Make sigaltstack as per-threaded, because per-process sigaltstack state
is useless for threaded programs, multiple threads can not share same
stack.
The alternative signal stack is private for thread

Make sigaltstack as per-threaded, because per-process sigaltstack state
is useless for threaded programs, multiple threads can not share same
stack.
The alternative signal stack is private for thread, no lock is needed,
the orignal P_ALTSTACK is now moved into td_pflags and renamed to
TDP_ALTSTACK.
For single thread or Linux clone() based threaded program, there is no
semantic changed, because those programs only have one kernel thread
in every process.

Reviewed by: deischen, dfr

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Removed mostly-dead code for setting switchtime after the idle loop
clobbers this variable. Long ago, when the idle loop wasn't in a
process, it set switchtime.tv_sec to zero to indicate that the ti

Removed mostly-dead code for setting switchtime after the idle loop
clobbers this variable. Long ago, when the idle loop wasn't in a
process, it set switchtime.tv_sec to zero to indicate that the time
needs to be read after the idle loop finishes. The special case for
this isn't needed now that there is an idle process (for each CPU).
The time is read in the normal way when the idle process is switched
away from. The seconds component of the time is only zero for the
first second after the uptime is set, and the mostly-dead code was only
executed during this time. (This was slightly broken by using uptimes
instead of times relative to the Epoch -- in the original version the
seconds component of the time was only 0 for the first second after
the Epoch.)

In mi_switch(), moved the setting of switchticks to just after the
first (and now only) setting of switchtime. This setting used to be
delayed since a late setting was needed for the idle case and an early
setting was not needed. Now the early setting is needed so that
fork_exit() doesn't need to set either switchtime or switchticks.
Removed now-completely-rotted comment attached to this. Most of the
code described by the comment had already moved to sched_switch().

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Removed sched_nest variable in sched_switch(). Context switches always
begin with sched_lock held but not recursed, so this variable was
always 0.

Removed fixup of sched_lock.mtx_recurse after cont

Removed sched_nest variable in sched_switch(). Context switches always
begin with sched_lock held but not recursed, so this variable was
always 0.

Removed fixup of sched_lock.mtx_recurse after context switches in
sched_switch(). Context switches always end with this variable in the
same state that it began in, so there is no need to fix it up. Only
sched_lock.mtx_lock really needs a fixup.

Replaced fixup of sched_lock.mtx_recurse in fork_exit() by an assertion
that sched_lock is owned and not recursed after it is fixed up. This
assertion much match the one in mi_switch(), and if sched_lock were
recursed then a non-null fixup of sched_lock.mtx_recurse would probably
be needed again, unlike in sched_switch(), since fork_exit() doesn't
return to its caller in the normal way.

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Change instances of callout_init that specify MPSAFE behaviour to
use CALLOUT_MPSAFE instead of "1" for the second parameter. This
does not change the behaviour; it just makes the intent more clear.

- Various style fixes in both code and comments.
- Update some stale comments.
- Sort a couple of includes.
- Only set 'newcpu' in updatepri() if we use it.
- No functional changes.

Obtained from: b

- Various style fixes in both code and comments.
- Update some stale comments.
- Sort a couple of includes.
- Only set 'newcpu' in updatepri() if we use it.
- No functional changes.

Obtained from: bde (via an old diff I got a long time ago)

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Adjust a comment to remove staleness and take slightly less implementation
specific perspective.

Add a ratelimited message of the form
"maxproc limit exceeded by uid %i, please see tuning(7) and login.conf(5)."

Which will be triggered whenever a user hits his/her maxproc limit or
the systemwide

Add a ratelimited message of the form
"maxproc limit exceeded by uid %i, please see tuning(7) and login.conf(5)."

Which will be triggered whenever a user hits his/her maxproc limit or
the systemwide maxproc limit is reached.

MFC after: 1 week

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Rename P_THREADED to P_SA. P_SA means a process is using scheduler
activations.

Move the *_new_altkstack() and *_dispose_altkstack() functions out of the
various pmap implementations into the machine-independent vm. They were
all identical.

Use __FBSDID().

Add tracking of process leaders sharing a file descriptor table and
allow a file descriptor table to be shared between multiple process
leaders.

PR: 50923

- Merge struct procsig with struct sigacts.
- Move struct sigacts out of the u-area and malloc() it using the
M_SUBPROC malloc bucket.
- Add a small sigacts_*() API for managing sigacts structures:

- Merge struct procsig with struct sigacts.
- Move struct sigacts out of the u-area and malloc() it using the
M_SUBPROC malloc bucket.
- Add a small sigacts_*() API for managing sigacts structures: sigacts_alloc(),
sigacts_free(), sigacts_copy(), sigacts_share(), and sigacts_shared().
- Remove the p_sigignore, p_sigacts, and p_sigcatch macros.
- Add a mutex to struct sigacts that protects all the members of the struct.
- Add sigacts locking.
- Remove Giant from nosys(), kill(), killpg(), and kern_sigaction() now
that sigacts is locked.
- Several in-kernel functions such as psignal(), tdsignal(), trapsignal(),
and thread_stopped() are now MP safe.

Reviewed by: arch@
Approved by: re (rwatson)

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Initialize and destroy the struct proc mutex in the proc zone's init and
fini routines instead of in fork() and wait(). This has the nice side
benefit that the proc lock of any process on the allpro

Initialize and destroy the struct proc mutex in the proc zone's init and
fini routines instead of in fork() and wait(). This has the nice side
benefit that the proc lock of any process on the allproc list is always
valid and sched_lock doesn't have to be used to test against PRS_NEW
anymore.

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Instead of recording the Unix time in a process when it starts, record the
uptime. Where necessary, convert it back to Unix time by adding boottime
to it. This fixes a potential problem in the acco

Instead of recording the Unix time in a process when it starts, record the
uptime. Where necessary, convert it back to Unix time by adding boottime
to it. This fixes a potential problem in the accounting code, which would
compute the elapsed time incorrectly if the Unix time was stepped during
the lifetime of the process.

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Axe a stale comment.

Fix some easy, global, lint warnings. In most cases, this means
making some local variables static. In a couple of cases, this means
removing an unused variable.

- Move PS_PROFIL and its new cousin PS_STOPPROF back over to p_flag and
rename them appropriately. Protect both flags with both the proc lock
and the sched_lock.
- Protect p_profthreads with the

- Move PS_PROFIL and its new cousin PS_STOPPROF back over to p_flag and
rename them appropriately. Protect both flags with both the proc lock
and the sched_lock.
- Protect p_profthreads with the proc lock.
- Remove Giant from profil(2).

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- Push Giant down into the fork1() function a small bit.
- Set p_acflag earlier while already hold the proc lock in fork1().
- Mark the realitexpire() callout MPSAFE for new processes. It was alread

- Push Giant down into the fork1() function a small bit.
- Set p_acflag earlier while already hold the proc lock in fork1().
- Mark the realitexpire() callout MPSAFE for new processes. It was already
marked safe for proc0 a long while ago.

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- Adjust sched hooks for fork and exec to take processes as arguments instead
of ksegs since they primarily operation on processes.
- KSEs take ticks so pass the kse through sched_clock().
- Add

- Adjust sched hooks for fork and exec to take processes as arguments instead
of ksegs since they primarily operation on processes.
- KSEs take ticks so pass the kse through sched_clock().
- Add a sched_class() routine that adjusts a ksegrp pri class.
- Define a sched_fork_{kse,thread,ksegrp} and sched_exit_{kse,thread,ksegrp}
that will be used to tell the scheduler about new instances of these
structures within the same process. These will be used by THR and KSE.
- Change sched_4bsd to reflect this API update.

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Move the _oncpu entry from the KSE to the thread.
The entry in the KSE still exists but it's purpose will change a bit
when we add the ability to lock a KSE to a cpu.

- Borrow the KSE single threading code for exec and exit. We use the check
if (p->p_numthreads > 1) and not a flag because action is only necessary
if there are other threads. The rest of the

- Borrow the KSE single threading code for exec and exit. We use the check
if (p->p_numthreads > 1) and not a flag because action is only necessary
if there are other threads. The rest of the system has no need to
identify thr threaded processes.
- In kern_thread.c use thr_exit1() instead of thread_exit() if P_THREADED
is not set.

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Replace the at_fork, at_exec, and at_exit functions with the slightly more
flexible process_fork, process_exec, and process_exit eventhandlers. This
reduces code duplication and also means that I do

Replace the at_fork, at_exec, and at_exit functions with the slightly more
flexible process_fork, process_exec, and process_exit eventhandlers. This
reduces code duplication and also means that I don't have to go duplicate
the eventhandler locking three more times for each of at_fork, at_exec, and
at_exit.

Reviewed by: phk, jake, almost complete silence on arch@

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- Cache a reference to the credential of the thread that starts a ktrace in
struct proc as p_tracecred alongside the current cache of the vnode in
p_tracep. This credential is then used for all

- Cache a reference to the credential of the thread that starts a ktrace in
struct proc as p_tracecred alongside the current cache of the vnode in
p_tracep. This credential is then used for all later ktrace operations on
this file rather than using the credential of the current thread at the
time of each ktrace event.
- Now that we have multiple ktrace-related items in struct proc that are
pointers, rename p_tracep to p_tracevp to make it less ambiguous.

Requested by: rwatson (1)

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Change the process flags P_KSES to be P_THREADED.
This is just a cosmetic change but I've been meaning to do it for about a year.

Remove the PL_SHAREMOD flag from struct plimit, which could have been
used to share resource limits between rfork threads, but never was.
Removing it makes resource limit locking much simpler -- only

Remove the PL_SHAREMOD flag from struct plimit, which could have been
used to share resource limits between rfork threads, but never was.
Removing it makes resource limit locking much simpler -- only the current
process can change the contents of the structure that p_limit points to.

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