From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx164.postini.com [74.125.245.164]) by kanga.kvack.org (Postfix) with SMTP id CCCDD6B0062 for ; Wed, 8 May 2013 20:19:26 -0400 (EDT) Subject: [PATCH] COMPACTION: bugfix of improper cache flush in MIGRATION code. From: Leonid Yegoshin Date: Wed, 8 May 2013 17:18:21 -0700 Message-ID: <20130509001821.15951.98705.stgit@linux-yegoshin> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: riel@redhat.com, mhocko@suse.cz, akpm@linux-foundation.org, mgorman@suse.de, kamezawa.hiroyu@jp.fujitsu.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org 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 --- mm/migrate.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 2fd8b4a..4c6250a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -165,7 +165,7 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, pte = arch_make_huge_pte(pte, vma, new, 0); } #endif - flush_cache_page(vma, addr, pte_pfn(pte)); + flush_dcache_page(new); set_pte_at(mm, addr, ptep, pte); if (PageHuge(new)) { -- 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