[PATCH v2] landlock: Use kmem for landlock_object
Greg KH
gregkh at linuxfoundation.org
Sat Mar 30 16:12:18 UTC 2024
On Sat, Mar 30, 2024 at 07:24:19PM +0530, Ayush Tiwari wrote:
> Use kmem_cache replace kzalloc() calls with kmem_cache_zalloc() for
> struct landlock_object and update the related dependencies to improve
> memory allocation and deallocation performance.
So it's faster? Great, what are the measurements?
> This patch does not
> change kfree() and kfree_rcu() calls because according to kernel commit
> ae65a5211d90("mm/slab: document kfree() as allowed for
> kmem_cache_alloc() objects"), starting from kernel 6.4 with
> CONFIG_SLOB, kfree() is safe to use for such objects.
There is no CONFIG_SLOB anymore so why mention it?
>
> Signed-off-by: Ayush Tiwari <ayushtiw0110 at gmail.com>
> ---
>
> Changes in v2: Used clang-format and corrected the removal of kfree_rcu.
> Tried to use KMEM macro but due to lack of cache pointer in that macro,
> had to explicitly define landlock_object_cache, as done in security.c.
>
> security/landlock/object.c | 12 +++++++++++-
> security/landlock/object.h | 2 ++
> security/landlock/setup.c | 1 +
> 3 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/security/landlock/object.c b/security/landlock/object.c
> index 1f50612f0185..cfc367725624 100644
> --- a/security/landlock/object.c
> +++ b/security/landlock/object.c
> @@ -17,6 +17,15 @@
>
> #include "object.h"
>
> +static struct kmem_cache *landlock_object_cache;
> +
> +void __init landlock_object_cache_init(void)
> +{
> + landlock_object_cache = kmem_cache_create(
> + "landlock_object_cache", sizeof(struct landlock_object), 0,
> + SLAB_PANIC, NULL);
You really want SLAB_PANIC? Why?
> +}
> +
> struct landlock_object *
> landlock_create_object(const struct landlock_object_underops *const underops,
> void *const underobj)
> @@ -25,7 +34,8 @@ landlock_create_object(const struct landlock_object_underops *const underops,
>
> if (WARN_ON_ONCE(!underops || !underobj))
> return ERR_PTR(-ENOENT);
> - new_object = kzalloc(sizeof(*new_object), GFP_KERNEL_ACCOUNT);
> + new_object =
> + kmem_cache_zalloc(landlock_object_cache, GFP_KERNEL_ACCOUNT);
Odd indentation, why?
thanks,
greg k-h
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