From: Pavel Emelyanov <xemul@openvz.org>
Date: Wed, 16 Apr 2008 09:17:42 +0000 (-0700)
Subject: [NET]: Do not allocate unneeded memory for dev->priv alignment.
X-Git-Tag: v2.6.26-rc1~1138^2~14
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d0498d9ae1a5cebac363e38907266d5cd2eedf89;p=pandora-kernel.git

[NET]: Do not allocate unneeded memory for dev->priv alignment.

The alloc_netdev_mq() tries to produce 32-bytes alignment for both
the net_device itself and its private data. The second alignment is
achieved by adding the NETDEV_ALIGN_CONST to the whole size of
the memory to be allocated.

However, for those devices that do not need the private area, this
addition just makes the net_device weight 1024 + 32 = 1068 bytes,
i.e. consume twice as much memory.

Since loopback device is such (sizeof_priv == 0 for it), and each
net namespace creates one, this can save a noticeable amount of
memory for kernel with net namespaces turned on.

After this set the lo device is actually allocated from a size-1024
kmem cache on i386 box even with NETPOLL and WIRELESS_EXT turned on.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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