selinux: Use a kmem_cache for allocation struct file_security_struct (63205654) · Commits · 戴 / test

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.park@lge.com> Acked-by:

Stephen Smalley <sds@tycho.nsa.gov> [PM: removed extra subject prefix] Signed-off-by:

Paul Moore <pmoore@redhat.com>

security/selinux/hooks.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -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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