On 10/05/2015 01:45 AM, Sangwoo wrote:
> The size of struct file_security_struct is 16byte at my setup.
> But, the real allocation size for per each file_security_struct
> is 64bytes in my setup that kmalloc min size is 64bytes
> because ARCH_DMA_MINALIGN is 64.
>
> This allocation is called every times at file allocation(alloc_file()).
> So, the total slack memory size(allocated size - request size)
> is increased exponentially.
>
> E.g) Min Kmalloc Size : 64bytes, Unit : bytes
> Allocated Size | Request Size | Slack Size | Allocation Count
> ---------------------------------------------------------------
> 770048 | 192512 | 577536 | 12032
>
> At the result, this change reduce memory usage 42bytes per each
> file_security_struct
>
> Signed-off-by: Sangwoo <sangwoo2.p...@lge.com>
Acked-by: Stephen Smalley <s...@tycho.nsa.gov>
> ---
> security/selinux/hooks.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 3f8d567..c20e082 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -126,6 +126,7 @@ int selinux_enabled = 1;
> #endif
>
> static struct kmem_cache *sel_inode_cache;
> +static struct kmem_cache *file_security_cache;
>
> /**
> * selinux_secmark_enabled - Check to see if SECMARK is currently enabled
> @@ -287,7 +288,7 @@ static int file_alloc_security(struct file *file)
> struct file_security_struct *fsec;
> u32 sid = current_sid();
>
> - fsec = kzalloc(sizeof(struct file_security_struct), GFP_KERNEL);
> + fsec = kmem_cache_zalloc(file_security_cache, GFP_KERNEL);
> if (!fsec)
> return -ENOMEM;
>
> @@ -302,7 +303,7 @@ static void file_free_security(struct file *file)
> {
> struct file_security_struct *fsec = file->f_security;
> file->f_security = NULL;
> - kfree(fsec);
> + kmem_cache_free(file_security_cache, fsec);
> }
>
> static int superblock_alloc_security(struct super_block *sb)
> @@ -6086,6 +6087,9 @@ static __init int selinux_init(void)
> sel_inode_cache = kmem_cache_create("selinux_inode_security",
> sizeof(struct
> inode_security_struct),
> 0, SLAB_PANIC, NULL);
> + file_security_cache = kmem_cache_create("selinux_file_security",
> + sizeof(struct file_security_struct),
> + 0, SLAB_PANIC, NULL);
> avc_init();
>
> security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks));
>
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