From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751146Ab2A2FRc (ORCPT ); Sun, 29 Jan 2012 00:17:32 -0500 Received: from mga14.intel.com ([143.182.124.37]:65108 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1749667Ab2A2FRa (ORCPT ); Sun, 29 Jan 2012 00:17:30 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="100765246" Date: Sun, 29 Jan 2012 13:07:22 +0800 From: Wu Fengguang To: Andrew Morton Cc: Christoph Lameter , Andi Kleen , Ingo Molnar , Jens Axboe , Peter Zijlstra , Rik van Riel , Linux Memory Management List , linux-fsdevel@vger.kernel.org, LKML Subject: Re: [PATCH 6/9] readahead: add /debug/readahead/stats Message-ID: <20120129050722.GC26244@localhost> References: <20120127030524.854259561@intel.com> <20120127031327.159293683@intel.com> <20120127121551.acd256aa.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120127121551.acd256aa.akpm@linux-foundation.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 27, 2012 at 12:15:51PM -0800, Andrew Morton wrote: > > The accounting code will be compiled in by default > > (CONFIG_READAHEAD_STATS=y), and will remain inactive by default. > > I agree with those choices. They effectively mean that the stats will > be a developer-only/debugger-only thing. So even if the atomic_inc() > costs are measurable during these develop/debug sessions, is anyone > likely to care? Sorry I have changed the default to CONFIG_READAHEAD_STATS=n to avoid bloating the kernel (and forgot to edit the changelog accordingly). I'm not sure how many people are going to check the readahead stats. Thanks, Fengguang