rid of the MTX_DUPOK flag on channel mutexes, which allows witness to
do a better job of lock order checking. Nuke snd_chnmtxcreate() since
it is no longer needed.
Tested by: matk
channel at a time unless it is actually necessary to lock both.
This avoids problems with lock order reversal and malloc() calls
with a mutex held when lower level code unlocks a channel, calls malloc(),
and relocks the channel. This also avoids the cost of some unnecessary
locking and unlocking.
Tested by: matk
Rather small diff for the userland (in contrast to the kernel):
- Some header file location/differences
- Clean compilation on 64bit arch (identified by bento a long time ago)
- ALTQ not (yet) available. Leave a switch for patchsets and future ...
- most files can be used from the vendor branch
Approved by: bms(in general)
Testing on cluster ref machine with just delaying make_dev() seems
to work, and results in printf() output appearing sooner in boot
cycle instead of going to /dev/null.
Caught by: bde
Pointy hat: kensmith
Approved by: rwatson (mentor)
patterns. (These lines are correct the other two times they appear.)
Reported by: "Ted Unangst" <tedu@coverity.com>
Approved by: rwatson (mentor), ken (scsi)
1: Document -follow under COMPATIBILITY.
2: Update an example to be a little more 'safe'.
3: Use '/' in place of '.' for an example; similar to other manual pages.
PR: 40196 (1), 39532 (2, 3)
Submitted by: Marc Silver <marcs@draenor.org> (2 and 3)
Discussed with: des (1)
remove unused pid field of file context struct
map nfs4 error codes to errnos
eliminate redundant code from nfs4_request
use zero stateid on setattr that doesn't set file size
use same clientid on all mounts until reboot
invalidate dirty bufs in nfs4_close, to play it safe
open file for writing if truncating and it's not already open
Approved by: alfred
subtle problems with how alpha was handling the promcons device. This
moves the call to make_dev() for the promcons device to a later point of
the boot-up sequence than where promcons initially gets attached, make_dev()
called during the first attach crashes due to kernel stack issues.
Reviewed by: gallatin, marcel, phk
Discussed on: -current@, -alpha@
Approved by: rwatson (mentor)
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
and condition variables. Having sleep qeueus in a hash table avoids
having to allocate a queue head for each wait channel. Thus, struct cv
has shrunk down to just a single char * pointer now. However, the
hash table does not hold threads directly, but queue heads. This means
that once you have located a queue in the hash bucket, you no longer have
to walk the rest of the hash chain looking for threads. Instead, you have
a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
differentiates between cv's and sleep/wakeup. For example, calls to
abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
Thus, the TDF_CVWAITQ flag is removed. Also, calls to unsleep() and
cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
sleep's no longer inherently bump the priority. Instead, this is soley
a propery of msleep() which explicitly calls sched_prio() before
blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used. The
associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
dropped and replaced with a single explicit clearing of td_wchan.
TD_SET_ONSLEEPQ() would really have only made sense if it had taken
the wait channel and message as arguments anyway. Now that that only
happens in one place, a macro would be overkill.
the process state to zombie when a process exits to avoid a lock order
reversal with the sleepqueue locks. This appears to be the only place
that we call wakeup() with sched_lock held.
to queue threads sleeping on a wait channel similar to how turnstiles are
used to queue threads waiting for a lock. This subsystem will be used as
the backend for sleep/wakeup and condition variables initially. Eventually
it will also be used to replace the ithread-specific iwait thread
inhibitor.
Sleep queues are also not locked by sched_lock, so this splits sched_lock
up a bit further increasing concurrency within the scheduler. Sleep queues
also natively support timeouts on sleeps and interruptible sleeps allowing
for the reduction of a lot of duplicated code between the sleep/wakeup and
condition variable implementations. For more details on the sleep queue
implementation, check the comments in sys/sleepqueue.h and
kern/subr_sleepqueue.c.
statements and nowhere else in the kernel seems to use them for single
statements. Also, all other users of do { } while(0) use multiple lines
rather than cramming it all onto one line.
