From: Anthony Liguori <anthony@codemonkey.ws>
To: Amit Shah <amit.shah@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
qemu list <qemu-devel@nongnu.org>,
Juan Quintela <quintela@redhat.com>
Subject: [Qemu-devel] Re: [PATCH v6 18/18] virtio-serial-bus: wake up iothread upon guest read notification
Date: Wed, 28 Apr 2010 08:25:59 -0500 [thread overview]
Message-ID: <4BD83767.7040806@codemonkey.ws> (raw)
In-Reply-To: <20100428072921.GT27314@amit-x200.redhat.com>
On 04/28/2010 02:29 AM, Amit Shah wrote:
> On (Tue) Apr 27 2010 [12:41:27], Anthony Liguori wrote:
>
>> On 04/27/2010 07:34 AM, Amit Shah wrote:
>>
>>> From: Marcelo Tosatti<mtosatti@redhat.com>
>>>
>>> Wake up iothread when buffers are consumed.
>>>
>>> Signed-off-by: Marcelo Tosatti<mtosatti@redhat.com>
>>> Signed-off-by: Amit Shah<amit.shah@redhat.com>
>>>
>>>
>> What's the race here? This looks very odd to me.
>>
> When the guest indicates it has added buffers to the vq, the iothread
> can then start consuming them. Without this notification, the iothread
> only polls for free buffers when it times out or gets woken up
> otherwise.
>
When you say, polls for free buffers, what do you mean by that?
You mean, there's a can_read() somewhere that checks for free buffers?
I think switching to qemu_set_fd_handler() would be a better solution.
Regards,
Anthony Liguori
> Other virtio devices do it similarly as well.
>
> Amit
>
next prev parent reply other threads:[~2010-04-28 13:26 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-27 12:33 [Qemu-devel] [PATCH v6 00/18] PULL: virtio-serial fixes Amit Shah
2010-04-27 12:33 ` [Qemu-devel] [PATCH v6 01/18] virtio-serial: save/load: Ensure target has enough ports Amit Shah
2010-04-27 12:33 ` [Qemu-devel] [PATCH v6 02/18] virtio-serial: save/load: Ensure nr_ports on src and dest are same Amit Shah
2010-04-27 12:33 ` [Qemu-devel] [PATCH v6 03/18] virtio-serial: save/load: Ensure we have hot-plugged ports instantiated Amit Shah
2010-04-27 12:33 ` [Qemu-devel] [PATCH v6 04/18] virtio-serial: save/load: Send target host connection status if different Amit Shah
2010-04-27 12:33 ` [Qemu-devel] [PATCH v6 05/18] virtio-serial: Use control messages to notify guest of new ports Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 06/18] virtio-serial: whitespace: match surrounding code Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 07/18] virtio-serial: Remove redundant check for 0-sized write request Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 08/18] virtio-serial: Update copyright year to 2010 Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 09/18] virtio-serial: Propagate errors in initialising ports / devices in guest Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 10/18] virtio-serial: Send out guest data to ports only if port is opened Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 11/18] iov: Introduce a new file for helpers around iovs, add iov_from_buf() Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 12/18] iov: Add iov_to_buf and iov_size helpers Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 13/18] virtio-serial: Handle scatter-gather buffers for control messages Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 14/18] virtio-serial: Handle scatter/gather input from the guest Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 15/18] virtio-serial: Apps should consume all data that guest sends out / Fix virtio api abuse Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 16/18] virtio-serial: Discard data that guest sends us when ports aren't connected Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 17/18] virtio-serial: Implement flow control for individual ports Amit Shah
2010-04-27 12:34 ` [Qemu-devel] [PATCH v6 18/18] virtio-serial-bus: wake up iothread upon guest read notification Amit Shah
2010-04-27 17:41 ` [Qemu-devel] " Anthony Liguori
2010-04-27 17:58 ` Marcelo Tosatti
2010-04-27 18:13 ` Anthony Liguori
2010-04-28 7:29 ` Amit Shah
2010-04-28 13:25 ` Anthony Liguori [this message]
2010-04-28 16:34 ` Amit Shah
2010-04-27 17:37 ` [Qemu-devel] Re: [PATCH v6 05/18] virtio-serial: Use control messages to notify guest of new ports Anthony Liguori
2010-04-28 4:27 ` Amit Shah
2010-04-28 13:26 ` Anthony Liguori
2010-04-28 17:54 ` [Qemu-devel] Re: [PATCH v6 01/18] virtio-serial: save/load: Ensure target has enough ports Anthony Liguori
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