From: Rusty Russell <rusty@rustcorp.com.au>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Amit Shah <amit.shah@redhat.com>,
netdev@vger.kernel.org, Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH RFC] virtio_net: fix refill related races
Date: Tue, 13 Dec 2011 13:05:11 +1030 [thread overview]
Message-ID: <87iplltd0g.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20111212115405.GB7946@redhat.com>
On Mon, 12 Dec 2011 13:54:06 +0200, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Mon, Dec 12, 2011 at 09:25:07AM +1030, Rusty Russell wrote:
> > Orthogonally, the refill-stop code is still buggy, as you noted.
>
> Sorry I don't understand how it's still buggy.
Both places where we call:
cancel_delayed_work_sync(&vi->refill);
Do not actually guarantee that vi->refill isn't running, because it
can requeue itself. A 'bool no_more_refill' field seems like the
simplest fix for this, but I don't think it's sufficient.
Tejun, is this correct? What's the correct way to synchronously stop a
delayed_work which can "schedule_delayed_work(&vi->refill, HZ/2);" on
itself?
Thanks,
Rusty.
WARNING: multiple messages have this Message-ID (diff)
From: Rusty Russell <rusty@rustcorp.com.au>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Amit Shah <amit.shah@redhat.com>,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH RFC] virtio_net: fix refill related races
Date: Tue, 13 Dec 2011 13:05:11 +1030 [thread overview]
Message-ID: <87iplltd0g.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20111212115405.GB7946@redhat.com>
On Mon, 12 Dec 2011 13:54:06 +0200, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Mon, Dec 12, 2011 at 09:25:07AM +1030, Rusty Russell wrote:
> > Orthogonally, the refill-stop code is still buggy, as you noted.
>
> Sorry I don't understand how it's still buggy.
Both places where we call:
cancel_delayed_work_sync(&vi->refill);
Do not actually guarantee that vi->refill isn't running, because it
can requeue itself. A 'bool no_more_refill' field seems like the
simplest fix for this, but I don't think it's sufficient.
Tejun, is this correct? What's the correct way to synchronously stop a
delayed_work which can "schedule_delayed_work(&vi->refill, HZ/2);" on
itself?
Thanks,
Rusty.
next prev parent reply other threads:[~2011-12-13 2:35 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-07 15:21 [PATCH RFC] virtio_net: fix refill related races Michael S. Tsirkin
2011-12-07 15:21 ` Michael S. Tsirkin
2011-12-08 4:37 ` Rusty Russell
2011-12-08 4:37 ` Rusty Russell
2011-12-08 4:37 ` Rusty Russell
2011-12-11 14:44 ` Michael S. Tsirkin
2011-12-11 14:44 ` Michael S. Tsirkin
2011-12-11 22:55 ` Rusty Russell
2011-12-11 22:55 ` Rusty Russell
2011-12-12 11:54 ` Michael S. Tsirkin
2011-12-12 11:54 ` Michael S. Tsirkin
2011-12-13 2:35 ` Rusty Russell [this message]
2011-12-13 2:35 ` Rusty Russell
2011-12-14 23:54 ` Tejun Heo
2011-12-14 23:54 ` Tejun Heo
2011-12-20 19:09 ` Michael S. Tsirkin
2011-12-20 19:09 ` Michael S. Tsirkin
2011-12-20 19:09 ` Tejun Heo
2011-12-20 19:09 ` Tejun Heo
2011-12-20 19:30 ` Michael S. Tsirkin
2011-12-20 19:30 ` Michael S. Tsirkin
2011-12-20 19:31 ` Tejun Heo
2011-12-20 19:31 ` Tejun Heo
2011-12-20 19:45 ` Michael S. Tsirkin
2011-12-20 19:45 ` Michael S. Tsirkin
2011-12-20 23:43 ` Rusty Russell
2011-12-20 23:43 ` Rusty Russell
2011-12-21 9:06 ` Michael S. Tsirkin
2011-12-21 9:06 ` Michael S. Tsirkin
2011-12-22 3:53 ` Rusty Russell
2011-12-22 3:53 ` Rusty Russell
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