Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753751Ab0DAHJl (ORCPT ); Thu, 1 Apr 2010 03:09:41 -0400 Received: from waste.org ([173.11.57.241]:47876 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753019Ab0DAHJf (ORCPT ); Thu, 1 Apr 2010 03:09:35 -0400 Subject: Re: [PATCH] proc: pagemap: Hold mmap_sem during page walk From: Matt Mackall To: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro , Linus Torvalds , San Mehat , linux-kernel@vger.kernel.org, Brian Swetland , Dave Hansen , Andrew Morton , n-horiguchi@ah.jp.nec.com In-Reply-To: <20100401153428.d49c6345.kamezawa.hiroyu@jp.fujitsu.com> References: <20100401144329.BE42.A69D9226@jp.fujitsu.com> <20100401145509.47f7f1c3.kamezawa.hiroyu@jp.fujitsu.com> <20100401150128.BE45.A69D9226@jp.fujitsu.com> <20100401150956.4f6821c2.kamezawa.hiroyu@jp.fujitsu.com> <20100401153428.d49c6345.kamezawa.hiroyu@jp.fujitsu.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 01 Apr 2010 02:09:31 -0500 Message-ID: <1270105771.3552.1143.camel@calx> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1182 Lines: 33 On Thu, 2010-04-01 at 15:34 +0900, KAMEZAWA Hiroyuki wrote: > On Thu, 1 Apr 2010 15:09:56 +0900 > KAMEZAWA Hiroyuki wrote: > > > > > + pm.pos = 0; > > + start_vaddr += PAGEMAP_WALK_SIZE; > > + end = start_vaddr + PAGEMAP_WALK_SIZE; > > Sigh...this is bad.. > > == > From: KAMEZAWA Hiroyuki > > In initial design, walk_page_range() was designed just for walking page table and > it didn't require mmap_sem. Now, find_vma() etc.. are used in walk_page_range() > and we need mmap_sem around it. This looks pretty reasonable. However, it also looks very similar to my first version of pagemap (which started with double-buffering). It's going to need re-testing to make sure it hasn't reintroduced any wrapping, alignment, or off-by-one bugs that have already been ironed out once or twice. -- http://selenic.com : development and support for Mercurial and Linux -- 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/