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| author |   Pavel Emelyanov <xemul@openvz.org> | 2008-04-16 02:17:42 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2008-04-16 02:17:42 -0700 |
| commit | d0498d9ae1a5cebac363e38907266d5cd2eedf89 (patch) | |
| tree | 7d138b369cfe61652844c964a8f0c6ca72a54bbd /net | |
| parent | [NETNS]: Add netns refcnt debug for network devices. (diff) | |
| download | linux-dev-d0498d9ae1a5cebac363e38907266d5cd2eedf89.tar.xz linux-dev-d0498d9ae1a5cebac363e38907266d5cd2eedf89.zip | |
[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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dev.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 77530e9a34fc..c16a07fde388 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4000,7 +4000,8 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name, alloc_size = (sizeof(*dev) + NETDEV_ALIGN_CONST + (sizeof(struct net_device_subqueue) * (queue_count - 1))) & ~NETDEV_ALIGN_CONST; - alloc_size += sizeof_priv + NETDEV_ALIGN_CONST; + if (sizeof_priv) + alloc_size += sizeof_priv + NETDEV_ALIGN_CONST; p = kzalloc(alloc_size, GFP_KERNEL); if (!p) { |