(declaim (inline futex-wait futex-wake))
(sb!alien:define-alien-routine "futex_wait"
- int (word unsigned-long) (old-value unsigned-long))
+ int (word unsigned-long) (old-value unsigned-long)
+ (to-sec long) (to-usec unsigned-long))
(sb!alien:define-alien-routine "futex_wake"
int (word unsigned-long) (n unsigned-long))))
(sb!vm::current-thread-offset-sap n))
;;;; spinlocks
-#!+sb-thread
(define-structure-slot-compare-and-swap
compare-and-swap-spinlock-value
:structure spinlock
(declaim (inline get-spinlock release-spinlock))
(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 0 (compare-and-swap-spinlock-value spinlock 0 1)))
+ (declare (optimize (speed 3) (safety 0)))
+ (let* ((new *current-thread*)
+ (old (compare-and-swap-spinlock-value spinlock nil new)))
+ (when old
+ (when (eq old new)
+ (error "Recursive lock attempt on ~S." spinlock))
+ #!+sb-thread
+ (loop while (compare-and-swap-spinlock-value spinlock nil new))))
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)
+ (declare (optimize (speed 3) (safety 0)))
+ (setf (spinlock-value spinlock) nil)
nil)
;;;; mutexes
:structure mutex
:slot value))
-(defun get-mutex (mutex &optional (new-value *current-thread*) (wait-p t))
+(defun get-mutex (mutex &optional (new-value *current-thread*) (waitp 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
+value if NIL. If WAITP 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 ~
+ (let ((old (mutex-value mutex)))
+ (when (and old waitp)
+ (error "In unithread mode, mutex ~S was requested with WAITP ~S and ~
new-value ~S, but has already been acquired (with value ~S)."
- mutex wait-p new-value old-value))
+ mutex waitp new-value old))
(setf (mutex-value mutex) new-value)
t)
#!+sb-thread
(format *debug-io* "Thread: ~A~%" *current-thread*)
(sb!debug:backtrace most-positive-fixnum *debug-io*)
(force-output *debug-io*))
+ ;; FIXME: Lutexes do not currently support deadlines, as at least
+ ;; on Darwin pthread_foo_timedbar functions are not supported:
+ ;; this means that we probably need to use the Carbon multiprocessing
+ ;; functions on Darwin.
#!+sb-lutex
(when (zerop (with-lutex-address (lutex (mutex-lutex mutex))
- (if wait-p
+ (if waitp
(%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)))))))
+ (when (and (setf old (compare-and-swap-mutex-value mutex nil new-value))
+ waitp)
+ (loop while old
+ do (multiple-value-bind (to-sec to-usec) (decode-timeout nil)
+ (when (= 1 (with-pinned-objects (mutex old)
+ (futex-wait (mutex-value-address mutex)
+ (get-lisp-obj-address old)
+ (or to-sec -1)
+ (or to-usec 0))))
+ (signal-deadline)))
+ (setf old (compare-and-swap-mutex-value mutex nil new-value))))
+ (not old))))
(defun release-mutex (mutex)
#!+sb-doc
;; 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))))
+ ;; Ergo, no lost wakeup. We may get spurious wakeups,
+ ;; but that's ok.
+ (multiple-value-bind (to-sec to-usec) (decode-timeout nil)
+ (when (= 1 (with-pinned-objects (queue me)
+ (futex-wait (waitqueue-data-address queue)
+ (get-lisp-obj-address me)
+ (or to-sec -1) ;; our way if saying "no timeout"
+ (or to-usec 0))))
+ (signal-deadline))))
;; 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
(with-mutex ((thread-interruptions-lock ,thread))
,@body)))
-;; Called from the signal handler.
+;; Called from the signal handler in C.
(defun run-interruption ()
(in-interruption ()
(loop
(let ((interruption (with-interruptions-lock (*current-thread*)
(pop (thread-interruptions *current-thread*)))))
(if interruption
+ ;; This is safe because it's the IN-INTERRUPTION that
+ ;; has disabled interrupts.
(with-interrupts
(funcall interruption))
(return))))))
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)))))))
+ (flet ((interrupt-self ()
+ ;; *IN-INTERRUPTION* is true IFF we're being called as an
+ ;; interruption without an intervening WITHOUT-INTERRUPTS,
+ ;; in which case it is safe to enable interrupts. Otherwise
+ ;; interrupts are either already enabled, or there is an outer
+ ;; WITHOUT-INTERRUPTS we know nothing about, which makes it
+ ;; unsafe to enable interrupts.
+ (if *in-interruption*
+ (with-interrupts (funcall function))
+ (funcall function))))
+ #!-sb-thread
+ (interrupt-self)
+ #!+sb-thread
+ (if (eq thread *current-thread*)
+ (interrupt-self)
+ (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
projects / sbcl.git / blobdiff