In D28592#640118, @mjg wrote:

I have no comments about usefulness of adding these counters. I have to note the patch negatively affects scalability as it adds loads from the page form something which gets modified by other threads. If adding these stats, it would have to happen inside of vm_page_busy_sleep.

Whitespace

Seemed like a cute driver and a fun thing to do with some spare time while I was traveling.
I've verified that spkrtest(8) cycles through the notes without error, but since I'm away from the one machine I have with an actual speaker, I haven't been able to test by ear.

Factor locking/unlocking into kenv_acquire() and kenv_release(), and use them for some light cleanup

Return kenv_lock to a mutex

In D26010#576845, @mjg wrote:

The statement was that rmlocks distribute the lock per-CPU which means increased memory use. There are cases where this is perfectly warranted of course, I just doubt this one qualifies.

kenv should almost never be used past boot and even then I highly doubt the lock is contended enough to warrant any non-trivial changes. There may be offenders which keep re-reading the same value when they could do it once, but I don't think they are worth tracking down either. I do suspect there are nice wins to get like avoiding memory alloc (which also happen to fix bugs), but past that I would suggest not messing with the area.

In my opinion justifying this particular conversion would require a real world workload running into the problem which happens to not abuse the interface (like aforementioned re-reads of the same stuff), but I doubt there is something legitimate like this out there. However, I'm not going to stand in the way.

In D26010#576843, @mjg wrote:

Is kenv frequently used to begin with? rm lock would add memory use per-cpu, so arguably it would be a pessimization. I also suspect we may be able to get away without any locks to begin with with some trickery.

Either way, I think the change to strtok in place is a good idea and an equivalent should be done for other routines if applicable.

That said, can you please open a separate review for the locking change and only keep the actual bugfix here?

ping

Fix another typo

Remove another unnecessary WITNESS check in the shared x86 bus_dma_tag_create()
implementation. Both DMAR and bounce implementations use
common_bus_dma_tag_create(), which allocates the tag with M_NOWAIT.

Light cleanup of cursor position handling

Ensure the visible rect is invalidated on CONS_CLRHIST

In D24815#551397, @emaste wrote:

LGTM

I noticed one nit - after clearing history you can press Scroll Lock and scroll up through the cleared history buffer, while we probably want to reset that as well. However, I'd suggest that you commit this now and we can address that in a followup. I also did not check how sc(4) behaves with respect to this.

In D24815#546965, @emaste wrote:

I will try this out shortly

In D24373#536140, @imp wrote:

This looks fine, but given the age of config. It feels a bit like effort might be better spent on a rewrite

More review feedback

Code review feedback from markj

In D23142#507493, @markj wrote:

This mostly looks right to me. Would you be willing to add some basic regression tests for the garbage collector to tests/sys/kern/unix_passfd_test.c?

Replace assignment of unp_gcflag with KASSERT