From: David Miller <davem@davemloft.net>
To: jasowang@redhat.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
mst@redhat.com, stefanha@redhat.com, gregory.v.rose@intel.com
Subject: Re: [PATCH net V2 2/2] macvtap: limit head length of skb allocated
Date: Thu, 14 Nov 2013 16:06:44 -0500 (EST) [thread overview]
Message-ID: <20131114.160644.936677620948788988.davem@davemloft.net> (raw)
In-Reply-To: <1384322440-29038-2-git-send-email-jasowang@redhat.com>
From: Jason Wang <jasowang@redhat.com>
Date: Wed, 13 Nov 2013 14:00:40 +0800
> We currently use hdr_len as a hint of head length which is advertised by
> guest. But when guest advertise a very big value, it can lead to an 64K+
> allocating of kmalloc() which has a very high possibility of failure when host
> memory is fragmented or under heavy stress. The huge hdr_len also reduce the
> effect of zerocopy or even disable if a gso skb is linearized in guest.
>
> To solves those issues, this patch introduces an upper limit (PAGE_SIZE) of the
> head, which guarantees an order 0 allocation each time.
>
> Cc: Stefan Hajnoczi <stefanha@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Applied and queued up for -stable.
next prev parent reply other threads:[~2013-11-14 21:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-13 6:00 [PATCH net V2 1/2] tuntap: limit head length of skb allocated Jason Wang
2013-11-13 6:00 ` [PATCH net V2 2/2] macvtap: " Jason Wang
2013-11-14 21:06 ` David Miller [this message]
2013-11-14 21:06 ` [PATCH net V2 1/2] tuntap: " David Miller
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