Re: [PATCH 11/11] fs: Remove aops->writepage

[Matthew Wilcox <willy@infradead.org>]

On Tue, Mar 18, 2025 at 09:10:38AM +0100, Thomas Hellström wrote:
> On Mon, 2025-03-17 at 22:30 +0000, Matthew Wilcox wrote:
> > This patch fixes the compilation problem.  But I don't understand why
> > it's messing with the reclaim flag.  Thomas, can you explain?
> 
> Hi, Sorry for not responding earlier. The patch that uses writepage()
> here has been around for quite some time waiting for reviews / acks so
> I failed to notice that it's going away.

My turn to be sorry for dropping this conversation ...

> Anyway the reclaim flag clearing follows that of pageout() in vmscan.c
> which was also the case for the i915_gem_shmem.c usage in
> __shmem_writeback(). My understanding was that if the writeback was
> already completed at that point, the reclaim flag was no longer
> desirable.

I think the question is really why you're setting it in the first place.
Setting the reclaim flag indicates that you want the folio removed from
the page cache as soon as possible.  Other changes in flight are about
to make this more aggressive --  instead of waiting for the folio to
reach the end of the writeout queue, it'll be removed upon I/O completion.

It doesn't seem to me that this is what you actually want for TTM,
but perhaps I've misunderstood the intent of the code.