On Sat, Jun 05, 2021 at 05:26:59AM +0100, Matthew Wilcox wrote:

On Thu, May 27, 2021 at 09:16:42AM +0100, Christoph Hellwig wrote:

quoted

On Tue, May 11, 2021 at 10:47:10PM +0100, Matthew Wilcox (Oracle) wrote:

quoted

+static inline bool folio_ref_try_add_rcu(struct folio *folio, int count)

Should this have a __ prefix and/or a don't use direct comment?

I think it will get used directly ... its page counterpart is:

mm/gup.c:       if (unlikely(!page_cache_add_speculative(head, refs)))

I deliberately left kernel-doc off this function so it's not described,
but described folio_try_get_rcu() in excruciating detail.  I hope that's
enough.  There's no comment on page_cache_add_speculative() today, so
again, we're status quo.

Ok.  Seems a little weird, but so does much in this area.

quoted

Is this really a good place for the comment?  I'd expect it either near
a relevant function or at the top of a file.

It's right before mapping_get_entry() which is the main lookup function
for the page cache, so I think it meets your first criteria?

I guess it does, yes.