From: "Radim Krčmář" <rkrcmar@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Christoffer Dall <cdall@linaro.org>,
Andrew Jones <drjones@redhat.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Cornelia Huck <cornelia.huck@de.ibm.com>,
James Hogan <james.hogan@imgtec.com>,
Paul Mackerras <paulus@ozlabs.org>
Subject: [PATCH 6/6] KVM: perform a wake_up in kvm_make_all_cpus_request
Date: Thu, 6 Apr 2017 22:20:56 +0200 [thread overview]
Message-ID: <20170406202056.18379-7-rkrcmar@redhat.com> (raw)
In-Reply-To: <20170406202056.18379-1-rkrcmar@redhat.com>
We want to have kvm_make_all_cpus_request() to be an optmized version of
kvm_for_each_vcpu(i, vcpu, kvm) {
kvm_make_request(vcpu, request);
kvm_vcpu_kick(vcpu);
}
and kvm_vcpu_kick() wakes up the target vcpu. We know which requests do
not need the wake up and use it to optimize the loop.
Thanks to that, this patch doesn't change the behavior of current users
(the all don't need the wake up) and only prepares for future where the
wake up is going to be needed.
I think that most requests do not need the wake up, so we would flip the
bit then.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
virt/kvm/kvm_main.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a486c6ad27a6..1db503bab3dc 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -186,6 +186,9 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
/* Set ->requests bit before we read ->mode. */
smp_mb__after_atomic();
+ if (!(req & KVM_REQUEST_NO_WAKEUP))
+ kvm_vcpu_wake_up(vcpu);
+
if (cpus != NULL && cpu != -1 && cpu != me &&
kvm_arch_vcpu_should_kick(vcpu))
cpumask_set_cpu(cpu, cpus);
--
2.12.0
next prev parent reply other threads:[~2017-04-06 20:21 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-06 20:20 [PATCH 0/6] KVM: towards maintainable kvm_make_all_cpus_request() Radim Krčmář
2017-04-06 20:20 ` [PATCH RFC 1/6] KVM: fix guest_mode optimization in kvm_make_all_cpus_request() Radim Krčmář
2017-04-06 21:02 ` James Hogan
2017-04-10 15:59 ` Andrew Jones
2017-04-11 10:43 ` James Hogan
2017-04-11 5:25 ` Paolo Bonzini
2017-04-11 9:37 ` James Hogan
2017-04-11 19:31 ` Radim Krčmář
2017-04-11 19:45 ` Paolo Bonzini
2017-04-11 20:45 ` Radim Krčmář
2017-04-12 0:15 ` Paolo Bonzini
2017-04-07 10:47 ` Christian Borntraeger
2017-04-06 20:20 ` [PATCH 2/6] KVM: use kvm_{test,clear}_request instead of {test,clear}_bit Radim Krčmář
2017-04-07 10:55 ` Christian Borntraeger
2017-04-07 12:24 ` Radim Krčmář
2017-04-07 14:05 ` Radim Krčmář
2017-04-06 20:20 ` [PATCH 3/6] KVM: x86: use kvm_make_request instead of set_bit Radim Krčmář
2017-04-07 8:18 ` David Hildenbrand
2017-04-06 20:20 ` [PATCH 4/6] KVM: remove #ifndef CONFIG_S390 around kvm_vcpu_wake_up Radim Krčmář
2017-04-07 11:01 ` Christian Borntraeger
2017-04-06 20:20 ` [PATCH RFC 5/6] KVM: mark requests that do not need a wakeup Radim Krčmář
2017-04-07 8:27 ` Marc Zyngier
2017-04-07 12:29 ` Radim Krčmář
2017-04-06 20:20 ` Radim Krčmář [this message]
2017-04-10 11:14 ` [PATCH 6/6] KVM: perform a wake_up in kvm_make_all_cpus_request Andrew Jones
2017-04-11 5:34 ` Paolo Bonzini
2017-04-11 12:04 ` Andrew Jones
2017-04-11 5:37 ` Paolo Bonzini
2017-04-11 8:55 ` Paolo Bonzini
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