On 30/04/21 19:43, Christian Borntraeger wrote:
On 29.04.21 18:22, Venkatesh Srinivas wrote:
From: Benjamin Segall <bsegall@xxxxxxxxxx>
single_task_running() is usually more general than need_resched()
but CFS_BANDWIDTH throttling will use resched_task() when there
is just one task to get the task to block. This was causing
long-need_resched warnings and was likely allowing VMs to
overrun their quota when halt polling.
Signed-off-by: Ben Segall <bsegall@xxxxxxxxxx>
Signed-off-by: Venkatesh Srinivas <venkateshs@xxxxxxxxxxxx>
would that qualify for stable?
Good idea indeed, I added the Cc.
Paolo
---
virt/kvm/kvm_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2799c6660cce..b9f12da6af0e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2973,7 +2973,8 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
goto out;
}
poll_end = cur = ktime_get();
- } while (single_task_running() && ktime_before(cur, stop));
+ } while (single_task_running() && !need_resched() &&
+ ktime_before(cur, stop));
}
prepare_to_rcuwait(&vcpu->wait);
