(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
+;;; Of the WITH-PINNED-OBJECTS in this file, not every single one is
+;;; necessary because threads are only supported with the conservative
+;;; gencgc and numbers on the stack (returned by GET-LISP-OBJ-ADDRESS)
+;;; are treated as references.
+
+;;; set the doc here because in early-thread FDOCUMENTATION is not
+;;; available, yet
+#!+sb-doc
+(setf (fdocumentation '*current-thread* 'variable)
+ "Bound in each thread to the thread itself.")
+
+(defstruct (thread (:constructor %make-thread))
+ #!+sb-doc
+ "Thread type. Do not rely on threads being structs as it may change
+in future versions."
+ name
+ %alive-p
+ os-thread
+ interruptions
+ (interruptions-lock (make-mutex :name "thread interruptions lock"))
+ result
+ (result-lock (make-mutex :name "thread result lock")))
+
+#!+sb-doc
+(setf (fdocumentation 'thread-name 'function)
+ "The name of the thread. Setfable.")
+
+(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-alive-p (thread)
+ #!+sb-doc
+ "Check if THREAD is running."
+ (thread-%alive-p 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"))
+
+(defmacro with-all-threads-lock (&body body)
+ #!-sb-thread
+ `(locally ,@body)
+ #!+sb-thread
+ `(without-interrupts
+ (with-mutex (*all-threads-lock*)
+ ,@body)))
+
+(defun list-all-threads ()
+ #!+sb-doc
+ "Return a list of the live threads."
+ (with-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 ()
+ (sap-int
+ (sb!vm::current-thread-offset-sap sb!vm::thread-os-thread-slot)))
+
+(defun init-initial-thread ()
+ (/show0 "Entering INIT-INITIAL-THREAD")
+ (let ((initial-thread (%make-thread :name "initial thread"
+ :%alive-p t
+ :os-thread (current-thread-sap-id))))
+ (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))))
-(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))
-
-(defvar *session* nil)
+;;;;
-;;;; queues, locks
+#!+sb-thread
+(progn
+ ;; 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_interrupt_thread"
+ integer (os-thread unsigned-long))
+
+ (define-alien-routine "block_deferrable_signals"
+ void)
+
+ #!+sb-lutex
+ (progn
+ (declaim (inline %lutex-init %lutex-wait %lutex-wake
+ %lutex-lock %lutex-unlock))
+
+ (sb!alien:define-alien-routine ("lutex_init" %lutex-init)
+ int (lutex unsigned-long))
+
+ (sb!alien:define-alien-routine ("lutex_wait" %lutex-wait)
+ int (queue-lutex unsigned-long) (mutex-lutex unsigned-long))
+
+ (sb!alien:define-alien-routine ("lutex_wake" %lutex-wake)
+ int (lutex unsigned-long) (n int))
+
+ (sb!alien:define-alien-routine ("lutex_lock" %lutex-lock)
+ int (lutex unsigned-long))
+
+ (sb!alien:define-alien-routine ("lutex_trylock" %lutex-trylock)
+ int (lutex unsigned-long))
+
+ (sb!alien:define-alien-routine ("lutex_unlock" %lutex-unlock)
+ int (lutex unsigned-long))
+
+ (sb!alien:define-alien-routine ("lutex_destroy" %lutex-destroy)
+ int (lutex unsigned-long))
+
+ ;; FIXME: Defining a whole bunch of alien-type machinery just for
+ ;; passing primitive lutex objects directly to foreign functions
+ ;; doesn't seem like fun right now. So instead we just manually
+ ;; pin the lutex, get its address, and let the callee untag it.
+ (defmacro with-lutex-address ((name lutex) &body body)
+ `(let ((,name ,lutex))
+ (with-pinned-objects (,name)
+ (let ((,name (get-lisp-obj-address ,name)))
+ ,@body))))
+
+ (defun make-lutex ()
+ (/show0 "Entering MAKE-LUTEX")
+ ;; Suppress GC until the lutex has been properly registered with
+ ;; the GC.
+ (without-gcing
+ (let ((lutex (sb!vm::%make-lutex)))
+ (/show0 "LUTEX=..")
+ (/hexstr lutex)
+ (with-lutex-address (lutex lutex)
+ (%lutex-init lutex))
+ lutex))))
+
+ #!-sb-lutex
+ (progn
+ (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))))
+
+;;; used by debug-int.lisp to access interrupt contexts
+#!-(or sb-fluid sb-thread) (declaim (inline sb!vm::current-thread-offset-sap))
+#!-sb-thread
+(defun sb!vm::current-thread-offset-sap (n)
+ (declare (type (unsigned-byte 27) n))
+ (sap-ref-sap (alien-sap (extern-alien "all_threads" (* t)))
+ (* n sb!vm:n-word-bytes)))
+
+#!+sb-thread
+(defun sb!vm::current-thread-offset-sap (n)
+ (declare (type (unsigned-byte 27) n))
+ (sb!vm::current-thread-offset-sap n))
+
+;;;; spinlocks
+#!+sb-thread
+(define-structure-slot-compare-and-swap
+ compare-and-swap-spinlock-value
+ :structure spinlock
+ :slot value)
-;; 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)))
+(defun get-spinlock (spinlock)
+ (declare (optimize (speed 3) (safety 0))
+ #!-sb-thread
+ (ignore spinlock))
+ ;; %instance-set-conditional can test for 0 (which is a fixnum) and
+ ;; store any value
+ #!+sb-thread
(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)))))
-
+ (eql 0 (compare-and-swap-spinlock-value spinlock 0 1)))
+ t)
+
+(defun release-spinlock (spinlock)
+ (declare (optimize (speed 3) (safety 0))
+ #!-sb-thread (ignore spinlock))
+ ;; %instance-set-conditional cannot compare arbitrary objects
+ ;; meaningfully, so (compare-and-swap-spinlock-value our-value 0)
+ ;; does not work for bignum thread ids.
+ #!+sb-thread
+ (setf (spinlock-value spinlock) 0)
+ nil)
+
+;;;; mutexes
+
+#!+sb-doc
+(setf (fdocumentation 'make-mutex 'function)
+ "Create a mutex."
+ (fdocumentation 'mutex-name 'function)
+ "The name of the mutex. Setfable."
+ (fdocumentation 'mutex-value 'function)
+ "The value of the mutex. NIL if the mutex is free. Setfable.")
+
+#!+(and sb-thread (not sb-lutex))
+(progn
+ (define-structure-slot-addressor mutex-value-address
+ :structure mutex
+ :slot value)
+ (define-structure-slot-compare-and-swap
+ compare-and-swap-mutex-value
+ :structure mutex
+ :slot value))
+
+(defun get-mutex (mutex &optional (new-value *current-thread*) (wait-p t))
+ #!+sb-doc
+ "Acquire MUTEX, setting it to NEW-VALUE or some suitable default
+value if NIL. If WAIT-P is non-NIL and the mutex is in use, sleep
+until it is available."
+ (declare (type mutex mutex) (optimize (speed 3)))
+ (/show0 "Entering GET-MUTEX")
+ (unless new-value
+ (setq new-value *current-thread*))
+ #!-sb-thread
+ (let ((old-value (mutex-value mutex)))
+ (when (and old-value wait-p)
+ (error "In unithread mode, mutex ~S was requested with WAIT-P ~S and ~
+ new-value ~S, but has already been acquired (with value ~S)."
+ mutex wait-p new-value old-value))
+ (setf (mutex-value mutex) new-value)
+ t)
+ #!+sb-thread
+ (progn
+ (when (eql new-value (mutex-value mutex))
+ (warn "recursive lock attempt ~S~%" mutex)
+ (format *debug-io* "Thread: ~A~%" *current-thread*)
+ (sb!debug:backtrace most-positive-fixnum *debug-io*)
+ (force-output *debug-io*))
+ #!+sb-lutex
+ (when (zerop (with-lutex-address (lutex (mutex-lutex mutex))
+ (if wait-p
+ (%lutex-lock lutex)
+ (%lutex-trylock lutex))))
+ (setf (mutex-value mutex) new-value))
+ #!-sb-lutex
+ (let (old)
+ (loop
+ (unless
+ (setf old
+ (compare-and-swap-mutex-value mutex nil new-value))
+ (return t))
+ (unless wait-p (return nil))
+ (with-pinned-objects (mutex old)
+ (futex-wait (mutex-value-address mutex)
+ (get-lisp-obj-address old)))))))
+
+(defun release-mutex (mutex)
+ #!+sb-doc
+ "Release MUTEX by setting it to NIL. Wake up threads waiting for
+this mutex."
+ (declare (type mutex mutex))
+ (/show0 "Entering RELEASE-MUTEX")
+ (setf (mutex-value mutex) nil)
+ #!+sb-thread
+ (progn
+ #!+sb-lutex
+ (with-lutex-address (lutex (mutex-lutex mutex))
+ (%lutex-unlock lutex))
+ #!-sb-lutex
+ (futex-wake (mutex-value-address mutex) 1)))
+
+;;;; waitqueues/condition variables
+
+(defstruct (waitqueue (:constructor %make-waitqueue))
+ #!+sb-doc
+ "Waitqueue type."
+ (name nil :type (or null simple-string))
+ #!+(and sb-lutex sb-thread)
+ (lutex (make-lutex))
+ #!-sb-lutex
+ (data nil))
-;;;; the higher-level locking operations are based on waitqueues
+(defun make-waitqueue (&key name)
+ #!+sb-doc
+ "Create a waitqueue."
+ (%make-waitqueue :name name))
-(declaim (inline waitqueue-data-address mutex-value-address))
+#!+sb-doc
+(setf (fdocumentation 'waitqueue-name 'function)
+ "The name of the waitqueue. Setfable.")
-(defstruct waitqueue
- (name nil :type (or null simple-base-string))
- (lock 0)
- (data nil))
+#!+(and sb-thread (not sb-lutex))
+(define-structure-slot-addressor waitqueue-data-address
+ :structure waitqueue
+ :slot data)
-;;; 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))))
-
-(sb!alien:define-alien-routine "block_sigcont" void)
-(sb!alien:define-alien-routine "unblock_sigcont_and_sleep" void)
-
-#!+sb-futex
-(declaim (inline futex-wait futex-wake))
-#!+sb-futex
-(sb!alien:define-alien-routine
- "futex_wait" int (word unsigned-long) (old-value unsigned-long))
-#!+sb-futex
-(sb!alien:define-alien-routine
- "futex_wake" int (word unsigned-long) (n unsigned-long))
-
-
-;;; this should only be called while holding the queue spinlock.
-;;; it releases the spinlock before sleeping
-(defun wait-on-queue (queue &optional lock)
- (let ((pid (current-thread-id)))
- (block-sigcont)
- (when lock (release-mutex lock))
- (sb!sys:without-interrupts
- (pushnew pid (waitqueue-data queue)))
- (setf (waitqueue-lock queue) 0)
- (unblock-sigcont-and-sleep)))
-
-;;; this should only be called while holding the queue spinlock. It doesn't
-;;; release it
-(defun dequeue (queue)
- (let ((pid (current-thread-id)))
- (sb!sys:without-interrupts
- (setf (waitqueue-data queue)
- (delete pid (waitqueue-data queue))))))
-
-;;; this should only be called while holding the queue spinlock.
-(defun signal-queue-head (queue)
- (let ((p (car (waitqueue-data queue))))
- (when p (signal-thread-to-dequeue p))))
-
-;;;; mutex
-
-;;; i suspect there may be a race still in this: the futex version requires
-;;; the old mutex value before sleeping, so how do we get away without it
-(defun get-mutex (lock &optional new-value (wait-p t))
- (declare (type mutex lock) (optimize (speed 3)))
- (let ((pid (current-thread-id)))
- (unless new-value (setf new-value pid))
- (assert (not (eql new-value (mutex-value lock))))
- (get-spinlock lock 2 pid)
- (loop
- (unless
- ;; args are object slot-num old-value new-value
- (sb!vm::%instance-set-conditional lock 4 nil new-value)
- (dequeue lock)
- (setf (waitqueue-lock lock) 0)
- (return t))
- (unless wait-p
- (setf (waitqueue-lock lock) 0)
- (return nil))
- (wait-on-queue lock nil))))
-
-#!+sb-futex
-(defun get-mutex/futex (lock &optional new-value (wait-p t))
- (declare (type mutex lock) (optimize (speed 3)))
- (let ((pid (current-thread-id))
- old)
- (unless new-value (setf new-value pid))
- (assert (not (eql new-value (mutex-value 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 &optional (new-value nil))
- (declare (type mutex lock))
- ;; we assume the lock is ours to release
- (with-spinlock (lock)
- (setf (mutex-value lock) new-value)
- (signal-queue-head lock)))
-
-#!+sb-futex
-(defun release-mutex/futex (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
+(defun condition-wait (queue mutex)
+ #!+sb-doc
+ "Atomically release MUTEX 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)))
+time we reacquire MUTEX and return to the caller."
+ #!-sb-thread (declare (ignore queue))
+ (assert mutex)
+ #!-sb-thread (error "Not supported in unithread builds.")
+ #!+sb-thread
+ (let ((value (mutex-value mutex)))
+ (/show0 "CONDITION-WAITing")
+ #!+sb-lutex
+ (progn
+ (setf (mutex-value mutex) nil)
+ (with-lutex-address (queue-lutex-address (waitqueue-lutex queue))
+ (with-lutex-address (mutex-lutex-address (mutex-lutex mutex))
+ (%lutex-wait queue-lutex-address mutex-lutex-address)))
+ (setf (mutex-value mutex) value))
+ #!-sb-lutex
(unwind-protect
- (progn
- (get-spinlock queue 2 (current-thread-id))
- (wait-on-queue queue lock))
+ (let ((me *current-thread*))
+ ;; 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 mutex)
+ ;; Now we go to sleep using futex-wait. If anyone else
+ ;; manages to grab MUTEX 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
+ (with-pinned-objects (queue me)
+ (futex-wait (waitqueue-data-address queue)
+ (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.
- (with-spinlock (queue)
- (dequeue queue))
- (get-mutex lock value))))
-
-#!+sb-futex
-(defun condition-wait/futex (queue lock)
- (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"
- (with-spinlock (queue) (signal-queue-head queue)))
-
-#!+sb-futex
-(defun condition-notify/futex (queue)
- "Notify one of the processes waiting on QUEUE."
- (let ((me (current-thread-id)))
+ (get-mutex mutex value))))
+
+(defun condition-notify (queue &optional (n 1))
+ #!+sb-doc
+ "Notify N threads waiting on QUEUE."
+ #!-sb-thread (declare (ignore queue n))
+ #!-sb-thread (error "Not supported in unithread builds.")
+ #!+sb-thread
+ (declare (type (and fixnum (integer 1)) n))
+ (/show0 "Entering CONDITION-NOTIFY")
+ #!+sb-thread
+ (progn
+ #!+sb-lutex
+ (with-lutex-address (lutex (waitqueue-lutex queue))
+ (%lutex-wake lutex n))
;; 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)))
-
-#!+sb-futex
-(defun condition-broadcast/futex (queue)
- (let ((me (current-thread-id)))
- (setf (waitqueue-data queue) me)
- (futex-wake (waitqueue-data-address queue) (ash 1 30))))
+ #!-sb-lutex
+ (let ((me *current-thread*))
+ (progn
+ (setf (waitqueue-data queue) me)
+ (with-pinned-objects (queue)
+ (futex-wake (waitqueue-data-address queue) n))))))
(defun condition-broadcast (queue)
- "Notify all of the processes waiting on QUEUE."
- (with-spinlock (queue)
- (map nil #'signal-thread-to-dequeue (waitqueue-data queue))))
-
-;;; Futexes may be available at compile time but not runtime, so we
-;;; default to not using them unless os_init says they're available
-(defun maybe-install-futex-functions ()
- #!+sb-futex
- (unless (zerop (extern-alien "linux_supports_futex" int))
- (setf (fdefinition 'get-mutex) #'get-mutex/futex
- (fdefinition 'release-mutex) #'release-mutex/futex
- (fdefinition 'condition-wait) #'condition-wait/futex
- (fdefinition 'condition-broadcast) #'condition-broadcast/futex
- (fdefinition 'condition-notify) #'condition-notify/futex)
- t))
-
-(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!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)
- (sb!unix:unix-exit
- (catch 'sb!impl::%end-of-the-world
- (with-simple-restart
- (destroy-thread
- (format nil "~~@<Destroy this thread (~A)~~@:>"
- (current-thread-id)))
- (funcall real-function))
- 0))))))))
- (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
-
-(defun interrupt-thread (thread function)
- "Interrupt THREAD and make it run FUNCTION."
- (let ((function (coerce function 'function)))
- (sb!sys:with-pinned-objects (function)
- (sb!unix::syscall* ("interrupt_thread"
- sb!alien:unsigned-long sb!alien:unsigned-long)
- thread
- thread
- (sb!kernel:get-lisp-obj-address function)))))
-
-(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 (* 4 sb!vm::thread-next-slot))
- until (sb!sys:sap= thread (sb!sys:int-sap 0))
- collect (funcall function thread))))
+ #!+sb-doc
+ "Notify all threads waiting on QUEUE."
+ (condition-notify queue
+ ;; On a 64-bit platform truncating M-P-F to an int results
+ ;; in -1, which wakes up only one thread.
+ (ldb (byte 29 0)
+ most-positive-fixnum)))
+
+;;;; semaphores
+
+(defstruct (semaphore (:constructor %make-semaphore))
+ #!+sb-doc
+ "Semaphore type."
+ (name nil :type (or null simple-string))
+ (count 0 :type (integer 0))
+ (mutex (make-mutex))
+ (queue (make-waitqueue)))
+
+(defun make-semaphore (&key name (count 0))
+ #!+sb-doc
+ "Create a semaphore with the supplied COUNT."
+ (%make-semaphore :name name :count count))
+
+(setf (fdocumentation 'semaphore-name 'function)
+ "The name of the semaphore. Setfable.")
+
+(defun wait-on-semaphore (sem)
+ #!+sb-doc
+ "Decrement the count of SEM if the count would not be negative. Else
+block until the semaphore can be decremented."
+ ;; a more direct implementation based directly on futexes should be
+ ;; possible
+ (with-mutex ((semaphore-mutex sem))
+ (loop until (> (semaphore-count sem) 0)
+ do (condition-wait (semaphore-queue sem) (semaphore-mutex sem))
+ finally (decf (semaphore-count sem)))))
+
+(defun signal-semaphore (sem &optional (n 1))
+ #!+sb-doc
+ "Increment the count of SEM by N. If there are threads waiting on
+this semaphore, then N of them is woken up."
+ (declare (type (and fixnum (integer 1)) n))
+ (with-mutex ((semaphore-mutex sem))
+ (when (= n (incf (semaphore-count sem) n))
+ (condition-notify (semaphore-queue sem) n))))
;;;; job control, independent listeners
-(defstruct session
- (lock (make-mutex))
+(defstruct session
+ (lock (make-mutex :name "session lock"))
(threads nil)
(interactive-threads nil)
(interactive-threads-queue (make-waitqueue)))
+(defvar *session* nil)
+
+;;; the debugger itself tries to acquire the session lock, don't let
+;;; funny situations (like getting a sigint while holding the session
+;;; lock) occur
+(defmacro with-session-lock ((session) &body body)
+ #!-sb-thread (declare (ignore session))
+ #!-sb-thread
+ `(locally ,@body)
+ #!+sb-thread
+ `(without-interrupts
+ (with-mutex ((session-lock ,session))
+ ,@body)))
+
(defun new-session ()
- (let ((tid (current-thread-id)))
- (make-session :threads (list tid)
- :interactive-threads (list tid))))
+ (make-session :threads (list *current-thread*)
+ :interactive-threads (list *current-thread*)))
(defun init-job-control ()
- (setf *session* (new-session)))
+ (/show0 "Entering INIT-JOB-CONTROL")
+ (setf *session* (new-session))
+ (/show0 "Exiting INIT-JOB-CONTROL"))
-(defun %delete-thread-from-session (tid)
- (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 %delete-thread-from-session (thread session)
+ (with-session-lock (session)
+ (setf (session-threads session)
+ (delete thread (session-threads session))
+ (session-interactive-threads session)
+ (delete thread (session-interactive-threads session)))))
(defun call-with-new-session (fn)
- (%delete-thread-from-session (current-thread-id))
- (let ((*session* (new-session))) (funcall fn)))
+ (%delete-thread-from-session *current-thread* *session*)
+ (let ((*session* (new-session)))
+ (funcall fn)))
(defmacro with-new-session (args &body forms)
- (declare (ignore args)) ;for extensibility
+ (declare (ignore args)) ;for extensibility
(sb!int:with-unique-names (fb-name)
`(labels ((,fb-name () ,@forms))
(call-with-new-session (function ,fb-name)))))
-;;; this is called from a C signal handler: some signals may be masked
-(defun handle-thread-exit (tid)
- "Remove thread id TID from the session, if it's there"
- (%delete-thread-from-session tid))
-
+;;; Remove thread from its session, if it has one.
+#!+sb-thread
+(defun handle-thread-exit (thread)
+ (/show0 "HANDLING THREAD EXIT")
+ ;; We're going down, can't handle interrupts sanely anymore.
+ ;; GC remains enabled.
+ (block-deferrable-signals)
+ ;; Lisp-side cleanup
+ (with-all-threads-lock
+ (setf (thread-%alive-p thread) nil)
+ (setf (thread-os-thread thread) nil)
+ (setq *all-threads* (delete thread *all-threads*))
+ (when *session*
+ (%delete-thread-from-session thread *session*)))
+ #!+sb-lutex
+ (without-gcing
+ (/show0 "FREEING MUTEX LUTEX")
+ (with-lutex-address (lutex (mutex-lutex (thread-interruptions-lock thread)))
+ (%lutex-destroy lutex))))
+
(defun terminate-session ()
- "Kill all threads in session exept for this one. Does nothing if current
-thread is not the foreground thread"
- (let* ((tid (current-thread-id))
- (to-kill
- (with-mutex ((session-lock *session*))
- (and (eql tid (car (session-interactive-threads *session*)))
- (session-threads *session*)))))
+ #!+sb-doc
+ "Kill all threads in session except for this one. Does nothing if current
+thread is not the foreground thread."
+ ;; FIXME: threads created in other threads may escape termination
+ (let ((to-kill
+ (with-session-lock (*session*)
+ (and (eq *current-thread*
+ (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)))))
+ (dolist (thread to-kill)
+ (unless (eq thread *current-thread*)
+ ;; terminate the thread but don't be surprised if it has
+ ;; exited in the meantime
+ (handler-case (terminate-thread thread)
+ (interrupt-thread-error ()))))))
;;; 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))
+ #!-sb-thread nil
+ #!+sb-thread
(prog1
- (with-mutex ((session-lock *session*))
- (not (member (current-thread-id)
- (session-interactive-threads *session*))))
+ (with-session-lock (*session*)
+ (not (member *current-thread*
+ (session-interactive-threads *session*))))
(get-foreground)))
-
(defun get-foreground ()
+ #!-sb-thread t
+ #!+sb-thread
(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*)))))))
+ (/show0 "Looping in GET-FOREGROUND")
+ (with-session-lock (*session*)
+ (let ((int-t (session-interactive-threads *session*)))
+ (when (eq (car int-t) *current-thread*)
+ (unless was-foreground
+ (format *query-io* "Resuming thread ~A~%" *current-thread*))
+ (return-from get-foreground t))
+ (setf was-foreground nil)
+ (unless (member *current-thread* int-t)
+ (setf (cdr (last int-t))
+ (list *current-thread*)))
+ (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)))
+ #!+sb-doc
+ "Background this thread. If NEXT is supplied, arrange for it to
+have the foreground next."
+ #!-sb-thread (declare (ignore next))
+ #!-sb-thread nil
+ #!+sb-thread
+ (with-session-lock (*session*)
+ (when (rest (session-interactive-threads *session*))
+ (setf (session-interactive-threads *session*)
+ (delete *current-thread* (session-interactive-threads *session*))))
+ (when next
(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)
+ (list* next
+ (delete next (session-interactive-threads *session*)))))
+ (condition-broadcast (session-interactive-threads-queue *session*))))
+
+(defun foreground-thread ()
+ (car (session-interactive-threads *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))
- (sb!impl::*stdout*
- (sb!sys:make-fd-stream out :output t :buffering :line))
- (sb!impl::*stderr*
- (sb!sys:make-fd-stream err :output t :buffering :line))
- (sb!impl::*tty*
- (sb!sys:make-fd-stream err :input t :output t :buffering :line))
- (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))))))
+ (out (sb!unix:unix-dup in))
+ (err (sb!unix:unix-dup in)))
+ (labels ((thread-repl ()
+ (sb!unix::unix-setsid)
+ (let* ((sb!impl::*stdin*
+ (make-fd-stream in :input t :buffering :line
+ :dual-channel-p t))
+ (sb!impl::*stdout*
+ (make-fd-stream out :output t :buffering :line
+ :dual-channel-p t))
+ (sb!impl::*stderr*
+ (make-fd-stream err :output t :buffering :line
+ :dual-channel-p t))
+ (sb!impl::*tty*
+ (make-fd-stream err :input t :output t
+ :buffering :line
+ :dual-channel-p t))
+ (sb!impl::*descriptor-handlers* nil))
+ (with-new-session ()
+ (unwind-protect
+ (sb!impl::toplevel-repl nil)
+ (sb!int:flush-standard-output-streams))))))
(make-thread #'thread-repl))))
+
+;;;; the beef
+
+(defun make-thread (function &key name)
+ #!+sb-doc
+ "Create a new thread of NAME that runs FUNCTION. When the function
+returns the thread exits. The return values of FUNCTION are kept
+around and can be retrieved by JOIN-THREAD."
+ #!-sb-thread (declare (ignore function name))
+ #!-sb-thread (error "Not supported in unithread builds.")
+ #!+sb-thread
+ (let* ((thread (%make-thread :name name))
+ (setup-sem (make-semaphore :name "Thread setup semaphore"))
+ (real-function (coerce function 'function))
+ (initial-function
+ (lambda ()
+ ;; In time we'll move some of the binding presently done in C
+ ;; here too.
+ ;;
+ ;; KLUDGE: Here we have a magic list of variables that are
+ ;; not thread-safe for one reason or another. As people
+ ;; report problems with the thread safety of certain
+ ;; variables, (e.g. "*print-case* in multiple threads
+ ;; broken", sbcl-devel 2006-07-14), we add a few more
+ ;; bindings here. The Right Thing is probably some variant
+ ;; of Allegro's *cl-default-special-bindings*, as that is at
+ ;; least accessible to users to secure their own libraries.
+ ;; --njf, 2006-07-15
+ (let ((*current-thread* thread)
+ (*restart-clusters* nil)
+ (*handler-clusters* nil)
+ (*condition-restarts* nil)
+ (sb!impl::*step-out* nil)
+ ;; internal printer variables
+ (sb!impl::*previous-case* nil)
+ (sb!impl::*previous-readtable-case* nil)
+ (sb!impl::*merge-sort-temp-vector* (vector)) ; keep these small!
+ (sb!impl::*zap-array-data-temp* (vector)) ;
+ (sb!impl::*internal-symbol-output-fun* nil)
+ (sb!impl::*descriptor-handlers* nil)) ; serve-event
+ (setf (thread-os-thread thread) (current-thread-sap-id))
+ (with-mutex ((thread-result-lock thread))
+ (with-all-threads-lock
+ (push thread *all-threads*))
+ (with-session-lock (*session*)
+ (push thread (session-threads *session*)))
+ (setf (thread-%alive-p thread) t)
+ (signal-semaphore setup-sem)
+ ;; 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::toplevel-catcher
+ (catch 'sb!impl::%end-of-the-world
+ (with-simple-restart
+ (terminate-thread
+ (format nil
+ "~~@<Terminate this thread (~A)~~@:>"
+ *current-thread*))
+ (unwind-protect
+ (progn
+ ;; 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)
+ (setf (thread-result thread)
+ (cons t
+ (multiple-value-list
+ (funcall real-function)))))
+ (handle-thread-exit thread)))))))
+ (values))))
+ ;; Keep INITIAL-FUNCTION pinned until the child thread is
+ ;; initialized properly.
+ (with-pinned-objects (initial-function)
+ (let ((os-thread
+ (%create-thread
+ (get-lisp-obj-address initial-function))))
+ (when (zerop os-thread)
+ (error "Can't create a new thread"))
+ (wait-on-semaphore setup-sem)
+ thread))))
+
+(define-condition join-thread-error (error)
+ ((thread :reader join-thread-error-thread :initarg :thread))
+ #!+sb-doc
+ (:documentation "Joining thread failed.")
+ (:report (lambda (c s)
+ (format s "Joining thread failed: thread ~A ~
+ has not returned normally."
+ (join-thread-error-thread c)))))
+
+#!+sb-doc
+(setf (fdocumentation 'join-thread-error-thread 'function)
+ "The thread that we failed to join.")
+
+(defun join-thread (thread &key (default nil defaultp))
+ #!+sb-doc
+ "Suspend current thread until THREAD exits. Returns the result
+values of the thread function. If the thread does not exit normally,
+return DEFAULT if given or else signal JOIN-THREAD-ERROR."
+ (with-mutex ((thread-result-lock thread))
+ (cond ((car (thread-result thread))
+ (values-list (cdr (thread-result thread))))
+ (defaultp
+ default)
+ (t
+ (error 'join-thread-error :thread thread)))))
+
+(defun destroy-thread (thread)
+ #!+sb-doc
+ "Deprecated. Same as TERMINATE-THREAD."
+ (terminate-thread thread))
+
+(define-condition interrupt-thread-error (error)
+ ((thread :reader interrupt-thread-error-thread :initarg :thread))
+ #!+sb-doc
+ (:documentation "Interrupting thread failed.")
+ (:report (lambda (c s)
+ (format s "Interrupt thread failed: thread ~A has exited."
+ (interrupt-thread-error-thread c)))))
+
+#!+sb-doc
+(setf (fdocumentation 'interrupt-thread-error-thread 'function)
+ "The thread that was not interrupted.")
+
+(defmacro with-interruptions-lock ((thread) &body body)
+ `(without-interrupts
+ (with-mutex ((thread-interruptions-lock ,thread))
+ ,@body)))
+
+;; Called from the signal handler.
+(defun run-interruption ()
+ (in-interruption ()
+ (loop
+ (let ((interruption (with-interruptions-lock (*current-thread*)
+ (pop (thread-interruptions *current-thread*)))))
+ (if interruption
+ (with-interrupts
+ (funcall interruption))
+ (return))))))
+
+;; The order of interrupt execution is peculiar. If thread A
+;; interrupts thread B with I1, I2 and B for some reason receives I1
+;; when FUN2 is already on the list, then it is FUN2 that gets to run
+;; first. But when FUN2 is run SIG_INTERRUPT_THREAD is enabled again
+;; and I2 hits pretty soon in FUN2 and run FUN1. This is of course
+;; just one scenario, and the order of thread interrupt execution is
+;; undefined.
+(defun interrupt-thread (thread function)
+ #!+sb-doc
+ "Interrupt the live THREAD and make it run FUNCTION. 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."
+ #!-sb-thread (declare (ignore thread))
+ ;; not quite perfect, because it does not take WITHOUT-INTERRUPTS
+ ;; into account
+ #!-sb-thread
+ (funcall function)
+ #!+sb-thread
+ (if (eq thread *current-thread*)
+ (funcall function)
+ (let ((os-thread (thread-os-thread thread)))
+ (cond ((not os-thread)
+ (error 'interrupt-thread-error :thread thread))
+ (t
+ (with-interruptions-lock (thread)
+ (push function (thread-interruptions thread)))
+ (when (minusp (signal-interrupt-thread os-thread))
+ (error 'interrupt-thread-error :thread thread)))))))
+
+(defun terminate-thread (thread)
+ #!+sb-doc
+ "Terminate the thread identified by THREAD, by causing it to run
+SB-EXT:QUIT - the usual cleanup forms will be evaluated"
+ (interrupt-thread thread 'sb!ext:quit))
+
+;;; 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
+#!+sb-thread
+(defun thread-sap-for-id (id)
+ (let ((thread-sap (alien-sap (extern-alien "all_threads" (* t)))))
+ (loop
+ (when (sap= thread-sap (int-sap 0)) (return nil))
+ (let ((os-thread (sap-ref-word thread-sap
+ (* sb!vm:n-word-bytes
+ sb!vm::thread-os-thread-slot))))
+ (when (= os-thread id) (return thread-sap))
+ (setf thread-sap
+ (sap-ref-sap thread-sap (* sb!vm:n-word-bytes
+ sb!vm::thread-next-slot)))))))
+
+#!+sb-thread
+(defun symbol-value-in-thread (symbol thread-sap)
+ (let* ((index (sb!vm::symbol-tls-index symbol))
+ (tl-val (sap-ref-word thread-sap
+ (* sb!vm:n-word-bytes index))))
+ (if (eql tl-val sb!vm::no-tls-value-marker-widetag)
+ (sb!vm::symbol-global-value symbol)
+ (make-lisp-obj tl-val))))
+
+(defun sb!vm::locked-symbol-global-value-add (symbol-name delta)
+ (sb!vm::locked-symbol-global-value-add symbol-name delta))
+
+;;; Stepping
+
+(defun thread-stepping ()
+ (make-lisp-obj
+ (sap-ref-word (current-thread-sap)
+ (* sb!vm::thread-stepping-slot sb!vm:n-word-bytes))))
+
+(defun (setf thread-stepping) (value)
+ (setf (sap-ref-word (current-thread-sap)
+ (* sb!vm::thread-stepping-slot sb!vm:n-word-bytes))
+ (get-lisp-obj-address value)))
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