Re: Question about code in fs/ceph/addr.c

[slava@dubeyko.com]

Hi Fan,

+ CC David Howells <dhowells@redhat.com>
+ CC ceph-devel@vger.kernel.org

On Tue, 2025-03-18 at 11:30 -0700, Fan Ni wrote:
> Hi Viacheslav,
> 
> This is Fan Ni. Recently I started to work on some mm work. One thing
> that I am working on is to reduce the use of &folio->page. When I
> check
> the fs/ceph code, I find some code that may be good candidate for the
> work to be done.
> 
> I see you sent some patches to add ceph_submit_write(), since the
> change
> I am planning to do is closely related to it, so I reach out to you
> to
> see if you have some input for me.
> 
> Based on my reading of the code, it seems ceph_wbc->pages[i] will
> always be the head page of the folio involved. I am thinking maybe we
> can
> keep folios instead of pages here, do you see any reason we should
> not
> use folios here and must be pages?
> 

I believe we need to switch from pages to folios in CephFS code. But it
is painful modification. We need to be really careful in this.

As far as I know, David Howells is making significant modification
namely in this direction. I think you need to synchronize the
implementation activity with him. I'd love to be involved but,
currently, I am focused on fixing other issues in CephFS code. :)

Thanks,
Slava.