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* Deliver signals posted via an upcall to the appropriate thread.mini2003-02-171-0/+31
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* Schedule an idle context to block until timeouts expire without blockingmini2002-11-121-0/+12
| | | | further upcalls.
* Use KSE to schedule threads.mini2002-10-301-11/+16
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* Make libpthread KSE aware.mini2002-09-161-158/+16
| | | | | Reviewed by: deischen, julian Approved by: -arch
* Make the changes needed for libpthread to compile in its new home.mini2002-09-161-1/+1
| | | | | | | | 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
* Revamp suspend and resume. While I'm here add pthread_suspend_all_np()deischen2002-05-241-7/+21
| | | | | | | | | | | | | and pthread_resume_all_np(). These suspend and resume all threads except the current thread, respectively. The existing functions pthread_single_np() and pthread_multi_np(), which formerly had no effect, now exhibit the same behaviour and pthread_suspend_all_np() and pthread_resume_all_np(). These functions have been added mostly for the native java port. Don't allow the uthread kernel pipe to use the same descriptors as stdio. Mostily submitted by Oswald Buddenhagen <ossi@kde.org>. Correct some minor style nits.
* Undo namespace pollution by prefixing the globals pthread_guard_default andalfred2002-05-151-7/+7
| | | | | | | | pthread_page_size. Fix a bunch line wrapping. Pointed out by: deischen
* Don't use PAGE_SIZE in userland, instead use getpagesize(), this is toalfred2002-05-131-3/+14
| | | | | | | allow running on other arches when the instructions are supported but the page size granularity is not. Glanced at by: peter
* Add the ability to recognize old references to keys, and return NULLdeischen2002-03-191-1/+1
| | | | | when old keys are referenced (after pthread_key_delete()) via pthread_getspecific().
* This has been sitting in my local tree long enough. Remove the usedeischen2002-02-091-12/+0
| | | | | | | | | | | | | | of an alternate signal stack for handling signals. Let the kernel send signals on the stack of the current thread and teach the threads signal handler how to deliver signals to the current thread if it needs to. Also, always store a threads context as a jmp_buf. Eventually this will change to be a ucontext_t or mcontext_t. Other small nits. Use struct pthread * instead of pthread_t in internal library routines. The threads code wants struct pthread *, and pthread_t doesn't necessarily have to be the same. Reviewed by: jasone
* Fix the retrieval of USRSTACK via sysctl so that it works for 64-bitdeischen2001-12-181-2/+2
| | | | | | archs. This should fix libc_r on alpha. Submitted by: Bernd Walter <ticso@cicely9.cicely.de>
* Make libc_r check the kern.usrstack sysctl instead of using internalpeter2001-10-261-3/+8
| | | | | | | kernel #defines to figure out where the stack is located. This stops libc_r from exploding when the kernel is compiled with a different KVM size. IMHO this is all kinda bogus, it would be better to just check %esp and work from that.
* Compensate for "Compensate for header dethreading" by backing it out.bde2001-10-101-2/+0
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* Implement pthread_attr_[gs]etguardsize(). Non-default-size stacks used tojasone2001-07-201-4/+1
| | | | | | | | be malloc()ed, but they are now allocated using mmap(), just as the default-size stacks are. A separate cache of stacks is kept for non-default-size stacks. Collaboration with: deischen
* Instead of using a join queue for each thread, use a single pointer tojasone2001-05-201-2/+2
| | | | | | | | | | | keep track of a joiner. POSIX only supports a single joiner, so this simplification is acceptable. At the same time, make sure to mark a joined thread as detached so that its resources can be freed. Reviewed by: deischen PR: 24345
* Compenate for header dethreading.markm2001-05-011-0/+2
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* Limit threads clock resolution to no less than 1000usec (1000Hz).deischen2001-02-261-1/+2
| | | | | PR: 25300 Submitted by: Tom Pavel <pavel@alum.mit.edu> (in part)
* Add weak definitions for wrapped system calls. In general:deischen2001-01-241-91/+119
| | | | | | | | | | | | | | | | | | | | | | | | | | | _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
* Force strong references to several pthread_* functions which are weaklyobrien2001-01-061-0/+32
| | | | | | | | | | | | | | | | referenced to by libgcc.a. This is needed when linking statically as SVR4 (ie, ELF) behavior is to only link in a module if it satisfies an undefined strong reference from somewhere. (this surprises a lot of people) Things are different when using shared libs, the entire library and its modules and their symbols are available at run-time (when the weak reference is seen to still be unsatisfied and is satisfied on the spot), this is not the case with static libs. Thus one can have a static binary with unresolved week references, and at run-time dereference a NULL pointer. Submitted by: eischen
* When entering the scheduler from the signal handler, telldeischen2000-11-141-6/+9
| | | | | | | | | | | the kernel to (re)use the alternate signal stack. In this case, we don't return normally from the signal handler, so the kernel still thinks we are using the signal stack. The fixes a nasty bug where the signal handler can start fiddling with the stack of a thread while the handler is actually running on the same stack. MFC candidate
* Don't needlessly poll file descriptors when there are nodeischen2000-11-091-29/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | file descriptors needing to be polled (Doh!). Reported by Dan Nelson <dnelson@emsphone.com>. Don't install and start the scheduling timer until the first thread is created. This prevents the overhead of having a periodic scheduling signal in a single threaded program. Reported by Dan Nelson <dnelson@emsphone.com>. Allow builtin longjmps out of application installed signal handlers without the need perform any post-handler cleanup: o Change signal handling to save the threads interrupted context on the stack. The threads current context is now always stored in the same place (in the pthread). If and when a signal handler returns, the interrupted context is copied back to the storage area in the pthread. o Before calling invoking a signal handler for a thread, back the thread out of any internal waiting queues (mutex, CV, join, etc) to which it belongs. Rework uthread_info.c a bit to make it easier to change the format of a thread dump. Use an alternal signal stack for the thread library's signal handler. This allows us to fiddle with the main threads stack without fear of it being in use. Reviewed by: jasone
* Implement zero system call thread switching. Performance ofdeischen2000-10-131-15/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* If multiple threads are blocked in sigwait() for the same signal that doesjasone2000-06-271-0/+3
| | | | | | | | | | | | | | | not have a user-supplied signal handler, when a signal is delivered, one thread will receive the signal, and then the code reverts to having no signal handler for the signal. This can leave the other sigwait()ing threads stranded permanently if the signal is later ignored, or can result in process termination when the process should have delivered the signal to one of the threads in sigwait(). To fix this problem, maintain a count of sigwait()ers for each signal that has no default signal handler. Use the count to correctly install/uninstall dummy signal handlers. Reviewed by: deischen
* Implement continuations to correctly handle [sig|_]longjmp() inside of ajasone2000-01-191-0/+12
| | | | | | | | | | | | | | | | | | | | | | 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
* Properly initialize the last active time of the initial thread. This fixesdeischen2000-01-181-0/+6
| | | | | | | the case that a CPU hungry main thread is prevented from being preempted due to a negative calculation of its time slice. Reported by: Alexander Litvin <archer@lucky.net>
* Don't explicitly mmap() red zones at the bottom of thread stacks (exceptjasone1999-12-291-1/+7
| | | | | | | | | | the initial thread). Instead, just leave an unmapped gap between thread stacks and make sure that the thread stacks won't grow into these gaps, simply by limiting the size of the stacks with the 'len' argument to mmap(). This (if I understand correctly) reduces VM overhead considerably. Reviewed by: deischen
* Change stack allocation algorithm to make better use of memorydeischen1999-12-281-7/+5
| | | | | (it was leaving an unused block). Also protect the global stack pointer from context changes while fiddling with it.
* add pthread_cancel, obtained from OpenBSD.alfred1999-11-281-0/+5
| | | | | | | | | | | | | | 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
* $Id$ -> $FreeBSD$peter1999-08-281-1/+1
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* Fix thread initialization to allow for the case where stdio filedeischen1999-08-051-8/+12
| | | | | | | descriptors are not opened. PR: bin/12853 Reviewed by: jb
* Use USRSTACK (defined in <machine/vmparam.h>) to get top of the initial stack.dt1999-07-121-3/+4
| | | | PTHREAD_STACK_TOP was wrong for all supported architectures.
* Modify previous changes to conform better to libc_r's coding style.jasone1999-07-111-4/+6
| | | | | | | | Always use mmap() for default-size stack allocation. Use MAP_ANON instead of MAP_STACK on the alpha architecture. Reduce the amount of code executed while owning _gc_mutex during stack allocation.
* Always use growable thread stacks on the i386. The VM_STACK kernel optionjasone1999-07-061-4/+2
| | | | | must be made default for the alpha before growable thread stacks are enabled for the alpha.
* Use growable stacks for thread stacks that are the default stack size.jasone1999-07-051-15/+28
| | | | | | | | | | | | | Cache discarded default thread stacks for use in subsequent thread creations. Create a red zone at the end of each stack (including the initial thread stack), with the hope of causing a segfault if a stack overflows. To activate these modifications, add -D_PTHREAD_GSTACK to CFLAGS in src/lib/libc_r/Makefile. Since the modifications depend on the VM_STACK kernel option, I'm not sure how to safely use growable stacks by default. Testing, as well as algorithmic and stylistic comments are welcome.
* Fix few warnings on the alpha.dt1999-06-231-2/+2
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* In the words of the author:jb1999-06-201-10/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [ The author's description... ]jb1999-03-231-5/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* Move the cleanup code that frees memory allocated for a dead thread fromjb1998-09-301-0/+5
| | | | | | | | | | | | | | the thread kernel into a garbage collector thread which is started when the fisrt thread is created (other than the initial thread). This removes the window of opportunity where a context switch will cause a thread that has locked the malloc spinlock, to enter the thread kernel, find there is a dead thread and try to free memory, therefore trying to lock the malloc spinlock against itself. The garbage collector thread acts just like any other thread, so instead of having a spinlock to control accesses to the dead thread list, it uses a mutex and a condition variable so that it can happily wait to be signalled when a thread exists.
* Add extra initialisation code that is required for processes thatjb1998-08-101-1/+29
| | | | | | | are started instead of init (pid = 1). This allows an embedded implementation quite like VxWorks, with (possibly) a single threaded program running instead of init. The neat thing is that the same threaded process can run in a multi-user workstation environment too.
* Change signal model to match POSIX (i.e. one set of signal handlersjb1998-04-291-33/+22
| | | | | | | | | | | | | | | | | | | | 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!
* Fixes from Jeremy Allison and Terry Lambert for pthreads:julian1998-02-131-1/+35
| | | | | | | | | | | | | | | | | | | | | 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.
* Fixed overallocation of _thread_fd_table.alex1997-05-131-1/+1
| | | | | PR: 3494 Submitted by: Steve Bauer <sbauer@rock.sdsmt.edu>
* Submitted by: John Birrelljulian1997-02-051-3/+17
| | | | uthreads update from the author.
* Submitted by: John Birrell <cimaxp1!jb@werple.net.au>julian1996-08-201-12/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* Added a new module "uthread_autoinit.cc". This is a small C++ module.jdp1996-02-171-0/+12
| | | | | | | | | | | | | | It uses a static constructor to call _thread_init() at program start-up time. That eliminates the need for any initialization hooks in crt0.o. Added a symbol reference in "uthread_init.c", to ensure that the new module will always be pulled in when the archive version of the library is used. In "Makefile.inc", defined CPLUSPLUSLIB, so that the constructor will be properly invoked in the shared library. Suggested by: Christopher Provenzano, Peter Wemm, and others.
* Reviewed by: julianjulian1996-01-221-0/+214
Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
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