From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx172.postini.com [74.125.245.172]) by kanga.kvack.org (Postfix) with SMTP id 322A96B0034 for ; Fri, 10 May 2013 05:52:17 -0400 (EDT) Date: Fri, 10 May 2013 10:52:12 +0100 From: Mel Gorman Subject: Re: [PATCH] COMPACTION: bugfix of improper cache flush in MIGRATION code. Message-ID: <20130510095212.GM11497@suse.de> References: <20130509001821.15951.98705.stgit@linux-yegoshin> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20130509001821.15951.98705.stgit@linux-yegoshin> Sender: owner-linux-mm@kvack.org List-ID: To: Leonid Yegoshin Cc: riel@redhat.com, mhocko@suse.cz, akpm@linux-foundation.org, kamezawa.hiroyu@jp.fujitsu.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, May 08, 2013 at 05:18:21PM -0700, 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. > > Author: Leonid Yegoshin > Signed-off-by: Leonid Yegoshin Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- 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