On Thu, 2025-01-23 at 07:39 +1100, NeilBrown wrote: > On Thu, 23 Jan 2025, Jeff Layton wrote: > > > > @@ -854,7 +855,9 @@ nfsd_alloc_fcache_disposal(void) > > > if (!l) > > > return NULL; > > > spin_lock_init(&l->lock); > > > - INIT_DELAYED_WORK(&l->filecache_laundrette, nfsd_file_gc_worker); > > > + timer_setup(&l->timer, nfsd_file_gc_worker, 0); > > > + INIT_LIST_HEAD(&l->recent); > > > + INIT_LIST_HEAD(&l->older); > > > INIT_LIST_HEAD(&l->recent); > > > INIT_LIST_HEAD(&l->older); > > > > No need to do the list initializations twice. ^^^ > > Thanks. I fixed up a few other merge-errors too. > > > > > It does seem like this is lightweight enough now that we can do the GC > > in interrupt context. I'm not certain that's best for latency, but it's > > worth experimenting. > > What sort of latency are you thinking of? By avoiding a scheduler > switch into the workqueue task we should be reducing overhead. > In the old code a timer would wake a thread which would need to be > scheduled to do the work. In the new thread and identical time will do > the work directly. > > Anytime we have to take *_bh locks, we block interrupts. In this case, I think you're right that that's probably the lesser evil, but we will be taking these locks somewhat frequently. It's certainly worth starting here though, and only offloading to a workqueue if that proves to be a problem. -- Jeff Layton <jlayton@xxxxxxxxxx>
