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Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to rem
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call |
Date: |
Wed, 24 Jan 2018 10:14:57 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 |
On 24/01/2018 10:05, Greg Kurz wrote:
> On Wed, 24 Jan 2018 09:46:21 +0100
> Greg Kurz <address@hidden> wrote:
>
>> Please note that Peter usually doesn't work on Wednesdays. The master branch
>> might remain broken for everyone until tomorrow... :-\
>>
>> And I don't think this is the right fix anyway. See below.
>>
>> On Wed, 24 Jan 2018 00:44:14 +0200
>> "Michael S. Tsirkin" <address@hidden> wrote:
>>
>>> From: Jose Ricardo Ziviani <address@hidden>
>>>
>>> This commit partially reverts the commit 4fe6d78b2e because of issues
>>> reported in the virtio.
>>>
>>> Examples:
>>>
>>> $ qemu-system-ppc64 -cpu POWER8 -nographic -vga none -m 4G \
>>> -M pseries,accel=kvm -netdev type=user,id=net0 \
>>> -device virtio-net-pci,netdev=net0 -drive file=../disk.qcow2,if=virtio
>>>
>>> Populating /vdevice/address@hidden
>>> Populating /vdevice/address@hidden
>>> SCSI: Looking for devices
>>> 8200000000000000 CD-ROM : "QEMU QEMU CD-ROM 2.5+"
>>> Populating /address@hidden
>>> 00 0000 (D) : 1af4 1000 virtio [ net ]
>>> Aborted
>>>
>>> $ qemu-system-x86_64 -m 4G -enable-kvm -drive file=util.qcow2,if=virtio
>>>
>>> Running QEMU with GTK 2.x is deprecated, and will be removed
>>> in a future release. Please switch to GTK 3.x instead
>>> [1] 5282 abort
>>>
>>> Reference
>>> http://lists.nongnu.org/archive/html/qemu-devel/2018-01/msg05457.html
>>>
>>> Reported-by: Anton Blanchard <address@hidden>
>>> Signed-off-by: Jose Ricardo Ziviani <address@hidden>
>>> Reviewed-by: Daniel Henrique Barboza <address@hidden>
>>> Tested-by: Daniel Henrique Barboza <address@hidden>
>>> Reviewed-by: Michael S. Tsirkin <address@hidden>
>>> Signed-off-by: Michael S. Tsirkin <address@hidden>
>>> ---
>>> accel/kvm/kvm-all.c | 4 ----
>>> 1 file changed, 4 deletions(-)
>>>
>>> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
>>> index 071f4f5..f290f48 100644
>>> --- a/accel/kvm/kvm-all.c
>>> +++ b/accel/kvm/kvm-all.c
>>> @@ -812,10 +812,6 @@ static void kvm_mem_ioeventfd_del(MemoryListener
>>> *listener,
>>> if (r < 0) {
>>> abort();
>>> }
>>> -
>>> - if (e->cleanup) {
>>> - e->cleanup(e);
>>> - }
>>
>> This looks wrong as the cleanup is expected to do things like closing fds:
>>
>> static void virtio_bus_cleanup_event_notifier(EventNotifier *notifier)
>> {
>> /* Test and clear notifier after disabling event,
>> * in case poll callback didn't have time to run.
>> */
>> virtio_queue_host_notifier_read(notifier);
>> event_notifier_cleanup(notifier);
>> }
>>
>> void event_notifier_cleanup(EventNotifier *e)
>> {
>> if (e->rfd != e->wfd) {
>> close(e->rfd);
>> }
>> close(e->wfd);
>> e->rfd = -1;
>> e->wfd = -1;
>> e->cleanup = NULL;
>> }
>>
>> And indeed, with this patch applied, QEMU leaks eventfds on every machine
>> reset.
>>
>
> Reverting 4fe6d78b2e entirely isn't even enough and QEMU aborts at the
> next machine reset. The following commit must be reverted as well:
>
> commit 6f0bb230722931d17fb284eee8efd40b9d653822
> Author: Gal Hammer <address@hidden>
> Date: Sun Jan 14 12:06:56 2018 +0200
>
> virtio: improve virtio devices initialization time
I'm a bit confused by this patch. The basic idea of wrapping with
transaction_begin/commit is clear (without it you have quadratic
behavior from removing one ioeventfd at a time), but I don't understand
why the new ->cleanup member is needed.
Paolo
- [Qemu-devel] [PULL 0/1] virtio: quick fix, Michael S. Tsirkin, 2018/01/23
- [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call, Michael S. Tsirkin, 2018/01/23
- Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call, Greg Kurz, 2018/01/24
- Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call, Greg Kurz, 2018/01/24
- Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call,
Paolo Bonzini <=
- Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call, Greg Kurz, 2018/01/24
- Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call, Paolo Bonzini, 2018/01/24
- Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call, Michael S. Tsirkin, 2018/01/24
- Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call, Gal Hammer, 2018/01/28
- Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call, Michael S. Tsirkin, 2018/01/28
- Re: [Qemu-devel] [PULL 1/1] kvm-all: Partially reverts 4fe6d78b2e to remove the cleanup call, Gal Hammer, 2018/01/29
Re: [Qemu-devel] [PULL 0/1] virtio: quick fix, Peter Maydell, 2018/01/24