From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <junkio@cox.net>
Subject: Re: git-svnimport failed and now git-repack hates me
Date: Fri, 05 Jan 2007 15:58:31 -0800
Message-ID: <7vac0xc9g8.fsf@assigned-by-dhcp.cox.net>
References: <204011cb0701031552j8292d23v950f828279702d3@mail.gmail.com>
	<Pine.LNX.4.64.0701031737300.4989@woody.osdl.org>
	<7v1wmbnw9x.fsf@assigned-by-dhcp.cox.net>
	<204011cb0701040958k884b613i8a4639201ae6443b@mail.gmail.com>
	<7v1wmalez6.fsf@assigned-by-dhcp.cox.net>
	<204011cb0701050919w2001105asefe2fd99165dfa95@mail.gmail.com>
	<7vbqldfg56.fsf@assigned-by-dhcp.cox.net>
	<204011cb0701051133r1ede14a6gd5093a3e7fa88cb5@mail.gmail.com>
	<20070105193958.GE8753@spearce.org>
	<7vtzz5duk1.fsf@assigned-by-dhcp.cox.net>
	<204011cb0701051503m3a431e07qc12662eecc08884f@mail.gmail.com>
	<7v64bldqas.fsf@assigned-by-dhcp.cox.net>
	<Pine.LNX.4.64.0701051515000.3661@woody.osdl.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: Chris Lee <chris133@gmail.com>,
	"Shawn O. Pearce" <spearce@spearce.org>, git@vger.kernel.org
X-From: git-owner@vger.kernel.org Sat Jan 06 00:58:40 2007
Return-path: <git-owner@vger.kernel.org>
Envelope-to: gcvg-git@gmane.org
Received: from vger.kernel.org ([209.132.176.167])
	by lo.gmane.org with esmtp (Exim 4.50)
	id 1H2yxJ-0006zn-1N
	for gcvg-git@gmane.org; Sat, 06 Jan 2007 00:58:37 +0100
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1750919AbXAEX6d (ORCPT <rfc822;gcvg-git@m.gmane.org>);
	Fri, 5 Jan 2007 18:58:33 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750925AbXAEX6d
	(ORCPT <rfc822;git-outgoing>); Fri, 5 Jan 2007 18:58:33 -0500
Received: from fed1rmmtao08.cox.net ([68.230.241.31]:63099 "EHLO
	fed1rmmtao08.cox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1750919AbXAEX6c (ORCPT <rfc822;git@vger.kernel.org>);
	Fri, 5 Jan 2007 18:58:32 -0500
Received: from fed1rmimpo01.cox.net ([70.169.32.71])
          by fed1rmmtao08.cox.net
          (InterMail vM.6.01.06.03 201-2131-130-104-20060516) with ESMTP
          id <20070105235831.UEJO16632.fed1rmmtao08.cox.net@fed1rmimpo01.cox.net>;
          Fri, 5 Jan 2007 18:58:31 -0500
Received: from assigned-by-dhcp.cox.net ([68.5.247.80])
	by fed1rmimpo01.cox.net with bizsmtp
	id 7bxj1W0041kojtg0000000; Fri, 05 Jan 2007 18:57:43 -0500
To: Linus Torvalds <torvalds@osdl.org>
In-Reply-To: <Pine.LNX.4.64.0701051515000.3661@woody.osdl.org> (Linus
	Torvalds's message of "Fri, 5 Jan 2007 15:17:30 -0800 (PST)")
User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux)
Sender: git-owner@vger.kernel.org
Precedence: bulk
X-Mailing-List: git@vger.kernel.org
Archived-At: <http://permalink.gmane.org/gmane.comp.version-control.git/36052>

Linus Torvalds <torvalds@osdl.org> writes:

> It does actually end up forcing the kernel to do more work (it's harder to 
> re-use a mapped page than it is to reuse one that isn't), and in that 
> sense, if you have less than <n> GB of RAM and can't just keep it all in 
> memory at the same time, doing one large mmap is possibly more expensive 
> than chunking things up.

Even if it is a read-only private mapping?  Would MAP_SHARED
help?