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* Remove libc_r threading library. It has been disconnected from the buildEd Maste2010-11-131-1054/+0
| | | | | | | | | for four years (since r162846). Submitted by: Alexander Best arundel@ Notes: svn path=/head/; revision=215269
* Remove 3rd clause, renumber, ok per emailWarner Losh2007-01-121-4/+1
| | | | Notes: svn path=/head/; revision=165967
* Remove much of the dereferencing of the fd table entries to lookDaniel Eischen2002-08-291-0/+16
| | | | | | | | | | | | | | at file flags and replace it with functions that will avoid null pointer checks. MFC to be done by archie ;-) PR: 42100 Reviewed by: archie, robert MFC after: 3 days Notes: svn path=/head/; revision=102590
* In the words of the submitter:Daniel Eischen2001-10-211-2/+10
| | | | | | | | | | | | | | | | In libc_r, if _FDLOCKS_ENABLED is not defined, there is no guarantee in many of the sycall wrappers that _thread_fd_table[fd] is initialized. This causes problems for programs that pass in file descriptors and execve() another program; when the exec'ed program tries to do an fcntl() or other syscall on the passed-in fd, it fails. Add calls to initialize the FD table entry for _thread_fd_lock and _thread_fd_lock_debug. Submitted by: Peter S. Housel <housel@acm.org> Notes: svn path=/head/; revision=85290
* Remove (int) file descriptor locking. It should be up to theDaniel Eischen2001-02-111-0/+40
| | | | | | | | | | | | | | | | application to provide locking for I/O operations. This doesn't break any of my tests, but the old behavior can be restored by compiling with _FDLOCKS_ENABLED. This will eventually be removed when it is obvious it does not cause any problems. Remove most of flockfile implementation, with the exception of flockfile_debug. Make error messages more informational (submitted by Mike Heffner <spock@techfour.net>, who's now known as mikeh@FreeBSD.org). Notes: svn path=/head/; revision=72374
* _exit in libc is now __sys_exit not __sys__exit.Daniel Eischen2001-01-291-0/+3
| | | | | | | | | Add another check for thread library initialization (jdp, we really need a way to get _thread_init called at program start before any constructors are run). Notes: svn path=/head/; revision=71771
* Add weak definitions for wrapped system calls. In general:Daniel Eischen2001-01-241-54/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | _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 Notes: svn path=/head/; revision=71581
* Implement zero system call thread switching. Performance ofDaniel Eischen2000-10-131-10/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | thread switches should be on par with that under scheduler activations. o Timing is achieved through the use of a fixed interval timer (ITIMER_PROF) to count scheduling ticks instead of retrieving the time-of-day upon every thread switch and calculating elapsed real time. o Polling for I/O readiness is performed once for each scheduling tick instead of every thread switch. o The non-signal saving/restoring versions of setjmp/longjmp are used to save and restore thread contexts. This may allow the removal of _THREAD_SAFE macros from setjmp() and longjmp() - needs more investigation. Change signal handling so that signals are handled in the context of the thread that is receiving the signal. When signals are dispatched to a thread, a special signal handling frame is created on top of the target threads stack. The frame contains the threads saved state information and a new context in which the thread can run. The applications signal handler is invoked through a wrapper routine that knows how to restore the threads saved state and unwind to previous frames. Fix interruption of threads due to signals. Some states were being improperly interrupted while other states were not being interrupted. This should fix several PRs. Signal handlers, which are invoked as a result of a process signal (not by pthread_kill()), are now called with the code (or siginfo_t if SA_SIGINFO was set in sa_flags) and sigcontext_t as received from the process signal handler. Modify the search for a thread to which a signal is delivered. The search algorithm is now: o First thread found in sigwait() with signal in wait mask. o First thread found sigsuspend()'d on the signal. o Current thread if signal is unmasked. o First thread found with signal unmasked. Collapse machine dependent support into macros defined in pthread_private.h. These should probably eventually be moved into separate MD files. Change the range of settable priorities to be compliant with POSIX (0-31). The threads library uses higher priorities internally for real-time threads (not yet implemented) and threads executing signal handlers. Real-time threads and threads running signal handlers add 64 and 32, respectively, to a threads base priority. Some other small changes and cleanups. PR: 17757 18559 21943 Reviewed by: jasone Notes: svn path=/head/; revision=67097
* Implement continuations to correctly handle [sig|_]longjmp() inside of aJason Evans2000-01-191-16/+8
| | | | | | | | | | | | | | | | | | | | | | | | | signal handler. Explicitly check for jumps to anywhere other than the current stack, since such jumps are undefined according to POSIX. While we're at it, convert thread cancellation to use continuations, since it's cleaner than the original cancellation code. Avoid delivering a signal to a thread twice. This was a pre-existing bug, but was likely unexposed until these other changes were made. Defer signals generated by pthread_kill() so that they can be delivered on the appropriate stack. deischen claims that this is unnecessary, which is likely true, but without this change, pthread_kill() can cause undefined priority queue states and/or PANICs in [sig|_]longjmp(), so I'm leaving this in for now. To compile this code out and exercise the bug, define the _NO_UNDISPATCH cpp macro. Defining _PTHREADS_INVARIANTS as well will cause earlier crashes. PR: kern/14685 Collaboration with: deischen Notes: svn path=/head/; revision=56277
* Fix problems with cancellation while in critical regions.Daniel Eischen1999-12-171-15/+30
| | | | | | | | | | | | | | o Cancellation flags were not getting properly set/cleared. o Loops waiting for internal locks were not being exited correctly by a cancelled thread. o Minor spelling (cancelation -> cancellation) and formatting corrections (missing tab). Found by: tg Reviewed by: jasone Notes: svn path=/head/; revision=54708
* add pthread_cancel, obtained from OpenBSD.Alfred Perlstein1999-11-281-23/+193
| | | | | | | | | | | | | | | | | eischen (Daniel Eischen) added wrappers to protect against cancled threads orphaning internal resources. the cancelability code is still a bit fuzzy but works for test programs of my own, OpenBSD's and some examples from ORA's books. add readdir_r to both libc and libc_r add some 'const' attributes to function parameters Reviewed by: eischen, jasone Notes: svn path=/head/; revision=53812
* $Id$ -> $FreeBSD$Peter Wemm1999-08-281-1/+1
| | | | Notes: svn path=/head/; revision=50476
* Fix thread initialization to allow for the case where stdio fileDaniel Eischen1999-08-051-6/+6
| | | | | | | | | | descriptors are not opened. PR: bin/12853 Reviewed by: jb Notes: svn path=/head/; revision=49438
* In the words of the author:John Birrell1999-06-201-15/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | o The polling mechanism for I/O readiness was changed from select() to poll(). In additon, a wrapped version of poll() is now provided. o The wrapped select routine now converts each fd_set to a poll array so that the thread scheduler doesn't have to perform a bitwise search for selected fds each time file descriptors are polled for I/O readiness. o The thread scheduler was modified to use a new queue (_workq) for threads that need work. Threads waiting for I/O readiness and spinblocks are added to the work queue in addition to the waiting queue. This reduces the time spent forming/searching the array of file descriptors being polled. o The waiting queue (_waitingq) is now maintained in order of thread wakeup time. This allows the thread scheduler to find the nearest wakeup time by looking at the first thread in the queue instead of searching the entire queue. o Removed file descriptor locking for select/poll routines. An application should not rely on the threads library for providing this locking; if necessary, the application should use mutexes to protect selecting/polling of file descriptors. o Retrieve and use the kernel clock rate/resolution at startup instead of hardcoding the clock resolution to 10 msec (tested with kernel running at 1000 HZ). o All queues have been changed to use queue.h macros. These include the queues of all threads, dead threads, and threads waiting for file descriptor locks. o Added reinitialization of the GC mutex and condition variable after a fork. Also prevented reallocation of the ready queue after a fork. o Prevented the wrapped close routine from closing the thread kernel pipes. o Initialized file descriptor table for stdio entries at thread init. o Provided additional flags to indicate to what queues threads belong. o Moved TAILQ initialization for statically allocated mutex and condition variables to after the spinlock. o Added dispatching of signals to pthread_kill. Removing the dispatching of signals from thread activation broke sigsuspend when pthread_kill was used to send a signal to a thread. o Temporarily set the state of a thread to PS_SUSPENDED when it is first created and placed in the list of threads so that it will not be accidentally scheduled before becoming a member of one of the scheduling queues. o Change the signal handler to queue signals to the thread kernel pipe if the scheduling queues are protected. When scheduling queues are unprotected, signals are then dequeued and handled. o Ensured that all installed signal handlers block the scheduling signal and that the scheduling signal handler blocks all other signals. This ensures that the signal handler is only interruptible for and by non-scheduling signals. An atomic lock is used to decide which instance of the signal handler will handle pending signals. o Removed _lock_thread_list and _unlock_thread_list as they are no longer used to protect the thread list. o Added missing RCS IDs to modified files. o Added checks for appropriate queue membership and activity when adding, removing, and searching the scheduling queues. These checks add very little overhead and are enabled when compiled with _PTHREADS_INVARIANTS defined. Suggested and implemented by Tor Egge with some modification by me. o Close a race condition in uthread_close. (Tor Egge) o Protect the scheduling queues while modifying them in pthread_cond_signal and _thread_fd_unlock. (Tor Egge) o Ensure that when a thread gets a mutex, the mutex is on that threads list of owned mutexes. (Tor Egge) o Set the kernel-in-scheduler flag in _thread_kern_sched_state and _thread_kern_sched_state_unlock to prevent a scheduling signal from calling the scheduler again. (Tor Egge) o Don't use TAILQ_FOREACH macro while searching the waiting queue for threads in a sigwait state, because a change of state destroys the TAILQ link. It is actually safe to do so, though, because once a sigwaiting thread is found, the loop ends and the function returns. (Tor Egge) o When dispatching signals to threads, make the thread inherit the signal deferral flag of the currently running thread. (Tor Egge) Submitted by: Daniel Eischen <eischen@vigrid.com> and Tor Egge <Tor.Egge@fast.no> Notes: svn path=/head/; revision=48046
* [ The author's description... ]John Birrell1999-03-231-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | o Runnable threads are now maintained in priority queues. The implementation requires two things: 1.) The priority queues must be protected during insertion and removal of threads. Since the kernel scheduler must modify the priority queues, a spinlock for protection cannot be used. The functions _thread_kern_sched_defer() and _thread_kern_sched_undefer() were added to {un}defer kernel scheduler activation. 2.) A thread (active) priority change can be performed only when the thread is removed from the priority queue. The implementation uses a threads active priority when inserting it into the queue. A by-product is that thread switches are much faster. A separate queue is used for waiting and/or blocked threads, and it is searched at most 2 times in the kernel scheduler when there are active threads. It should be possible to reduce this to once by combining polling of threads waiting on I/O with the loop that looks for timed out threads and the minimum timeout value. o Functions to defer kernel scheduler activation were added. These are _thread_kern_sched_defer() and _thread_kern_sched_undefer() and may be called recursively. These routines do not block the scheduling signal, but latch its occurrence. The signal handler will not call the kernel scheduler when the running thread has deferred scheduling, but it will be called when running thread undefers scheduling. o Added support for _POSIX_THREAD_PRIORITY_SCHEDULING. All the POSIX routines required by this should now be implemented. One note, SCHED_OTHER, SCHED_FIFO, and SCHED_RR are required to be defined by including pthread.h. These defines are currently in sched.h. I modified pthread.h to include sched.h but don't know if this is the proper thing to do. o Added support for priority protection and inheritence mutexes. This allows definition of _POSIX_THREAD_PRIO_PROTECT and _POSIX_THREAD_PRIO_INHERIT. o Added additional error checks required by POSIX for mutexes and condition variables. o Provided a wrapper for sigpending which is marked as a hidden syscall. o Added a non-portable function as a debugging aid to allow an application to monitor thread context switches. An application can install a routine that gets called everytime a thread (explicitly created by the application) gets context switched. The routine gets passed the pthread IDs of the threads that are being switched in and out. Submitted by: Dan Eischen <eischen@vigrid.com> Changes by me: o Added a PS_SPINBLOCK state to deal with the priority inversion problem most often (I think) seen by threads calling malloc/free/realloc. o Dispatch signals to the running thread directly rather than at a context switch to avoid the situation where the switch never occurs. Notes: svn path=/head/; revision=44963
* Don't clobber errno if we are not going to fail.Dmitrij Tejblum1998-09-131-1/+4
| | | | Notes: svn path=/head/; revision=39127
* Add compile time debug instead of doing this all the time. Reduce theJohn Birrell1998-06-091-46/+333
| | | | | | | | | | time that a thread keeps the file descriptor table locked. In particular, perform malloc/free calls outside the lock and handle the situation where two threads can race to initialise the table entry for the same file descriptor. Notes: svn path=/head/; revision=36829
* Remove error check from call to set the file descriptor to non-blockingJohn Birrell1998-05-271-12/+9
| | | | | | | | instead of explicitly ignoring some errors. This allows for the case where a device is naturally non-blocking. Notes: svn path=/head/; revision=36401
* Change signal model to match POSIX (i.e. one set of signal handlersJohn Birrell1998-04-291-36/+53
| | | | | | | | | | | | | | | | | | | | | | | for the process, not a separate set for each thread). By default, the process now only has signal handlers installed for SIGVTALRM, SIGINFO and SIGCHLD. The thread kernel signal handler is installed for other signals on demand. This means that SIG_IGN and SIG_DFL processing is now left to the kernel, not the thread kernel. Change the signal dispatch to no longer use a signal thread, and call the signal handler using the stack of the thread that has the signal pending. Change the atomic lock method to use test-and-set asm code with a yield if blocked. This introduces separate locks for each type of object instead of blocking signals to prevent a context switch. It was this blocking of signals that caused the performance degradation the people have noted. This is a *big* change! Notes: svn path=/head/; revision=35509
* Fixes from Jeremy Allison and Terry Lambert for pthreads:Julian Elischer1998-02-131-10/+22
| | | | | | | | | | | | | | | | | | | | | | | | specifically: uthread_accept.c: Fix for inherited socket not getting correct entry in pthread flags. uthread_create.c: Fix to allow pthread_t pointer return to be null if caller doesn't care about return. uthread_fd.c: Fix for return codes to be placed into correct errno. uthread_init.c: Changes to make gcc-2.8 thread aware for exception stack frames (WARNING: This is #ifdef'ed out by default and is different from the Cygnus egcs fix). uthread_ioctl.c: Fix for blocking/non-blocking ioctl. uthread_kern.c: Signal handling fixes (only one case left to fix, that of an externally sent SIGSEGV and friends - a fairly unusual case). uthread_write.c: Fix for lock of fd - ask for write lock, not read/write. uthread_writev.c: Fix for lock of fd - ask for write lock, not read/write. Pthreads now works well enough to run the LDAP and ACAPD(with the gcc 2.8 fix) sample implementations. Notes: svn path=/head/; revision=33292
* Make error checking less zealous to handle devices like /dev/nullJohn Birrell1997-04-011-2/+10
| | | | | | | | | | | | | | which don't provide a non-blocking interface. This is a short term "fix" which changes a half-lose to a half-win. The thread that accesses a device that does not provide a non-blocking interface will block for its time slice. A medium term solution would be to use rfork. A long-term solution would be some sort of kernel thread/SMP implementation. Notes: svn path=/head/; revision=24519
* Submitted by: John BirrellJulian Elischer1997-02-051-16/+35
| | | | | | | uthreads update from the author. Notes: svn path=/head/; revision=22315
* Submitted by: John Birrell <cimaxp1!jb@werple.net.au>Julian Elischer1996-08-201-5/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here are the diffs for libc_r to get it one step closer to P1003.1c These make most of the thread/mutex/condvar structures opaque to the user. There are three functions which have been renamed with _np suffixes because they are extensions to P1003.1c (I did them for JAVA, which needs to suspend/resume threads and also start threads suspended). I've created a new header (pthread_np.h) for the non-POSIX stuff. The egrep tags stuff in /usr/src/lib/libc_r/Makefile that I uncommented doesn't work. I think its best to delete it. I don't think libc_r needs tags anyway, 'cause most of the source is in libc which does have tags. also: Here's the first batch of man pages for the thread functions. The diff to /usr/src/lib/libc_r/Makefile removes some stuff that was inherited from /usr/src/lib/libc/Makefile that should only be done with libc. also: I should have sent this diff with the pthread(3) man page. It allows people to type make -DWANT_LIBC_R world to get libc_r built with the rest of the world. I put this in the pthread(3) man page. The default is still not to build libc_r. also: The diff attached adds a pthread(3) man page to /usr/src/share/man/man3. The idea is that without libc_r installed, this man page will give people enough info to know that they have to build libc_r. Notes: svn path=/head/; revision=17706
* Reviewed by: julianJulian Elischer1996-01-221-0/+364
Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete Notes: svn path=/head/; revision=13546