On Thu 16-01-25 16:53:21, Al Viro wrote: > On Thu, Jan 16, 2025 at 07:49:49AM -0500, Theodore Ts'o wrote: > > > Secondly, we've had a very long time to let the dentry interface > > mature, and so (a) the fundamental architecture of the dcache hasn't > > been changing as much in the past few years, and (b) we should have > > enough understanding of the interface to understand where we could put > > tracepoints (e.g., close to the syscall interface) which would make it > > much less likely that there would be any need to make > > backwards-incompatible changes to tracepoints. > > FWIW, earlier this week I'd been going through the piles of tracepoints > playing with ->d_name. Mature interface or not, they do manage to > fuck that up... Well, tracepoints are like any other rarely executed kernel code. The bugs do accumulate there with higher probability due to lack of testing. But I guess that's not strong enough reason to refuse them. I remember you were refusing tracepoints in VFS in the past on the grounds that it could make code changes harder due to concerns of breaking tracepoint users. That is a fair concern but I guess it is also a fair question whether we shouldn't reconsider this decision given how the rest of the Linux kernel and the tracing ecosystem around it evolves... Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
