From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Nieder Subject: Re: [PATCH 1/2] Use git_open_noatime when accessing pack data Date: Thu, 4 Nov 2010 00:04:37 -0500 Message-ID: <20101104050437.GB15018@burratino> References: <1288652061-19614-1-git-send-email-spearce@spearce.org> <1288652061-19614-2-git-send-email-spearce@spearce.org> <7v8w1axrnp.fsf@alter.siamese.dyndns.org> <20101103174148.GB13377@burratino> <7vvd4ew687.fsf@alter.siamese.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Shawn O. Pearce" , git@vger.kernel.org To: Junio C Hamano X-From: git-owner@vger.kernel.org Thu Nov 04 06:05:46 2010 Return-path: Envelope-to: gcvg-git-2@lo.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1PDs1A-0000Wn-8K for gcvg-git-2@lo.gmane.org; Thu, 04 Nov 2010 06:05:44 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753207Ab0KDFFB (ORCPT ); Thu, 4 Nov 2010 01:05:01 -0400 Received: from mail-yw0-f46.google.com ([209.85.213.46]:63195 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752942Ab0KDFFA (ORCPT ); Thu, 4 Nov 2010 01:05:00 -0400 Received: by ywc21 with SMTP id 21so1063426ywc.19 for ; Wed, 03 Nov 2010 22:04:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:date:from:to:cc:subject :message-id:references:mime-version:content-type:content-disposition :in-reply-to:user-agent; bh=HtEvhPiw2LTvdg+7LzZ+a+xzY5WuWacHyKWGTV/hw9s=; b=CD0PB4EqpVNPaWGDEreSQJw6MjWq0BLQIv5YfvG6hg9KVbN0+eokly7pYWz6wXGSXg KKOWqJacm71y9kWk8rETGvSSR1izOEYZHdBqVn4nIAhkPLjQsJIJa+Pl0jNsn2K2ZZWT mQbM7UOSKH/Ef34ckRNIURZ+u1TxGcRIpjkMA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=YWVvn7J+PQp9Izdxit8rKtvnt0mjYG3mpaZiZr2L9yYzpsC6g8OhPHHT6PMEtNBaYJ hNUuqSASJAeonLCrWahCvjau5Tj2ywoxY9v1L4c7urCgKM5971ZKIvo8puiT63c7kenx 6ihR4+Nr0LkX7zdRbNlVLobgMGqegMu8yBp+E= Received: by 10.91.9.1 with SMTP id m1mr624432agi.21.1288847099373; Wed, 03 Nov 2010 22:04:59 -0700 (PDT) Received: from burratino (adsl-68-255-106-176.dsl.chcgil.sbcglobal.net [68.255.106.176]) by mx.google.com with ESMTPS id g29sm6296258anh.36.2010.11.03.22.04.56 (version=SSLv3 cipher=RC4-MD5); Wed, 03 Nov 2010 22:04:57 -0700 (PDT) Content-Disposition: inline In-Reply-To: <7vvd4ew687.fsf@alter.siamese.dyndns.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Junio C Hamano wrote: > Jonathan Nieder writes: >> Judging from these three use cases, readonly open()s to the worktree >> should indeed use noatime, but open()s of .git/config, say, should >> not. Hmm. > > Why not, when you are talking about readonly open? A .git/config frequently accessed by git is being used, so tmpwatch shouldn't delete it. (Meanwhile, a worktree frequently accessed by git is not precious on that account, and letting git touch the atime there might mask more useful information about when other programs touched the files.) But that is all very fuzzy to me. I tend to mount noatime except on /usr (for popularity-contest). I guess I should put it another way. What if anything does readonly have to do with O_NOATIME? Why shouldn't we always use O_NOATIME? Why should the operating system provide atime at all?