Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752821AbXFLEan (ORCPT ); Tue, 12 Jun 2007 00:30:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751028AbXFLEaf (ORCPT ); Tue, 12 Jun 2007 00:30:35 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:55797 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750933AbXFLEae (ORCPT ); Tue, 12 Jun 2007 00:30:34 -0400 Date: Mon, 11 Jun 2007 21:30:20 -0700 From: Andrew Morton To: Adam Litke Cc: dean gaudet , William Lee Irwin III , "Eric W. Biederman" , linux-kernel@vger.kernel.org, ak@suse.de, clameter@sgi.com Subject: Re: [shm][hugetlb] Fix get_policy for stacked shared memory files Message-Id: <20070611213020.b3d91757.akpm@linux-foundation.org> In-Reply-To: <1181597696.22671.2.camel@localhost.localdomain> References: <20070516061259.GZ19966@holomorphy.com> <1181597696.22671.2.camel@localhost.localdomain> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1597 Lines: 51 On Mon, 11 Jun 2007 16:34:54 -0500 Adam Litke wrote: > Here's another breakage as a result of shared memory stacked files :( > > The NUMA policy for a VMA is determined by checking the following (in the order > given): > > 1) vma->vm_ops->get_policy() (if defined) > 2) vma->vm_policy (if defined) > 3) task->mempolicy (if defined) > 4) Fall back to default_policy > > By switching to stacked files for shared memory, get_policy() is now always set > to shm_get_policy which is a wrapper function. This causes us to stop at step > 1, which yields NULL for hugetlb instead of task->mempolicy which was the > previous (and correct) result. > > This patch modifies the shm_get_policy() wrapper to maintain steps 1-3 for the > wrapped vm_ops. Andi and Christoph, does this look right to you? > Can we just double-check the refcounting please? > index 4fefbad..8d2672d 100644 > --- a/ipc/shm.c > +++ b/ipc/shm.c > @@ -254,8 +254,10 @@ struct mempolicy *shm_get_policy(struct vm_area_struct *vma, unsigned long addr) > > if (sfd->vm_ops->get_policy) > pol = sfd->vm_ops->get_policy(vma, addr); afacit this takes a ref on the underlying policy > - else > + else if (vma->vm_policy) > pol = vma->vm_policy; > + else > + pol = current->mempolicy; but these two do not. > return pol; > } > #endif Is is all correct? - 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/