tree 20a699807d78bc0af86b19443dc751415c0cc6f7
parent 93d81d1aca26e64a75d06a85f7e128b5f49053e7
author Peter Zijlstra <a.p.zijlstra@chello.nl> 1231943786 +0100
committer Ingo Molnar <mingo@elte.hu> 1231952940 +0100

mutex: preemption fixes

The problem is that dropping the spinlock right before schedule is a voluntary
preemption point and can cause a schedule, right after which we schedule again.

Fix this inefficiency by keeping preemption disabled until we schedule, do this
by explicity disabling preemption and providing a schedule() variant that
assumes preemption is already disabled.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>