From a767f680e34bf14a36fefbbb6d85783eef99fd57 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Tue, 23 Jul 2013 17:38:41 -0400 Subject: [PATCH] SELinux: Increase ebitmap_node size for 64-bit configuration Currently, the ebitmap_node structure has a fixed size of 32 bytes. On a 32-bit system, the overhead is 8 bytes, leaving 24 bytes for being used as bitmaps. The overhead ratio is 1/4. On a 64-bit system, the overhead is 16 bytes. Therefore, only 16 bytes are left for bitmap purpose and the overhead ratio is 1/2. With a 3.8.2 kernel, a boot-up operation will cause the ebitmap_get_bit() function to be called about 9 million times. The average number of ebitmap_node traversal is about 3.7. This patch increases the size of the ebitmap_node structure to 64 bytes for 64-bit system to keep the overhead ratio at 1/4. This may also improve performance a little bit by making node to node traversal less frequent (< 2) as more bits are available in each node. Signed-off-by: Waiman Long Acked-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Eric Paris --- Reading git-format-patch failed