Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753166Ab2E3Tq3 (ORCPT ); Wed, 30 May 2012 15:46:29 -0400 Received: from mail-yw0-f46.google.com ([209.85.213.46]:51614 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751305Ab2E3Tq1 (ORCPT ); Wed, 30 May 2012 15:46:27 -0400 MIME-Version: 1.0 In-Reply-To: References: <1338368529-21784-1-git-send-email-kosaki.motohiro@gmail.com> <1338368529-21784-3-git-send-email-kosaki.motohiro@gmail.com> From: KOSAKI Motohiro Date: Wed, 30 May 2012 15:46:05 -0400 Message-ID: Subject: Re: [PATCH 2/6] mempolicy: Kill all mempolicy sharing To: Christoph Lameter Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Dave Jones , Mel Gorman , Linus Torvalds , stable@vger.kernel.org, hughd@google.com, Andrew Morton , andi@firstfloor.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1120 Lines: 24 On Wed, May 30, 2012 at 3:41 PM, Christoph Lameter wrote: > On Wed, 30 May 2012, kosaki.motohiro@gmail.com wrote: > >> refcount will be decreased even though was not increased whenever alloc_page_vma() >> is called. As you know, mere mbind(MPOL_MF_MOVE) calls alloc_page_vma(). > > Most of these issues are about memory migration and shared memory. If we > exempt shared memory from memory migration (after all that shared memory > has its own distinct memory policies already!) then a lot of these issues > wont arise. The final point is, to make proper cow for struct mempolicy. but until fixing cpuset bindings issue, we can't use mempolicy sharing anyway. Moreover, now most core piece of mempolicy life cycle, say split_vma() and dup_mmap(), don't use mempolicy sharing. Only mbind() does. Thus, this patch don't increase normal workload memory usage. -- 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/