Re: SLUB sysfs support

Christoph Lameter
2007-12-27T23:22:42Z

On Thu, 27 Dec 2007, Al Viro wrote:

> On Thu, Dec 27, 2007 at 12:28:14PM -0800, Christoph Lameter wrote:
> > Hmmm.. If I separately allocate the kobject then I can no longer get to
> > the kmem_cache structure from the kobject.
> >
> > I need to add a second kobject_del to sysfs_slab_remove() to make sysfs
> > completely forget about the object?
> >
> > Probably should track down any remaining symlinks at that point and nuke
> > them too. Isnt there some way to convince sysfs to remove the symlinks
> > if the target vanishes?
>
> Don't bother with separate allocation.
>
> a) remove symlink when slab goes away

Ok. Need to think about how to code that.

> b) instead of kfree() in slab removal do kobject_put() if you have sysfs stuff

Hmmmm.... Okay. Patch follows but its strange to do a kobject_put after a
kobject_del().

> c) have ->release() of these kobjects do kfree()

In slab_ktype?

---
mm/slub.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2007-12-27 15:09:38.000000000 -0800
+++ linux-2.6/mm/slub.c 2007-12-27 15:21:12.000000000 -0800
@@ -247,7 +247,10 @@ static void sysfs_slab_remove(struct kme
static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
{ return 0; }
-static inline void sysfs_slab_remove(struct kmem_cache *s) {}
+static inline void sysfs_slab_remove(struct kmem_cache *s)
+{
+ kfree(s);
+}
#endif

/********************************************************************
@@ -2322,7 +2325,6 @@ void kmem_cache_destroy(struct kmem_cach
if (kmem_cache_close(s))
WARN_ON(1);
sysfs_slab_remove(s);
- kfree(s);
} else
up_write(&slub_lock);
}
@@ -3940,6 +3942,13 @@ static ssize_t slab_attr_store(struct ko
return err;
}

+static void slab_release(struct kobject *kobj)
+{
+ struct kmem_cache *s = to_slab(kobj);
+
+ kfree(s);
+}
+
static struct sysfs_ops slab_sysfs_ops = {
.show = slab_attr_show,
.store = slab_attr_store,
@@ -3947,6 +3956,7 @@ static struct sysfs_ops slab_sysfs_ops =

static struct kobj_type slab_ktype = {
.sysfs_ops = &slab_sysfs_ops,
+ .release = slab_release
};

static int uevent_filter(struct kset *kset, struct kobject *kobj)
@@ -4048,6 +4058,7 @@ static void sysfs_slab_remove(struct kme
{
kobject_uevent(&s->kobj, KOBJ_REMOVE);
kobject_del(&s->kobj);
+ kobject_put(&s->kobj);
}

/*