count is protected by the mutex that protects the condition, so the count
does not require any extra locking or atomic operations. It serves as an
optimization to avoid calling into the sleepqueue code at all if there are
no waiters.
Note that the count can get temporarily out of sync when threads sleeping
on a condition variable time out or are aborted. However, it doesn't hurt
to call the sleepqueue code for either a signal or a broadcast when there
are no waiters, and the count is never out of sync in the opposite
direction unless we have more than INT_MAX sleeping threads.
to awaken all waiters when a contested mutex is released instead of just
the highest priority waiter. If the various threads are awakened in
sequence then each thread may acquire and release the lock in question
without contention resulting in fewer expensive unlock and lock
operations. This old behavior of waking just the highest priority is
still used if this option is specified. Making the algorithm conditional
on a kernel option will allows us to benchmark both cases later and
determine which one should be used by default.
Requested by: tanimura-san
more consistent with other APIs. sleepq and cv's use signal/broadcast, and
msleep uses wakeup_one/wakeup. Prior to this turnstiles were using a
signal/wakeup mixture.
and permissions specified per rc.conf(5) now apply both to the md
device and to the mountpoint directory, after the mount has completed.
This has to be done in two steps, because chown is not available
until after /usr has been mounted, but the mdconfig and newfs steps
have to complete before fstab processing.
to implement this mistake.
Fixed some nearby style bugs (initialization in declaration, misformatting
of this initialization, missing blank line after the declaration, and
comparision of the non-boolean result of the initialization with 0 using
"!". In KNF, "!" is not even used to compare booleans with 0).
- don't say what a small subset of the options includes are for.
- don't mark up functions which use all their args with /* ARGSUSED */.
The markup should have been removed when the unused retval parameter
was removed.
- don't comment on what routine suser() checks do. Removed nearby
excessive vertical whitespace.
While here, begin fixing dependencies of <sys/mount.h> on normal namespace
pollution (__BSD_VISIBLE) by not using u_int in the prototype for nmount(2),
although it is used in the man page.
While there, begin cleaning up another set of prototypes:
- use u_int in the prototype for the kernel part of nmount().
- consistently don't use parameter names in prototypes in the
"exported vnode operations" set of prototypes, although style(9) says to
use names in the kernel.
status registers for error conditions and updating statistics
when there are cycles left (inspired by the nge(4) driver).
- Removed the TX list counter and the producer/consumer gap; it's
enough to just ensure we don't reuse the last (free) descriptor,
as the chip may not have read its next pointer yet. If we reuse
it, the TX may stall under a heavy TX load with polling enabled.
- Dropped code to recharge the watchdog timer, it's pointless; the
watchdog routine will re-init the chip and both RX and TX lists.
with 'star' ACL handling, though there's still a
bit more work needed in this area.
Added 'write_open_fd' and 'read_open_fd' to simplify, e.g.,
tar's u and r modes. Eliminated old 'write_open_file_position'
as a bad idea. (It required closing/reopening files to
do updates, which led to unpleasant implications.)
Various other minor fixes, API tweaks, etc.
on temporary nameserver failure. This is necessary to get
getipnodebyname(3) to correctly return h_errno=TRY_AGAIN instead
of HOST_NOT_FOUND.
Reviewed by: green, thomas
MFC after: 1 week
