On Thu, Apr 23, 2020 at 7:45 AM Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> wrote: > > On Thu, Apr 23, 2020 at 12:40:50AM -0400, Joel Fernandes (Google) wrote: > > While reading the famous slab paper [1], I noticed that the conn->lock > > spinlock and conn->list hlist in fsnotify code is being initialized > > during every object allocation. This seems a good fit for the > > constructor within the slab to take advantage of the slab design. Move > > the initializtion to that. > > > > spin_lock_init(&conn->lock); > > INIT_HLIST_HEAD(&conn->list); > > > > [1] https://pdfs.semanticscholar.org/1acc/3a14da69dd240f2fbc11d00e09610263bdbd.pdf > > > > The commit message could be better. Just to clarify, doing it this way is > more efficient because the object will only have its spinlock init and hlist > init happen during object construction, not object allocation. > This change may be correct, but completely unjustified IMO. conn objects are very rarely allocated, from user syscall path only. I see no reason to micro optimize this. Perhaps there is another justification to do this, but not efficiency. Thanks, Amir.
