Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752632Ab0K0KhA (ORCPT ); Sat, 27 Nov 2010 05:37:00 -0500 Received: from ipmail04.adl6.internode.on.net ([150.101.137.141]:36552 "EHLO ipmail04.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752320Ab0K0Kg7 (ORCPT ); Sat, 27 Nov 2010 05:36:59 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEAGdt8Ex5Lcx2/2dsb2JhbACjC3K+AYVHBA Date: Sat, 27 Nov 2010 21:36:56 +1100 From: Nick Piggin To: Jeremy Fitzhardinge Cc: Nick Piggin , "Xen-devel@lists.xensource.com" , Linux Kernel Mailing List Subject: Re: Could we do immediate pte zaps in vunmap? Message-ID: <20101127103656.GA6884@amd> References: <4CEF6B8B.8080206@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CEF6B8B.8080206@goop.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 861 Lines: 20 On Fri, Nov 26, 2010 at 12:10:51AM -0800, Jeremy Fitzhardinge wrote: > What if vm_unmap_ram() and co. immediately zeroed out the ptes, but > lazily deferred the tlb flushes? It seems to me there's no benefit in > batching up the pte clearing since that can't be amortized like the tlb > flush. Yes that can be done. > I think that would solve the problem we have with the interactions > between lazy unmap and Xen. The issue is having stray pte entries > around (because Xen keeps track of those as part of its page-type > mechanism), but stale tlb entries are no problem. It would be great if that solves it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/