Do some refactoring and minor cleanups of the thread_single() code in
preparation for the global stop commit.

Move the code to weed suspended or sleeping threads into the
appropriate state, into the

Do some refactoring and minor cleanups of the thread_single() code in
preparation for the global stop commit.

Move the code to weed suspended or sleeping threads into the
appropriate state, into the helper weed_inhib(). Current code already
has deep nesting and hard to follow [1].

Add currently useless helper remain_for_mode(), which returns the
count of threads which are allowed to run, according to the
single-threading mode.

In thread_single_end(), do not save curthread into local variable, it
is unused after, except to find curproc.

Remove stray empty line.

Requested by: avg [1]
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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Thread waiting for the vfork(2)-ed child to exec or exit, must allow
for the suspension.

Currently, the loop performs uninterruptible cv_wait(9) call, which
prevents suspension until child allows fu

Thread waiting for the vfork(2)-ed child to exec or exit, must allow
for the suspension.

Currently, the loop performs uninterruptible cv_wait(9) call, which
prevents suspension until child allows further execution of parent.
If child is stopped, suspension or single-threading is delayed
indefinitely.

Create a helper thread_suspend_check_needed() to identify the need for
a call to thread_suspend_check(). It is required since call to the
thread_suspend_check() cannot be safely done while owning the child
(p2) process lock. Only when suspension is needed, drop p2 lock and
call thread_suspend_check(). Perform wait for cv with timeout, in
case suspend is requested after wait started; I do not see a better
way to interrupt the wait.

Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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MFHead @ r275232

Merge ^/head r275118 through r275209.

The process spin lock currently has the following distinct uses:

- Threads lifetime cycle, in particular, counting of the threads in
the process, and interlocking with process mutex and thread loc

The process spin lock currently has the following distinct uses:

- Threads lifetime cycle, in particular, counting of the threads in
the process, and interlocking with process mutex and thread lock.
The main reason of this is that turnstile locks are after thread
locks, so you e.g. cannot unlock blockable mutex (think process
mutex) while owning thread lock.

- Virtual and profiling itimers, since the timers activation is done
from the clock interrupt context. Replace the p_slock by p_itimmtx
and PROC_ITIMLOCK().

- Profiling code (profil(2)), for similar reason. Replace the p_slock
by p_profmtx and PROC_PROFLOCK().

- Resource usage accounting. Need for the spinlock there is subtle,
my understanding is that spinlock blocks context switching for the
current thread, which prevents td_runtime and similar fields from
changing (updates are done at the mi_switch()). Replace the p_slock
by p_statmtx and PROC_STATLOCK().

The split is done mostly for code clarity, and should not affect
scalability.

Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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Merge from head@274682

IFC @r271694

Sync to HEAD@r271160.

Style.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Retire thread_unthread(), it has only one caller. Update comment in
the block of code before the previous call to thread_unthread().

Discussed with: alc
Sponsored by: The FreeBSD Foundation
MFC aft

Retire thread_unthread(), it has only one caller. Update comment in
the block of code before the previous call to thread_unthread().

Discussed with: alc
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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Right now, thread_single(SINGLE_EXIT) returns after the p_numthreads
reaches 1. The p_numthreads counter is decremented in thread_exit() by
a call to thread_unlink(). This means that the exiting thre

Right now, thread_single(SINGLE_EXIT) returns after the p_numthreads
reaches 1. The p_numthreads counter is decremented in thread_exit() by
a call to thread_unlink(). This means that the exiting threads may
still execute on other CPUs when thread_single(SINGLE_EXIT) returns.
As result, vmspace could be destroyed while paging structures are
still used on other CPUs by exiting threads.

Delay the return from thread_single(SINGLE_EXIT) until all threads are
really destroyed by thread_stash() after the last switch out. The
p_exitthreads counter already provides the required mechanism, move
the wait from the thread_wait() (which is called from wait(2) code)
into thread_single().

Reported by: many (as "panic: pmap active <addr>")
Reviewed by: alc, jhb
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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IFC @r269962

Submitted by: Anish Gupta (akgupt3@gmail.com)

Merge head from 7/28

Sync to HEAD@r269943.

Insert new threads at the end of the thread list in the process
instead of at the beginning. This allows an intra process signal
to be sent to the oldest thread with the signal unmasked - which,
if

Insert new threads at the end of the thread list in the process
instead of at the beginning. This allows an intra process signal
to be sent to the oldest thread with the signal unmasked - which,
if it still exists, is the main thread. This mimics behavior
found in Linux and Solaris.

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Remove ia64.

This includes:
o All directories named *ia64*
o All files named *ia64*
o All ia64-specific code guarded by __ia64__
o All ia64-specific makefile logic
o Mention of ia64 in com

Remove ia64.

This includes:
o All directories named *ia64*
o All files named *ia64*
o All ia64-specific code guarded by __ia64__
o All ia64-specific makefile logic
o Mention of ia64 in comments and documentation

This excludes:
o Everything under contrib/
o Everything under crypto/
o sys/xen/interface
o sys/sys/elf_common.h

Discussed at: BSDcan

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Merge head

IFC @264767

Merge head up to r262222 (last merge was incomplete).

MFC @ r259205 in preparation for some SVM updates. (for real this time)

dtrace sdt: remove the ugly sname parameter of SDT_PROBE_DEFINE

In its stead use the Solaris / illumos approach of emulating '-' (dash)
in probe names with '__' (two consecutive underscores).

Revie

dtrace sdt: remove the ugly sname parameter of SDT_PROBE_DEFINE

In its stead use the Solaris / illumos approach of emulating '-' (dash)
in probe names with '__' (two consecutive underscores).

Reviewed by: markj
MFC after: 3 weeks

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- For kernel compiled only with KDTRACE_HOOKS and not any lock debugging
option, unbreak the lock tracing release semantic by embedding
calls to LOCKSTAT_PROFILE_RELEASE_LOCK() direclty in the in

- For kernel compiled only with KDTRACE_HOOKS and not any lock debugging
option, unbreak the lock tracing release semantic by embedding
calls to LOCKSTAT_PROFILE_RELEASE_LOCK() direclty in the inlined
version of the releasing functions for mutex, rwlock and sxlock.
Failing to do so skips the lockstat_probe_func invokation for
unlocking.
- As part of the LOCKSTAT support is inlined in mutex operation, for
kernel compiled without lock debugging options, potentially every
consumer must be compiled including opt_kdtrace.h.
Fix this by moving KDTRACE_HOOKS into opt_global.h and remove the
dependency by opt_kdtrace.h for all files, as now only KDTRACE_FRAMES
is linked there and it is only used as a compile-time stub [0].

[0] immediately shows some new bug as DTRACE-derived support for debug
in sfxge is broken and it was never really tested. As it was not
including correctly opt_kdtrace.h before it was never enabled so it
was kept broken for a while. Fix this by using a protection stub,
leaving sfxge driver authors the responsibility for fixing it
appropriately [1].

Sponsored by: EMC / Isilon storage division
Discussed with: rstone
[0] Reported by: rstone
[1] Discussed with: philip

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IFC @253398

Merge fresh head.

sync from head