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Subject[PATCH] selinux: Use kmem_cache for hashtab_node
Date
During random test as own device to check slub account,
we found some slack memory from hashtab_node(kmalloc-64).
By using kzalloc(), middle of test result like below:
allocated size 240768
request size 45144
slack size 195624
allocation count 3762

So, we want to use kmem_cache_zalloc() and that
can reduce memory size 52byte(slack size/alloc count) per each struct.

Signed-off-by: Kyeongdon Kim <kyeongdon.kim@lge.com>
---
security/selinux/ss/hashtab.c | 17 +++++++++++++++--
security/selinux/ss/hashtab.h | 4 ++++
security/selinux/ss/services.c | 4 ++++
3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/security/selinux/ss/hashtab.c b/security/selinux/ss/hashtab.c
index 686c391..bef7577 100644
--- a/security/selinux/ss/hashtab.c
+++ b/security/selinux/ss/hashtab.c
@@ -9,6 +9,8 @@
#include <linux/sched.h>
#include "hashtab.h"

+static struct kmem_cache *hashtab_node_cachep;
+
struct hashtab *hashtab_create(u32 (*hash_value)(struct hashtab *h, const void *key),
int (*keycmp)(struct hashtab *h, const void *key1, const void *key2),
u32 size)
@@ -57,7 +59,7 @@ int hashtab_insert(struct hashtab *h, void *key, void *datum)
if (cur && (h->keycmp(h, key, cur->key) == 0))
return -EEXIST;

- newnode = kzalloc(sizeof(*newnode), GFP_KERNEL);
+ newnode = kmem_cache_zalloc(hashtab_node_cachep, GFP_KERNEL);
if (!newnode)
return -ENOMEM;
newnode->key = key;
@@ -106,7 +108,7 @@ void hashtab_destroy(struct hashtab *h)
while (cur) {
temp = cur;
cur = cur->next;
- kfree(temp);
+ kmem_cache_free(hashtab_node_cachep, temp);
}
h->htable[i] = NULL;
}
@@ -166,3 +168,14 @@ void hashtab_stat(struct hashtab *h, struct hashtab_info *info)
info->slots_used = slots_used;
info->max_chain_len = max_chain_len;
}
+void hashtab_cache_init(void)
+{
+ hashtab_node_cachep = kmem_cache_create("hashtab_node",
+ sizeof(struct hashtab_node),
+ 0, SLAB_PANIC, NULL);
+}
+
+void hashtab_cache_destroy(void)
+{
+ kmem_cache_destroy(hashtab_node_cachep);
+}
diff --git a/security/selinux/ss/hashtab.h b/security/selinux/ss/hashtab.h
index 009fb5e..d6883d3 100644
--- a/security/selinux/ss/hashtab.h
+++ b/security/selinux/ss/hashtab.h
@@ -84,4 +84,8 @@ int hashtab_map(struct hashtab *h,
/* Fill info with some hash table statistics */
void hashtab_stat(struct hashtab *h, struct hashtab_info *info);

+/* Use kmem_cache for hashtab_node */
+void hashtab_cache_init(void);
+void hashtab_cache_destroy(void);
+
#endif /* _SS_HASHTAB_H */
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index e4a1c0d..33cfe5d 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2060,10 +2060,12 @@ int security_load_policy(void *data, size_t len)
if (!ss_initialized) {
avtab_cache_init();
ebitmap_cache_init();
+ hashtab_cache_init();
rc = policydb_read(&policydb, fp);
if (rc) {
avtab_cache_destroy();
ebitmap_cache_destroy();
+ hashtab_cache_destroy();
goto out;
}

@@ -2075,6 +2077,7 @@ int security_load_policy(void *data, size_t len)
policydb_destroy(&policydb);
avtab_cache_destroy();
ebitmap_cache_destroy();
+ hashtab_cache_destroy();
goto out;
}

@@ -2083,6 +2086,7 @@ int security_load_policy(void *data, size_t len)
policydb_destroy(&policydb);
avtab_cache_destroy();
ebitmap_cache_destroy();
+ hashtab_cache_destroy();
goto out;
}

--
2.6.2
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