Re: [PATCH 02/11] blkcg: __blkg_lookup_create() doesn't have to fail on radix tree preload failure

Tejun Heo
2012-04-27T14:47:15Z

Hello,

On Fri, Apr 27, 2012 at 10:42:58AM -0400, Vivek Goyal wrote:
> On Thu, Apr 26, 2012 at 02:59:12PM -0700, Tejun Heo wrote:
> > __blkg_lookup_create() currently fails if radix_tree_preload() fails;
> > however, preload failrue doesn't imply insertion failure. Don't fail
> > __blkg_lookup_create() on preload failure.
> >
>
> If we are going to try the insertion anyway irrespective of the fact
> whether preload succeeded or not, they why call radix_tree_preload()
> at all? How does that help?

Hmmm... it seems I originally misread radix_tree_node_alloc() - I
thought it didn't go through kmem_cache_alloc() if gfp_mask didn't
contain __GFP_WAIT. If we don't use more permissible GFP flag during
preloading there's no point in preloading. Will drop it.

Thanks.

--
tejun