Revert "CPU hotplug, cpusets, suspend: Don't touch cpusets during suspend/resume"
authorLinus Torvalds <torvalds@linux-foundation.org>
Wed, 7 Mar 2012 16:21:19 +0000 (08:21 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 7 Mar 2012 16:21:19 +0000 (08:21 -0800)
commit4293f20c19f44ca66e5ac836b411d25e14b9f185
tree4f9ab09ca1f775907af2a78ebb8754b945570d39
parentdac12d1f5ef228e132c2457dc214e0703533b016
Revert "CPU hotplug, cpusets, suspend: Don't touch cpusets during suspend/resume"

This reverts commit 8f2f748b0656257153bcf0941df8d6060acc5ca6.

It causes some odd regression that we have not figured out, and it's too
late in the -rc series to try to figure it out now.

As reported by Konstantin Khlebnikov, it causes consistent hangs on his
laptop (Thinkpad x220: 2x cores + HT).  They can be avoided by adding
calls to "rebuild_sched_domains();" in cpuset_cpu_[in]active() for the
CPU_{ONLINE/DOWN_FAILED/DOWN_PREPARE}_FROZEN cases, but it's not at all
clear why, and it makes no sense.

Konstantin's config doesn't even have CONFIG_CPUSETS enabled, just to
make things even more interesting.  So it's not the cpusets, it's just
the scheduling domains.

So until this is understood, revert.

Bisected-reported-and-tested-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/sched/core.c