Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752910AbaBDGg7 (ORCPT ); Tue, 4 Feb 2014 01:36:59 -0500 Received: from mail-pa0-f48.google.com ([209.85.220.48]:39916 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751336AbaBDGgx (ORCPT ); Tue, 4 Feb 2014 01:36:53 -0500 Date: Mon, 3 Feb 2014 22:36:48 -0800 From: Matt Wilson To: Zoltan Kiss Cc: Konrad Rzeszutek Wilk , Boris Ostrovsky , David Vrabel , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, Roger Pau =?iso-8859-1?Q?Monn=E9?= , Jan Beulich , Ian Campbell , stefano.stabellini@eu.citrix.com, Anthony Liguori , Matt Wilson Subject: Re: [PATCH v7] xen/grant-table: Avoid m2p_override during mapping Message-ID: <20140204063648.GB19177@u109add4315675089e695.ant.amazon.com> References: <1391433898-10533-1-git-send-email-zoltan.kiss@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1391433898-10533-1-git-send-email-zoltan.kiss@citrix.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 03, 2014 at 01:24:58PM +0000, Zoltan Kiss wrote: > The grant mapping API does m2p_override unnecessarily: only gntdev needs it, > for blkback and future netback patches it just cause a lock contention, as > those pages never go to userspace. Therefore this series does the following: > - the original functions were renamed to __gnttab_[un]map_refs, with a new > parameter m2p_override > - based on m2p_override either they follow the original behaviour, or just set > the private flag and call set_phys_to_machine > - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with > m2p_override false > - a new function gnttab_[un]map_refs_userspace provides the old behaviour > > It also removes a stray space from page.h and change ret to 0 if > XENFEAT_auto_translated_physmap, as that is the only possible return value > there. > > v2: > - move the storing of the old mfn in page->index to gnttab_map_refs > - move the function header update to a separate patch > > v3: > - a new approach to retain old behaviour where it needed > - squash the patches into one > > v4: > - move out the common bits from m2p* functions, and pass pfn/mfn as parameter > - clear page->private before doing anything with the page, so m2p_find_override > won't race with this > > v5: > - change return value handling in __gnttab_[un]map_refs > - remove a stray space in page.h > - add detail why ret = 0 now at some places > > v6: > - don't pass pfn to m2p* functions, just get it locally > > v7: > - the previous version broke build on ARM, as there is no need for those p2m > changes. I've put them into arch specific functions, which are stubs on arm > > Signed-off-by: Zoltan Kiss > Suggested-by: David Vrabel You're still forgetting that this was originally proposed by Anthony Liguori . https://lkml.kernel.org/r/1384307336-5328-1-git-send-email-anthony@codemonkey.ws --msw -- 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/