[LSF/MM/BPF TOPIC] State Of The Page

[Yang Shi]

On Tue, Feb 21, 2023 at 10:08 AM Gao Xiang <hsiangkao at linux.alibaba.com> wrote:
>
>
>
> On 2023/1/27 00:40, Matthew Wilcox wrote:
> > I'd like to do another session on how the struct page dismemberment
> > is going and what remains to be done.  Given how widely struct page is
> > used, I think there will be interest from more than just MM, so I'd
> > suggest a plenary session.
> >
> > If I were hosting this session today, topics would include:
> >
> > Splitting out users:
> >
> >   - slab (done!)
> >   - netmem (in progress)
> >   - hugetlb (in akpm)
> >   - tail pages (in akpm)
> >   - page tables
> >   - ZONE_DEVICE
> >
> > Users that really should have their own types:
> >
> >   - zsmalloc
> >   - bootmem
> >   - percpu
> >   - buddy
> >   - vmalloc
> >
> > Converting filesystems to folios:
> >
> >   - XFS (done)
> >   - AFS (done)
> >   - NFS (in progress)
> >   - ext4 (in progress)
> >   - f2fs (in progress)
> >   - ... others?
> >
> > Unresolved challenges:
> >
> >   - mapcount
> >   - AnonExclusive
> >   - Splitting anon & file folios apart
> >   - Removing PG_error & PG_private
>
> I'm interested in this topic too, also I'd like to get some idea of the
> future of the page dismemberment timeline so that I can have time to keep
> the pace with it since some embedded use cases like Android are
> memory-sensitive all the time.
>
> Minor, it seems some apis still use ->lru field to chain bulk pages,
> perhaps it needs some changes as well:
> https://lore.kernel.org/r/20221222124412.rpnl2vojnx7izoow@techsingularity.net
> https://lore.kernel.org/r/20230214190221.1156876-2-shy828301@gmail.com

The dm-crypt patches don't use list anymore. The bulk allocator still
supports the list version, but so far there is no user, so it may be
gone soon.

>
> Thanks,
> Gao Xiang
>
> >
> > This will probably all change before May.
> >
> > I'd like to nominate Vishal Moola & Sidhartha Kumar as invitees based on
> > their work to convert various functions from pages to folios.
>