Re: [PATCH 12/12] xfs: add lockless xfs_buf_readahead_map fast path

On Fri, Jul 24, 2026 at 10:03:16AM -0700, Darrick J. Wong wrote:
> On Wed, Jul 15, 2026 at 04:51:05PM +0200, Christoph Hellwig wrote:
> > Readahead currently always locks the buffer, which can cause contention
> > with actual users of the buffer.  Add a fast path without taking any
> > locks if the buffer is uptodate and not stale.
> 
> So we're trying to cut down on b_sema contention for detecting the case
> where the buffer is already uptodate?  And I guess the idea here is that
> if you had per-fsblock filesystem metadata, you'd want to be able to
> readahead that metadata into memory during setup for file IO without
> so much locking?

Yes.