Messages in this thread | | | Date | Thu, 01 Mar 2012 13:55:27 -0500 | From | Steven Rostedt <> | Subject | [PATCH RT 0/9][RFC] rt: Fix hotplugging and other nasties |
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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
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