X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Ftarget-thread.lisp;h=dd25ecbbce9595f49501c954a98ded9342935dfe;hb=9f409e8f8b0a0530725a13805f2b1b3c121ad46a;hp=97c81f176c0a1d01754370875f07022af3d59c17;hpb=952798e77d09b8dcc27d8eea4f22cab552528ae7;p=sbcl.git diff --git a/src/code/target-thread.lisp b/src/code/target-thread.lisp index 97c81f1..dd25ecb 100644 --- a/src/code/target-thread.lisp +++ b/src/code/target-thread.lisp @@ -1,4 +1,5 @@ -;;;; support for threads in the target machine +;;;; support for threads in the target machine common to uni- and +;;;; multithread systems ;;;; This software is part of the SBCL system. See the README file for ;;;; more information. @@ -11,395 +12,70 @@ (in-package "SB!THREAD") -;;; FIXME it would be good to define what a thread id is or isn't (our -;;; current assumption is that it's a fixnum). It so happens that on -;;; Linux it's a pid, but it might not be on posix thread implementations - -(define-alien-routine ("create_thread" %create-thread) - unsigned-long - (lisp-fun-address unsigned-long)) - -(define-alien-routine "signal_thread_to_dequeue" - unsigned-int - (thread-id unsigned-long)) - -(define-alien-routine reap-dead-threads void) - -(defvar *session* nil) - -;;;; queues, locks - -;; spinlocks use 0 as "free" value: higher-level locks use NIL -(declaim (inline get-spinlock release-spinlock)) - -(defun get-spinlock (lock offset new-value) - (declare (optimize (speed 3) (safety 0))) - (loop until - (eql (sb!vm::%instance-set-conditional lock offset 0 new-value) 0))) - -;; this should do nothing if we didn't own the lock, so safe to use in -;; unwind-protect cleanups when lock acquisition failed for some reason -(defun release-spinlock (lock offset our-value) - (declare (optimize (speed 3) (safety 0))) - (sb!vm::%instance-set-conditional lock offset our-value 0)) - -(defmacro with-spinlock ((queue) &body body) - (with-unique-names (pid) - `(let ((,pid (current-thread-id))) - (unwind-protect - (progn - (get-spinlock ,queue 2 ,pid) - ,@body) - (release-spinlock ,queue 2 ,pid))))) - - -;;;; the higher-level locking operations are based on waitqueues - -(declaim (inline waitqueue-data-address mutex-value-address)) - -(defstruct waitqueue - (name nil :type (or null simple-string)) - (lock 0) - (data nil)) - -;;; The bare 4 here and 5 below are offsets of the slots in the struct. -;;; There ought to be some better way to get these numbers -(defun waitqueue-data-address (lock) - (declare (optimize (speed 3))) - (sb!ext:truly-the - (unsigned-byte 32) - (+ (sb!kernel:get-lisp-obj-address lock) - (- (* 4 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag)))) - -(defstruct (mutex (:include waitqueue)) - (value nil)) - -(defun mutex-value-address (lock) - (declare (optimize (speed 3))) - (sb!ext:truly-the - (unsigned-byte 32) - (+ (sb!kernel:get-lisp-obj-address lock) - (- (* 5 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag)))) - -(declaim (inline futex-wait futex-wake)) -(sb!alien:define-alien-routine - "futex_wait" int (word unsigned-long) (old-value unsigned-long)) -(sb!alien:define-alien-routine - "futex_wake" int (word unsigned-long) (n unsigned-long)) - - -;;;; mutex - -(defun get-mutex (lock &optional new-value (wait-p t)) - "Acquire LOCK, setting it to NEW-VALUE or some suitable default value -if NIL. If WAIT-P is non-NIL and the lock is in use, sleep until it -is available" - (declare (type mutex lock) (optimize (speed 3))) - (let ((pid (current-thread-id)) - old) - (unless new-value (setf new-value pid)) - (when (eql new-value (mutex-value lock)) - (warn "recursive lock attempt ~S~%" lock)) - (loop - (unless - (setf old (sb!vm::%instance-set-conditional lock 4 nil new-value)) - (return t)) - (unless wait-p (return nil)) - (futex-wait (mutex-value-address lock) - (sb!kernel:get-lisp-obj-address old))))) - -(defun release-mutex (lock) - (declare (type mutex lock)) - (setf (mutex-value lock) nil) - (futex-wake (mutex-value-address lock) 1)) - -;;;; condition variables - -(defun condition-wait (queue lock) - "Atomically release LOCK and enqueue ourselves on QUEUE. Another -thread may subsequently notify us using CONDITION-NOTIFY, at which -time we reacquire LOCK and return to the caller." - (assert lock) - (let ((value (mutex-value lock))) - (unwind-protect - (let ((me (current-thread-id))) - ;; XXX we should do something to ensure that the result of this setf - ;; is visible to all CPUs - (setf (waitqueue-data queue) me) - (release-mutex lock) - ;; Now we go to sleep using futex-wait. If anyone else - ;; manages to grab LOCK and call CONDITION-NOTIFY during - ;; this comment, it will change queue->data, and so - ;; futex-wait returns immediately instead of sleeping. - ;; Ergo, no lost wakeup - (futex-wait (waitqueue-data-address queue) - (sb!kernel:get-lisp-obj-address me))) - ;; If we are interrupted while waiting, we should do these things - ;; before returning. Ideally, in the case of an unhandled signal, - ;; we should do them before entering the debugger, but this is - ;; better than nothing. - (get-mutex lock value)))) - - -(defun condition-notify (queue) - "Notify one of the processes waiting on QUEUE" - (let ((me (current-thread-id))) - ;; no problem if >1 thread notifies during the comment in - ;; condition-wait: as long as the value in queue-data isn't the - ;; waiting thread's id, it matters not what it is - ;; XXX we should do something to ensure that the result of this setf - ;; is visible to all CPUs - (setf (waitqueue-data queue) me) - (futex-wake (waitqueue-data-address queue) 1))) - -(defun condition-broadcast (queue) - (let ((me (current-thread-id))) - (setf (waitqueue-data queue) me) - (futex-wake (waitqueue-data-address queue) (ash 1 30)))) - -(defun make-thread (function) - (let* ((real-function (coerce function 'function)) - (tid - (%create-thread - (sb!kernel:get-lisp-obj-address - (lambda () - ;; in time we'll move some of the binding presently done in C - ;; here too - (let ((sb!kernel::*restart-clusters* nil) - (sb!kernel::*handler-clusters* nil) - (sb!kernel::*condition-restarts* nil) - (sb!impl::*descriptor-handlers* nil) ; serve-event - (sb!impl::*available-buffers* nil)) ;for fd-stream - ;; can't use handling-end-of-the-world, because that flushes - ;; output streams, and we don't necessarily have any (or we - ;; could be sharing them) - (sb!sys:enable-interrupt sb!unix:sigint :ignore) - (catch 'sb!impl::%end-of-the-world - (with-simple-restart - (destroy-thread - (format nil "~~@" - (current-thread-id))) - (funcall real-function)) - 0)) - (values)))))) - (when (zerop tid) (error "Can't create a new thread")) - (with-mutex ((session-lock *session*)) - (pushnew tid (session-threads *session*))) - tid)) - -;;; Really, you don't want to use these: they'll get into trouble with -;;; garbage collection. Use a lock or a waitqueue instead -(defun suspend-thread (thread-id) - (sb!unix:unix-kill thread-id sb!unix:sigstop)) -(defun resume-thread (thread-id) - (sb!unix:unix-kill thread-id sb!unix:sigcont)) -;;; Note warning about cleanup forms -(defun destroy-thread (thread-id) - "Destroy the thread identified by THREAD-ID abruptly, without running cleanup forms" - (sb!unix:unix-kill thread-id sb!unix:sigterm) - ;; may have been stopped for some reason, so now wake it up to - ;; deliver the TERM - (sb!unix:unix-kill thread-id sb!unix:sigcont)) - - - - -;;; a moderate degree of care is expected for use of interrupt-thread, -;;; due to its nature: if you interrupt a thread that was holding -;;; important locks then do something that turns out to need those -;;; locks, you probably won't like the effect. Used with thought -;;; though, it's a good deal gentler than the last-resort functions above - -(define-condition interrupt-thread-error (error) - ((thread :reader interrupt-thread-error-thread :initarg :thread) - (errno :reader interrupt-thread-error-errno :initarg :errno)) - (:report (lambda (c s) - (format s "interrupt thread ~A failed (~A: ~A)" - (interrupt-thread-error-thread c) - (interrupt-thread-error-errno c) - (strerror (interrupt-thread-error-errno c)))))) - -(defun interrupt-thread (thread function) - "Interrupt THREAD and make it run FUNCTION." - (let ((function (coerce function 'function))) - (sb!sys:with-pinned-objects - (function) - (multiple-value-bind (res err) - (sb!unix::syscall ("interrupt_thread" - sb!alien:unsigned-long sb!alien:unsigned-long) - thread - thread - (sb!kernel:get-lisp-obj-address function)) - (unless res - (error 'interrupt-thread-error :thread thread :errno err)))))) - - -(defun terminate-thread (thread-id) - "Terminate the thread identified by THREAD-ID, by causing it to run -SB-EXT:QUIT - the usual cleanup forms will be evaluated" - (interrupt-thread thread-id 'sb!ext:quit)) - -(declaim (inline current-thread-id)) -(defun current-thread-id () - (logand - (sb!sys:sap-int - (sb!vm::current-thread-offset-sap sb!vm::thread-pid-slot)) - ;; KLUDGE pids are 16 bit really. Avoid boxing the return value - (1- (ash 1 16)))) - -;;;; iterate over the in-memory threads - -(defun mapcar-threads (function) - "Call FUNCTION once for each known thread, giving it the thread structure as argument" - (let ((function (coerce function 'function))) - (loop for thread = (alien-sap (extern-alien "all_threads" (* t))) - then (sb!sys:sap-ref-sap thread (* sb!vm:n-word-bytes - sb!vm::thread-next-slot)) - until (sb!sys:sap= thread (sb!sys:int-sap 0)) - collect (funcall function thread)))) - -(defun thread-sap-from-id (id) - (let ((thread (alien-sap (extern-alien "all_threads" (* t))))) - (loop - (when (sb!sys:sap= thread (sb!sys:int-sap 0)) (return nil)) - (let ((pid (sb!sys:sap-ref-32 thread (* sb!vm:n-word-bytes - sb!vm::thread-pid-slot)))) - (when (= pid id) (return thread)) - (setf thread (sb!sys:sap-ref-sap thread (* sb!vm:n-word-bytes - sb!vm::thread-next-slot))))))) - -;;; internal use only. If you think you need to use this, either you -;;; are an SBCL developer, are doing something that you should discuss -;;; with an SBCL developer first, or are doing something that you -;;; should probably discuss with a professional psychiatrist first -(defun symbol-value-in-thread (symbol thread-id) - (let ((thread (thread-sap-from-id thread-id))) - (when thread - (let* ((index (sb!vm::symbol-tls-index symbol)) - (tl-val (sb!sys:sap-ref-word thread - (* sb!vm:n-word-bytes index)))) - (if (eql tl-val sb!vm::unbound-marker-widetag) - (sb!vm::symbol-global-value symbol) - (sb!kernel:make-lisp-obj tl-val)))))) - -;;;; job control, independent listeners - -(defstruct session - (lock (make-mutex)) - (threads nil) - (interactive-threads nil) - (interactive-threads-queue (make-waitqueue))) - -(defun new-session () - (let ((tid (current-thread-id))) - (make-session :threads (list tid) - :interactive-threads (list tid)))) - -(defun init-job-control () - (setf *session* (new-session))) - -(defun %delete-thread-from-session (tid session) - (with-mutex ((session-lock session)) - (setf (session-threads session) - (delete tid (session-threads session)) - (session-interactive-threads session) - (delete tid (session-interactive-threads session))))) - -(defun call-with-new-session (fn) - (%delete-thread-from-session (current-thread-id) *session*) - (let ((*session* (new-session))) (funcall fn))) - -(defmacro with-new-session (args &body forms) - (declare (ignore args)) ;for extensibility - (sb!int:with-unique-names (fb-name) - `(labels ((,fb-name () ,@forms)) - (call-with-new-session (function ,fb-name))))) - -;;; Remove thread id TID from its session, if it has one. This is -;;; called from C reap_dead_threads() so is run in the context of -;;; whichever thread called that (usually after a GC), which may not have -;;; any meaningful parent/child/sibling relationship with the dead thread -(defun handle-thread-exit (tid) - (let ((session (symbol-value-in-thread '*session* tid))) - (and session (%delete-thread-from-session tid session)))) - -(defun terminate-session () - "Kill all threads in session except for this one. Does nothing if current -thread is not the foreground thread" - (reap-dead-threads) - (let* ((tid (current-thread-id)) - (to-kill - (with-mutex ((session-lock *session*)) - (and (eql tid (car (session-interactive-threads *session*))) - (session-threads *session*))))) - ;; do the kill after dropping the mutex; unwind forms in dying - ;; threads may want to do session things - (dolist (p to-kill) - (unless (eql p tid) (terminate-thread p))))) - -;;; called from top of invoke-debugger -(defun debugger-wait-until-foreground-thread (stream) - "Returns T if thread had been running in background, NIL if it was -interactive." - (declare (ignore stream)) - (prog1 - (with-mutex ((session-lock *session*)) - (not (member (current-thread-id) - (session-interactive-threads *session*)))) - (get-foreground))) - - -(defun get-foreground () - (let ((was-foreground t)) - (loop - (with-mutex ((session-lock *session*)) - (let ((tid (current-thread-id)) - (int-t (session-interactive-threads *session*))) - (when (eql (car int-t) tid) - (unless was-foreground - (format *query-io* "Resuming thread ~A~%" tid)) - (sb!sys:enable-interrupt sb!unix:sigint #'sb!unix::sigint-handler) - (return-from get-foreground t)) - (setf was-foreground nil) - (unless (member tid int-t) - (setf (cdr (last int-t)) - (list tid))) - (condition-wait - (session-interactive-threads-queue *session*) - (session-lock *session*))))))) - -(defun release-foreground (&optional next) - "Background this thread. If NEXT is supplied, arrange for it to have the foreground next" - (with-mutex ((session-lock *session*)) - (let ((tid (current-thread-id))) - (setf (session-interactive-threads *session*) - (delete tid (session-interactive-threads *session*))) - (sb!sys:enable-interrupt sb!unix:sigint :ignore) - (when next - (setf (session-interactive-threads *session*) - (list* next - (delete next (session-interactive-threads *session*))))) - (condition-broadcast (session-interactive-threads-queue *session*))))) - -(defun make-listener-thread (tty-name) - (assert (probe-file tty-name)) - (let* ((in (sb!unix:unix-open (namestring tty-name) sb!unix:o_rdwr #o666)) - (out (sb!unix:unix-dup in)) - (err (sb!unix:unix-dup in))) - (labels ((thread-repl () - (sb!unix::unix-setsid) - (let* ((sb!impl::*stdin* - (sb!sys:make-fd-stream in :input t :buffering :line :dual-channel-p t)) - (sb!impl::*stdout* - (sb!sys:make-fd-stream out :output t :buffering :line :dual-channel-p t)) - (sb!impl::*stderr* - (sb!sys:make-fd-stream err :output t :buffering :line :dual-channel-p t)) - (sb!impl::*tty* - (sb!sys:make-fd-stream err :input t :output t :buffering :line :dual-channel-p t)) - (sb!impl::*descriptor-handlers* nil)) - (with-new-session () - (sb!sys:enable-interrupt sb!unix:sigint #'sb!unix::sigint-handler) - (unwind-protect - (sb!impl::toplevel-repl nil) - (sb!int:flush-standard-output-streams)))))) - (make-thread #'thread-repl)))) +(defstruct (thread (:constructor %make-thread)) + name + %sap) + +(def!method print-object ((thread thread) stream) + (if (thread-name thread) + (print-unreadable-object (thread stream :type t :identity t) + (prin1 (thread-name thread) stream)) + (print-unreadable-object (thread stream :type t :identity t) + ;; body is empty => there is only one space between type and + ;; identity + )) + thread) + +(defun thread-state (thread) + (let ((state + (sb!sys:sap-int + (sb!sys:sap-ref-sap (thread-%sap thread) + (* sb!vm::thread-state-slot + sb!vm::n-word-bytes))))) + (ecase state + (#.(sb!vm:fixnumize 0) :starting) + (#.(sb!vm:fixnumize 1) :running) + (#.(sb!vm:fixnumize 2) :suspended) + (#.(sb!vm:fixnumize 3) :dead)))) + +(defun %set-thread-state (thread state) + (setf (sb!sys:sap-ref-sap (thread-%sap thread) + (* sb!vm::thread-state-slot + sb!vm::n-word-bytes)) + (sb!sys:int-sap + (ecase state + (:starting #.(sb!vm:fixnumize 0)) + (:running #.(sb!vm:fixnumize 1)) + (:suspended #.(sb!vm:fixnumize 2)) + (:dead #.(sb!vm:fixnumize 3)))))) + +(defun thread-alive-p (thread) + (not (eq :dead (thread-state thread)))) + +;; A thread is eligible for gc iff it has finished and there are no +;; more references to it. This list is supposed to keep a reference to +;; all running threads. +(defvar *all-threads* ()) +(defvar *all-threads-lock* (make-mutex :name "all threads lock")) + +(defun list-all-threads () + (with-mutex (*all-threads-lock*) + (copy-list *all-threads*))) + +(declaim (inline current-thread-sap)) +(defun current-thread-sap () + (sb!vm::current-thread-offset-sap sb!vm::thread-this-slot)) + +(declaim (inline current-thread-sap-id)) +(defun current-thread-sap-id () + (sb!sys:sap-int + (sb!vm::current-thread-offset-sap sb!vm::thread-os-thread-slot))) + +(defun init-initial-thread () + (let ((initial-thread (%make-thread :name "initial thread" + :%sap (current-thread-sap)))) + (setq *current-thread* initial-thread) + ;; Either *all-threads* is empty or it contains exactly one thread + ;; in case we are in reinit since saving core with multiple + ;; threads doesn't work. + (setq *all-threads* (list initial-thread))))