Re: build error: sparsemem + SLOB

Randy Dunlap
2006-11-20T17:08:10Z

Christoph Lameter wrote:
> On Sun, 19 Nov 2006, Randy Dunlap wrote:
>
>> mm/sparse.c: line 35 uses slab_is_available() but SLAB=n, SLOB=y.
>
> I wonder if its worth bothering about SLOB?

It's OK with me to make some combination of SLOB and SPARSEMEM
an invalid config, as long as that is implemented in Kconfig.

> As far as I can tell SLOB is fundamentally racy since it does not support
> SLAB_DESTROY_BY_RCU correctly. F.e. The constructor for the anon_vma will
> be called on alloc without regard for RCU, we free an item and reuse it
> without regard to RCU. This can potentially mess up the anon_vma locking
> state while we access it.
>
> Is SLOB used at all or have we been lucky so far?

--
~Randy