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%.
Signed-off-by: Tomasz Stanislawski <t.stanisl...@samsung.com>
---
security/smack/smack.h | 3 +++
security/smack/smack_lsm.c | 11 ++++++++++-
security/smack/smackfs.c | 2 +-
3 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 8ad3095..38ba673 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -233,6 +233,9 @@ 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;
/*
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index d52c780..7aa696a 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3564,6 +3564,9 @@ static __init void init_smack_known_list(void)
list_add(&smack_known_web.list, &smack_known_list);
}
+/* KMEM caches for fast and thrifty allocations */
+struct kmem_cache *smack_rule_cache;
+
/**
* smack_init - initialize the smack system
*
@@ -3577,10 +3580,16 @@ 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.smk_known,
smack_known_floor.smk_known, 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 34d146b..4615242 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -217,7 +217,7 @@ 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;
--
1.7.9.5
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