On Thu, Oct 29, 2020 at 08:19:09PM -0400, Kent Overstreet wrote:
> On Thu, Oct 29, 2020 at 07:33:53PM +0000, Matthew Wilcox (Oracle) wrote:
> > Add mapping_get_read_heads() which returns the head pages which
> > represent a contiguous array of bytes in the file. It also stops
> > when encountering a page marked as Readahead or !Uptodate (but
> > does return that page) so it can be handled appropriately by
> > gfbr_get_pages().
>
> I don't like the _heads naming - this is like find_get_pages_contig() except it
> returns compound pages instead of single pages, and the naming should reflect
> that. And, working with compound pages should be the default in the future -
> code working with individual pages should be considered a code smell in the
> future, i.e. find_get_pages() et. all. should be considered deprecated.
You're right. It should just be called mapping_get_(something)_thps.
> Also - you're implementing new core functionality with a pecularity of the read
> path, the two probably be split out. Perhaps find_get_cpages (compound_pages)
> that can also be passed a stop condition.
It isn't clear to me _how_ to do that, so in the absence of that obvious,
I decided to implement what we need right now, and we can figure out how
to abstract it later.
So until we have a better idea, I'm going with "read" for the (something)
above.
> > + if (writably_mapped) {
> > + int j;
> > +
> > + for (j = 0; j < thp_nr_pages(page); j++)
> > + flush_dcache_page(page + j);
> > + }
>
> this should be a new helper
Good point. One flush_dcache_thp() coming right up!
