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* Change low-level locking a bit so that we can tell ifdeischen2003-05-241-92/+175
| | | | | | | | | | | | | | | | | | | | | | | | | | a lock is being waitied on. Fix a races in join and cancellation. When trying to wait on a CV and the library is not yet threaded, make it threaded so that waiting actually works. When trying to nanosleep() and we're not threaded, just call the system call nanosleep instead of adding the thread to the wait queue. Clean up adding/removing new threads to the "all threads queue", assigning them unique ids, and tracking how many active threads there are. Do it all when the thread is added to the scheduling queue instead of making pthread_create() know how to do it. Fix a race where a thread could be marked for signal delivery but it could be exited before we actually add the signal to it. Other minor cleanups and bug fixes. Submitted by: davidxu Approved by: re@ (blanket for libpthread)
* Eek, staticize a couple of functions that shouldn'tdeischen2003-05-191-1/+6
| | | | | | | | | | | | be external (initialize()!). Remove cancellation points from _pthread_cond_wait and _pthread_cond_timedwait (single underscore versions are libc private functions). Point the weak reference(!) for these functions to the versions with cancellation points. Approved by: re@(blanket till 5/19) Pointed out by: kan (cancellation point bug)
* Add a method of yielding the current thread with the schedulerdeischen2003-05-161-116/+157
| | | | | | | | | | | | | | | | | | | | | | | lock held (_thr_sched_switch_unlocked()) and use this to avoid dropping the scheduler lock and having the scheduler retake the same lock again. Add a better way of detecting if a low-level lock is in use. When switching out a thread due to blocking in the UTS, don't switch to the KSE's scheduler stack only to switch back to another thread. If possible switch to the new thread directly from the old thread and avoid the overhead of the extra context switch. Check for pending signals on a thread when entering the scheduler and add them to the threads signal frame. This includes some other minor signal fixes. Most of this was a joint effor between davidxu and myself. Reviewed by: davidxu Approved by: re@ (blanket for libpthread)
* call dump_queues() only when DEBUG_THREAD_KERN is defined, save somedavidxu2003-05-051-0/+2
| | | | cpu cycles.
* Fix suspend and resume.deischen2003-05-041-16/+28
| | | | Submitted (in part) by: Kazuaki Oda <kaakun@highway.ne.jp>
* Move the mailbox to the beginning of the thread and align thedeischen2003-04-301-3/+9
| | | | thread so that the context (SSE FPU state) is also aligned.
* Call kse_wakeup_mutli() after remove current thread from RUNQ to avoiddavidxu2003-04-301-1/+1
| | | | doing unnecessary idle kse wakeup.
* Call kse_wakeup_multi() to wakeup idle KSEs when there are threads readydavidxu2003-04-301-0/+1
| | | | to run.
* o Don't add a scope system thread's KSE to the list of availabledeischen2003-04-281-40/+121
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | KSEs when it's thread exits; allow the GC handler to do that. o Make spinlock/spinlock critical regions. The following were submitted by davidxu o Alow thr_switch() to take a null mailbox argument. o Better protect cancellation checks. o Don't set KSE specific data when creating new KSEs; rely on the first upcall of the KSE to set it. o Add the ability to set the maximum concurrency level and do this automatically. We should have a way to enable/disable this with some sort of tunable because some applications may not want this to be the default. o Hold the scheduling lock across thread switch calls. o If scheduling of a thread fails, make sure to remove it from the list of active threads. o Better protect accesses to a joining threads when the target thread is exited and detached. o Remove some macro definitions that are now provided by <sys/kse.h>. o Don't leave the library in threaded mode if creation of the initial KSE fails. o Wakeup idle KSEs when there are threads ready to run. o Maintain the number of threads active in the priority queue.
* Protect thread errno from being changed while operatingdeischen2003-04-231-0/+31
| | | | | | | | on behalf of the KSE. Add a kse_reinit function to reinitialize a reused KSE. Submitted by: davidxu
* Set the quantum for scope system threads to 0 (no quantum).deischen2003-04-221-0/+2
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* Add a couple asserts to pthread_cond_foo to ensure the (low-level)deischen2003-04-221-19/+45
| | | | | | | | | | | | | | | lock level is 0. Thus far, the threads implementation doesn't use mutexes or condition variables so the lock level should be 0. Save the return value when trying to schedule a new thread and use this to return an error from pthread_create(). Change the max sleep time for an idle KSE to 1 minute from 2 minutes. Maintain a count of the number of KSEs within a KSEG. With these changes scope system threads seem to work, but heavy use of them crash the kernel (supposedly VM bugs).
* Add an i386-specifc hack to always set %gs. There still seemsdeischen2003-04-211-155/+231
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | to be instances where the kernel doesn't properly save and/or restore it. Use noupcall and nocompleted flags in the KSE mailbox. These require kernel changes to work which will be committed sometime later. Things still work without the changes. Remove the general kse entry function and use two different functions -- one for scope system threads and one for scope process threads. The scope system function is not yet enabled and we use the same function for all threads at the moment. Keep a copy of the KSE stack for the case that a KSE runs a scope system thread and uses the same stack as the thread (no upcalls are generated, so a separate stack isn't needed). This isn't enabled yet. Use a separate field for the KSE waiting flag. It isn't correct to use the mailbox flags field. The following fixes were provided by David Xu: o Initialize condition variable locks with thread versions of the low-level locking functions instead of the kse versions. o Enable threading before creating the first thread instead of after. o Don't enter critical regions when trying to malloc/free or call functions that malloc/free. o Take the scheduling lock when inheriting thread attributes. o Check the attribute's stack pointer instead of the attributes stack size for null when allocating a thread's stack. o Add a kseg reinit function so we don't have to destroy and then recreate the same lock. o Check the return value of kse_create() and return an appropriate error if it fails. o Don't forget to destroy a thread's locks when freeing it. o Examine the correct flags word for checking to see if a thread is in a synchronization queue. Things should now work on an SMP kernel.
* Remove duplicate $FreeBSD$ id.deischen2003-04-181-3/+1
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* Sorry folks; I accidentally committed a patch from what I was workingdeischen2003-04-181-130/+176
| | | | | | on a couple of days ago. This should be the most recent changes. Noticed by: davidxu
* Revamp libpthread so that it has a chance of working in an SMPdeischen2003-04-181-405/+1602
| | | | | | | | | | | | | | | | | | | 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
* Fix compiling error.davidxu2003-02-261-1/+1
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* Deliver signals posted via an upcall to the appropriate thread.mini2003-02-171-1/+8
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* Schedule spinlocked threads by moving them through the work queue, insteadmini2002-11-241-2/+15
| | | | | | | of the wait queue. Approved by: re (blanket) Stolen from: davidxu
* Get the wall clock time from the KSE mailbox, rather than doing anothermini2002-11-241-2/+2
| | | | syscall.
* Fix idle timeout bug, use correct current time of day.davidxu2002-11-201-2/+2
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* Schedule an idle context to block until timeouts expire without blockingmini2002-11-121-107/+65
| | | | further upcalls.
* Use KSE to schedule threads.mini2002-10-301-212/+204
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* Make libpthread KSE aware.mini2002-09-161-585/+79
| | | | | 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
* When poll(2)'ing for readability or writability of a file descriptorarchie2002-08-291-2/+6
| | | | | | | | on behalf of a thread, we should check the POLLERR, POLLHUP, and POLLNVAL flags as well to wake up the thread in these cases. Suggested by: deischen MFC after: 3 days
* Replace various spelling with FALLTHROUGH which is lint()ablecharnier2002-08-251-1/+1
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* This has been sitting in my local tree long enough. Remove the usedeischen2002-02-091-83/+55
| | | | | | | | | | | | | | 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
* Limit maximum poll interval to 60 seconds. This prevents an overflowdeischen2001-10-071-0/+3
| | | | | | | from occurring when converting from a timeval/timespec to a timeout in milliseconds. Submitted by: dwmalone
* Move the check for a pending signals to after the thread has beendeischen2001-05-041-6/+15
| | | | | | | | | | | | | | | placed in any scheduling queue(s). The process of dispatching signals to a thread can change its state which will attempt to add or remove the thread from any scheduling queue to which it belongs. This can break some assertions if the thread isn't in the queue(s) implied by its state. When adding dispatching a pending signal to a thread, be sure to remove the signal from the threads set of pending signals. PR: 27035 Tested by: brian MFC in: 1 week
* Add weak definitions for wrapped system calls. In general:deischen2001-01-241-101/+133
| | | | | | | | | | | | | | | | | | | | | | | | | | | _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
* Enable check for pending signals after calling a signal handler.deischen2000-12-201-0/+3
| | | | | | | Restoration of a threads signal mask after invocation of a signal handler may allow pending signals to become deliverable. PR: 23647
* Delete 4 lines of misleading/incorrect comments.deischen2000-11-161-4/+0
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* When entering the scheduler from the signal handler, telldeischen2000-11-141-11/+24
| | | | | | | | | | | 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
* Correct the logic for checking the emptiness of the waiting queue.deischen2000-11-111-1/+1
| | | | | | | This fixes a potential problem where the file descriptors would not be polled causing waiting threads to stay waiting. Doh! MFC candidate.
* Don't needlessly poll file descriptors when there are nodeischen2000-11-091-42/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 ofdeischen2000-10-131-327/+261
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Add wrapper for kevent() syscalljlemon2000-08-071-1/+1
| | | | Noted as missing by: nicolas.leonard@animaths.com
* Fix pthread_suspend_np/pthread_resume_np. For the record, suspending adeischen2000-03-151-2/+3
| | | | | | | | | | | | | | thread waiting on an event (I/O, condvar, etc) will, when resumed using pthread_resume_np, return with EINTR. For example, suspending and resuming a thread blocked on read() will not requeue the thread for the read, but will return -1 with errno = EINTR. If the suspended thread is in a critical region, the thread is suspended as soon as it leaves the critical region. Fix a bogon in pthread_kill() where a signal was being delivered twice to threads waiting in sigwait(). Reported by (suspend/resume bug): jdp Reviewed by: jasone
* Do signal deferral for pthread_kill() as it was done in the old days.jasone2000-01-201-5/+3
| | | | Submitted by: deischen
* Implement continuations to correctly handle [sig|_]longjmp() inside of ajasone2000-01-191-4/+44
| | | | | | | | | | | | | | | | | | | | | | 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
* Fix problems with cancellation while in critical regions.deischen1999-12-171-1/+1
| | | | | | | | | | | 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
* Fixes for signal handling:deischen1999-12-171-1/+6
| | | | | | | | | | | | | | o Don't call signal handlers with the signal handler access lock held. o Remove pending signals before calling signal handlers. If pending signals were not removed prior to handling them, invocation of the handler could cause the handler to be called more than once for the same signal. Found by: JB o When SIGCHLD arrives, wake up all threads in PS_WAIT_WAIT (wait4). PR: bin/15328 Reviewed by: jasone
* add pthread_cancel, obtained from OpenBSD.alfred1999-11-281-7/+20
| | | | | | | | | | | | | | 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
* sigset_t change (part 5 of 5)marcel1999-09-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ----------------------------- Most of the userland changes are in libc. For both the alpha and the i386 setjmp has been changed to accomodate for the new sigset_t. Internally, libc is mostly rewritten to use the new syscalls. The exception is in compat-43/sigcompat.c The POSIX thread library has also been rewritten to use the new sigset_t. Except, that it currently only handles NSIG signals instead of the maximum _SIG_MAXSIG. This should not be a problem because current applications don't use any signals higher than NSIG. There are version bumps for the following libraries: libdialog libreadline libc libc_r libedit libftpio libss These libraries either a) have one of the modified structures visible in the interface, or b) use sigset_t internally and may cause breakage if new binaries are used against libraries that don't have the sigset_t change. This not an immediate issue, but will be as soon as applications start using the new range to its fullest. NOTE: libncurses already had an version bump and has not been given one now. NOTE: doscmd is a real casualty and has been disconnected for the moment. Reconnection will eventually happen after doscmd has been fixed. I'm aware that being the last one to touch it, I'm automaticly promoted to being maintainer. According to good taste this means that I will receive a badge which either will be glued or mechanically stapled, drilled or otherwise violently forced onto me :-) NOTE: pcvt/vttest cannot be compiled with -traditional. The change cause sys/types to be included along the way which contains the const and volatile modifiers. I don't consider this a solution, but more a workaround.
* $Id$ -> $FreeBSD$peter1999-08-281-1/+1
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* handle under/overflow of time values in a more robust manner,alfred1999-08-191-3/+3
| | | | | | | | there may be an overflow that need to be adjusted more than once. Pointed out by: Fabian Thylmann <fthylmann@stats.net> Reviewed by: eivind, jb
* Add check for runnable threads before polling file descriptors.deischen1999-08-121-14/+16
| | | | Submitted by: tegge
* In the words of the author:jb1999-06-201-831/+650
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Back out patch for cond_timedwait() bug from -current, since other changesjasone1999-05-081-10/+1
| | | | | | | have made the patch obsolete, as pointed out by Daniel Eischen <eischen@vigrid.com>. PR: bin/8872
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