From: jooseong.lee <jooseong.lee@samsung.com>
Date: Wed, 25 Mar 2015 01:58:44 +0000 (+0900)
Subject: security: smack: add kmem_cache for smack_rule allocations
X-Git-Tag: submit/tizen/20160422.055611~1^2~72
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f2be802502df388bf55de717a9dc4c6ba4c25a98;p=sdk%2Femulator%2Femulator-kernel.git

security: smack: add kmem_cache for smack_rule allocations

On ARM, sizeof(struct smack_rule)==20. Allocation by kmalloc() uses a
32-byte-long chunk to allocate 20 bytes. Just ask ksize().  It means that 40%
of memory is simply wasted for padding bytes.

The problem is fixed in this patch by using kmem_cache. The cache allocates
struct smack_rule using 24-byte-long chunks according to ksize(). This reduces
amount of used memory by 25%.

Change-Id: I2753cabc78c31b695ac07bf76cc8861232b64b1d
Signed-off-by: jooseong.lee <jooseong.lee@samsung.com>
---

diff --git a/security/smack/smack.h b/security/smack/smack.h
index 020307ef0972..45aa224b91ae 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -266,6 +266,9 @@ extern struct mutex	smack_known_lock;
 extern struct list_head smack_known_list;
 extern struct list_head smk_netlbladdr_list;
 
+/* Cache for fast and thrifty allocations */
+extern struct kmem_cache *smack_rule_cache;
+
 extern struct security_operations smack_ops;
 
 #define SMACK_HASH_SLOTS 16
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 4b5515ec8620..523e106a274c 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4016,6 +4016,9 @@ static __init void init_smack_known_list(void)
 	smk_insert_entry(&smack_known_web);
 }
 
+/* KMEM caches for fast and thrifty allocations */
+struct kmem_cache *smack_rule_cache;
+
 /**
  * smack_init - initialize the smack system
  *
@@ -4029,10 +4032,16 @@ static __init int smack_init(void)
 	if (!security_module_enable(&smack_ops))
 		return 0;
 
+	smack_rule_cache = KMEM_CACHE(smack_rule, 0);
+	if (!smack_rule_cache)
+		return -ENOMEM;
+
 	tsp = new_task_smack(&smack_known_floor, &smack_known_floor,
 				GFP_KERNEL);
-	if (tsp == NULL)
+	if (tsp == NULL) {
+		kmem_cache_destroy(smack_rule_cache);
 		return -ENOMEM;
+	}
 
 	printk(KERN_INFO "Smack:  Initializing.\n");
 
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 32b248820840..e602a34bf7e1 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -235,7 +235,7 @@ static int smk_set_access(struct smack_parsed_rule *srp,
 	}
 
 	if (found == 0) {
-		sp = kzalloc(sizeof(*sp), GFP_KERNEL);
+		sp = kmem_cache_zalloc(smack_rule_cache, GFP_KERNEL);
 		if (sp == NULL) {
 			rc = -ENOMEM;
 			goto out;