Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760014AbXEaWI6 (ORCPT ); Thu, 31 May 2007 18:08:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759402AbXEaWIs (ORCPT ); Thu, 31 May 2007 18:08:48 -0400 Received: from rgminet01.oracle.com ([148.87.113.118]:11560 "EHLO rgminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759358AbXEaWIr (ORCPT ); Thu, 31 May 2007 18:08:47 -0400 Date: Thu, 31 May 2007 15:07:16 -0700 From: Zach Brown To: Jeff Dike Cc: Ingo Molnar , LKML , uml-devel Subject: Re: [PATCH] Syslets - Fix cachemiss_thread return value Message-ID: <20070531220716.GL5488@mami.zabbo.net> References: <20070531181923.GA9904@c2.user-mode-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070531181923.GA9904@c2.user-mode-linux.org> User-Agent: Mutt/1.4.2.1i X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1226 Lines: 25 > cachemiss_thread should explicitly return 0 or error instead of > task_ret_reg(current) (which is -ENOSYS anyway) because > async_thread_helper is careful to put the return value in eax anyway. Can you explain what motivated you to send out this patch? It used to return 0. It was changed because, unlike the syslet syscalls, sys_io_submit() doesn't have a simple 0 value to indicate success. The current implementation wants to return the number of iocbs that were processed, including the one which blocked, from the cachemiss thread. So before calling into an operation it sets task_ret_ret() so that the cachemiss thread can return it if it takes over. task_ret_reg() is holding a return value that is being returned by the cachemiss thread on behalf of a sys_io_submit() which blocked. When I made the change I didn't really audit its effect on the other paths. I suppose it's time to do that, and you could help by telling me if you saw something bad happen :). - z - 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/