Messages in this thread Patch in this message | | | From | Pan Xinhui <> | Subject | [PATCH v2] locking/pvqspinlock: Wait early if vCPU is preempted | Date | Tue, 10 Jan 2017 02:56:46 -0500 |
| |
If prev node is not in runnig state or its vCPU is preempted, we can give up our vCPU slices ASAP in pv_wait_node. After commit d9345c65eb79 ("sched/core: Introduce the vcpu_is_preempted(cpu) interface") kernel has knowledge of one vCPU is running or not.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> --- v2: rewrite the commit message as Ingo pointed out the mistake. --- kernel/locking/qspinlock_paravirt.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index e3b5520..48648dc 100644 --- a/kernel/locking/qspinlock_paravirt.h +++ b/kernel/locking/qspinlock_paravirt.h @@ -263,7 +263,8 @@ pv_wait_early(struct pv_node *prev, int loop) if ((loop & PV_PREV_CHECK_MASK) != 0) return false; - return READ_ONCE(prev->state) != vcpu_running; + return READ_ONCE(prev->state) != vcpu_running || + vcpu_is_preempted(prev->cpu); } /* -- 2.4.11
| |