Return-Path: Received: from one.firstfloor.org ([213.235.205.2]:42582 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752369Ab0HRRup (ORCPT ); Wed, 18 Aug 2010 13:50:45 -0400 Date: Wed, 18 Aug 2010 19:50:40 +0200 From: Andi Kleen To: Neil Brown Cc: "J. Bruce Fields" , Alan Cox , "Patrick J. LoPresti" , Andi Kleen , linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-kernel Subject: Re: Proposal: Use hi-res clock for file timestamps Message-ID: <20100818175040.GA6567@basil.fritz.box> References: <87aaolwar8.fsf@basil.nowhere.org> <20100817174134.GA23176@fieldses.org> <20100817182920.GD18161@basil.fritz.box> <20100817190447.GA28049@fieldses.org> <20100817203941.729830b7@lxorguk.ukuu.org.uk> <20100817192937.GD26609@fieldses.org> <20100818155359.66b9ddb6@notabene> Content-Type: text/plain; charset=us-ascii In-Reply-To: <20100818155359.66b9ddb6@notabene> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 > - nfsd updates it whenever it reads an mtime out of an inode that matches > current_fs_time to the granularity of 1/HZ. That means you have a very very hot cache line on a larger system if there are a lot of mtime changes. Probably a bad idea. -Andi