From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id 3EF286B0069 for ; Mon, 17 Nov 2014 16:33:57 -0500 (EST) Received: by mail-pa0-f54.google.com with SMTP id hz1so11906053pad.13 for ; Mon, 17 Nov 2014 13:33:57 -0800 (PST) Received: from relay.sgi.com (relay2.sgi.com. [192.48.180.65]) by mx.google.com with ESMTP id gg1si36045566pbc.237.2014.11.17.13.33.55 for ; Mon, 17 Nov 2014 13:33:56 -0800 (PST) Date: Mon, 17 Nov 2014 15:34:15 -0600 From: Alex Thorlton Subject: Re: [PATCH 0/4] Convert khugepaged to a task_work function Message-ID: <20141117213415.GU21147@sgi.com> References: <1414032567-109765-1-git-send-email-athorlton@sgi.com> <87lho0pf4l.fsf@tassilo.jf.intel.com> <544F9302.4010001@redhat.com> <544FB8A8.1090402@redhat.com> <5453F0A4.4090708@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5453F0A4.4090708@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: Rik van Riel , Andi Kleen , Alex Thorlton , linux-mm@kvack.org, Andrew Morton , Bob Liu , David Rientjes , "Eric W. Biederman" , Hugh Dickins , Ingo Molnar , Kees Cook , "Kirill A. Shutemov" , Mel Gorman , Oleg Nesterov , Peter Zijlstra , Thomas Gleixner , Vladimir Davydov , linux-kernel@vger.kernel.org On Fri, Oct 31, 2014 at 09:27:16PM +0100, Vlastimil Babka wrote: > What could help would be to cache one or few free huge pages per > zone with cache > re-fill done asynchronously, e.g. via work queues. The cache could > benefit fault-THP > allocations as well. And adding some logic that if nobody uses the > cached pages and > memory is low, then free them. And importantly, if it's not possible > to allocate huge > pages for the cache, then prevent scanning for collapse candidates > as there's no point. > (well this is probably more complex if some nodes can allocate huge > pages and others > not). I think this would be a pretty cool addition, even separately from this effort. If we keep a page cached on each NUMA node, then we could, theoretically, really speed up the khugepaged scans (even if we don't move those scans to task_work), and regular THP faults. I'll add it to my ever-growing wish list :) - Alex -- 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