On Fri 19-01-24 20:59:22, Kefeng Wang wrote: > > > > GFP_TRANSHUGE_LIGHT is more interesting though because those do not dive > > > > into the direct reclaim at all. With the current code they will reclaim > > > > charges to free up the space for the allocated THP page and that defeats > > > > the light mode. I have a vague recollection of preparing a patch to > > > > > > We are interesting to GFP_TRANSHUGE_LIGHT and _GFP_NORETRY as mentioned > > > above. > > > > if mTHP can be smaller than COSTLY_ORDER then you are correct and > > NORETRY makes a difference. Please mention that in the changelog as > > well. > > > > For memory cgroup charge, _GFP_NORETRY checked to make us directly skip > mem_cgroup_oom(), it has no concern with folio order or COSTLY_ORDER when > check _GFP_NORETRY in try_charge_memcg(), so I think NORETRY should > always make difference for all large order folio. we do not OOM on COSTLY_ORDER (see mem_cgroup_oom). So NORETRY really makes a difference for small orders. -- Michal Hocko SUSE Labs
