From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f200.google.com (mail-wj0-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id 7F02B6B0038 for ; Fri, 30 Dec 2016 09:08:41 -0500 (EST) Received: by mail-wj0-f200.google.com with SMTP id n3so43038950wjy.6 for ; Fri, 30 Dec 2016 06:08:41 -0800 (PST) Received: from outbound-smtp08.blacknight.com (outbound-smtp08.blacknight.com. [46.22.139.13]) by mx.google.com with ESMTPS id kr2si62279838wjc.288.2016.12.30.06.08.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 30 Dec 2016 06:08:40 -0800 (PST) Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp08.blacknight.com (Postfix) with ESMTPS id CFBBA1C1398 for ; Fri, 30 Dec 2016 14:08:39 +0000 (GMT) Date: Fri, 30 Dec 2016 14:08:39 +0000 From: Mel Gorman Subject: Re: [patch] mm, thp: always direct reclaim for MADV_HUGEPAGE even when deferred Message-ID: <20161230140839.qg3maz4ifyf7nwgq@techsingularity.net> References: <20161222100009.GA6055@dhcp22.suse.cz> <20161230123620.jcuquzof3bpxomdn@techsingularity.net> <20161230125615.GH13301@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20161230125615.GH13301@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: David Rientjes , Andrew Morton , Jonathan Corbet , "Kirill A. Shutemov" , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Fri, Dec 30, 2016 at 01:56:16PM +0100, Michal Hocko wrote: > On Fri 30-12-16 12:36:20, Mel Gorman wrote: > [...] > > I'll neither ack nor nak this patch. However, I would much prefer an > > additional option be added to sysfs called defer-fault that would avoid > > all fault-based stalls but still potentially stall for MADV_HUGEPAGE. > > Would you consider changing the semantic of defer=madvise to invoke > KSWAPD for !madvised vmas as acceptable. It would be a change in > semantic but I am wondering what would be a risk and potential > regression space. > I'd worry a little, but not a lot. The concern would be that kswapd waking up would reclaim pages and cause major faults that would have remained resident with the current semantics. -- 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