From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757321AbXJaMmy (ORCPT ); Wed, 31 Oct 2007 08:42:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755299AbXJaMmp (ORCPT ); Wed, 31 Oct 2007 08:42:45 -0400 Received: from smtp106.mail.mud.yahoo.com ([209.191.85.216]:43425 "HELO smtp106.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753128AbXJaMmo (ORCPT ); Wed, 31 Oct 2007 08:42:44 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=6nRzuk/YqPMUt5LxBl5oR4vEqqPYg4Vyhfd0whOldKalI52Bpi/mU+tgFMrBLbB6zA7wPmGk2+arzESnT0xvYWwlihJMGh9WP/EdUovrYGouORta3vDr6OceKOEeURJRrTGSkRtX0GVHBl8y47wyP0s4AAswdaMeKM6UVXe1210= ; X-YMail-OSG: BOYaA1sVM1nHKRa1mZJEZDqMgpROoa5UzY4QoC8PAA.gDYqrNs5aeTfhRsAf2ZM4noJoBUEnZA-- From: Nick Piggin To: Peter Zijlstra Subject: Re: [PATCH 03/33] mm: slub: add knowledge of reserve pages Date: Wed, 31 Oct 2007 22:25:06 +1100 User-Agent: KMail/1.9.5 Cc: Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, trond.myklebust@fys.uio.no References: <20071030160401.296770000@chello.nl> <200710312146.03351.nickpiggin@yahoo.com.au> <1193833072.27652.167.camel@twins> In-Reply-To: <1193833072.27652.167.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200710312225.07249.nickpiggin@yahoo.com.au> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 31 October 2007 23:17, Peter Zijlstra wrote: > On Wed, 2007-10-31 at 21:46 +1100, Nick Piggin wrote: > > And I'd prevent these ones from doing so. > > > > Without keeping track of "reserve" pages, which doesn't feel > > too clean. > > The problem with that is that once a slab was allocated with the right > allocation context, anybody can get objects from these slabs. [snip] I understand that. > So we either reserve a page per object, which for 32 byte objects is a > large waste, or we stop anybody who doesn't have the right permissions > from obtaining objects. I took the latter approach. What I'm saying is that the slab allocator slowpath should always just check watermarks against the current task. Instead of this ->reserve stuff.