right now already with > >> ZONE_MOVABLE and MIGRATE_CMA when trying to pin a page residing on these > > > > ZONE_MOVALBE is also changed dynamically? > > > > Sorry, with "same issue" I meant failing to pin if having to migrate and > the page is temporarily unmovable. > > >> there are temporarily unmovable and we fail to migrate. But it would now > >> apply even without ZONE_MOVABLE or MIGRATE_CMA. Hm... > > > > Didn't parse your last mention. > > On a system that neither uses ZONE_MOVABLE nor MIGRATE_CMA we might have > to migrate now when pinning. I don't understand your point. My problem is pin_user_pages with FOLL_LONGTERM. It shouldn't pin a page from ZONE_MOVABLE and cma area without migrating page out of movable zone or CMA area. That's why try_grab_folio checks whether target page stays in those movable areas. However, to check CMA area, is_migrate_cma_page is racy so the FOLL_LONGTERM flag semantic is broken right now. Do you see any problem of the fix? A thing to get some attention is whether we need READ_ONCE or not for the local variable mt.