On Mon, Jun 07, 2021 at 09:14:11AM -0300, Jason Gunthorpe wrote: > On Mon, Jun 07, 2021 at 12:25:03PM +0200, Greg KH wrote: > > On Mon, Jun 07, 2021 at 11:17:35AM +0300, Leon Romanovsky wrote: > > > From: Jason Gunthorpe <jgg@xxxxxxxxxx> > > > > > > This code is trying to attach a list of counters grouped into 4 groups to > > > the ib_port sysfs. Instead of creating a bunch of kobjects simply express > > > everything naturally as an ib_port_attribute and add a single > > > attribute_groups list. > > > > > > Remove all the naked kobject manipulations. > > > > Much nicer. > > > > But why do you need your counters to be atomic in the first place? What > > are they counting that requires this? > > The write side of the counter is being updated from concurrent kernel > threads without locking, so this is an atomic because the write side > needs atomic_add(). So the atomic write forces a lock :( > Making them a naked u64 will cause significant corruption on the write > side, and packet counters that are not accurate after quiescence are > not very useful things. How "accurate" do these have to be? And have you all tried them? I'm pushing back here as I see a lot of atomics used for debugging statistics for no good reason all over the place. Especially when userspace just does not care. thanks, greg k-h
