Re: [PATCH] slub: fix __kmem_cache_empty for !CONFIG_SLUB_DEBUG

On 06/20/2018 12:33 AM, Shakeel Butt wrote:

For !CONFIG_SLUB_DEBUG, SLUB does not maintain the number of slabs allocated per node for a kmem_cache. Thus, slabs_node() in __kmem_cache_empty() will always return 0. So, in such situation, it is required to check per-cpu slabs to make sure if a kmem_cache is empty or not.

Please note that __kmem_cache_shutdown() and __kmem_cache_shrink() are not affected by !CONFIG_SLUB_DEBUG as they call flush_all() to clear per-cpu slabs.

So what? Yes, they call flush_all() and then check if there are non-empty slabs left. And that check doesn't work in case of disabled CONFIG_SLUB_DEBUG. How is flush_all() or per-cpu slabs even relevant here?