Re: [PATCH v6 26/29] Aggregate memcg cache values in slabinfo

Andrew Morton
2012-11-06T00:57:09Z

On Thu, 1 Nov 2012 16:07:42 +0400
Glauber Costa <glommer@parallels.com> wrote:

> When we create caches in memcgs, we need to display their usage
> information somewhere. We'll adopt a scheme similar to /proc/meminfo,
> with aggregate totals shown in the global file, and per-group
> information stored in the group itself.
>
> For the time being, only reads are allowed in the per-group cache.
>
> ...
>
> +#define for_each_memcg_cache_index(_idx) \
> + for ((_idx) = 0; i < memcg_limited_groups_array_size; (_idx)++)

Use of this requires slab_mutex, yes?

Please add a comment, and confirm that all callers do indeed hold the
correct lock.

We could add a mutex_is_locked() check to the macro perhaps, but this
isn't the place to assume the presence of slab_mutex, so it gets messy.

>
> ...
>