Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758509AbXEORYm (ORCPT ); Tue, 15 May 2007 13:24:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755138AbXEORYg (ORCPT ); Tue, 15 May 2007 13:24:36 -0400 Received: from mail1.webmaster.com ([216.152.64.169]:1707 "EHLO mail1.webmaster.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755657AbXEORYf (ORCPT ); Tue, 15 May 2007 13:24:35 -0400 From: "David Schwartz" To: "Linux-Kernel@Vger. Kernel. Org" Subject: RE: Why can't we sleep in an ISR? Date: Tue, 15 May 2007 10:23:34 -0700 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.6604 (9.0.2911.0) In-Reply-To: <4649E680.9020102@cfl.rr.com> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 Importance: Normal X-Authenticated-Sender: joelkatz@webmaster.com X-Spam-Processed: mail1.webmaster.com, Tue, 15 May 2007 11:23:56 -0700 (not processed: message from trusted or authenticated source) X-MDRemoteIP: 206.171.168.138 X-Return-Path: davids@webmaster.com X-MDaemon-Deliver-To: linux-kernel@vger.kernel.org Reply-To: davids@webmaster.com X-MDAV-Processed: mail1.webmaster.com, Tue, 15 May 2007 11:23:57 -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1013 Lines: 28 > No, the term context here has a specific meaning. It refers to those > things which flow from the current pointer, including the virtual memory > space, file descriptor table, current uid, and so forth. And none of these things are used by an ISR. > Because the > current pointer is not changed on entry to an ISR, the ISR is executing > in the context of the interrupted process, and thus uses that process' > virtual memory, etc. You mean it would be if it ever looked at the current pointer. It is not the setting of the current pointer that determines the context but actually *using* that pointer. As you said, it is the "things which flow from the current pointer" that matter, not the value of the pointer itself. An ISR uses none of those things. DS - 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/