Re: [PATCH v2] memcg: replace memcg ID idr with xarray

[Michal Hocko]

On Thu 15-08-24 22:16:27, Matthew Wilcox wrote:
> On Thu, Aug 15, 2024 at 07:31:43PM +0000, Roman Gushchin wrote:
> > There is another subtle change here: xa_alloc() returns -EBUSY in the case
> > of the address space exhaustion, while the old code returned -ENOSPC.
> > It's unlikely a big practical problem.
> 
> I decided that EBUSY was the right errno for this situation;
> 
> #define EBUSY           16      /* Device or resource busy */
> #define ENOSPC          28      /* No space left on device */
> 
> ENOSPC seemed wrong; the device isn't out of space.

The thing is that this is observable by userspace - mkdir would return a
different and potentially unexpected errno. We can try and see whether
anybody complains or just translate the error.

-- 
Michal Hocko
SUSE Labs