to select a KSE with a slice of 0 we will update its slice and insert it
onto the next queue.
- Pass the KSE instead of the ksegrp into sched_slice(). This more
accurately reflects the behavior of the code. Slices are granted to kses.
- Add a function kseq_nice_min() which finds the smallest nice value
assigned to the kseg of any KSE on the queue.
- Rewrite the logic in sched_slice(). Add a large comment describing the
new slice selection scheme. To summarize, slices are assigned based on
the nice value. Priorities are still calculated based on the nice and
interactivity of a process. Slice sizes of 0 may be granted for KSEs
whos nice is 20 or futher away from the lowest nice on the run queue.
Other nice values are scaled across the range [min, min+20]. This fixes
ULEs bad behavior with positively niced processes.
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.
- umtx_lock() is defined as an inline in umtx.h. It tries to do an
uncontested acquire of a lock which falls back to the _umtx_lock()
system-call if that fails.
- umtx_unlock() is also an inline which falls back to _umtx_unlock() if the
uncontested unlock fails.
- Locks are keyed off of the thr_id_t of the currently running thread which
is currently just the pointer to the 'struct thread' in kernel.
- _umtx_lock() uses the proc pointer to synchronize access to blocked thread
queues which are stored in the first blocked thread.
- sys/thr.h contains the user space visible api that is intended only for
use in threading library packages.
- kern/kern_thr.c contains thr system calls and other thr specific code.
kern_sigtimedwait() which is capable of supporting all of their semantics.
- These should be POSIX compliant but more careful review is needed before
we announce this.
a follow on commit to kern_sig.c
- signotify() now operates on a thread since unmasked pending signals are
stored in the thread.
- PS_NEEDSIGCHK moves to TDF_NEEDSIGCHK.
- Change all consumers to pass in a thread.
Right now this does not cause any functional changes but it will be important
later when signals can be delivered to specific threads.
of sf_buf_alloc() instead of expecting sf_buf_alloc()'s caller to map it.
The ultimate reason for this change is to enable two optimizations:
(1) that there never be more than one sf_buf mapping a vm_page at a time
and (2) 64-bit architectures can transparently use their 1-1 virtual
to physical mapping (e.g., "K0SEG") avoiding the overhead of pmap_qenter()
and pmap_qremove().
time a character is written. Use this at boot time to reject the
existing buffer contents if they are corrupt. This fixes a problem
seen on some hardware (especially laptops) where the message buffer
gets partially corrupted during a short power cycle or reset, but
the msgbuf structure is left intact so it gets reused, resulting
in random junk and control characters appearing in dmesg and
/var/log/messages.
PR: kern/28497
that the feature can be enabled during the boot process. Note the
continued limitation that FreeBSD fails so rapidly with this setting
enabled that it's hard to narrow down particular failures for
correction; we really need per-malloc type failure rates.
in a debugging feature causing M_NOWAIT allocations to fail at
a specified rate. This can be useful for detecting poor
handling of M_NOWAIT: the most frequent problems I've bumped
into are unconditional deference of the pointer even though
it's NULL, and hangs as a result of a lost event where memory
for the event couldn't be allocated. Two sysctls are added:
debug.malloc.failure_rate
How often to generate a failure: if set to 0 (default), this
feature is disabled. Otherwise, the frequency of failures --
I've been using 10 (one in ten mallocs fails), but other
popular settings might be much lower or much higher.
debug.malloc.failure_count
Number of times a coerced malloc failure has occurred as a
result of this feature. Useful for tracking what might have
happened and whether failures are being generated.
Useful possible additions: tying failure rate to malloc type,
printfs indicating the thread that experienced the coerced
failure.
Reviewed by: jeffr, jhb
additional flags argument to indicate blocking disposition, and
pass in M_NOWAIT from the IP reassembly code to indicate that
blocking is not OK when labeling a new IP fragment reassembly
queue. This should eliminate some of the WITNESS warnings that
have started popping up since fine-grained IP stack locking
started going in; if memory allocation fails, the creation of
the fragment queue will be aborted.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
where physical addresses larger than virtual addresses, such as i386s
with PAE.
- Use this to represent physical addresses in the MI vm system and in the
i386 pmap code. This also changes the paddr parameter to d_mmap_t.
- Fix printf formats to handle physical addresses >4G in the i386 memory
detection code, and due to kvtop returning vm_paddr_t instead of u_long.
Note that this is a name change only; vm_paddr_t is still the same as
vm_offset_t on all currently supported platforms.
Sponsored by: DARPA, Network Associates Laboratories
Discussed with: re, phk (cdevsw change)
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@
is set to 0, it now has the same affect as setting witness_dead used to
have.
- Added a sysctl handler that allows root to change witness_watch from a
non-zero value to zero to disable witness at runtime. Note that you
can't turn witness back on once it is off. You can only turn it off as
a one-way switch.
- Added a comment describing the possible values of witness_watch.
kse_mailbox to schedule an upcall, this is useful for userland timeout
routine, for example pthread_cond_timedwait().
Also extract upcall scheduling code from kse_reassign and create
a new function called thread_switchout to include these code.
Reviewed by: julain
