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authorPavel Emelyanov <xemul@openvz.org>2008-03-27 02:27:22 +0300
committerDavid S. Miller <davem@davemloft.net>2008-03-27 02:27:22 +0300
commit67727184f28c38d06013c6659560bb046c1d9f9c (patch)
treefce5871c7fe554e05aa61fcc2d2d86afe7befdbc /include
parent789e41e6f496022ac1639aaae38ea1943606a9d0 (diff)
downloadlinux-67727184f28c38d06013c6659560bb046c1d9f9c.tar.xz
[VLAN]: Reduce memory consumed by vlan_groups
Currently each vlan_groupd contains 8 pointers on arrays with 512 pointers on struct net_device each :) Such a construction "in many cases ... wastes memory". My proposal is to allow for some of these arrays pointers be NULL, meaning that there are no devices in it. When a new device is added to the vlan_group, the appropriate array is allocated. The check in vlan_group_get_device's is safe, since the pointer vg->vlan_devices_arrays[x] can only switch from NULL to not-NULL. The vlan_group_prealloc_vid() is guarded with rtnl lock and is also safe. I've checked (I hope that) all the places, that use these arrays and found, that the register_vlan_dev is the only place, that can put a vlan device on an empty vlan_group. Rough calculations shows, that after the patch a setup with a single vlan dev (or up to 512 vlans with sequential vids) will occupy approximately 8 times less memory. The question I have is - does this patch makes sense, or a totally new structures are required to store the vlan_devs? Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'include')
-rw-r--r--include/linux/if_vlan.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index 79504b22a932..edd55af7ebd6 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -93,7 +93,7 @@ static inline struct net_device *vlan_group_get_device(struct vlan_group *vg,
{
struct net_device **array;
array = vg->vlan_devices_arrays[vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
- return array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN];
+ return array ? array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN] : NULL;
}
static inline void vlan_group_set_device(struct vlan_group *vg,