Re: [PATCH v2] mm,thp,shmem: limit shmem THP alloc gfp_mask

[Michal Hocko]

On Thu 22-10-20 23:40:53, Rik van Riel wrote:
> On Thu, 2020-10-22 at 19:54 -0700, Hugh Dickins wrote:
[...]
> > But it's likely that they have accumulated some defrag wisdom, which
> > tmpfs can take on board - but please accept that in using a huge
> > mount,
> > the preference for huge has already been expressed, so I don't expect
> > anon THP alloc_hugepage_direct_gfpmask() choices will map one to one.
> 
> In my mind, the huge= mount options for tmpfs corresponded
> to the "enabled" anon THP options, denoting a desired end
> state, not necessarily how much we will stall allocations
> to get there immediately.

It is really unfortunate that our configuration space is so huge and
messy but we have to live with that now.

Anyway, I would tend to agree that with an absense of per-mount defrag
configuration it makes sense to use the global one. Is anybody aware of
usecases where a mount specific configuration would make sense?
-- 
Michal Hocko
SUSE Labs