From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 6F83B6B0071 for ; Tue, 30 Nov 2010 19:30:16 -0500 (EST) Date: Tue, 30 Nov 2010 16:29:38 -0800 From: Andrew Morton Subject: Re: [PATCH RFC] vmalloc: eagerly clear ptes on vunmap Message-Id: <20101130162938.8a6b0df4.akpm@linux-foundation.org> In-Reply-To: <4CF40DCB.5010007@goop.org> References: <4CEF6B8B.8080206@goop.org> <20101127103656.GA6884@amd> <4CF40DCB.5010007@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Jeremy Fitzhardinge Cc: Nick Piggin , "Xen-devel@lists.xensource.com" , Linux Kernel Mailing List , Linux Memory Management List , Trond Myklebust , Bryan Schumaker , Konrad Rzeszutek Wilk List-ID: On Mon, 29 Nov 2010 12:32:11 -0800 Jeremy Fitzhardinge wrote: > When unmapping a region in the vmalloc space, clear the ptes immediately. > There's no point in deferring this because there's no amortization > benefit. > > The TLBs are left dirty, and they are flushed lazily to amortize the > cost of the IPIs. > > This specific motivation for this patch is a regression since 2.6.36 when > using NFS under Xen, triggered by the NFS client's use of vm_map_ram() > introduced in 56e4ebf877b6043c289bda32a5a7385b80c17dee. XFS also uses > vm_map_ram() and could cause similar problems. > Do we have any quantitative info on that regression? The patch fixed it, I assume? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org