Re: [RFC PATCH 0/7] mm: Make more use of readahead_control

[David Howells]

Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:

> > Note that I've been
> > passing the number of pages to read in rac->_nr_pages, and then saving it
> > and changing it certain points, e.g. page_cache_readahead_unbounded().
> 
> I do not like this.  You're essentially mutating the meaning of _nr_pages
> as the ractl moves down the stack, and that's going to lead to bugs.
> I'd keep it as a separate argument.

The meaning isn't specified in linux/pagemap.h.  Can you adjust the comments
on the struct and on readahead_count() to make it more clear what the value
represents?

Thanks,
David