From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx206.postini.com [74.125.245.206]) by kanga.kvack.org (Postfix) with SMTP id 9F0636B0033 for ; Fri, 31 May 2013 15:46:41 -0400 (EDT) Date: Fri, 31 May 2013 15:46:24 -0400 From: Naoya Horiguchi Message-ID: <1370029584-qjpvbow1-mutt-n-horiguchi@ah.jp.nec.com> In-Reply-To: <20130531123003.1baf00c89bb25514de63c4f6@linux-foundation.org> References: <1369770771-8447-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1369770771-8447-3-git-send-email-n-horiguchi@ah.jp.nec.com> <20130531123003.1baf00c89bb25514de63c4f6@linux-foundation.org> Subject: Re: [PATCH v3 2/2] migrate: add migrate_entry_wait_huge() Mime-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, Mel Gorman , Andi Kleen , Michal Hocko , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org > That changelog is not suitable for a -stable patch. People who > maintain and utilize the stable trees need to know in some detail what > is the end-user impact of the patch (or, equivalently, of the bug > which the patch fixes). OK. So, could you insert the following sentence? On Fri, May 31, 2013 at 12:30:03PM -0700, Andrew Morton wrote: > On Tue, 28 May 2013 15:52:51 -0400 Naoya Horiguchi wrote: > > > When we have a page fault for the address which is backed by a hugepage > > under migration, the kernel can't wait correctly and do busy looping on > > hugepage fault until the migration finishes. As a result, users who try to kick hugepage migration (via soft offlining, for example) occasionally experience long delay or soft lockup. Thanks, Naoya > > This is because pte_offset_map_lock() can't get a correct migration entry > > or a correct page table lock for hugepage. > > This patch introduces migration_entry_wait_huge() to solve this. > > > > Note that the caller, hugetlb_fault(), gets the pointer to the "leaf" > > entry with huge_pte_offset() inside which all the arch-dependency of > > the page table structure are. So migration_entry_wait_huge() and > > __migration_entry_wait() are free from arch-dependency. > > > > ChangeLog v3: > > - use huge_pte_lockptr > > > > ChangeLog v2: > > - remove dup in migrate_entry_wait_huge() > > > > Signed-off-by: Naoya Horiguchi > > Reviewed-by: Rik van Riel > > Cc: stable@vger.kernel.org # 2.6.35 > > That changelog is not suitable for a -stable patch. People who > maintain and utilize the stable trees need to know in some detail what > is the end-user impact of the patch (or, equivalently, of the bug > which the patch fixes). -- 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/ . Don't email: email@kvack.org