]> git.baikalelectronics.ru Git - kernel.git/commit
KVM/s390: Set preempted flag during vcpu wakeup and interrupt delivery
authorMichael Mueller <mimu@linux.vnet.ibm.com>
Wed, 26 Feb 2014 15:14:19 +0000 (16:14 +0100)
committerPaolo Bonzini <pbonzini@redhat.com>
Wed, 26 Feb 2014 16:32:12 +0000 (17:32 +0100)
commit1beb91b80fcb39c490d579c27d8850a14b01930c
tree31aa15f442745714842aff4aba4049096af3b2d4
parenteff0f90577e0bac09d4aefa647f80c6d9582f8ec
KVM/s390: Set preempted flag during vcpu wakeup and interrupt delivery

Commit "kvm: Record the preemption status of vcpus using preempt notifiers"
caused a performance regression on s390. It turned out that in the case that
if a former sleeping cpu, that was woken up, this cpu is not a yield candidate
since it gave up the cpu voluntarily. To retain this candiate its preempted
flag is set during wakeup and interrupt delivery time.

Significant performance measurement work and code analysis to solve this
issue was provided by Mao Chuan Li and his team in Beijing.

Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
arch/s390/kvm/interrupt.c