From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Shawn O. Pearce" Subject: Re: Be more careful about updating refs Date: Thu, 17 Jan 2008 22:22:22 -0500 Message-ID: <20080118032222.GX24004@spearce.org> References: <478F3367.8050307@viscovery.net> <20080117110132.GB12285@hashpling.org> <478F4CDC.2090703@viscovery.net> <7vbq7jkixg.fsf@gitster.siamese.dyndns.org> <7v63xrki29.fsf@gitster.siamese.dyndns.org> <20080118021300.GR24004@spearce.org> <7v1w8fkgy9.fsf@gitster.siamese.dyndns.org> <20080118023327.GT24004@spearce.org> <20080118025837.GU24004@spearce.org> <20080118031831.GW24004@spearce.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Johannes Sixt , Charles Bailey , Linus Torvalds , Git Mailing List To: Junio C Hamano X-From: git-owner@vger.kernel.org Fri Jan 18 04:22:59 2008 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1JFhon-0003RG-P8 for gcvg-git-2@gmane.org; Fri, 18 Jan 2008 04:22:58 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752052AbYARDW2 (ORCPT ); Thu, 17 Jan 2008 22:22:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752034AbYARDW2 (ORCPT ); Thu, 17 Jan 2008 22:22:28 -0500 Received: from corvette.plexpod.net ([64.38.20.226]:40626 "EHLO corvette.plexpod.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751102AbYARDW2 (ORCPT ); Thu, 17 Jan 2008 22:22:28 -0500 Received: from cpe-74-70-48-173.nycap.res.rr.com ([74.70.48.173] helo=asimov.home.spearce.org) by corvette.plexpod.net with esmtpa (Exim 4.68) (envelope-from ) id 1JFho4-0006QD-2U; Thu, 17 Jan 2008 22:22:12 -0500 Received: by asimov.home.spearce.org (Postfix, from userid 1000) id 39D6020FBAE; Thu, 17 Jan 2008 22:22:22 -0500 (EST) Content-Disposition: inline In-Reply-To: <20080118031831.GW24004@spearce.org> User-Agent: Mutt/1.5.11 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - corvette.plexpod.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - spearce.org Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: "Shawn O. Pearce" wrote: > "Shawn O. Pearce" wrote: > > "Shawn O. Pearce" wrote: > > > Junio C Hamano wrote: > > > > > > > > Especially, I am not sure if the issue only exists at the > > > > end_packfile() boundary. Don't we have the same issue reading > > > > from the packfile being built, and isn't the only reason my hack > > > > works it around is because access patterns of the testsuite > > > > happens to not trigger it? > > > > > > Yes, that's my take on it as well (see my other email). The > > > testsuite must just be really lucky that its not hitting the > > > boundary condition. > > > > > > I almost said gfi_unpack_entry() was immune from this bug, but > > > I went back and read the code again and determined that it does > > > in fact suffer from this under NO_MMAP, and we're just really > > > damn lucky nobody has caused it. > > > > I think this solves the problem. Its based on your first patch, but > > would replace it. The trick here is we close the cached windows if > > we are accessing data from the packfile we are appending into and we > > have increased the file length. This way we don't blow away windows > > during high read/low write periods, like during branch cache reloads. > > Junio pointed out my first attempt at this didn't update the > memory pressure values, so we could "run out of memory" even > if we had plenty free. > > Try #2... OK, that was crap. Don't even try it. I'm holding off sending anything more until I get the test suite to actually run without telling me the bus crashed into the wall. -- Shawn.