Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264018AbTH1NA5 (ORCPT ); Thu, 28 Aug 2003 09:00:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264019AbTH1NA5 (ORCPT ); Thu, 28 Aug 2003 09:00:57 -0400 Received: from mail.jlokier.co.uk ([81.29.64.88]:4231 "EHLO mail.jlokier.co.uk") by vger.kernel.org with ESMTP id S264018AbTH1NAz (ORCPT ); Thu, 28 Aug 2003 09:00:55 -0400 Date: Thu, 28 Aug 2003 14:00:44 +0100 From: Jamie Lokier To: Nagendra Singh Tomar Cc: Timo Sirainen , David Schwartz , linux-kernel@vger.kernel.org Subject: Re: Lockless file reading Message-ID: <20030828130043.GE6800@mail.jlokier.co.uk> References: <20030828121823.GB6800@mail.jlokier.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 952 Lines: 20 Nagendra Singh Tomar wrote: > While the write had "12" in its buffers and it would have grabbed the > page lock to write it into the page cache, won't it set some flag saying > that I don't want to be prempted now. I think there is a small primitive > for it in from 2.5 onwards. I don't think it will be a good idea to prempt > while it is holding the page lock. How is it possible that it just wrote > "1" and did not write "2" though it had grabbed the page lock for that > purpose. Nope. I don't see any disabling of preemption while the page is held. It wouldn't make sense anyway, because the copies to/from userspace can sleep, so there's nothing to gain by disabling preemption. -- Jamie - 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/