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In-Reply-To: <20231215122251.bad09400b337dfb1965f6976@linux-foundation.org>
From: Yu Zhao <yuzhao@google.com>
Date: Fri, 15 Dec 2023 21:56:54 -0700
Message-ID: <CAOUHufbcB9Lxeez=NcUY4uzxyX6x71dy2N0SMgj=ALooq+MetQ@mail.gmail.com>
Subject: Re: [GIT PULL] hotfixes for 6.7-rc6
To: Andrew Morton <akpm@linux-foundation.org>, 
	Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, 
	Jesse Barnes <jsbarnes@google.com>, Suren Baghdasaryan <surenb@google.com>, 
	Guru Anbalagane <gurua@google.com>, David Rientjes <rientjes@google.com>
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On Fri, Dec 15, 2023 at 1:22=E2=80=AFPM Andrew Morton <akpm@linux-foundatio=
n.org> wrote:
>
> On Fri, 15 Dec 2023 12:11:42 -0800 Linus Torvalds <torvalds@linux-foundat=
ion.org> wrote:
>
> > On Fri, 15 Dec 2023 at 07:16, Andrew Morton <akpm@linux-foundation.org>=
 wrote:
> > >
> > > Yu Zhao (4):
> > >       mm/mglru: fix underprotected page cache
> > >       mm/mglru: try to stop at high watermarks
> > >       mm/mglru: respect min_ttl_ms with memcgs
> > >       mm/mglru: reclaim offlined memcgs harder
> >
> > Entirely unrelated to this pull request (which I already pulled and
> > pushed out, as noted by pr-tracker-bot), since I looked at these it
> > just reminded me about a question I've had for a while...
> >
> > Do we have any long-term (or even short-term?) plans to just make
> > mglru be the one and only model?
>
> I hope so, but I haven't heard specific plans.

I don't know when we'll get there, if we can get there at all. But we
have been steadily moving toward that goal:
1. We worked with all major distros that follow the mainline closely
to switch to MGLRU this summer (Arch, Debian, Fedora, Gentoo and
Ubuntu).
2. We hired more kernel developers after we demonstrated the ability
to substantially lower hardware cost by overcommitting memory at
scale.

There has been a short-term plan, i.e., moving some of folio->flags to
the lower bits of folio->lru so that we can drop the Kconfig
constraint. I have discussed this with Willy but never acted on it. My
priority has been to surface more of our ideas that can potentially
save users money on memory to the community. I'm CC'ing our team
leads. Please feel free to let us know your preference on the
priority. Thanks.