Received: by 2002:ad5:474a:0:0:0:0:0 with SMTP id i10csp1669224imu; Tue, 20 Nov 2018 23:32:50 -0800 (PST) X-Google-Smtp-Source: AJdET5eOpMFiolaeEBvslh5MW6HjoQp10tqOshmw5eaK8KuhPTrbqKVxXpFzfEDx5h9QwHf5rhYJ X-Received: by 2002:a62:5ac3:: with SMTP id o186-v6mr5854867pfb.40.1542785570947; Tue, 20 Nov 2018 23:32:50 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1542785570; cv=none; d=google.com; s=arc-20160816; b=RDcExR62ns9MTHgH61HrldMgNDIcFC3ISnE9Yp7oYxUo8/gcilvpkINA4m8HBSFnRn EFLY6uFK8RG9/l7u+mpEQwNDx/MXB2CZ4bu1LbeVN1dx95uKRjLxed+XHz6B7+RpA1gh 1iuYKcb9QatGR5NiGY8IfgH6xX3lPgk1XNv2utbTSEx07rfcypooPYj9awZD4jHYcF0p nhDasmb0/3xZsSQdHDKPZzXXyn9DrdYqgEboU/vMwv/fb3SrxoDWL/qvEQdHHKq+yzvN GysYucQXpEyHyrCxbf644hGxP0G0hRzu5sr6Rfl7mWNY5m5RVfpQ3orqa+pEpbdf4KUn KdXw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date; bh=ARq90Zq2NRuo5SzjTrdtx0AhEq1e6cOCn9o8qBiw6Yg=; b=tfp+ImdymmIB6MNxHJ1+QBaqSyUJp3CV4OPEYRhRt5jK4YFRFSMhJEFUdFcZxYmrFx 7BaXlAXDDAUqLQsKnR/2JiI2jDtv53J0YE264hsnelziyzz+7dpwlWEak2lzqrYhMb/i 6fu8pkjzjrzA6wumT7yoC3b1aN3ftuejTpomCrkeqexDwb3dTk52o6l43GsicjtJyNVB vdNQgMYPkYUQMMfAW9A1c2+At70J8hapbwnFX9a93vzg1c4pnauFiCBtaCp4OnRYkgAm uhJZhOu/av0ryIP5xTGnRPsZoCyw1crrEzSmI3cfgCJpwQraIuQ9WNVb7JsY4e74iY0h QHXQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id j7si10159364plb.91.2018.11.20.23.32.34; Tue, 20 Nov 2018 23:32:50 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726550AbeKURkq (ORCPT + 99 others); Wed, 21 Nov 2018 12:40:46 -0500 Received: from mx2.suse.de ([195.135.220.15]:58358 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725999AbeKURkq (ORCPT ); Wed, 21 Nov 2018 12:40:46 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 7A023ACB4; Wed, 21 Nov 2018 07:07:27 +0000 (UTC) Date: Wed, 21 Nov 2018 08:07:26 +0100 From: Michal Hocko To: William Kucharski Cc: "Kirill A. Shutemov" , Linux-MM , Andrew Morton , Oscar Salvador , Pavel Tatashin , David Hildenbrand , LKML Subject: Re: [RFC PATCH 3/3] mm, fault_around: do not take a reference to a locked page Message-ID: <20181121070726.GC12932@dhcp22.suse.cz> References: <20181120134323.13007-1-mhocko@kernel.org> <20181120134323.13007-4-mhocko@kernel.org> <20181120140715.mouc7okin3ht5krr@kshutemo-mobl1> <20181120141207.GK22247@dhcp22.suse.cz> <29F15A96-D6EB-450E-B54B-A4CB460ED9B3@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <29F15A96-D6EB-450E-B54B-A4CB460ED9B3@oracle.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 20-11-18 21:51:39, William Kucharski wrote: > > > > On Nov 20, 2018, at 7:12 AM, Michal Hocko wrote: > > > > + /* > > + * Check the locked pages before taking a reference to not > > + * go in the way of migration. > > + */ > > Could you make this a tiny bit more explanative, something like: > > + /* > + * Check for a locked page first, as a speculative > + * reference may adversely influence page migration. > + */ sure > > Reviewed-by: William Kucharski Thanks! -- Michal Hocko SUSE Labs