On Tue, 10 Jun 2025, Steve French wrote: > Instead of the usual 10 to 12 minutes to run generic/676 (on all > kernels up to 6.15), we are now seeing 23-30 minutes to run > generic/676, much more than twice as slow. It looks like this is due > to unnecessary revalidates now being sent to the fs (starting with > 6.16-rc1 kernels) on every file in a directory, and is caused by > readdir. Bharath was trying to isolate the commit that caused this, > but this recently merged series could be related: > > 06c567403ae5 Use try_lookup_noperm() instead of d_hash_and_lookup() > outside of VFS > fa6fe07d1536 VFS: rename lookup_one_len family to lookup_noperm and > remove permission check Thanks for the report. The cause is almost certainly the first of these. No callers of try_lookup_noperm() need or want the revalidate. Before my patch the only user was autofs which doesn't even have a d_revalidate(). I'll write and post a patch. Thanks, NeilBrown > > Has anyone else noticed this perf regression? > > For the case of cifs.ko mounts, it is easy to repro with generic/676. > And also could be reproduced with simple "ls" of large directories. > > -- > Thanks, > > Steve >
