From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Galbraith Subject: Re: [patch 0/6] 3.14-rt1 fixes Date: Sat, 03 May 2014 16:03:27 +0200 Message-ID: <1399125807.5326.128.camel@marge.simpson.net> References: <1399029159.5233.124.camel@marge.simpson.net> <5363840B.6020402@pavlinux.ru> <1399031023.5233.145.camel@marge.simpson.net> <20140503083257.GA16242@opentech.at> <1399113657.5326.58.camel@marge.simpson.net> <20140503123146.GB15945@opentech.at> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: pavel@pavlinux.ru, RT , Sebastian Andrzej Siewior , Steven Rostedt , Thomas Gleixner To: Nicholas Mc Guire Return-path: Received: from mail-ee0-f49.google.com ([74.125.83.49]:43568 "EHLO mail-ee0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751038AbaECODa (ORCPT ); Sat, 3 May 2014 10:03:30 -0400 Received: by mail-ee0-f49.google.com with SMTP id e53so3920246eek.36 for ; Sat, 03 May 2014 07:03:29 -0700 (PDT) In-Reply-To: <20140503123146.GB15945@opentech.at> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Sat, 2014-05-03 at 14:31 +0200, Nicholas Mc Guire wrote: > On Sat, 03 May 2014, Mike Galbraith wrote: > > If this is in fact safe, you should be able to move each and every > > migrate_disable() to post acquisition. > > yup Having just seen working -> brick transition, color me skeptical. > > I have a virtual nickle that > > says your box will have a severe allergic reaction to such a patch. > > > Actually that is what the pushdowns in the read_lock/write_lock api did and > I did not notice any of the systems having problems with that. If you had tested hotplug, you would have met the deadlock, and would have verified that the change to read_lock() was the culprit instead of me doing that. Steven also verified that. You too can flip back and forth, drive boxen into the wall as many times as it take to convince yourself that that change really really did induce the breakage. I'll read the rest later, I'm getting all grumpy. -Mike