-;;; 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 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)))
- ;; %instance-set-conditional can test for 0 (which is a fixnum) and
- ;; store any value
- (loop until
- (eql (sb!vm::%instance-set-conditional lock offset 0 new-value) 0)))
-
-(defun release-spinlock (lock offset)
- (declare (optimize (speed 3) (safety 0)))
- ;; %instance-set-conditional cannot compare arbitrary objects
- ;; meaningfully, so
- ;; (sb!vm::%instance-set-conditional lock offset our-value 0)
- ;; does not work for bignum thread ids.
- (sb!vm::%instance-set lock offset 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)))))
-
-
-;;;; 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)
- (catch 'sb!impl::%end-of-the-world
- (with-simple-restart
- (terminate-thread
- (format nil "~~@<Terminate this thread (~A)~~@:>"
- (current-thread-id)))
- ;; now that most things have a chance to work
- ;; properly without messing up other threads, it's
- ;; time to enable signals
- (sb!unix::reset-signal-mask)
- (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))
-
-(defun destroy-thread (thread-id)
- "Deprecated. Soon to be removed or reimplemented using pthread_cancel."
- (terminate-thread thread-id))
-
-;;; 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)))
- (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 ()
+(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 ()