On Mon, Jan 27, 2025 at 10:02:00AM +0100, Sebastian Andrzej Siewior wrote: > On 2025-01-24 13:15:32 [-1000], Tejun Heo wrote: > > Hello, > > > > On Fri, Jan 24, 2025 at 06:46:12PM +0100, Sebastian Andrzej Siewior wrote: > > ... > > > to avoid holding a global lock during a page fault. The lock drop is > > > wrong since the support of renames and not a big burden since the lock > > > is no longer global. > > > > It's still a pretty big lock. Hopefully, at least name accesses can be > > converted to rcu protected ones later? > > Not sure what you mean by "rcu protected ones". The name is already RCU > protected which is part of the problem :P > Assuming an upper length of name to be around 255 and > kernfs_fop_readdir() to be very early on the chain then we could copy > the name on stack within the RCU section and do this without > ::kernfs_rwsem. Please ignore me on this one. I'll take a better look next round. Thanks. -- tejun
