Re: revisiting alloc_pages_bulks semantics?

[Matthew Wilcox <willy@infradead.org>]

On Wed, May 27, 2026 at 02:19:20PM +0200, Christoph Hellwig wrote:
> > > There is one single user (svc_fill_pages in sunrpc) that relies on it.
> > > For everyone else it creates extra burden and is very error prone
> > > (speaking from experience).
> > 
> > Sounds good to me. Will sunrpc be easy to convert, or should it be another
> > flag to opt-in to the current behavior, that it would use?
> 
> I've added Chuck to the Cc list, but from memory sunrpc actually does
> make use of this feature and he objected to previous attempts to
> change it.  So a first step would be to have a lower-level helper
> that works as-is and a wrapper that zeroes the array, even if that
> doesn't feel as efficient as it could be.

I think the problem is that sunrpc uses the pages as a queue instead of
a stack.  If it consumed pages from the end instead of the beginning,
it could just refill the entire tail of the array.