Re: [PATCH v7 14/24] btrfs: Convert from readpages to readahead

From: Matthew Wilcox
Date: Thu Feb 20 2020 - 08:48:52 EST

On Thu, Feb 20, 2020 at 09:42:19AM +0000, Johannes Thumshirn wrote:
> On 19/02/2020 22:03, Matthew Wilcox wrote:
> > From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
> >
> > Use the new readahead operation in btrfs. Add a
> > readahead_for_each_batch() iterator to optimise the loop in the XArray.
> OK I must admit I haven't followed this series closely, but what
> happened to said readahead_for_each_batch()?
> As far as I can see it's now:
> [...]
> > + while ((nr = readahead_page_batch(rac, pagepool))) {

Oops, forgot to update the changelog there. Yes, that's exactly what it
changed to. That discussion was here:

... and then Christoph pointed out the iterators weren't really adding
much value at that point, so they got deleted. New changelog for
this patch:

btrfs: Convert from readpages to readahead

Implement the new readahead method in btrfs. Add a readahead_page_batch()
to optimise fetching a batch of pages at once.