Re: [PATCH] Revert "mm/page_alloc.c: don't show protection in zone's ->lowmem_reserve[] for empty zone"

[Michal Hocko <mhocko@suse.com>]

On Wed 26-02-25 11:52:41, Michal Hocko wrote:
> On Wed 26-02-25 18:00:26, Baoquan He wrote:
> > On 02/26/25 at 07:54am, Michal Hocko wrote:
> [...]
> > > In any case 96a5c186efff seems incorrect because it assumes that the
> > > protection has anything to do with how higher zone is populated while
> > > the protection fundamentaly protects lower zone from higher zones
> > > allocation. Those allocations are independent on the actual memory in
> > > that zone.
> > 
> > The protection value was introduced in non-NUMA time, and later adapted
> > to NUMA system. While it still only reflects each zone with other zones
> > within one specific node. We may need take this opportunity to
> > reconsider it, e.g in the FALLBACK zonelists case it needs take crossing
> > nodes into account.
> 
> Are you suggesting zone fallback list to interleave nodes? I.e.
> numa_zonelist_order we used to have in the past and that has been
> removed by c9bff3eebc09 ("mm, page_alloc: rip out ZONELIST_ORDER_ZONE").

Btw. has 96a5c186efff tried to fix any actual runtime problem? The
changelog doesn't say much about that. 

-- 
Michal Hocko
SUSE Labs