Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937196AbYCSXyU (ORCPT ); Wed, 19 Mar 2008 19:54:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754745AbYCSW1v (ORCPT ); Wed, 19 Mar 2008 18:27:51 -0400 Received: from ug-out-1314.google.com ([66.249.92.174]:35621 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941150AbYCSW1t (ORCPT ); Wed, 19 Mar 2008 18:27:49 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:x-enigmail-version:content-type:content-transfer-encoding; b=bBJKicoXKbf52ChVZTKLkcj3Xl0nEF6OW27enMVmpwD8WIsIIWalTn8sFizKBay0S4pUgEYDNtY1hTxQAL6M6CKfD10Le5LvYEc1DtmzxKQ+d3KnK0PmVVJ2PZQv/cvoDZrW2DpUBehnRREiJLpBPp6M6rY/hqIQ/dGOA2QlraY= Message-ID: <47E19361.1010407@gmail.com> Date: Wed, 19 Mar 2008 23:27:45 +0100 From: Jiri Slaby User-Agent: Thunderbird 2.0.0.12 (X11/20080213) MIME-Version: 1.0 To: Rick Brown CC: Linux Kernel Subject: Re: preempt_disable() question References: <7783925d0803181914n16b0a221l179cc350bc2f3f89@mail.gmail.com> In-Reply-To: <7783925d0803181914n16b0a221l179cc350bc2f3f89@mail.gmail.com> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 842 Lines: 18 On 03/19/2008 03:14 AM, Rick Brown wrote: > Hi, > > I've asked this on kernel newbies before, but not enough responses. > > Does preempt_disable() disable preemption on all the processors, or > just the local processor? AFAIU preempt_disable increments preempt count of the current task, so that nobody will take the cpu which it is executing on (scheduler doesn't allow that) while the task is running until preempt count lowers to 0. How do you mean the "disabling preemption on local processor", how/why would you want to disable preemption of task potentially running on the other one? -- 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/