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authorJohn Brooks <john.brooks@jolla.com>2015-03-24 23:54:17 +0300
committerPaul Moore <pmoore@redhat.com>2015-04-07 03:16:21 +0300
commit33ebc1932a07efd8728975750409741940334489 (patch)
treece88911dbfbfa42b6cfd4c06631a25b74f94d53a /security/selinux/ss/avtab.h
parentba39db6e0519aa8362dbda6523ceb69349a18dc3 (diff)
downloadlinux-33ebc1932a07efd8728975750409741940334489.tar.xz
selinux: Use a better hash function for avtab
This function, based on murmurhash3, has much better distribution than the original. Using the current default of 2048 buckets, there are many fewer collisions: Before: 101421 entries and 2048/2048 buckets used, longest chain length 374 After: 101421 entries and 2048/2048 buckets used, longest chain length 81 The difference becomes much more significant when buckets are increased. A naive attempt to expand the current function to larger outputs doesn't yield any significant improvement; so this function is a prerequisite for increasing the bucket size. sds: Adapted from the original patches for libsepol to the kernel. Signed-off-by: John Brooks <john.brooks@jolla.com> Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <pmoore@redhat.com>
Diffstat (limited to 'security/selinux/ss/avtab.h')
-rw-r--r--security/selinux/ss/avtab.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/security/selinux/ss/avtab.h b/security/selinux/ss/avtab.h
index 9318b2b8f6c9..6d794a2eee57 100644
--- a/security/selinux/ss/avtab.h
+++ b/security/selinux/ss/avtab.h
@@ -56,7 +56,7 @@ struct avtab {
struct flex_array *htable;
u32 nel; /* number of elements */
u32 nslot; /* number of hash slots */
- u16 mask; /* mask to compute hash func */
+ u32 mask; /* mask to compute hash func */
};