Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422928AbWLUJRJ (ORCPT ); Thu, 21 Dec 2006 04:17:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422912AbWLUJRE (ORCPT ); Thu, 21 Dec 2006 04:17:04 -0500 Received: from mtagate4.uk.ibm.com ([195.212.29.137]:13327 "EHLO mtagate4.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422910AbWLUJQn (ORCPT ); Thu, 21 Dec 2006 04:16:43 -0500 Subject: Re: [PATCH] mm: fix page_mkclean_one (was: 2.6.19 file content corruption on ext3) From: Martin Schwidefsky Reply-To: schwidefsky@de.ibm.com To: Peter Zijlstra Cc: Linus Torvalds , Martin Michlmayr , Hugh Dickins , Nick Piggin , Arjan van de Ven , Andrei Popa , Andrew Morton , Linux Kernel Mailing List , Florian Weimer , Marc Haber , Heiko Carstens , Arnd Bergmann , gordonfarquharson@gmail.com In-Reply-To: <1166655805.30008.18.camel@twins> References: <1166571749.10372.178.camel@twins> <1166605296.10372.191.camel@twins> <1166607554.3365.1354.camel@laptopd505.fenrus.org> <1166614001.10372.205.camel@twins> <1166622979.10372.224.camel@twins> <20061220170323.GA12989@deprecation.cyrius.com> <20061220175309.GT30106@deprecation.cyrius.com> <1166652901.30008.1.camel@twins> <1166655805.30008.18.camel@twins> Content-Type: text/plain Organization: IBM Corporation Date: Thu, 21 Dec 2006 10:16:26 +0100 Message-Id: <1166692586.27750.4.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1485 Lines: 55 On Thu, 2006-12-21 at 00:03 +0100, Peter Zijlstra wrote: > current version Nitpicking .. > @@ -444,17 +444,18 @@ static int page_mkclean_one(struct page > if (!pte) > goto out; > > - if (!pte_dirty(*pte) && !pte_write(*pte)) > - goto unlock; > + while (pte_dirty(*pte) || pte_write(*pte)) { > + pte_t entry; > > - entry = ptep_get_and_clear(mm, address, pte); > - entry = pte_mkclean(entry); > - entry = pte_wrprotect(entry); > - ptep_establish(vma, address, pte, entry); > - lazy_mmu_prot_update(entry); > - ret = 1; > + flush_cache_page(vma, address, pte_pfn(*pte)); > + entry = ptep_clear_flush(vma, address, pte); > + entry = pte_wrprotect(entry); > + entry = pte_mkclean(entry); > + ptep_establish(vma, address, pte, entry); Now you are flushing the tlb twice. ptep_clear_flush clears the pte and flushes the tlb, ptep_establish sets the new pte and flushes the tlb. Not good. Use set_pte_at instead of the ptep_establish. > + lazy_mmu_prot_update(entry); > + ret = 1; > + } > > -unlock: > pte_unmap_unlock(pte, ptl); > out: > return ret; -- blue skies, Martin. Martin Schwidefsky Linux for zSeries Development & Services IBM Deutschland Entwicklung GmbH "Reality continues to ruin my life." - Calvin. - 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/