From: "Michael S. Tsirkin" <mst@redhat.com>
To: Michael Dalton <mwdalton@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
lf-virt <virtualization@lists.linux-foundation.org>,
Eric Dumazet <edumazet@google.com>
Subject: Re: [PATCH net] virtio-net: fix page refcnt leaking when fail to allocate frag skb
Date: Wed, 20 Nov 2013 11:06:27 +0200 [thread overview]
Message-ID: <20131120090627.GE19341@redhat.com> (raw)
In-Reply-To: <CANJ5vPKmP6rFsBgMGFM8DcuGww7B9PxJMSBkUMHNZOa7LJOA2g@mail.gmail.com>
On Tue, Nov 19, 2013 at 01:38:16PM -0800, Michael Dalton wrote:
> Great catch Jason. I agree this now raises the larger issue of how to
> handle a memory alloc failure in the middle of receive. As Eric mentioned,
> we can drop the packet and free the remaining (num_buf) frags.
>
> Michael, perhaps I'm missing something, but why would you prefer
> pre-allocating buffers in this case? If the guest kernel is OOM'ing,
> dropping packets should provide backpressure.
>
> Also, we could just as easily fail the initial skb alloc in page_to_skb,
> and I think that case also needs to be handled now in the same fashion as
> a memory allocation failure in receive_mergeable.
>
> Best,
>
> Mike
Yes I missed this last night. Thanks a lot Eric and Michael for pointing
this out.
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Michael Dalton <mwdalton@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
Jason Wang <jasowang@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
lf-virt <virtualization@lists.linux-foundation.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Eric Dumazet <edumazet@google.com>
Subject: Re: [PATCH net] virtio-net: fix page refcnt leaking when fail to allocate frag skb
Date: Wed, 20 Nov 2013 11:06:27 +0200 [thread overview]
Message-ID: <20131120090627.GE19341@redhat.com> (raw)
In-Reply-To: <CANJ5vPKmP6rFsBgMGFM8DcuGww7B9PxJMSBkUMHNZOa7LJOA2g@mail.gmail.com>
On Tue, Nov 19, 2013 at 01:38:16PM -0800, Michael Dalton wrote:
> Great catch Jason. I agree this now raises the larger issue of how to
> handle a memory alloc failure in the middle of receive. As Eric mentioned,
> we can drop the packet and free the remaining (num_buf) frags.
>
> Michael, perhaps I'm missing something, but why would you prefer
> pre-allocating buffers in this case? If the guest kernel is OOM'ing,
> dropping packets should provide backpressure.
>
> Also, we could just as easily fail the initial skb alloc in page_to_skb,
> and I think that case also needs to be handled now in the same fashion as
> a memory allocation failure in receive_mergeable.
>
> Best,
>
> Mike
Yes I missed this last night. Thanks a lot Eric and Michael for pointing
this out.
next prev parent reply other threads:[~2013-11-20 9:06 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-19 8:05 [PATCH net] virtio-net: fix page refcnt leaking when fail to allocate frag skb Jason Wang
2013-11-19 8:05 ` Jason Wang
2013-11-19 14:03 ` Eric Dumazet
2013-11-19 14:03 ` Eric Dumazet
2013-11-19 18:44 ` Michael S. Tsirkin
2013-11-19 18:44 ` Michael S. Tsirkin
2013-11-19 20:49 ` Michael S. Tsirkin
2013-11-19 20:49 ` Michael S. Tsirkin
2013-11-19 21:36 ` Eric Dumazet
2013-11-19 21:36 ` Eric Dumazet
2013-11-19 21:53 ` Michael S. Tsirkin
2013-11-19 21:53 ` Michael S. Tsirkin
2013-11-19 22:00 ` Eric Dumazet
2013-11-19 22:00 ` Eric Dumazet
2013-11-20 1:34 ` Michael Dalton
2013-11-20 1:34 ` Michael Dalton
2013-11-20 3:17 ` Jason Wang
2013-11-20 3:17 ` Jason Wang
2013-11-20 9:00 ` Michael S. Tsirkin
2013-11-20 9:00 ` Michael S. Tsirkin
2013-11-20 8:58 ` Michael S. Tsirkin
2013-11-20 8:58 ` Michael S. Tsirkin
2013-11-20 15:16 ` Eric Dumazet
2013-11-20 15:16 ` Eric Dumazet
2013-11-20 16:06 ` Michael S. Tsirkin
2013-11-20 16:06 ` Michael S. Tsirkin
2013-11-20 16:14 ` Eric Dumazet
2013-11-20 16:14 ` Eric Dumazet
2013-11-20 17:03 ` Michael S. Tsirkin
2013-11-20 17:03 ` Michael S. Tsirkin
2013-11-19 21:38 ` Michael Dalton
2013-11-19 21:38 ` Michael Dalton
2013-11-20 9:06 ` Michael S. Tsirkin [this message]
2013-11-20 9:06 ` Michael S. Tsirkin
2013-11-20 3:05 ` Jason Wang
2013-11-20 3:05 ` Jason Wang
2013-11-20 3:00 ` Jason Wang
2013-11-20 3:00 ` Jason Wang
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