| Message ID | 87B246BB5ED53A4C98E4F9A35839EDE128F715AD@nkgeml506-mbs.china.huawei.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Jul 18, 2014 at 09:33:42AM +0000, Wangkai (Kevin,C) wrote: > fix vcpu long time io blocking on tap, when too many packets was delivered > to the guest os via tap interface. > > -- > Signed-off-by: Wangkai <wangkai86@huawei.com> Thanks, applied to my net-next tree: https://github.com/stefanha/qemu/commits/net-next The patch did not apply cleanly so I had to do it manually: Applying: Tap: fix vcpu long time io blocking on tap fatal: corrupt patch at line 32 Repository lacks necessary blobs to fall back on 3-way merge. Cannot fall back to three-way merge. Patch failed at 0001 Tap: fix vcpu long time io blocking on tap Please use git-send-email(1). I also adjusted the commit message and doc comments to fit QEMU style and for grammar. Stefan
> -----Original Message----- > From: Stefan Hajnoczi [mailto:stefanha@gmail.com] > Sent: Monday, July 28, 2014 11:53 PM > To: Wangkai (Kevin,C) > Cc: qemu-devel@nongnu.org; Lee yang; aliguori@amazon.com; Stefan > Hajnoczi > Subject: Re: [Qemu-devel] [PATCH v2] Tap: fix vcpu long time io > blocking on tap > > On Fri, Jul 18, 2014 at 09:33:42AM +0000, Wangkai (Kevin,C) wrote: > > fix vcpu long time io blocking on tap, when too many packets was > > delivered to the guest os via tap interface. > > > > -- > > Signed-off-by: Wangkai <wangkai86@huawei.com> > > Thanks, applied to my net-next tree: > https://github.com/stefanha/qemu/commits/net-next > > The patch did not apply cleanly so I had to do it manually: > > Applying: Tap: fix vcpu long time io blocking on tap > fatal: corrupt patch at line 32 > Repository lacks necessary blobs to fall back on 3-way merge. > Cannot fall back to three-way merge. > Patch failed at 0001 Tap: fix vcpu long time io blocking on tap > > Please use git-send-email(1). > > I also adjusted the commit message and doc comments to fit QEMU style > and for grammar. > > Stefan [Wangkai (Kevin,C)] Hi Stefan, I will send a patch v3 use git send-email to you. Wangkai
On Tue, Jul 29, 2014 at 1:02 PM, Wangkai (Kevin,C) <wangkai86@huawei.com> wrote: > > >> -----Original Message----- >> From: Stefan Hajnoczi [mailto:stefanha@gmail.com] >> Sent: Monday, July 28, 2014 11:53 PM >> To: Wangkai (Kevin,C) >> Cc: qemu-devel@nongnu.org; Lee yang; aliguori@amazon.com; Stefan >> Hajnoczi >> Subject: Re: [Qemu-devel] [PATCH v2] Tap: fix vcpu long time io >> blocking on tap >> >> On Fri, Jul 18, 2014 at 09:33:42AM +0000, Wangkai (Kevin,C) wrote: >> > fix vcpu long time io blocking on tap, when too many packets was >> > delivered to the guest os via tap interface. >> > >> > -- >> > Signed-off-by: Wangkai <wangkai86@huawei.com> >> >> Thanks, applied to my net-next tree: >> https://github.com/stefanha/qemu/commits/net-next >> >> The patch did not apply cleanly so I had to do it manually: >> >> Applying: Tap: fix vcpu long time io blocking on tap >> fatal: corrupt patch at line 32 >> Repository lacks necessary blobs to fall back on 3-way merge. >> Cannot fall back to three-way merge. >> Patch failed at 0001 Tap: fix vcpu long time io blocking on tap >> >> Please use git-send-email(1). >> >> I also adjusted the commit message and doc comments to fit QEMU style >> and for grammar. >> >> Stefan > [Wangkai (Kevin,C)] > > > Hi Stefan, > I will send a patch v3 use git send-email to you. There is no need, I have already applied v2. Thanks, Stefan
diff --git a/net/tap.c b/net/tap.c index a40f7f0..1da6d89 100644 --- a/net/tap.c +++ b/net/tap.c @@ -189,6 +189,7 @@ static void tap_send(void *opaque) { TAPState *s = opaque; int size; + int packets = 0; while (qemu_can_send_packet(&s->nc)) { uint8_t *buf = s->buf; @@ -210,6 +211,19 @@ static void tap_send(void *opaque) } else if (size < 0) { break; } + + /* + * When receive packets on tap, QEMU io was locked, if too many + * packets was delivered to the guest os via tap interface, + * tap_send() would keep looping, if then the VM required a io + * operation, would be blocked for a long time. + * Here we set the number to limit one tap interface receive time, + * keep io events fair and lock time little. + */ + packets++; + if (packets >= 50) { + break; + } } }
fix vcpu long time io blocking on tap, when too many packets was delivered to the guest os via tap interface. -- Signed-off-by: Wangkai <wangkai86@huawei.com> -- 2.0.0