From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031175AbbD1W2l (ORCPT ); Tue, 28 Apr 2015 18:28:41 -0400 Received: from mta-out1.inet.fi ([62.71.2.203]:35264 "EHLO jenni2.inet.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031021AbbD1W2k (ORCPT ); Tue, 28 Apr 2015 18:28:40 -0400 Date: Wed, 29 Apr 2015 01:28:28 +0300 From: "Kirill A. Shutemov" To: Andrew Morton Cc: "Kirill A. Shutemov" , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sasha Levin Subject: Re: [PATCH] compaction: fix isolate_migratepages_block() for THP=n Message-ID: <20150428222828.GA6072@node.dhcp.inet.fi> References: <1430134006-215317-1-git-send-email-kirill.shutemov@linux.intel.com> <20150428151420.227e7ac34745e9fe8e9bc145@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150428151420.227e7ac34745e9fe8e9bc145@linux-foundation.org> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 28, 2015 at 03:14:20PM -0700, Andrew Morton wrote: > On Mon, 27 Apr 2015 14:26:46 +0300 "Kirill A. Shutemov" wrote: > > > PageTrans* helpers are always-false if THP is disabled compile-time. > > It means the fucntion will fail to detect hugetlb pages in this case. > > > > Let's use PageCompound() instead. With small tweak to how we calculate > > next low_pfn it will make function ready to see tail pages. > > > > So this patch has no runtime effects at present? It is preparation for > something else? I wrote this to fix bug I originally attributed to refcounting patchset, but Sasha triggered the same bug on -next without the patchset applied: http://lkml.kernel.org/g/553EB993.7030401@oracle.com Now I think it's related to changing of PageLRU() behaviour on tail page by my page flags patchset. PageLRU() on tail pages now reports true if head page is on LRU. It means no we can go futher insede isolate_migratepages_block() with tail page. -- Kirill A. Shutemov