From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Frank Ch. Eigler" Subject: preempt-rt, need old style rwlocks for systemtap Date: Sat, 3 May 2008 09:23:27 -0400 Message-ID: <20080503132327.GA28881@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Return-path: Received: from mx1.redhat.com ([66.187.233.31]:47183 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752582AbYECNYU (ORCPT ); Sat, 3 May 2008 09:24:20 -0400 Content-Disposition: inline Sender: linux-rt-users-owner@vger.kernel.org List-ID: Hi - It has come to my attention that the preempt-rt patch suite deliberately defeats the potential concurrency intended by systemtap's use of rwlocks to permit concurrent readers of various data structures. Since systemtap's probe handlers are all atomic, nonblocking, nonpreemptable, it does not seem like there is any real-time-oriented benefit in this. What can we do to work around this and permit reader concurrency again in preempt-rt? - FChE