- prevent BLOCKED upcalls on double page faults and during upcalls
- make libpthread handle blocked threads which hold locks
- prevent UNBLOCKED upcalls from overtaking their BLOCKED upcall
this adds a new syscall sa_unblockyield
see also http://mail-index.netbsd.org/tech-kern/2003/09/15/0020.html
When disabling cancellation, clear the pt_cancel flag if it was set
and note the cancellation request with PT_FLAG_CS_PENDING. This avoids
a problem where a cancellation request entered but not acted upon before
pthread_setcanclstate(PTHREAD_CANCEL_DISABLE) is called would still be
aceted upon before cancellation was re-enabled.
in switchto targets and vitims, and print it in debug messages (including
indication of whether a context is trap or user context).
Remove obsolete pt_sleepuc handling.
thread from the continuation chain: Not only must it have released all
spinlocks, but it must have signaled completion by finishing pthread__switch
or by having stored into pt_switchto.
Together with the previous pthread_switch.S changes, this fixes a couple of
crasehes caused by race conditions in the examination and use of pt_next,
and by switching to empty pt_switchtouc's.
1. add new pthread__abort() and change pthread_assert(0) to it.
2. put constcond in the right place (in the macro).
3. no space after pthread__assert macro.
accumulate half of the total number. There are too many ways for
the SA subsystem to deadlock waiting for stacks that userland has no
reason to recycle.
* Consolidate switchto handling in pthread_resolve_locks().
* Add code to re-chain the preempting parents of switchtos.
* Tweak debuglog output in a couple of cases.
switch statement, and moving upcall-type-specific code into that switch.
Beneficial side effect: don't manipulate a statelock before lock resolution
occurs.
- Signal handlers now simply continue executing the current thread,
rather than trying to put themselves back on the queue that they came
from, which was rather fragile. As a result, all callers of
pthread__block() must be prepared to handle spurious wakeups.
- When a signal arrives for a thread that is blocked in the kernel,
note this in another field in pthread_st and set a flag. Process the
signal and set up the trampoline for the handler *after* the thread
unblocks, so that both the trampoline and the returned state from
the kernel are preserved.
- Factor out some code into a pthread__deliver_signal() routine;
the signal-taking code in pthread_sigmask() should be able to use this
soon.
This is still gross, and there are still some terrible MP issues lurking here,
but progress crawls along.
