Update comments, asserts, convert one more lookup to lookup_readonly.

Update ObsoleteFiles.inc.

Discard the "leaf parents of root" part.

In D50640#1156361, @markj wrote:

Do you mean that slab->us_free should still have type int *? Then, is the idea that BIT_* would only access the low 32 bits of each bitset (us_free and slab_dbg_bits()), so it's okay to let them overlap from the perspective of BIT_*?

Could you shrink uma_slab at still use BITSET?

Don't let ahead exceed after.

@alc advises that having lookup_range return a positive value in this case will be rare, and testing shows that. So, instead of using lookup_range to find a bunch of pages, try using lookup_ge to quickly identify a range of missing pages.

In D50515#1153918, @markj wrote:

If that's your regular user id, then the result is presumably the same. The killpg4.sh test assumes that nothing else on the system is running as that user. So, the problem isn't limited to "root" as I claimed earlier.

In D50515#1153880, @markj wrote:

Before running stress2 tests you have to run make in the test suite, and as part of that you are prompted to provide a value for the testuser variable. That gets saved in the file /tmp/stress2.d/$(hostname). If the saved value of testuser is "root", killpg4 will never terminate. You're supposed to ensure that testuser is a non-root user.

In D50515#1153696, @markj wrote:

Did you figure out why killpg4.sh is hanging?

It always hangs for me. It has always hung for me. I haven't tried to diagnose it. I'm only ever running the tests as root. If I'm supposed to run the tests some other way, I'm not aware of it.

Limit the changes to just vm_object_page_clean_flush. Provide more meaningful performance results.

Fixed.

@alc asks for a more commenting about why this code treats SMR and locked diferently. I oblige.

Correct ',' to '.' in comment.

Remove extra paren on KASSERT.

Add comments to explain end calculation. Add KASSERT to check that copied pages are not NULL.