Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932595AbZKDVBD (ORCPT ); Wed, 4 Nov 2009 16:01:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757304AbZKDVBC (ORCPT ); Wed, 4 Nov 2009 16:01:02 -0500 Received: from one.firstfloor.org ([213.235.205.2]:36173 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757253AbZKDVBB (ORCPT ); Wed, 4 Nov 2009 16:01:01 -0500 To: Christoph Lameter Cc: KAMEZAWA Hiroyuki , "hugh.dickins@tiscali.co.uk" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Tejun Heo Subject: Re: [MM] Make mm counters per cpu instead of atomic From: Andi Kleen References: Date: Wed, 04 Nov 2009 22:01:05 +0100 In-Reply-To: (Christoph Lameter's message of "Wed, 4 Nov 2009 14:14:41 -0500 (EST)") Message-ID: <87r5se80oe.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/22.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 586 Lines: 18 Christoph Lameter writes: > > One price to pay for these improvements is the need to scan over all percpu > counters when the actual count values are needed. Do you have numbers how costly alloc_percpu() is? I wonder what this does to fork() overhead. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/