From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: Re: [PATCH 01/17] mm: page_alloc: Do not update zlc unless the zlc is active Date: Thu, 1 May 2014 09:25:20 -0400 Message-ID: <20140501132520.GC23420@cmpxchg.org> References: <1398933888-4940-1-git-send-email-mgorman@suse.de> <1398933888-4940-2-git-send-email-mgorman@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linux-MM , Linux-FSDevel , Vlastimil Babka , Jan Kara , Michal Hocko , Hugh Dickins , Linux Kernel To: Mel Gorman Return-path: Content-Disposition: inline In-Reply-To: <1398933888-4940-2-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Thu, May 01, 2014 at 09:44:32AM +0100, Mel Gorman wrote: > The zlc is used on NUMA machines to quickly skip over zones that are full. > However it is always updated, even for the first zone scanned when the > zlc might not even be active. As it's a write to a bitmap that potentially > bounces cache line it's deceptively expensive and most machines will not > care. Only update the zlc if it was active. > > Signed-off-by: Mel Gorman Acked-by: Johannes Weiner -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753379AbaEANZ1 (ORCPT ); Thu, 1 May 2014 09:25:27 -0400 Received: from zene.cmpxchg.org ([85.214.230.12]:60065 "EHLO zene.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750741AbaEANZ0 (ORCPT ); Thu, 1 May 2014 09:25:26 -0400 Date: Thu, 1 May 2014 09:25:20 -0400 From: Johannes Weiner To: Mel Gorman Cc: Linux-MM , Linux-FSDevel , Vlastimil Babka , Jan Kara , Michal Hocko , Hugh Dickins , Linux Kernel Subject: Re: [PATCH 01/17] mm: page_alloc: Do not update zlc unless the zlc is active Message-ID: <20140501132520.GC23420@cmpxchg.org> References: <1398933888-4940-1-git-send-email-mgorman@suse.de> <1398933888-4940-2-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1398933888-4940-2-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 01, 2014 at 09:44:32AM +0100, Mel Gorman wrote: > The zlc is used on NUMA machines to quickly skip over zones that are full. > However it is always updated, even for the first zone scanned when the > zlc might not even be active. As it's a write to a bitmap that potentially > bounces cache line it's deceptively expensive and most machines will not > care. Only update the zlc if it was active. > > Signed-off-by: Mel Gorman Acked-by: Johannes Weiner