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

[Gao Xiang]

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

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.