Commit 262de410 authored by Benjamin Segall's avatar Benjamin Segall Committed by Paolo Bonzini
Browse files

kvm: exit halt polling on need_resched() as well 



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: default avatarBen Segall <bsegall@google.com>
Signed-off-by: default avatarVenkatesh Srinivas <venkateshs@chromium.org>
Message-Id: <20210429162233.116849-1-venkateshs@chromium.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarJim Mattson <jmattson@google.com>
parent d981dd15

virt/kvm/kvm_main.c

+2 −1
Original line number Diff line number Diff line
@@ -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);