Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753524Ab3EIOky (ORCPT ); Thu, 9 May 2013 10:40:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:17802 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751881Ab3EIOkx (ORCPT ); Thu, 9 May 2013 10:40:53 -0400 Message-ID: <518BB4F2.2040704@redhat.com> Date: Thu, 09 May 2013 10:38:42 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Leonid Yegoshin CC: mhocko@suse.cz, akpm@linux-foundation.org, mgorman@suse.de, kamezawa.hiroyu@jp.fujitsu.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] COMPACTION: bugfix of improper cache flush in MIGRATION code. References: <20130509001821.15951.98705.stgit@linux-yegoshin> In-Reply-To: <20130509001821.15951.98705.stgit@linux-yegoshin> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1330 Lines: 32 On 05/08/2013 08:18 PM, Leonid Yegoshin wrote: > Page 'new' during MIGRATION can't be flushed by flush_cache_page(). > Using flush_cache_page(vma, addr, pfn) is justified only if > page is already placed in process page table, and that is done right > after flush_cache_page(). But without it the arch function has > no knowledge of process PTE and does nothing. > > Besides that, flush_cache_page() flushes an application cache, > kernel has a different page virtual address and dirtied it. > > Replace it with flush_dcache_page(new) which is a proper usage. > > Old page is flushed in try_to_unmap_one() before MIGRATION. > > This bug takes place in Sead3 board with M14Kc MIPS CPU without > cache aliasing (but Harvard arch - separate I and D cache) > in tight memory environment (128MB) each 1-3days on SOAK test. > It fails in cc1 during kernel build (SIGILL, SIGBUS, SIGSEG) if > CONFIG_COMPACTION is switched ON. Good catch! > Author: Leonid Yegoshin > Signed-off-by: Leonid Yegoshin Acked-by: Rik van Riel -- 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/