In D46625#1094801, @imp wrote:

In D46625#1094783, @andrew wrote:

Not currently as no kernels support it. We could add an elf note when we support LPA2 in locore.S to tell loader the kernel supports executing from a higher address.

That would be great.

amd64 cpu_set_upcall() also calls cpu_thread_clean(), basically for the fresh thread. I suspect this call was copied.

I feel that the better place for this stuff would be cpu_machdep(9) rather then comments in the header.

Let me explain my PoV.

For the udata part, I agree.

vm_map_is_system()
Remove vm_flags_t
Some updates to vm_map(9)

Of course there are more deadlocks/live locks behind this change. But we wouldn't see them until this fix is done.

Add wrapper map_is_system_map().
Convert system_map and needs_wakeup to flags.

BTW, why does SYSINIT() enforces the cast? Isn't it more correct to not cast in the macro, and allow a compiler to check that the function passed matches the type?

Add a knob to select panicing behavior.

We can add a knob to control the behavior, panic/not panic.

In D24459#1092727, @kevans wrote:

Actually, it looks like our driver callbacks typically do timeouts when they actually submit to the controller: https://cgit.freebsd.org/src/tree/sys/dev/usb/serial/uftdi.c#n1688 -- so most of these should be reasonably bounded. Perhaps still good to be defensive, since I'm not about to audit every path out of usb_serial.c

Alan' notes. Remove outdated comment. Fix kassert message.

In D24459#1092724, @kevans wrote:

In D24459#1092714, @kib wrote:

So userspace might end up waiting uninterruptibly for hw to finish something?

Yes, though we could presumably implement usb_proc_mwait_sig() for an escape hatch. It would be an improvement even before this change, because open/close will both drop the tty lock and wait potentially uninterruptibly for the hardware.

Update comment about permissions for stack gap entries.

So userspace might end up waiting uninterruptibly for hw to finish something?

Rename MAP_STACK_GROWS_DOWN to MAP_STACK_AREA

Remove MAP_ENTRY_GROWS_UP

Reword comment.
Drop _DN suffixes, a separate commit.

In D47879#1091770, @olce wrote:

I've checked that nobody takes the address of the unaligned members.

In D47842#1090667, @markj wrote:

In D47842#1090650, @kib wrote:

May be a per-uid sysctl memlock limit is better.
BTW, why don't we account sysctl wired memory into the user wire limit?

It used to be that all user sysctl requests were serialized by a global lock, so it probably didn't matter very much since the wiring is always transient. Later, the sysctlmemlock was added, and we started serializing only those requests where oldsz > PAGE_SIZE. Perhaps we should modify vslock() to start counting these wirings, but I am not sure it is useful.

May be a per-uid sysctl memlock limit is better.
BTW, why don't we account sysctl wired memory into the user wire limit?