From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f199.google.com (mail-wj0-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id 5DC196B0033 for ; Mon, 6 Feb 2017 17:26:44 -0500 (EST) Received: by mail-wj0-f199.google.com with SMTP id c7so21510529wjb.7 for ; Mon, 06 Feb 2017 14:26:44 -0800 (PST) Received: from outbound-smtp03.blacknight.com (outbound-smtp03.blacknight.com. [81.17.249.16]) by mx.google.com with ESMTPS id g109si2594784wrd.9.2017.02.06.14.26.43 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 06 Feb 2017 14:26:43 -0800 (PST) Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp03.blacknight.com (Postfix) with ESMTPS id E7EA298B1E for ; Mon, 6 Feb 2017 22:26:42 +0000 (UTC) Date: Mon, 6 Feb 2017 22:26:42 +0000 From: Mel Gorman Subject: Re: [PATCH] mm/autonuma: don't use set_pte_at when updating protnone ptes Message-ID: <20170206222642.u2e5ip4h2udaehr4@techsingularity.net> References: <1486400776-28114-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1486400776-28114-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Aneesh Kumar K.V" Cc: akpm@linux-foundation.org, Rik van Riel , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Mon, Feb 06, 2017 at 10:36:16PM +0530, Aneesh Kumar K.V wrote: > Architectures like ppc64, use privilege access bit to mark pte non accessible. > This implies that kernel can do a copy_to_user to an address marked for numa fault. > This also implies that there can be a parallel hardware update for the pte. > set_pte_at cannot be used in such scenarios. Hence switch the pte > update to use ptep_get_and_clear and set_pte_at combination. > > Signed-off-by: Aneesh Kumar K.V Yeah, ok. The main thing is that it still avoids doing an unnecessary TLB flush so Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org