On Mon, Jan 19, 2015 at 02:23:21PM +0300, Vladimir Davydov wrote:

Currently, we release css->id in css_release_work_fn, right before
calling css_free callback, so that when css_free is called, the id may
have already been reused for a new cgroup.

I am going to use css->id to create unique names for per memcg kmem
caches. Since kmem caches are destroyed only on css_free, I need css->id
to be freed after css_free was called to avoid name clashes. This patch
therefore moves css->id removal to css_free_work_fn. To prevent
css_from_id from returning a pointer to a stale css, it makes
css_release_work_fn replace the css ptr at css_idr:css->id with NULL.

I think it'd be better if you create a separate id for this purpose.
The requirement is pretty unusual and likely contradictory with other
usages.

Thanks.

-- 
tejun

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>