From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754041AbdDKIVz (ORCPT ); Tue, 11 Apr 2017 04:21:55 -0400 Received: from mail-pg0-f68.google.com ([74.125.83.68]:36346 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752439AbdDKIU1 (ORCPT ); Tue, 11 Apr 2017 04:20:27 -0400 Message-ID: <1491898818.8380.3.camel@gmail.com> Subject: Re: [PATCH kernel v2] powerpc/iommu: Do not call PageTransHuge() on tail pages From: Balbir Singh To: Alexey Kardashevskiy , linuxppc-dev@lists.ozlabs.org Cc: Michael Ellerman , "Aneesh Kumar K . V" , Greg Kurz , Paul Mackerras , linux-kernel@vger.kernel.org, stable@vger.kernel.org, #@ozlabs.ru, v4.9+@ozlabs.ru Date: Tue, 11 Apr 2017 18:20:18 +1000 In-Reply-To: <20170411075457.28020-1-aik@ozlabs.ru> References: <20170411075457.28020-1-aik@ozlabs.ru> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6 (3.22.6-2.fc25) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2017-04-11 at 17:54 +1000, Alexey Kardashevskiy wrote: > The CMA pages migration code does not support compound pages at > the moment so it performs few tests before proceeding to actual page > migration. > > One of the tests - PageTransHuge() - has VM_BUG_ON_PAGE(PageTail()) as > it is designed to be called on head pages only. Since we also test for > PageCompound(), and it contains PageTail() and PageHead(), we can > simplify the check by leaving just PageCompound() and therefore avoid > possible VM_BUG_ON_PAGE. > > Fixes: 2e5bbb5461f1 ("KVM: PPC: Book3S HV: Migrate pinned pages out of CMA") > Cc: stable@vger.kernel.org # v4.9+ > Signed-off-by: Alexey Kardashevskiy > Acked-by: Balbir Singh > --- > > Changes: > v2: > * instead of moving PageCompound() to the beginning, this just drops > PageHuge() and PageTransHuge() > Looks good! My Acked-by is already present Balbir Singh.