From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762554AbXHNWYB (ORCPT ); Tue, 14 Aug 2007 18:24:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761493AbXHNWVy (ORCPT ); Tue, 14 Aug 2007 18:21:54 -0400 Received: from one.firstfloor.org ([213.235.205.2]:39329 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936005AbXHNWVw (ORCPT ); Tue, 14 Aug 2007 18:21:52 -0400 Date: Wed, 15 Aug 2007 00:21:50 +0200 From: Andi Kleen To: Christoph Lameter Cc: Andi Kleen , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC 4/9] Atomic reclaim: Save irq flags in vmscan.c Message-ID: <20070814222150.GI23308@one.firstfloor.org> References: <20070814212355.GA23308@one.firstfloor.org> <20070814212955.GC23308@one.firstfloor.org> <20070814214430.GD23308@one.firstfloor.org> <20070814215659.GF23308@one.firstfloor.org> <20070814221616.GG23308@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Ok I have a vague idea on how this could but its likely that the > changes make things worse rather than better. Additional reference to a > new cacheline (per cpu but still), preempt disable. Lots of code at all > call sites. Interrupt enable/disable is quite efficient in recent > processors. The goal of this was not to be faster than interrupt disable, but to avoid the interrupt latency impact. This might be a problem when spending a lot of time inside the locks. -Andi