Constify strings in symbol-related ddb interfaces, and make the iterator
callback interface a bit simpler.
ok beck@ claudio@ mpi@

clockintr: rename "struct clockintr_queue" to "struct clockqueue"

The code has outgrown the original name for this struct. Both the
external and internal APIs have used the "clockqueue" namespace f

clockintr: rename "struct clockintr_queue" to "struct clockqueue"

The code has outgrown the original name for this struct. Both the
external and internal APIs have used the "clockqueue" namespace for
some time when operating on it, and that name is eyeball-consistent
with "clockintr" and "clockrequest", so "clockqueue" it is.

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clockintr.h, kern_clockintr.c: add 2023, 2024 to copyright range

clockintr: rename clockqueue_reset_intrclock to clockqueue_intrclock_reprogram

The function should be in the clockqueue_intrclock namespace. Also,
"reprogram" is a better word for what the function

clockintr: rename clockqueue_reset_intrclock to clockqueue_intrclock_reprogram

The function should be in the clockqueue_intrclock namespace. Also,
"reprogram" is a better word for what the function actually does.

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kernel: disable hardclock() on secondary CPUs

There is no useful work left for secondary CPUs to do in hardclock().
Disable cq_hardclock on secondary CPUs and remove the now-unnecessary
early-return

kernel: disable hardclock() on secondary CPUs

There is no useful work left for secondary CPUs to do in hardclock().
Disable cq_hardclock on secondary CPUs and remove the now-unnecessary
early-return from hardclock().

This change reduces every system's normal clock interrupt rate by
(HZ - HZ/10) per secondary CPU. For example, an 8-core machine
with a HZ=100 kernel should see its clock interrupt rate drop from
~1600 to ~960.

Thread: https://marc.info/?l=openbsd-tech&m=170750140915898&w=2

ok kettenis@

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clockintr: add clockintr_unbind()

The clockintr_unbind() function cancels any pending execution of the
given clock interrupt object's callback and severs the binding between
the object and its host

clockintr: add clockintr_unbind()

The clockintr_unbind() function cancels any pending execution of the
given clock interrupt object's callback and severs the binding between
the object and its host CPU. Upon return from clockintr_unbind(), the
clock interrupt object may be rebound with a call to clockintr_bind().

The optional CL_BARRIER flag tells clockintr_unbind() to block if the
clockintr's callback function is executing at the moment of the call.
This is useful when the clockintr's arg is a shared reference and the
caller needs to be certain the reference is inactive.

Now that clockintrs can be bound and unbound repeatedly, there is more
room for error. To help catch programmer errors, clockintr_unbind()
sets cl_queue to NULL. Calls to other API functions after a clockintr
is unbound will then fault on a NULL dereference. clockintr_bind()
also KASSERTs that cl_queue is NULL to ensure the clockintr is not
already bound. These checks are not perfect, but they do catch some
common errors.

With input from mpi@.

Thread: https://marc.info/?l=openbsd-tech&m=170629367121800&w=2

ok mpi@

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clockintr: refactor clockintr_cancel() into clockintr_cancel_locked()

Move the mutex-protected portions of clockintr_cancel() into a separate
function, clockintr_cancel_locked(), so that the code ca

clockintr: refactor clockintr_cancel() into clockintr_cancel_locked()

Move the mutex-protected portions of clockintr_cancel() into a separate
function, clockintr_cancel_locked(), so that the code can be reused by
other callers.

Thread: https://marc.info/?l=openbsd-tech&m=170629367121800&w=2

ok mpi@

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clockintr: switch from callee- to caller-allocated clockintr structs

Currently, clockintr_establish() calls malloc(9) to allocate a
clockintr struct on behalf of the caller. mpi@ says this behavior

clockintr: switch from callee- to caller-allocated clockintr structs

Currently, clockintr_establish() calls malloc(9) to allocate a
clockintr struct on behalf of the caller. mpi@ says this behavior is
incompatible with dt(4). In particular, calling malloc(9) during the
initialization of a PCB outside of dt_pcb_alloc() is (a) awkward and
(b) may conflict with future changes/optimizations to PCB allocation.

To side-step the problem, this patch changes the clockintr subsystem
to use caller-allocated clockintr structs instead of callee-allocated
structs.

clockintr_establish() is named after softintr_establish(), which uses
malloc(9) internally to create softintr objects. The clockintr subsystem
is no longer using malloc(9), so the "establish" naming is no longer apt.
To avoid confusion, this patch also renames "clockintr_establish" to
"clockintr_bind".

Requested by mpi@. Tweaked by mpi@.

Thread: https://marc.info/?l=openbsd-tech&m=170597126103504&w=2

ok claudio@ mlarkin@ mpi@

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clockintr: move CLST_IGNORE_REQUESTS from cl_flags to cq_flags

In the near future, we will add support for destroying clockintr
objects. When this happens, it will no longer be safe to dereference

clockintr: move CLST_IGNORE_REQUESTS from cl_flags to cq_flags

In the near future, we will add support for destroying clockintr
objects. When this happens, it will no longer be safe to dereference
the pointer to the expired clockintr during the dispatch loop in
clockintr_dispatch() after reentering cq_mtx. This means we will not
be able to safely check for the CLST_IGNORE_REQUESTS flag.

So replace the CLST_IGNORE_REQUESTS flag in cl_flags with the
CQ_IGNORE_REQUESTS flag in cq_flags. The semantics are the same.
Both cl_flags and cq_flags are protected by cq_mtx.

Note that we cannot move the CLST_IGNORE_REQUESTS flag to cr_flags in
struct clockrequest: that member is owned by the dispatching CPU and
is not mutated with atomic operations.

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clockintr: move callback-specific API behaviors to "clockrequest" namespace

The API's behavior when invoked from a callback function is impossible
to document. Move the special behavior into a dist

clockintr: move callback-specific API behaviors to "clockrequest" namespace

The API's behavior when invoked from a callback function is impossible
to document. Move the special behavior into a distinct namespace,
"clockrequest".

- Add a 'struct clockrequest'. Basically a stripped-down 'struct clockintr'
for exclusive use during clockintr_dispatch().
- In clockintr_queue, replace the "cq_shadow" clockintr with a "cq_request"
clockrequest. They serve the same purpose.
- CLST_SHADOW_PENDING -> CR_RESCHEDULE; different namespace, same meaning.
- CLST_IGNORE_SHADOW -> CLST_IGNORE_REQUEST; same meaning.
- Move shadow branch in clockintr_advance() to clockrequest_advance().
- clockintr_request_random() becomes clockrequest_advance_random().
- Delete dead shadow branches in clockintr_cancel(), clockintr_schedule().
- Callback functions now get a clockrequest pointer instead of a special
clockintr pointer: update all prototypes, callers.

No functional change intended.

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clockintr: move clockintr_schedule() into public API

Prototype clockintr_schedule() in <sys/clockintr.h>.

clockintr_stagger: rename parameters: "n" -> "numer", "count" -> "denom"

Rename these parameters to align the code with the forthcoming
manpage. No functional change.

clockintr: move intrclock wrappers from sys/clockintr.h to kern_clockintr.c

intrclock_rearm() and intrclock_trigger() are not part of the public
API, so there's no reason to implement them in sys/cl

clockintr: move intrclock wrappers from sys/clockintr.h to kern_clockintr.c

intrclock_rearm() and intrclock_trigger() are not part of the public
API, so there's no reason to implement them in sys/clockintr.h. Move
them to kern_clockintr.c.

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ddb(4): clockintr: print cl_arg address when displaying a clockintr

kern_clockintr.c: remove extra newline

clockintr.h: forward-declare "struct cpu_info" for clockintr_establish()

With input from claudio@ and deraadt@.

struct clockintr_queue: rename "cq_est" to "cq_all"

"cq_all" is a more obvious name than "cq_est". It's the list of all
established clockintrs. Duh.

clockintr: remove clockintr_init(), clockintr_flags

All the state initialization once done in clockintr_init() has been
moved to other parts of the kernel. It's a dead function. Remove it.

Likewi

clockintr: remove clockintr_init(), clockintr_flags

All the state initialization once done in clockintr_init() has been
moved to other parts of the kernel. It's a dead function. Remove it.

Likewise, the clockintr_flags variable no longer sports any meaningful
flags. Remove it. This frees up the CL_* flag namespace, which might
be useful to the clockintr frontend if we ever need to add behavior
flags to any of those functions.

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work around cpu.h not coming into early scope on all arch

clockintr: move hz(9)-based initialization out to initclocks()

To separate the hardclock from the clock interrupt subsystem we'll
need to move all related state out first.

hz(9) is set when we retu

clockintr: move hz(9)-based initialization out to initclocks()

To separate the hardclock from the clock interrupt subsystem we'll
need to move all related state out first.

hz(9) is set when we return from cpu_initclocks(), so it's safe to
move hardclock_period and roundrobin_period initialization out into
initclocks(). Move hardclock_period itself out into kern_clock.c
alongside the statclock variables.

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clockintr, scheduler: move statclock handle from clockintr_queue to schedstate_percpu

Move the statclock handle from clockintr_queue.cq_statclock to
schedstate_percpu.spc_statclock. Establish spc_s

clockintr, scheduler: move statclock handle from clockintr_queue to schedstate_percpu

Move the statclock handle from clockintr_queue.cq_statclock to
schedstate_percpu.spc_statclock. Establish spc_statclock during
sched_init_cpu() alongside the other scheduler clock interrupts.

Thread: https://marc.info/?l=openbsd-tech&m=169428749720476&w=2

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clockintr, statclock: eliminate clockintr_statclock() wrapper

- Move remaining statclock variables from kern_clockintr.c to
kern_clock.c. Move statclock variable initialization from
clockintr_i

clockintr, statclock: eliminate clockintr_statclock() wrapper

- Move remaining statclock variables from kern_clockintr.c to
kern_clock.c. Move statclock variable initialization from
clockintr_init() into initclocks().

- Change statclock() prototype to make it a legal clockintr
callback function and establish the handle with statclock()
instead clockintr_statclock().

- Merge the contents of clockintr_statclock() into statclock().
statclock() can now reschedule itself and handles multiple
expirations transparently.

- Make statclock_avg visible from sys/systm.h so that clockintr_cpu_init()
can use it to advance the statclock across suspend/hibernate.

Thread: https://marc.info/?l=openbsd-tech&m=169428749720476&w=2

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clockintr: move clockintr_advance_random() prototype into sys/clockintr.h

statclock() is going to need this. Move the prototype into the public API.

Thread: https://marc.info/?l=openbsd-tech&m=169

clockintr: move clockintr_advance_random() prototype into sys/clockintr.h

statclock() is going to need this. Move the prototype into the public API.

Thread: https://marc.info/?l=openbsd-tech&m=169428749720476&w=2

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clockintr: replace CL_RNDSTAT with global variable statclock_is_randomized

In order to separate the statclock from the clock interrupt subsystem
we need to move all statclock state out into the broa

clockintr: replace CL_RNDSTAT with global variable statclock_is_randomized

In order to separate the statclock from the clock interrupt subsystem
we need to move all statclock state out into the broader kernel.

Start by replacing the CL_RNDSTAT flag with a new global variable,
"statclock_is_randomized", in kern_clock.c. Update all clockintr_init()
callers to set the boolean instead of passing the flag.

Thread: https://marc.info/?l=openbsd-tech&m=169428749720476&w=2

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clockintr: support an arbitrary callback function argument

Callers can now provide an argument pointer to clockintr_establish().
The pointer is kept in a new struct clockintr member, cl_arg. The
po

clockintr: support an arbitrary callback function argument

Callers can now provide an argument pointer to clockintr_establish().
The pointer is kept in a new struct clockintr member, cl_arg. The
pointer is passed as the third parameter to clockintr.cl_func when it
is executed during clockintr_dispatch(). Like the callback function,
the callback argument is immutable after the clockintr is established.

At present, nothing uses this. All current clockintr_establish()
callers pass a NULL arg pointer. However, I am confident that dt(4)'s
profile provider will need this in the near future.

Requested by dlg@ back in March.

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