Re: [PATCH 3/3] dcache: account external names as indirectly reclaimable memory

From: Michal Hocko
Date: Mon Apr 16 2018 - 07:41:51 EST


On Fri 13-04-18 10:37:16, Johannes Weiner wrote:
> On Fri, Apr 13, 2018 at 04:28:21PM +0200, Michal Hocko wrote:
> > On Fri 13-04-18 16:20:00, Vlastimil Babka wrote:
> > > We would need kmalloc-reclaimable-X variants. It could be worth it,
> > > especially if we find more similar usages. I suspect they would be more
> > > useful than the existing dma-kmalloc-X :)
> >
> > I am still not sure why __GFP_RECLAIMABLE cannot be made work as
> > expected and account slab pages as SLAB_RECLAIMABLE
>
> Can you outline how this would work without separate caches?

I thought that the cache would only maintain two sets of slab pages
depending on the allocation reuquests. I am pretty sure there will be
other details to iron out and maybe it will turn out that such a large
portion of the chache would need to duplicate the state that a
completely new cache would be more reasonable. Is this worth exploring
at least? I mean something like this should help with the fragmentation
already AFAIU. Accounting would be just free on top.

--
Michal Hocko
SUSE Labs