Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751009AbWISSzb (ORCPT ); Tue, 19 Sep 2006 14:55:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751933AbWISSza (ORCPT ); Tue, 19 Sep 2006 14:55:30 -0400 Received: from smtp107.mail.mud.yahoo.com ([209.191.85.217]:8593 "HELO smtp107.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S1751009AbWISSza (ORCPT ); Tue, 19 Sep 2006 14:55:30 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=j4mOjZtJLfx6qNNzDvhh6h/is4TfzyNOFE4ObCzz986ww2xyxebb+GeJiH4193JTB/LaJMLrKO5ZSgPkoVADKxAorLnpOs+PiXvusxR7YxJ56l5tL9FR5Z0WlDKiFDwGkzRvlSKNf5X2Qa9LNv+hI56LEZT0aWWJSxj8yXf7814= ; Message-ID: <45103D1D.20702@yahoo.com.au> Date: Wed, 20 Sep 2006 04:55:25 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Willy Tarreau CC: Linux Kernel , Marcelo Tosatti Subject: Re: Linux 2.4.34-pre3 References: <20060919173253.GA25470@hera.kernel.org> <45102BEE.9000501@yahoo.com.au> <20060919181738.GA3467@1wt.eu> In-Reply-To: <20060919181738.GA3467@1wt.eu> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1269 Lines: 37 Willy Tarreau wrote: > Hi Nick, > > On Wed, Sep 20, 2006 at 03:42:06AM +1000, Nick Piggin wrote: > > [cut -pre3 advertisement] > > >>I wonder if 2.4 doesn't need the memory ordering fix to prevent pagecache >>corruption in reclaim? (http://www.gatago.com/linux/kernel/14682626.html) >> >>What would need to be done is to test page_count before testing PageDirty, >>and putting an smp_rmb between the two. > > > I've read the thread, and Linus proposed to add an smp_wmb() in > set_page_dirty() too. I think that isn't needed because put_page is a RMW, which is defined to order memory. And presumably you wouldn't set the page dirty without a reference to the page. > I see that an smp_rmb() is already present > in shrink_cache() with the adequate comment. So there is! My mistake then, I was confused and looking at try_to_swap_out, but I see that doesn't actually free the page. Fine, I think 2.4 is OK then. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com - 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/