Re: [RFC PATCH] mm/mempolicy: add MPOL_PREFERRED_STRICT memory policy

[Michal Hocko <mhocko@suse.com>]

On Thu 14-10-21 15:58:29, Aneesh Kumar K.V wrote:
> On 10/14/21 15:08, Michal Hocko wrote:
[...]
> > Besides that it would be really great to finish the discussion about the
> > usecase before suggesting a new userspace API.
> > 
> 
> Application would like to hint a preferred node for allocating memory
> backing a va range and at the same time wants to avoid fallback to some set
> of nodes (in the use case I am interested don't fall back to slow memory
> nodes).

We do have means for that, right? You can set your memory policy and
then set the cpu afffinity to the node you want to allocate from
initially. You can migrate to a different cpu/node if this is not the
preferred affinity. Why is that not usable?

Also think about extensibility. Say I want to allocate from a set of
nodes first before falling back to the rest of the nodemask? If you want
to add a new API then think of other potential usecases.

-- 
Michal Hocko
SUSE Labs