From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vn0-f51.google.com (mail-vn0-f51.google.com [209.85.216.51]) by kanga.kvack.org (Postfix) with ESMTP id C6AA26B0038 for ; Sun, 26 Apr 2015 22:49:07 -0400 (EDT) Received: by vnbf129 with SMTP id f129so10371640vnb.9 for ; Sun, 26 Apr 2015 19:49:07 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id rn8si27940731vdb.105.2015.04.26.19.49.06 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 26 Apr 2015 19:49:07 -0700 (PDT) Message-ID: <553DA395.803@redhat.com> Date: Sun, 26 Apr 2015 22:48:53 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 2/3] mm: Send one IPI per CPU to TLB flush multiple pages that were recently unmapped References: <1429983942-4308-1-git-send-email-mgorman@suse.de> <1429983942-4308-3-git-send-email-mgorman@suse.de> In-Reply-To: <1429983942-4308-3-git-send-email-mgorman@suse.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman , Linux-MM Cc: Hugh Dickins , Minchan Kim , Dave Hansen , Andi Kleen , LKML On 04/25/2015 01:45 PM, Mel Gorman wrote: > An IPI is sent to flush remote TLBs when a page is unmapped that was > recently accessed by other CPUs. There are many circumstances where this > happens but the obvious one is kswapd reclaiming pages belonging to a > running process as kswapd and the task are likely running on separate CPUs. > It's still a noticeable improvement with vmstat showing interrupts went > from roughly 500K per second to 45K per second. > > The patch will have no impact on workloads with no memory pressure or > have relatively few mapped pages. > > Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel -- All rights reversed -- 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