From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752110AbbD0CtH (ORCPT ); Sun, 26 Apr 2015 22:49:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40920 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751909AbbD0CtG (ORCPT ); Sun, 26 Apr 2015 22:49:06 -0400 Message-ID: <553DA395.803@redhat.com> Date: Sun, 26 Apr 2015 22:48:53 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Mel Gorman , Linux-MM CC: Hugh Dickins , Minchan Kim , Dave Hansen , Andi Kleen , LKML 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: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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