From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>, John Kacur <jkacur@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Clark Williams <clark.williams@gmail.com>
Subject: [PATCH RT 0/9][RFC] rt: Fix hotplugging and other nasties
Date: Thu, 01 Mar 2012 13:55:27 -0500 [thread overview]
Message-ID: <20120301185527.064629423@goodmis.org> (raw)
On both 3.0-rt and 3.2-rt I ran a stress test on CPU hotplug and they
both failed miserably. These bugs also show themselves on suspend.
After spending 5 long days debugging this, and finding lots of bugs
I have a patch series that makes the CPU hot plugging rather stable.
The first few patches fix other broken RT features that were discovered
while debugging hotplug.
Patch 7 is a rework of how RT handles taking down a CPU. There were
several corner cases that the original approach failed on, and this
rework seems to cover them now.
Patch 8 and 9 revert the rework that was done on workqueue for RT.
Yes, letting workqueues play games with THREAD_BOUND is bad, but
the fixes introduced several more races that were very hard to fix.
Every fix seemed to produce a new race, and it was a bad game of
cat and mouse running around a goose hunt whacking moles!
Since the rework of the CPU down code no longer had issues with
workqueue messing with THREAD_BOUND, reverting the patches that did
the rework of workqueues fixed the bugs that I was hitting.
Lets fix CPU hotplug today, and leave the redesign of workqueues
for another day.
Comments,
-- Steve
next reply other threads:[~2012-03-01 18:55 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-01 18:55 Steven Rostedt [this message]
2012-03-01 18:55 ` [PATCH RT 1/9][RFC] [PATCH 1/9] timer: Fix hotplug for -rt Steven Rostedt
2012-03-01 18:55 ` [PATCH RT 2/9][RFC] [PATCH 2/9] futex/rt: Fix possible lockup when taking pi_lock in proxy handler Steven Rostedt
2012-03-01 18:55 ` [PATCH RT 3/9][RFC] [PATCH 3/9] lglock/rt: Use non-rt for_each_cpu() in -rt code Steven Rostedt
2012-03-02 7:25 ` Srivatsa S. Bhat
2012-03-02 14:20 ` Steven Rostedt
2012-03-01 18:55 ` [PATCH RT 4/9][RFC] [PATCH 4/9] rtmutex: Add new mutex_lock_savestate() API Steven Rostedt
2012-03-01 18:55 ` [PATCH RT 5/9][RFC] [PATCH 5/9] ring-buffer/rt: Check for irqs disabled before grabbing reader lock Steven Rostedt
2012-03-01 18:55 ` [PATCH RT 6/9][RFC] [PATCH 6/9] sched/rt: Fix wait_task_interactive() to test rt_spin_lock state Steven Rostedt
2012-03-01 18:55 ` [PATCH RT 7/9][RFC] [PATCH 7/9] cpu/rt: Rework cpu down for PREEMPT_RT Steven Rostedt
2012-03-02 14:52 ` Thomas Gleixner
2012-03-02 15:11 ` Steven Rostedt
2012-03-02 15:15 ` Steven Rostedt
2012-03-02 15:20 ` Thomas Gleixner
2012-03-02 15:36 ` Steven Rostedt
2012-03-02 15:39 ` Steven Rostedt
2012-03-02 15:40 ` Steven Rostedt
2012-03-02 15:51 ` Thomas Gleixner
2012-03-01 18:55 ` [PATCH RT 8/9][RFC] [PATCH 8/9] workqueue: Revert workqueue: Fix PF_THREAD_BOUND abuse Steven Rostedt
2012-03-01 18:55 ` [PATCH RT 9/9][RFC] [PATCH 9/9] workqueue: Revert workqueue: Fix cpuhotplug trainwreck Steven Rostedt
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