Reintegrate head: r274132-r277384

Sponsored by: The FreeBSD Foundation

Major callout subsystem cleanup and rewrite:
- Close a migration race where callout_reset() failed to set the
CALLOUT_ACTIVE flag.
- Callout callback functions are now allowed to be protected by

Major callout subsystem cleanup and rewrite:
- Close a migration race where callout_reset() failed to set the
CALLOUT_ACTIVE flag.
- Callout callback functions are now allowed to be protected by
spinlocks.
- Switching the callout CPU number cannot always be done on a
per-callout basis. See the updated timeout(9) manual page for more
information.
- The timeout(9) manual page has been updated to reflect how all the
functions inside the callout API are working. The manual page has
been made function oriented to make it easier to deduce how each of
the functions making up the callout API are working without having
to first read the whole manual page. Group all functions into a
handful of sections which should give a quick top-level overview
when the different functions should be used.
- The CALLOUT_SHAREDLOCK flag and its functionality has been removed
to reduce the complexity in the callout code and to avoid problems
about atomically stopping callouts via callout_stop(). If someone
needs it, it can be re-added. From my quick grep there are no
CALLOUT_SHAREDLOCK clients in the kernel.
- A new callout API function named "callout_drain_async()" has been
added. See the updated timeout(9) manual page for a complete
description.
- Update the callout clients in the "kern/" folder to use the callout
API properly, like cv_timedwait(). Previously there was some custom
sleepqueue code in the callout subsystem, which has been removed,
because we now allow callouts to be protected by spinlocks. This
allows us to tear down the callout like done with regular mutexes,
and a "td_slpmutex" has been added to "struct thread" to atomically
teardown the "td_slpcallout". Further the "TDF_TIMOFAIL" and
"SWT_SLEEPQTIMO" states can now be completely removed. Currently
they are marked as available and will be cleaned up in a follow up
commit.
- Bump the __FreeBSD_version to indicate kernel modules need
recompilation.
- There has been several reports that this patch "seems to squash a
serious bug leading to a callout timeout and panic".

Kernel build testing: all architectures were built
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D1438
Sponsored by: Mellanox Technologies
Reviewed by: jhb, adrian, sbruno and emaste

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Merge fresh head.

IFC @247348.

Sync with HEAD.

IFC @ r244983.

Add a comment on why inlining critical_enter() may not be a good idea
for the general case.

Reviewed by: bde
MFC after: 1 week

IFC @230489 (pending review).

IFC to head to catch up the bhyve branch

Approved by: grehan@

critical_exit: ignore td_owepreempt if kdb_active is set

calling mi_switch in such a context results in a recursion via
kdb_switch

Suggested by: jhb
Reviewed by: jhb
MFC after: 5 weeks

Merge svn+ssh://svn.freebsd.org/base/head@209086

Update several places that iterate over CPUs to use CPU_FOREACH().

Merge from head

- MFC

- Use DPCPU for SCHED_STATS. This is somewhat awkward because the
offset of the stat is not known until link time so we must emit a
function to call SYSCTL_ADD_PROC rather than using SYSCTL_PR

- Use DPCPU for SCHED_STATS. This is somewhat awkward because the
offset of the stat is not known until link time so we must emit a
function to call SYSCTL_ADD_PROC rather than using SYSCTL_PROC
directly.
- Eliminate the atomic from SCHED_STAT_INC now that it's using per-cpu
variables. Sched stats are always incremented while we're holding
a spinlock so no further protection is required.

Reviewed by: sam

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fix typo in runz_fuzz
noticed by:Elijah Buck

- Make SCHED_STATS more generic by adding a wrapper to create the
variables and sysctl nodes.
- In reset walk the children of kern_sched_stats and reset the counters
via the oid_arg1 pointer.

- Make SCHED_STATS more generic by adding a wrapper to create the
variables and sysctl nodes.
- In reset walk the children of kern_sched_stats and reset the counters
via the oid_arg1 pointer. This allows us to add arbitrary counters to
the tree and still reset them properly.
- Define a set of switch types to be passed with flags to mi_switch().
These types are named SWT_*. These types correspond to SCHED_STATS
counters and are automatically handled in this way.
- Make the new SWT_ types more specific than the older switch stats.
There are now stats for idle switches, remote idle wakeups, remote
preemption ithreads idling, etc.
- Add switch statistics for ULE's pickcpu algorithm. These stats include
how much migration there is, how often affinity was successful, how
often threads were migrated to the local cpu on wakeup, etc.

Sponsored by: Nokia

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- Restore runq to manipulating threads directly by putting runq links and
rqindex back in struct thread.
- Compile kern_switch.c independently again and stop #include'ing it from
schedulers.

- Restore runq to manipulating threads directly by putting runq links and
rqindex back in struct thread.
- Compile kern_switch.c independently again and stop #include'ing it from
schedulers.
- Remove the ts_thread backpointers and convert most code to go from
struct thread to struct td_sched.
- Cleanup the ts_flags #define garbage that was causing us to sometimes
do things that expanded to td->td_sched->ts_thread->td_flags in 4BSD.
- Export the kern.sched sysctl node in sysctl.h

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- Remove the unused and redundant sched_newproc() function.
- Remove the unused and redundant sched_newthread() which peaks into scheduler
private structures.

- Move maybe_preempt() from kern_switch.c to sched_4bsd.c. This is function
is only used by 4bsd.
- Create a new runq_choose_fuzz() function rather than polluting runq_choose()
with 4BSD spec

- Move maybe_preempt() from kern_switch.c to sched_4bsd.c. This is function
is only used by 4bsd.
- Create a new runq_choose_fuzz() function rather than polluting runq_choose()
with 4BSD specific code.
- Move the fuzz sysctl into sched_4bsd.c
- Remove some dead code from kern_switch.c

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In keeping with style(9)'s recommendations on macros, use a ';'
after each SYSINIT() macro invocation. This makes a number of
lightweight C parsers much happier with the FreeBSD kernel
source, inclu

In keeping with style(9)'s recommendations on macros, use a ';'
after each SYSINIT() macro invocation. This makes a number of
lightweight C parsers much happier with the FreeBSD kernel
source, including cflow's prcc and lxr.

MFC after: 1 month
Discussed with: imp, rink

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Remove kernel support for M:N threading.

While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potent

Remove kernel support for M:N threading.

While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potential. Backwards compatibility will be provided via
libmap.conf for dynamically linked binaries and static binaries will
be broken.

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generally we are interested in what thread did something as
opposed to what process. Since threads by default have teh name of the
process unless over-written with more useful information, just print

generally we are interested in what thread did something as
opposed to what process. Since threads by default have teh name of the
process unless over-written with more useful information, just print the
thread name instead.

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- Fix ULE in kernels without PREEMPTION compiled in by always enabling the
critical_exit() owepreempt check. ULE will always use owepreempt to
preempt the idle thread. This change does not ef

- Fix ULE in kernels without PREEMPTION compiled in by always enabling the
critical_exit() owepreempt check. ULE will always use owepreempt to
preempt the idle thread. This change does not effect 4BSD since it will
never set owepreempt without PREEMPTION enabled.
- Remove some unused code from choosethread().

Discussed with: jhb
Approved by: re

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Fix some entries in the locks static table of witness.
In particular:
- smp_tlb_mtx is no longer used, so it is axed.
- smp rendezvous lock isn't really a leaf spin-mutex. Its bad placement in
the

Fix some entries in the locks static table of witness.
In particular:
- smp_tlb_mtx is no longer used, so it is axed.
- smp rendezvous lock isn't really a leaf spin-mutex. Its bad placement in
the table, however, has been the source of a false positive LOR reporting
with the dt_lock. However, smp rendezvous lock would have had sched_lock
there for older lock, so it wasn't still a leaf lock.
- allpmaps is only used in ia32 architecture, so it is inserted in the
appropriate stub.

Addictionally:
- kse_zombie_lock is no longer present, so its definition is axed out.
- zombie_lock doesn't need to have an exported symbol, so just let's it be
declared as static.

Tested by: kris
Approved by: jeff (mentor)
Approved by: re

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