2020-04-23 19:04:05

by Michal Koutný

Subject: [PATCH RESEND] slub: Remove userspace notifier for cache add/remove

From: Christoph Lameter <[email protected]>

I came across some unnecessary uevents once again which reminded me
this. The patch seems to be lost in the leaves of the original
discussion [1], so resending.

[1] https://lore.kernel.org/r/[email protected]

8<---
Kmem caches are internal kernel structures so it is strange that
userspace notifiers would be needed. And I am not aware of any use
of these notifiers. These notifiers may just exist because in the
initial slub release the sysfs code was copied from another
subsystem.

Signed-off-by: Christoph Lameter <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Michal Koutný <[email protected]>
---
mm/slub.c | 17 +----------------
1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 332d4b459a90..ae6116adf875 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5665,19 +5665,6 @@ static struct kobj_type slab_ktype = {
.release = kmem_cache_release,
};

-static int uevent_filter(struct kset *kset, struct kobject *kobj)
-{
- struct kobj_type *ktype = get_ktype(kobj);
-
- if (ktype == &slab_ktype)
- return 1;
- return 0;
-}
-
-static const struct kset_uevent_ops slab_uevent_ops = {
- .filter = uevent_filter,
-};
-
static struct kset *slab_kset;

static inline struct kset *cache_kset(struct kmem_cache *s)
@@ -5745,7 +5732,6 @@ static void sysfs_slab_remove_workfn(struct work_struct *work)
#ifdef CONFIG_MEMCG
kset_unregister(s->memcg_kset);
#endif
- kobject_uevent(&s->kobj, KOBJ_REMOVE);
out:
kobject_put(&s->kobj);
}
@@ -5803,7 +5789,6 @@ static int sysfs_slab_add(struct kmem_cache *s)
}
#endif

- kobject_uevent(&s->kobj, KOBJ_ADD);
if (!unmergeable) {
/* Setup first alias */
sysfs_slab_alias(s, s->name);
@@ -5884,7 +5869,7 @@ static int __init slab_sysfs_init(void)

mutex_lock(&slab_mutex);

- slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
+ slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
if (!slab_kset) {
mutex_unlock(&slab_mutex);
pr_err("Cannot register slab subsystem.\n");
--
2.26.0

2020-04-23 20:06:41

by David Rientjes

Subject: Re: [PATCH RESEND] slub: Remove userspace notifier for cache add/remove

On Thu, 23 Apr 2020, Michal Koutný wrote:

> From: Christoph Lameter <[email protected]>
>
> I came across some unnecessary uevents once again which reminded me
> this. The patch seems to be lost in the leaves of the original
> discussion [1], so resending.
>
> [1] https://lore.kernel.org/r/[email protected]
>
> 8<---
> Kmem caches are internal kernel structures so it is strange that
> userspace notifiers would be needed. And I am not aware of any use
> of these notifiers. These notifiers may just exist because in the
> initial slub release the sysfs code was copied from another
> subsystem.
>
> Signed-off-by: Christoph Lameter <[email protected]>
> Acked-by: Vlastimil Babka <[email protected]>
> Acked-by: Michal Koutný <[email protected]>

Acked-by: David Rientjes <[email protected]>