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authorDmitry Kasatkin <dmitry.kasatkin@intel.com>2012-02-08 14:15:42 -0500
committerMimi Zohar <zohar@linux.vnet.ibm.com>2012-09-07 14:57:46 -0400
commita10bf26b2f53242836e9362c6c9c857b627b82a9 (patch)
tree98c7b83684f1df42571013af4c0572c7eeea8e76 /security/integrity
parentbf2276d10ce58ff44ab8857266a6718024496af6 (diff)
downloadvexpress-lsk-a10bf26b2f53242836e9362c6c9c857b627b82a9.tar.gz
ima: replace iint spinblock with rwlock/read_lock
For performance, replace the iint spinlock with rwlock/read_lock. Eric Paris questioned this change, from spinlocks to rwlocks, saying "rwlocks have been shown to actually be slower on multi processor systems in a number of cases due to the cache line bouncing required." Based on performance measurements compiling the kernel on a cold boot with multiple jobs with/without this patch, Dmitry Kasatkin and I found that rwlocks performed better than spinlocks, but very insignificantly. For example with total compilation time around 6 minutes, with rwlocks time was 1 - 3 seconds shorter... but always like that. Changelog v2: - new patch taken from the 'allocating iint improvements' patch Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Diffstat (limited to 'security/integrity')
-rw-r--r--security/integrity/iint.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index c91a436e13a..d82a5a13d85 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -22,7 +22,7 @@
#include "integrity.h"
static struct rb_root integrity_iint_tree = RB_ROOT;
-static DEFINE_SPINLOCK(integrity_iint_lock);
+static DEFINE_RWLOCK(integrity_iint_lock);
static struct kmem_cache *iint_cache __read_mostly;
int iint_initialized;
@@ -35,8 +35,6 @@ static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode)
struct integrity_iint_cache *iint;
struct rb_node *n = integrity_iint_tree.rb_node;
- assert_spin_locked(&integrity_iint_lock);
-
while (n) {
iint = rb_entry(n, struct integrity_iint_cache, rb_node);
@@ -63,9 +61,9 @@ struct integrity_iint_cache *integrity_iint_find(struct inode *inode)
if (!IS_IMA(inode))
return NULL;
- spin_lock(&integrity_iint_lock);
+ read_lock(&integrity_iint_lock);
iint = __integrity_iint_find(inode);
- spin_unlock(&integrity_iint_lock);
+ read_unlock(&integrity_iint_lock);
return iint;
}
@@ -100,7 +98,7 @@ struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
if (!iint)
return NULL;
- spin_lock(&integrity_iint_lock);
+ write_lock(&integrity_iint_lock);
p = &integrity_iint_tree.rb_node;
while (*p) {
@@ -119,7 +117,7 @@ struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
rb_link_node(node, parent, p);
rb_insert_color(node, &integrity_iint_tree);
- spin_unlock(&integrity_iint_lock);
+ write_unlock(&integrity_iint_lock);
return iint;
}
@@ -136,10 +134,10 @@ void integrity_inode_free(struct inode *inode)
if (!IS_IMA(inode))
return;
- spin_lock(&integrity_iint_lock);
+ write_lock(&integrity_iint_lock);
iint = __integrity_iint_find(inode);
rb_erase(&iint->rb_node, &integrity_iint_tree);
- spin_unlock(&integrity_iint_lock);
+ write_unlock(&integrity_iint_lock);
iint_free(iint);
}