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 D7C006B016A for ; Fri, 2 Sep 2011 03:31:26 -0400 (EDT) Received: by wyi11 with SMTP id 11so2655390wyi.14 for ; Fri, 02 Sep 2011 00:31:22 -0700 (PDT) Date: Fri, 02 Sep 2011 08:31:16 +0100 Subject: Re: [Xen-devel] Re: [Revert] Re: [PATCH] mm: sync vmalloc address space page tables in alloc_vm_area() From: Keir Fraser Message-ID: In-Reply-To: <1314948154.28989.158.camel@zakaz.uk.xensource.com> Mime-version: 1.0 Content-type: text/plain; charset="US-ASCII" Content-transfer-encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Ian Campbell , Jeremy Fitzhardinge Cc: "xen-devel@lists.xensource.com" , Konrad Rzeszutek Wilk , "namhyung@gmail.com" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , David Vrabel , "rientjes@google.com" , "akpm@linux-foundation.org" , "paulmck@linux.vnet.ibm.com" On 02/09/2011 08:22, "Ian Campbell" wrote: > On Thu, 2011-09-01 at 21:37 +0100, Jeremy Fitzhardinge wrote: >> On 09/01/2011 09:11 AM, Konrad Rzeszutek Wilk wrote: >>> On Thu, Sep 01, 2011 at 12:51:03PM +0100, David Vrabel wrote: >>>> From: David Vrabel >>> Andrew, >>> >>> I was wondering if you would be Ok with this patch for 3.1. >>> >>> It is a revert (I can prepare a proper revert if you would like >>> that instead of this patch). >>> >>> The users of this particular function (alloc_vm_area) are just >>> Xen. There are no others. >> >> I'd prefer to put explicit vmalloc_sync_all()s in the callsites where >> necessary, and ultimately try to work out ways of avoiding it altogether >> (like have some hypercall wrapper which touches the arg memory to make >> sure its mapped?). > > That only syncs the current pagetable though. If that is sufficient (and > it could well be) then perhaps just doing a vmalloc_sync_one on the > current page tables directly would be better than faulting to do it? It's probably sufficient unless the kernel has non-voluntary preemption, and we are not preempt_disable()d. -- Keir > It's the sort of thing you could hide inside the gnttab_set_map_op type > helpers I guess? > > Ian. > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel -- 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 internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org