On Wed, Sep 6, 2017 at 5:50 AM, Kyeongdon Kim <kyeongdon.kim@xxxxxxx> wrote:
> 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@xxxxxxx>
> ---
> 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(-)
This seems reasonale, but I'm going to refrain from merging this until
after the merge window closes.
> 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
>
--
paul moore
www.paul-moore.com
