Re: [PATCH -mm 2/3] slab: zap kmem_cache_shrink return value

[Christoph Lameter]

On Mon, 26 Jan 2015, Vladimir Davydov wrote:

> Right, but I just don't see why a subsystem using a kmem_cache would
> need to check whether there are any objects left in the cache. I mean,
> it should somehow keep track of the objects it's allocated anyway, e.g.
> by linking them in a list. That means it must already have a way to
> check if it is safe to destroy its cache or not.

The acpi subsystem did that at some point.

> Suppose we leave the return value as is. A subsystem, right before going
> to destroy a cache, calls kmem_cache_shrink, which returns 1 (slab is
> not empty). What is it supposed to do then?

That is up to the subsystem. If it has a means of tracking down the
missing object then it can deal with it. If not then it cannot shutdown
the cache and do a proper recovery action.

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