- cv_wait and friends: after resuming execution, check to see if we have
been restarted as a result of cv_signal. If we have, but cannot take
the wakeup (because of eg a pending Unix signal or timeout) then try to
ensure that another LWP sees it. This is necessary because there may
be multiple waiters, and at least one should take the wakeup if possible.
Prompted by a discussion with pooka@.
- typedef struct lwp lwp_t;
- int -> bool, struct lwp -> lwp_t in a few places.
- Better detect simple cycles of threads calling _lwp_wait and return
EDEADLK. Does not handle deeper cycles like t1 -> t2 -> t3 -> t1.
- If there are multiple threads in _lwp_wait, then make sure that
targeted waits take precedence over waits for any LWP to exit.
- When checking for deadlock, also count the number of zombies currently
in the process as potentially reapable. Whenever a zombie is murdered,
kick all waiters to make them check again for deadlock.
- Add more comments.
Also, while here:
- LOCK_ASSERT -> KASSERT in some places
- lwp_free: change boolean arguments to type 'bool'.
- proc_free: let lwp_free spin waiting for the last LWP to exit, there's
no reason to do it here.
- Don't bother sorting the sleep queues, since user space controls the
order of removal.
- Change setrunnable(t) to lwp_unsleep(t). No functional change from the
perspective of user applications.
- Minor cosmetic changes.
so it's not worth counting.
- lwp_wakeup: set LW_UNPARKED on the target. Ensures that _lwp_park will
always be awoken even if another system call eats the wakeup, e.g. as a
result of an intervening signal. To deal with this correctly for other
system calls will require a different approach.
- _lwp_unpark, _lwp_unpark_all: use setrunnable if the LWP is not parked
on the same sync queue: (1) simplifies the code a bit as there no point
doing anything special for this case (2) makes it possible for p_smutex
to be replaced by p_mutex and (3) restores the guarantee that the 'hint'
argument really is just a hint.
separate functions that don't do the copyout.
This allows all the compat_xxx versions to convert the 'struct stat' to
the correct format without using the 'stackgap'.
The stackgap isn't at all LWP friendly, and needs to be removed from
any compat functions that might involve threads (inc. clone()).
The code is still binary compatible with existing LKMs.
as possible. For that, split out a function which does the allocation
of a softc (without linking it into global structures) and a function
which inserts the device into the global alldevs lists and the per-driver
cd_devs.
There is a little semantic change involved: the pseudo-device code didn't
interpret FSTATE_STAR as such, for no good reason. This looks harmless;
I'll modify driver frontends as I find ways to test.
Get config_makeroom() out of the public namespace - that's clearly an
internal of autoconf which drivers can't be allowed to deal with.
