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From: "Jörn Engel" <joern@logfs.org>
To: David Miller <davem@davemloft.net>
Cc: virtio-dev@lists.oasis-open.org, anatol.pomozov@gmail.com,
	mst@redhat.com, gregkh@linuxfoundation.org,
	linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, qinchuanyu@huawei.com
Subject: Re: [PATCH net 1/3] kref: add kref_sub_return
Date: Wed, 12 Feb 2014 20:25:48 -0500	[thread overview]
Message-ID: <20140213012548.GA20953@logfs.org> (raw)
In-Reply-To: <20140212.190637.328045386111912135.davem@davemloft.net>

On Wed, 12 February 2014 19:06:37 -0500, David Miller wrote:
> 
> It isn't being used to determine when to destroy things.
> 
> They use it to as a heuristic of when to trigger polling.
> 
> Each ubuf attached gets a kref to the higher level virtio_net buffer
> holding object, they want to trigger polling when that reference drops
> to 1 or lower.
> 
> Right now they are reading the atomic refcount directly, which
> I think is much worse than this helper.

I disagree.  Reading the refcount directly is leaving noone under any
illusion that this might be a good idea.

Jörn

--
Victory in war is not repetitious.
-- Sun Tzu
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WARNING: multiple messages have this Message-ID (diff)
From: "Jörn Engel" <joern@logfs.org>
To: David Miller <davem@davemloft.net>
Cc: gregkh@linuxfoundation.org, mst@redhat.com,
	linux-kernel@vger.kernel.org, jasowang@redhat.com,
	virtio-dev@lists.oasis-open.org,
	virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, qinchuanyu@huawei.com,
	anatol.pomozov@gmail.com, nab@linux-iscsi.org
Subject: Re: [PATCH net 1/3] kref: add kref_sub_return
Date: Wed, 12 Feb 2014 20:25:48 -0500	[thread overview]
Message-ID: <20140213012548.GA20953@logfs.org> (raw)
In-Reply-To: <20140212.190637.328045386111912135.davem@davemloft.net>

On Wed, 12 February 2014 19:06:37 -0500, David Miller wrote:
> 
> It isn't being used to determine when to destroy things.
> 
> They use it to as a heuristic of when to trigger polling.
> 
> Each ubuf attached gets a kref to the higher level virtio_net buffer
> holding object, they want to trigger polling when that reference drops
> to 1 or lower.
> 
> Right now they are reading the atomic refcount directly, which
> I think is much worse than this helper.

I disagree.  Reading the refcount directly is leaving noone under any
illusion that this might be a good idea.

Jörn

--
Victory in war is not repetitious.
-- Sun Tzu

  reply	other threads:[~2014-02-13  1:25 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-12 16:37 [PATCH net 0/3] vhost fixes for 3.14, -stable Michael S. Tsirkin
2014-02-12 16:37 ` Michael S. Tsirkin
2014-02-12 16:36 ` [PATCH net 3/3] vhost: fix a theoretical race in device cleanup Michael S. Tsirkin
2014-02-12 16:36   ` Michael S. Tsirkin
2014-02-12 16:38 ` [PATCH net 2/3] vhost: fix ref cnt checking deadlock Michael S. Tsirkin
2014-02-12 16:38   ` Michael S. Tsirkin
2014-02-12 16:38 ` [PATCH net 1/3] kref: add kref_sub_return Michael S. Tsirkin
2014-02-12 16:38   ` Michael S. Tsirkin
2014-02-12 16:56   ` Greg Kroah-Hartman
2014-02-12 16:56     ` Greg Kroah-Hartman
2014-02-12 17:35     ` Michael S. Tsirkin
2014-02-12 17:35     ` Michael S. Tsirkin
2014-02-12 18:37       ` Greg Kroah-Hartman
2014-02-12 18:37         ` Greg Kroah-Hartman
2014-02-12 18:39       ` Anatol Pomozov
2014-02-12 18:39       ` Anatol Pomozov
2014-02-13  0:06     ` David Miller
2014-02-13  0:06       ` David Miller
2014-02-13  1:25       ` Jörn Engel [this message]
2014-02-13  1:25         ` Jörn Engel
2014-02-13  1:39       ` Greg KH
2014-02-13  1:39         ` Greg KH
2014-02-13  4:05         ` David Miller
2014-02-13  4:05           ` David Miller
2014-02-13  4:09           ` David Miller
2014-02-13  4:09             ` David Miller
2014-02-14  0:03             ` Greg KH
2014-02-14  0:03               ` Greg KH
2014-02-14  5:10               ` David Miller
2014-02-14  5:10                 ` David Miller

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