src/lib/libpthread/thread/thr_rwlock.c, branch releng/6.2

Add a simple work-around for deadlocking on recursive read locks

2004-01-08T15:37:09+00:00

on a rwlock while there are writers waiting.  We normally favor
writers but when a reader already has at least one other read lock,
we favor the reader.  We don't track all the rwlocks owned by a
thread, nor all the threads that own a rwlock -- we just keep
a count of all the read locks owned by a thread.

PR:	24641

Add small piece of code to support pthread_rwlock_timedrdlock and

2003-09-06T00:07:52+00:00

pthread_rwlock_timedrwlock.

Attempt to eliminate PLT relocations from rwlock aquire/release

2003-05-30T00:21:52+00:00

path, making them suitable for direct use by the dynamic loader.

Register libpthread-specific locking API with rtld on startup.

This still has some rough edges with signals which should be
addresses later.

Approved by:	re (scottl)

Revamp libpthread so that it has a chance of working in an SMP

2003-04-18T05:04:16+00:00

environment.  This includes support for multiple KSEs and KSEGs.

The ability to create more than 1 KSE via pthread_setconcurrency()
is in the works as well as support for PTHREAD_SCOPE_SYSTEM threads.
Those should come shortly.

There are still some known issues which davidxu and I are working
on, but it'll make it easier for us by committing what we have.

This library now passes all of the ACE tests that libc_r passes
with the exception of one.  It also seems to work OK with KDE
including konqueror, kwrite, etc.  I haven't been able to get
mozilla to run due to lack of java plugin, so I'd be interested
to see how it works with that.

Reviewed by:	davidxu

Backout last commit.

2003-03-15T04:45:42+00:00

Requested by: jhb

Fix a bug in rwlock. When a rwlock was locked by reader threads, a

2003-03-14T01:02:47+00:00

writter thread can block reader threads to get read lock.

Make the changes needed for libpthread to compile in its new home.

2002-09-16T08:45:36+00:00

The new libpthread will provide POSIX threading support using KSE.
These files were previously repo-copied from src/lib/libc_r.

Reviewed by:	deischen
Approved by:	-arch

Fix the return code from pthread_rwlock_try[rw|rd]lock() functions;

2002-03-15T18:27:58+00:00

these should return EBUSY when the calling thread would block.

MFC after: 2 weeks

To be consistent, use the __weak_reference macro from

2001-04-10T04:19:21+00:00

instead of #pragma weak to create weak definitions.

Suggested by:	bde

Add weak definitions for wrapped system calls. In general:

2001-01-24T13:03:38+00:00

	_foo - wrapped system call
	foo - weak definition to _foo

and for cancellation points:

	_foo - wrapped system call
	__foo - enter cancellation point, call _foo(), leave
	        cancellation point
	foo - weak definition to __foo

Change use of global _thread_run to call a function to get the
currently running thread.

Make all pthread_foo functions weak definitions to _pthread_foo,
where _pthread_foo is the implementation.  This allows an application
to provide its own pthread functions.

Provide slightly different versions of pthread_mutex_lock and
pthread_mutex_init so that we can tell the difference between
a libc mutex and an application mutex.  Threads holding mutexes
internal to libc should never be allowed to exit, call signal
handlers, or cancel.

Approved by:	-arch