From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761505AbYDKRVi (ORCPT ); Fri, 11 Apr 2008 13:21:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760590AbYDKRVb (ORCPT ); Fri, 11 Apr 2008 13:21:31 -0400 Received: from el-out-1112.google.com ([209.85.162.181]:51829 "EHLO el-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760497AbYDKRVa (ORCPT ); Fri, 11 Apr 2008 13:21:30 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=slyliB9l+kfkLJpNdciJoAMHB0lt8uTTqsQ3t2nHOtMrx1nGFZESAknvBisvmhP1U1soe/2+AJTqPy+ZiNbrw0xcOxuJmIDcgsI6Xh959fOe5eEue+A5JZAzCxYAptbzUmmRHKwFzn7mCQ7NoRvWii4LJ3oCBRF+aBi8wv46asY= Message-ID: Date: Fri, 11 Apr 2008 13:21:28 -0400 From: "Dan Upton" To: linux-kernel@vger.kernel.org Subject: CFS rq lock question MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I'm poking around with some scheduler stuff, and there's something I'm not clear on for the CFS runqueue locks. The comments before __load_balance_iterator(...) in sched_fair.c suggests things can be dequeued even though the runqueue lock is held. Can things also be added to the queue while the lock is held? (Also, either way, what's the rationale that dequeueing is a safe procedure when somebody else holds a lock?) -dan