Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1216080
| From | Jason Wang <jasowang@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses |
| Date | 2015-08-31 10:10 +0200 |
| Message-ID | <q3sk9-1RI-13@gated-at.bofh.it> (permalink) |
| References | (1 earlier) <q1iyE-2ao-53@gated-at.bofh.it> <q1l3s-5zR-13@gated-at.bofh.it> <q1BhT-4vP-3@gated-at.bofh.it> <q3nNv-3L4-1@gated-at.bofh.it> <q3rHs-T1-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 08/31/2015 03:29 PM, Michael S. Tsirkin wrote:
>>>>> Thinking more about this, invoking the 0-length write after
>>>>> > >> > the != 0 length one would be better: it would mean we only
>>>>> > >> > handle the userspace MMIO like this.
>>> > > Right.
>>> > >
>> >
>> > Using current unittest. This patch is about 2.9% slower than before, and
>> > invoking 0-length write after is still 1.1% slower (mmio-datamatch-eventfd).
>> >
>> > /patch/result/-+%/
>> > /base/2957/0/
>> > /V3/3043/+2.9%/
>> > /V3+invoking != 0 length first/2990/+1.1%/
>> >
>> > So looks like the best method is not searching KVM_FAST_MMIO_BUS during
>> > KVM_MMIO_BUS. Instead, let userspace to register both datamatch and
>> > wildcard in this case. Does this sound good to you?
> No - we can't change userspace.
Actually, the change was as simple as following. So I don't get the
reason why.
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 9935029..42ee986 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -288,6 +288,8 @@ static int
virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,
if (modern) {
memory_region_add_eventfd(modern_mr, modern_addr, 2,
true, n, notifier);
+ memory_region_add_eventfd(modern_mr, modern_addr, 0,
+ false, n, notifier);
}
if (legacy) {
memory_region_add_eventfd(legacy_mr, legacy_addr, 2,
@@ -297,6 +299,8 @@ static int
virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,
if (modern) {
memory_region_del_eventfd(modern_mr, modern_addr, 2,
true, n, notifier);
+ memory_region_del_eventfd(modern_mr, modern_addr, 0,
+ false, n, notifier);
}
if (legacy) {
memory_region_del_eventfd(legacy_mr, legacy_addr, 2,
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH V3 1/3] kvm: use kmalloc() instead of kzalloc() during iodev register/unregister Jason Wang <jasowang@redhat.com> - 2015-08-25 11:20 +0200
[PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses Jason Wang <jasowang@redhat.com> - 2015-08-25 11:20 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses Cornelia Huck <cornelia.huck@de.ibm.com> - 2015-08-25 13:00 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses "Michael S. Tsirkin" <mst@redhat.com> - 2015-08-25 13:40 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses "Michael S. Tsirkin" <mst@redhat.com> - 2015-08-25 14:00 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses Jason Wang <jasowang@redhat.com> - 2015-08-26 07:20 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses Jason Wang <jasowang@redhat.com> - 2015-08-31 05:20 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses "Michael S. Tsirkin" <mst@redhat.com> - 2015-08-31 09:30 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses Jason Wang <jasowang@redhat.com> - 2015-08-31 10:10 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses "Michael S. Tsirkin" <mst@redhat.com> - 2015-08-31 13:40 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses Jason Wang <jasowang@redhat.com> - 2015-09-01 05:40 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses "Michael S. Tsirkin" <mst@redhat.com> - 2015-09-01 06:40 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses Jason Wang <jasowang@redhat.com> - 2015-09-01 06:50 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses "Michael S. Tsirkin" <mst@redhat.com> - 2015-09-01 09:00 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses Jason Wang <jasowang@redhat.com> - 2015-09-01 10:30 +0200
Re: [PATCH V3 2/3] kvm: don't register wildcard MMIO EVENTFD on two buses "Michael S. Tsirkin" <mst@redhat.com> - 2015-09-01 10:40 +0200
[PATCH V3 3/3] kvm: add tracepoint for fast mmio Jason Wang <jasowang@redhat.com> - 2015-08-25 11:20 +0200
Re: [PATCH V3 3/3] kvm: add tracepoint for fast mmio "Michael S. Tsirkin" <mst@redhat.com> - 2015-08-25 13:40 +0200
csiph-web