;;; set the doc here because in early-thread FDOCUMENTATION is not
;;; available, yet
#!+sb-doc
-(setf (sb!kernel:fdocumentation '*current-thread* 'variable)
+(setf (fdocumentation '*current-thread* 'variable)
"Bound in each thread to the thread itself.")
(defstruct (thread (:constructor %make-thread))
(result-lock (make-mutex :name "thread result lock")))
#!+sb-doc
-(setf (sb!kernel:fdocumentation 'thread-name 'function)
+(setf (fdocumentation 'thread-name 'function)
"The name of the thread. Setfable.")
(def!method print-object ((thread thread) stream)
(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)))
+ `(call-with-system-mutex (lambda () ,@body) *all-threads-lock*))
(defun list-all-threads ()
#!+sb-doc
(declaim (inline %lutex-init %lutex-wait %lutex-wake
%lutex-lock %lutex-unlock))
- (sb!alien:define-alien-routine ("lutex_init" %lutex-init)
+ (define-alien-routine ("lutex_init" %lutex-init)
int (lutex unsigned-long))
- (sb!alien:define-alien-routine ("lutex_wait" %lutex-wait)
+ (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)
+ (define-alien-routine ("lutex_wake" %lutex-wake)
int (lutex unsigned-long) (n int))
- (sb!alien:define-alien-routine ("lutex_lock" %lutex-lock)
+ (define-alien-routine ("lutex_lock" %lutex-lock)
int (lutex unsigned-long))
- (sb!alien:define-alien-routine ("lutex_trylock" %lutex-trylock)
+ (define-alien-routine ("lutex_trylock" %lutex-trylock)
int (lutex unsigned-long))
- (sb!alien:define-alien-routine ("lutex_unlock" %lutex-unlock)
+ (define-alien-routine ("lutex_unlock" %lutex-unlock)
int (lutex unsigned-long))
- (sb!alien:define-alien-routine ("lutex_destroy" %lutex-destroy)
+ (define-alien-routine ("lutex_destroy" %lutex-destroy)
int (lutex unsigned-long))
;; FIXME: Defining a whole bunch of alien-type machinery just for
(defmacro with-lutex-address ((name lutex) &body body)
`(let ((,name ,lutex))
(with-pinned-objects (,name)
- (let ((,name (sb!kernel:get-lisp-obj-address ,name)))
+ (let ((,name (get-lisp-obj-address ,name)))
,@body))))
(defun make-lutex ()
#!-sb-lutex
(progn
- (declaim (inline futex-wait futex-wake))
+ (declaim (inline futex-wait %futex-wait futex-wake))
+
+ (define-alien-routine ("futex_wait" %futex-wait)
+ int (word unsigned-long) (old-value unsigned-long)
+ (to-sec long) (to-usec unsigned-long))
- (sb!alien:define-alien-routine "futex_wait"
- int (word unsigned-long) (old-value unsigned-long))
+ (defun futex-wait (word old to-sec to-usec)
+ (with-interrupts
+ (%futex-wait word old to-sec to-usec)))
- (sb!alien:define-alien-routine "futex_wake"
+ (define-alien-routine "futex_wake"
int (word unsigned-long) (n unsigned-long))))
;;; used by debug-int.lisp to access interrupt contexts
(declare (type (unsigned-byte 27) n))
(sb!vm::current-thread-offset-sap n))
-;;;; spinlocks
-
(declaim (inline get-spinlock release-spinlock))
-;;; The bare 2 here and below are offsets of the slots in the struct.
-;;; There ought to be some better way to get these numbers
+;; Should always be called with interrupts disabled.
(defun get-spinlock (spinlock)
- (declare (optimize (speed 3) (safety 0))
- #!-sb-thread
- (ignore spinlock new-value))
- ;; %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 spinlock 2 0 1) 0)))
+ (declare (optimize (speed 3) (safety 0)))
+ (let* ((new *current-thread*)
+ (old (sb!ext:compare-and-swap (spinlock-value spinlock) nil new)))
+ (when old
+ (when (eq old new)
+ (error "Recursive lock attempt on ~S." spinlock))
+ #!+sb-thread
+ (flet ((cas ()
+ (unless (sb!ext:compare-and-swap (spinlock-value spinlock) nil new)
+ (return-from get-spinlock t))))
+ (if (and (not *interrupts-enabled*) *allow-with-interrupts*)
+ ;; If interrupts are enabled, but we are allowed to enabled them,
+ ;; check for pending interrupts every once in a while.
+ (loop
+ (loop repeat 128 do (cas)) ; 128 is arbitrary here
+ (sb!unix::%check-interrupts))
+ (loop (cas)))))
+ t))
(defun release-spinlock (spinlock)
- (declare (optimize (speed 3) (safety 0))
- #!-sb-thread (ignore spinlock))
- ;; %instance-set-conditional cannot compare arbitrary objects
- ;; meaningfully, so
- ;; (sb!vm::%instance-set-conditional spinlock 2 our-value 0)
- ;; does not work for bignum thread ids.
- #!+sb-thread
- (sb!vm::%instance-set spinlock 2 0))
-
-(defmacro with-spinlock ((spinlock) &body body)
- (sb!int:with-unique-names (lock)
- `(let ((,lock ,spinlock))
- (get-spinlock ,lock)
- (unwind-protect
- (progn ,@body)
- (release-spinlock ,lock)))))
+ (declare (optimize (speed 3) (safety 0)))
+ (setf (spinlock-value spinlock) nil)
+ nil)
;;;; mutexes
#!+sb-doc
-(setf (sb!kernel:fdocumentation 'make-mutex 'function)
+(setf (fdocumentation 'make-mutex 'function)
"Create a mutex."
- (sb!kernel:fdocumentation 'mutex-name 'function)
- "The name of the mutex. Setfable."
- (sb!kernel:fdocumentation 'mutex-value 'function)
- "The value of the mutex. NIL if the mutex is free. Setfable.")
+ (fdocumentation 'mutex-name 'function)
+ "The name of the mutex. Setfable.")
#!+(and sb-thread (not sb-lutex))
(progn
- (declaim (inline mutex-value-address))
- (defun mutex-value-address (mutex)
- (declare (optimize (speed 3)))
- (sb!ext:truly-the
- sb!vm:word
- (+ (sb!kernel:get-lisp-obj-address mutex)
- (- (* 3 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag)))))
-
-(defun get-mutex (mutex &optional (new-value *current-thread*) (wait-p t))
+ (define-structure-slot-addressor mutex-state-address
+ :structure mutex
+ :slot state)
+ ;; Important: current code assumes these are fixnums or other
+ ;; lisp objects that don't need pinning.
+ (defconstant +lock-free+ 0)
+ (defconstant +lock-taken+ 1)
+ (defconstant +lock-contested+ 2))
+
+(defun get-mutex (mutex &optional (new-owner *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
-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)
+ "Acquire MUTEX for NEW-OWNER, which must be a thread or NIL. If
+NEW-OWNER is NIL, it defaults to the current thread. If WAITP is
+non-NIL and the mutex is in use, sleep until it is available.
+
+Note: using GET-MUTEX to assign a MUTEX to another thread then the
+current one is not recommended, and liable to be deprecated.
+
+GET-MUTEX is not interrupt safe. The correct way to call it is:
+
+ (WITHOUT-INTERRUPTS
+ ...
+ (ALLOW-WITH-INTERRUPTS (GET-MUTEX ...))
+ ...)
+
+WITHOUT-INTERRUPTS is necessary to avoid an interrupt unwinding the
+call while the mutex is in an inconsistent state while
+ALLOW-WITH-INTERRUPTS allows the call to be interrupted from sleep.
+
+It is recommended that you use WITH-MUTEX instead of calling GET-MUTEX
+directly."
+ (declare (type mutex mutex) (optimize (speed 3))
+ #!-sb-thread (ignore waitp))
+ (unless new-owner
+ (setq new-owner *current-thread*))
+ (when (eql new-owner (mutex-%owner mutex))
+ (error "Recursive lock attempt ~S." mutex))
#!+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*))
+ ;; 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.
+ ;;
+ ;; FIXME: This is definitely not interrupt safe: what happens if
+ ;; we get hit (1) during the lutex calls (ok, they may be safe,
+ ;; but has that been checked?) (2) after the lutex call, but
+ ;; before setting the mutex owner.
#!+sb-lutex
(when (zerop (with-lutex-address (lutex (mutex-lutex mutex))
- (if wait-p
- (%lutex-lock lutex)
+ (if waitp
+ (with-interrupts (%lutex-lock lutex))
(%lutex-trylock lutex))))
- (setf (mutex-value mutex) new-value))
+ (setf (mutex-%owner mutex) new-owner)
+ t)
#!-sb-lutex
- (let (old)
- (loop
- (unless
- (setf old (sb!vm::%instance-set-conditional mutex 2 nil
- new-value))
- (return t))
- (unless wait-p (return nil))
- (with-pinned-objects (mutex old)
- (futex-wait (mutex-value-address mutex)
- (sb!kernel:get-lisp-obj-address old)))))))
+ (let ((old (sb!ext:compare-and-swap (mutex-state mutex)
+ +lock-free+
+ +lock-taken+)))
+ (unless (or (eql +lock-free+ old) (not waitp))
+ (tagbody
+ :retry
+ (when (or (eql +lock-contested+ old)
+ (not (eql +lock-free+
+ (sb!ext:compare-and-swap (mutex-state mutex)
+ +lock-taken+
+ +lock-contested+))))
+ ;; Wait on the contested lock.
+ (multiple-value-bind (to-sec to-usec) (decode-timeout nil)
+ (when (= 1 (with-pinned-objects (mutex)
+ (futex-wait (mutex-state-address mutex)
+ (get-lisp-obj-address +lock-contested+)
+ (or to-sec -1)
+ (or to-usec 0))))
+ (signal-deadline))))
+ (setf old (sb!ext:compare-and-swap (mutex-state mutex)
+ +lock-free+
+ +lock-contested+))
+ ;; Did we get it?
+ (unless (eql +lock-free+ old)
+ (go :retry))))
+ (cond ((eql +lock-free+ old)
+ (let ((prev (sb!ext:compare-and-swap (mutex-%owner mutex)
+ nil new-owner)))
+ (when prev
+ (bug "Old owner in free mutex: ~S" prev))
+ t))
+ (waitp
+ (bug "Failed to acquire lock with WAITP."))))))
(defun release-mutex (mutex)
#!+sb-doc
"Release MUTEX by setting it to NIL. Wake up threads waiting for
-this mutex."
+this mutex.
+
+RELEASE-MUTEX is not interrupt safe: interrupts should be disabled
+around calls to it.
+
+Signals a WARNING is current thread is not the current owner of the
+mutex."
(declare (type mutex mutex))
- (/show0 "Entering RELEASE-MUTEX")
- (setf (mutex-value mutex) nil)
+ ;; Order matters: set owner to NIL before releasing state.
+ (let* ((self *current-thread*)
+ (old-owner (sb!ext:compare-and-swap (mutex-%owner mutex) self nil)))
+ (unless (eql self old-owner)
+ (warn "Releasing ~S, owned by another thread: ~S" mutex old-owner)
+ (setf (mutex-%owner 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)))
+ (let ((old (sb!ext:compare-and-swap (mutex-state mutex)
+ +lock-taken+ +lock-free+)))
+ (when (eql old +lock-contested+)
+ (sb!ext:compare-and-swap (mutex-state mutex)
+ +lock-contested+ +lock-free+)
+ (with-pinned-objects (mutex)
+ (futex-wake (mutex-state-address mutex) 1))))
+ nil))
;;;; waitqueues/condition variables
(%make-waitqueue :name name))
#!+sb-doc
-(setf (sb!kernel:fdocumentation 'waitqueue-name 'function)
+(setf (fdocumentation 'waitqueue-name 'function)
"The name of the waitqueue. Setfable.")
#!+(and sb-thread (not sb-lutex))
-(progn
- (declaim (inline waitqueue-data-address))
- (defun waitqueue-data-address (waitqueue)
- (declare (optimize (speed 3)))
- (sb!ext:truly-the
- sb!vm:word
- (+ (sb!kernel:get-lisp-obj-address waitqueue)
- (- (* 3 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag)))))
+(define-structure-slot-addressor waitqueue-data-address
+ :structure waitqueue
+ :slot data)
(defun condition-wait (queue mutex)
#!+sb-doc
(assert mutex)
#!-sb-thread (error "Not supported in unithread builds.")
#!+sb-thread
- (let ((value (mutex-value mutex)))
+ (let ((owner (mutex-%owner mutex)))
(/show0 "CONDITION-WAITing")
#!+sb-lutex
(progn
- (setf (mutex-value mutex) nil)
+ ;; FIXME: This doesn't look interrupt safe!
+ (setf (mutex-%owner 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))
+ (setf (mutex-%owner mutex) owner))
#!-sb-lutex
(unwind-protect
(let ((me *current-thread*))
- ;; XXX we should do something to ensure that the result of this setf
- ;; is visible to all CPUs
+ ;; FIXME: should we 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)
- (sb!kernel: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
;; better than nothing.
- (get-mutex mutex value))))
+ (get-mutex mutex owner))))
(defun condition-notify (queue &optional (n 1))
#!+sb-doc
;;;; semaphores
-(defstruct (semaphore (:constructor %make-semaphore))
+(defstruct (semaphore (:constructor %make-semaphore (name %count)))
#!+sb-doc
- "Semaphore type."
+ "Semaphore type. The fact that a SEMAPHORE is a STRUCTURE-OBJECT
+should be considered an implementation detail, and may change in the
+future."
(name nil :type (or null simple-string))
- (count 0 :type (integer 0))
+ (%count 0 :type (integer 0))
(mutex (make-mutex))
(queue (make-waitqueue)))
+(setf (fdocumentation 'semaphore-name 'function)
+ "The name of the semaphore INSTANCE. Setfable.")
+
+(declaim (inline semaphore-count))
+(defun semaphore-count (instance)
+ "Returns the current count of the semaphore INSTANCE."
+ (semaphore-%count instance))
+
(defun make-semaphore (&key name (count 0))
#!+sb-doc
- "Create a semaphore with the supplied COUNT."
- (%make-semaphore :name name :count count))
+ "Create a semaphore with the supplied COUNT and NAME."
+ (%make-semaphore name count))
-(setf (sb!kernel:fdocumentation 'semaphore-name 'function)
- "The name of the semaphore. Setfable.")
-
-(defun wait-on-semaphore (sem)
+(defun wait-on-semaphore (semaphore)
#!+sb-doc
- "Decrement the count of SEM if the count would not be negative. Else
-block until the semaphore can be decremented."
+ "Decrement the count of SEMAPHORE if the count would not be
+negative. Else blocks 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)))))
+ (with-mutex ((semaphore-mutex semaphore))
+ (loop until (> (semaphore-%count semaphore) 0)
+ do (condition-wait (semaphore-queue semaphore) (semaphore-mutex semaphore))
+ finally (decf (semaphore-%count semaphore)))))
-(defun signal-semaphore (sem &optional (n 1))
+(defun signal-semaphore (semaphore &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))))
+ "Increment the count of SEMAPHORE by N. If there are threads waiting
+on this semaphore, then N of them is woken up."
+ (declare (type (integer 1) n))
+ (with-mutex ((semaphore-mutex semaphore))
+ (when (= n (incf (semaphore-%count semaphore) n))
+ (condition-notify (semaphore-queue semaphore) n))))
;;;; job control, independent listeners
;;; 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)))
+ `(call-with-system-mutex (lambda () ,@body) (session-lock ,session)))
(defun new-session ()
(make-session :threads (list *current-thread*)
(when *session*
(%delete-thread-from-session thread *session*)))
#!+sb-lutex
- (when (thread-interruptions-lock thread)
+ (without-gcing
(/show0 "FREEING MUTEX LUTEX")
(with-lutex-address (lutex (mutex-lutex (thread-interruptions-lock thread)))
(%lutex-destroy lutex))))
;; least accessible to users to secure their own libraries.
;; --njf, 2006-07-15
(let ((*current-thread* thread)
- (sb!kernel::*restart-clusters* nil)
- (sb!kernel::*handler-clusters* nil)
- (sb!kernel::*condition-restarts* nil)
+ (*restart-clusters* nil)
+ (*handler-clusters* nil)
+ (*condition-restarts* nil)
+ (sb!impl::*deadline* nil)
(sb!impl::*step-out* nil)
;; internal printer variables
(sb!impl::*previous-case* nil)
(with-pinned-objects (initial-function)
(let ((os-thread
(%create-thread
- (sb!kernel:get-lisp-obj-address initial-function))))
+ (get-lisp-obj-address initial-function))))
(when (zerop os-thread)
(error "Can't create a new thread"))
(wait-on-semaphore setup-sem)
(join-thread-error-thread c)))))
#!+sb-doc
-(setf (sb!kernel:fdocumentation 'join-thread-error-thread 'function)
+(setf (fdocumentation 'join-thread-error-thread 'function)
"The thread that we failed to join.")
-(defun join-thread (thread &key (errorp t) default)
+(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 or signal JOIN-THREAD-ERROR depending on ERRORP."
+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))))
- (errorp
- (error 'join-thread-error :thread thread))
+ (defaultp
+ default)
(t
- default))))
+ (error 'join-thread-error :thread thread)))))
(defun destroy-thread (thread)
#!+sb-doc
(interrupt-thread-error-thread c)))))
#!+sb-doc
-(setf (sb!kernel:fdocumentation 'interrupt-thread-error-thread 'function)
+(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)))
+ `(call-with-system-mutex (lambda () ,@body) (thread-interruptions-lock ,thread)))
-;; Called from the signal handler.
+;; Called from the signal handler in C.
(defun run-interruption ()
(in-interruption ()
(loop
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)
+ (with-interrupt-bindings
+ (with-interrupts (funcall function)))
#!+sb-thread
(if (eq thread *current-thread*)
- (funcall function)
+ (with-interrupt-bindings
+ (with-interrupts (funcall function)))
(let ((os-thread (thread-os-thread thread)))
(cond ((not os-thread)
(error 'interrupt-thread-error :thread thread))
(sap-ref-sap thread-sap (* sb!vm:n-word-bytes
sb!vm::thread-next-slot)))))))
+(define-alien-routine "thread_yield" int)
+
+#!+sb-doc
+(setf (fdocumentation 'thread-yield 'function)
+ "Yield the processor to other threads.")
+
#!+sb-thread
(defun symbol-value-in-thread (symbol thread-sap)
(let* ((index (sb!vm::symbol-tls-index symbol))
(* sb!vm:n-word-bytes index))))
(if (eql tl-val sb!vm::no-tls-value-marker-widetag)
(sb!vm::symbol-global-value symbol)
- (sb!kernel:make-lisp-obj tl-val))))
+ (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 ()
- (sb!kernel:make-lisp-obj
+ (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))
- (sb!kernel:get-lisp-obj-address value)))
+ (get-lisp-obj-address value)))