From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Rowand Subject: Re: Interrupt Bottom Half Scheduling Date: Tue, 15 Feb 2011 10:40:17 -0800 Message-ID: <4D5AC891.9000705@am.sony.com> References: <4D5AC80F.1090205@am.sony.com> Reply-To: frank.rowand@am.sony.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Peter LaDow , Frank Rowand , linux-rt-users@vger.kernel.org To: frank.rowand@am.sony.com Return-path: Received: from mail-px0-f174.google.com ([209.85.212.174]:43862 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750994Ab1BOSkU (ORCPT ); Tue, 15 Feb 2011 13:40:20 -0500 Received: by pxi15 with SMTP id 15so68124pxi.19 for ; Tue, 15 Feb 2011 10:40:20 -0800 (PST) In-Reply-To: <4D5AC80F.1090205@am.sony.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 02/15/11 10:38, Frank Rowand wrote: > try_to_wake_up() is in the scheduler code (kernel/sched.c), but it is > not "the scheduler". If the task is not already running, > try_to_wake_up() will put the task on the run queue and set it's state > to TASK_RUNNING. If the priority of the newly woken thread was higher > than the current thread, then the newly woken thread would preempt > current. If a preemption occurred, then TIF_NEED_RESCHED is set. Oops, I slipped into using "thread" instead of "task". Just substitue "task" for each occurance of "thread" in that paragraph. > The actual "schedule" will occur on the exit path of the interrupt > only if TIF_NEED_RESCHED is set (see the call of preempt_schedule_irq()).