(in-package "SB!THREAD")
+;;; Conditions
+
+(define-condition thread-error (error)
+ ((thread :reader thread-error-thread :initarg :thread))
+ #!+sb-doc
+ (:documentation
+ "Conditions of type THREAD-ERROR are signalled when thread operations fail.
+The offending thread is initialized by the :THREAD initialization argument and
+read by the function THREAD-ERROR-THREAD."))
+
+#!+sb-doc
+(setf
+ (fdocumentation 'thread-error-thread 'function)
+ "Return the offending thread that the THREAD-ERROR pertains to.")
+
+(define-condition symbol-value-in-thread-error (cell-error thread-error)
+ ((info :reader symbol-value-in-thread-error-info :initarg :info))
+ (:report
+ (lambda (condition stream)
+ (destructuring-bind (op problem)
+ (symbol-value-in-thread-error-info condition)
+ (format stream "Cannot ~(~A~) value of ~S in ~S: ~S"
+ op
+ (cell-error-name condition)
+ (thread-error-thread condition)
+ (ecase problem
+ (:unbound-in-thread "the symbol is unbound in thread.")
+ (:no-tls-value "the symbol has no thread-local value.")
+ (:thread-dead "the thread has exited.")
+ (:invalid-tls-value "the thread-local value is not valid."))))))
+ #!+sb-doc
+ (:documentation
+ "Signalled when SYMBOL-VALUE-IN-THREAD or its SETF version fails due to eg.
+the symbol not having a thread-local value, or the target thread having
+exited. The offending symbol can be accessed using CELL-ERROR-NAME, and the
+offending thread using THREAD-ERROR-THREAD."))
+
+(define-condition join-thread-error (thread-error) ()
+ (:report (lambda (c s)
+ (format s "Joining thread failed: thread ~A ~
+ did not return normally."
+ (thread-error-thread c))))
+ #!+sb-doc
+ (:documentation
+ "Signalled when joining a thread fails due to abnormal exit of the thread
+to be joined. The offending thread can be accessed using
+THREAD-ERROR-THREAD."))
+
+(defun join-thread-error-thread (condition)
+ (thread-error-thread condition))
+(define-compiler-macro join-thread-error-thread (condition)
+ (deprecation-warning 'join-thread-error-thread 'thread-error-thread)
+ `(thread-error-thread ,condition))
+
+#!+sb-doc
+(setf
+ (fdocumentation 'join-thread-error-thread 'function)
+ "The thread that we failed to join. Deprecated, use THREAD-ERROR-THREAD
+instead.")
+
+(define-condition interrupt-thread-error (thread-error) ()
+ (:report (lambda (c s)
+ (format s "Interrupt thread failed: thread ~A has exited."
+ (thread-error-thread c))))
+ #!+sb-doc
+ (:documentation
+ "Signalled when interrupting a thread fails because the thread has already
+exited. The offending thread can be accessed using THREAD-ERROR-THREAD."))
+
+(defun interrupt-thread-error-thread (condition)
+ (thread-error-thread condition))
+(define-compiler-macro interrupt-thread-error-thread (condition)
+ (deprecation-warning 'join-thread-error-thread 'thread-error-thread)
+ `(thread-error-thread ,condition))
+
+#!+sb-doc
+(setf
+ (fdocumentation 'interrupt-thread-error-thread 'function)
+ "The thread that was not interrupted. Deprecated, use THREAD-ERROR-THREAD
+instead.")
+
+;;; 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 (sb!kernel:fdocumentation '*current-thread* 'variable)
+(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")))
-
#!+sb-doc
-(setf (sb!kernel:fdocumentation 'thread-name 'function)
- "The name of the thread. Setfable.")
+(setf
+ (fdocumentation 'thread-name 'function)
+ "Name of the thread. Can be assigned to using SETF. Thread names can be
+arbitrary printable objects, and need not be unique.")
(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)
+ (print-unreadable-object (thread stream :type t :identity t)
+ (let* ((cookie (list thread))
+ (info (if (thread-alive-p thread)
+ :running
+ (multiple-value-list
+ (join-thread thread :default cookie))))
+ (state (if (eq :running info)
+ info
+ (if (eq cookie (car info))
+ :aborted
+ :finished)))
+ (values (when (eq :finished state) info)))
+ (format stream
+ "~@[~S ~]~:[~A~;~A~:[ no values~; values: ~:*~{~S~^, ~}~]~]"
+ (thread-name thread)
+ (eq :finished state)
+ state
+ values))))
(defun thread-alive-p (thread)
#!+sb-doc
- "Check if THREAD is running."
+ "Return T if THREAD is still alive. Note that the return value is
+potentially stale even before the function returns, as the thread may exit at
+any time."
(thread-%alive-p thread))
;; A thread is eligible for gc iff it has finished and there are no
(defvar *all-threads* ())
(defvar *all-threads-lock* (make-mutex :name "all threads lock"))
+(defvar *default-alloc-signal* nil)
+
+(defmacro with-all-threads-lock (&body body)
+ `(with-system-mutex (*all-threads-lock*)
+ ,@body))
+
(defun list-all-threads ()
#!+sb-doc
- "Return a list of the live threads."
- (with-mutex (*all-threads-lock*)
+ "Return a list of the live threads. Note that the return value is
+potentially stale even before the function returns, as new threads may be
+created and old ones may exit at any time."
+ (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)))
+(declaim (inline current-thread-os-thread))
+(defun current-thread-os-thread ()
+ #!+sb-thread
+ (sap-int (sb!vm::current-thread-offset-sap sb!vm::thread-os-thread-slot))
+ #!-sb-thread
+ 0)
(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))))
+ :os-thread (current-thread-os-thread))))
(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))))
+\f
-;;;;
+;;;; Aliens, low level stuff
+
+(define-alien-routine "kill_safely"
+ integer
+ (os-thread #!-alpha unsigned-long #!+alpha unsigned-int)
+ (signal int))
#!+sb-thread
(progn
(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_blockable_signals"
- void)
-
- (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)))
+ (declaim (inline %block-deferrable-signals))
+ (define-alien-routine ("block_deferrable_signals" %block-deferrable-signals)
+ void
+ (where sb!alien:unsigned-long)
+ (old sb!alien:unsigned-long))
+
+ (defun block-deferrable-signals ()
+ (%block-deferrable-signals 0 0))
+
+ #!+sb-lutex
+ (progn
+ (declaim (inline %lutex-init %lutex-wait %lutex-wake
+ %lutex-lock %lutex-unlock))
+
+ (define-alien-routine ("lutex_init" %lutex-init)
+ int (lutex unsigned-long))
+
+ (define-alien-routine ("lutex_wait" %lutex-wait)
+ int (queue-lutex unsigned-long) (mutex-lutex unsigned-long))
+
+ (define-alien-routine ("lutex_wake" %lutex-wake)
+ int (lutex unsigned-long) (n int))
+
+ (define-alien-routine ("lutex_lock" %lutex-lock)
+ int (lutex unsigned-long))
+
+ (define-alien-routine ("lutex_trylock" %lutex-trylock)
+ int (lutex unsigned-long))
+
+ (define-alien-routine ("lutex_unlock" %lutex-unlock)
+ int (lutex unsigned-long))
+
+ (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-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))
+
+ (defun futex-wait (word old to-sec to-usec)
+ (with-interrupts
+ (%futex-wait word old to-sec to-usec)))
+
+ (define-alien-routine "futex_wake"
+ int (word unsigned-long) (n unsigned-long))))
;;; used by debug-int.lisp to access interrupt contexts
-#!-(and sb-fluid sb-thread) (declaim (inline sb!vm::current-thread-offset-sap))
+#!-(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)))
-;;;; spinlocks
+#!+sb-thread
+(defun sb!vm::current-thread-offset-sap (n)
+ (declare (type (unsigned-byte 27) n))
+ (sb!vm::current-thread-offset-sap n))
+\f
-(defstruct spinlock
- #!+sb-doc
- "Spinlock type."
- (name nil :type (or null simple-string))
- (value 0))
+;;;; 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
-(defun get-spinlock (spinlock new-value)
- (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 new-value) 0)))
+;;; Should always be called with interrupts disabled.
+(defun get-spinlock (spinlock)
+ (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 ()
+ (if (sb!ext:compare-and-swap (spinlock-value spinlock) nil new)
+ (thread-yield)
+ (return-from get-spinlock t))))
+ (if (and (not *interrupts-enabled*) *allow-with-interrupts*)
+ ;; If interrupts are disabled, but we are allowed to
+ ;; enabled them, check for pending interrupts every once
+ ;; in a while. %CHECK-INTERRUPTS is taking shortcuts, make
+ ;; sure that deferrables are unblocked by doing an empty
+ ;; WITH-INTERRUPTS once.
+ (progn
+ (with-interrupts)
+ (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 *current-thread*)
- (unwind-protect
- (progn ,@body)
- (release-spinlock ,lock)))))
-
-;;;; mutexes
-
-(defstruct mutex
- #!+sb-doc
- "Mutex type."
- (name nil :type (or null simple-string))
- (value nil))
+ (declare (optimize (speed 3) (safety 0)))
+ ;; On x86 and x86-64 we can get away with no memory barriers, (see
+ ;; Linux kernel mailing list "spin_unlock optimization(i386)"
+ ;; thread, summary at
+ ;; http://kt.iserv.nl/kernel-traffic/kt19991220_47.html#1.
+ ;;
+ ;; If the compiler may reorder this with other instructions, insert
+ ;; compiler barrier here.
+ ;;
+ ;; FIXME: this does not work on SMP Pentium Pro and OOSTORE systems,
+ ;; neither on most non-x86 architectures (but we don't have threads
+ ;; on those).
+ (setf (spinlock-value spinlock) nil))
+\f
+
+;;;; 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.")
-#!+sb-thread
-(declaim (inline mutex-value-address))
-#!+sb-thread
-(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))
+#!+(and sb-thread (not sb-lutex))
+(progn
+ (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 mutex-owner (mutex)
+ "Current owner of the mutex, NIL if the mutex is free. Naturally,
+this is racy by design (another thread may acquire the mutex after
+this function returns), it is intended for informative purposes. For
+testing whether the current thread is holding a mutex see
+HOLDING-MUTEX-P."
+ ;; Make sure to get the current value.
+ (sb!ext:compare-and-swap (mutex-%owner mutex) nil nil))
+
+(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)))
- (unless new-value
- (setq new-value *current-thread*))
+ "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*))
+ (let ((old (mutex-%owner mutex)))
+ (when (eq new-owner old)
+ (error "Recursive lock attempt ~S." mutex))
+ #!-sb-thread
+ (when old
+ (error "Strange deadlock on ~S in an unithreaded build?" mutex)))
#!-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)
+ (setf (mutex-%owner mutex) new-owner)
#!+sb-thread
- (let (old)
- (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*))
- (loop
- (unless
- (setf old (sb!vm::%instance-set-conditional mutex 2 nil new-value))
- (return t))
- (unless wait-p (return nil))
- (futex-wait (mutex-value-address mutex)
- (sb!kernel:get-lisp-obj-address old)))))
-
-(defun release-mutex (mutex)
+ (progn
+ ;; 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 waitp
+ (with-interrupts (%lutex-lock lutex))
+ (%lutex-trylock lutex))))
+ (setf (mutex-%owner mutex) new-owner)
+ t)
+ #!-sb-lutex
+ ;; This is a direct translation of the Mutex 2 algorithm from
+ ;; "Futexes are Tricky" by Ulrich Drepper.
+ (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.
+ (loop
+ (multiple-value-bind (to-sec to-usec) (decode-timeout nil)
+ (case (with-pinned-objects (mutex)
+ (futex-wait (mutex-state-address mutex)
+ (get-lisp-obj-address +lock-contested+)
+ (or to-sec -1)
+ (or to-usec 0)))
+ ((1) (signal-deadline))
+ ((2))
+ (otherwise (return))))))
+ (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 &key (if-not-owner :punt))
#!+sb-doc
"Release MUTEX by setting it to NIL. Wake up threads waiting for
-this mutex."
- (declare (type mutex mutex))
- (setf (mutex-value mutex) nil)
- #!+sb-thread
- (futex-wake (mutex-value-address mutex) 1))
+this mutex.
-;;;; waitqueues/condition variables
+RELEASE-MUTEX is not interrupt safe: interrupts should be disabled
+around calls to it.
+
+If the current thread is not the owner of the mutex then it silently
+returns without doing anything (if IF-NOT-OWNER is :PUNT), signals a
+WARNING (if IF-NOT-OWNER is :WARN), or releases the mutex anyway (if
+IF-NOT-OWNER is :FORCE)."
+ (declare (type mutex mutex))
+ ;; 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)
+ (ecase if-not-owner
+ ((:punt) (return-from release-mutex nil))
+ ((:warn)
+ (warn "Releasing ~S, owned by another thread: ~S" mutex old-owner))
+ ((:force))))
+ #!+sb-thread
+ (when old-owner
+ (setf (mutex-%owner mutex) nil)
+ #!+sb-lutex
+ (with-lutex-address (lutex (mutex-lutex mutex))
+ (%lutex-unlock lutex))
+ #!-sb-lutex
+ ;; FIXME: once ATOMIC-INCF supports struct slots with word sized
+ ;; unsigned-byte type this can be used:
+ ;;
+ ;; (let ((old (sb!ext:atomic-incf (mutex-state mutex) -1)))
+ ;; (unless (eql old +lock-free+)
+ ;; (setf (mutex-state mutex) +lock-free+)
+ ;; (with-pinned-objects (mutex)
+ ;; (futex-wake (mutex-state-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)))
+\f
+
+;;;; 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))
(defun make-waitqueue (&key name)
(%make-waitqueue :name name))
#!+sb-doc
-(setf (sb!kernel:fdocumentation 'waitqueue-name 'function)
+(setf (fdocumentation 'waitqueue-name 'function)
"The name of the waitqueue. Setfable.")
-#!+sb-thread
-(declaim (inline waitqueue-data-address))
-#!+sb-thread
-(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))))
+#!+(and sb-thread (not sb-lutex))
+(define-structure-slot-addressor waitqueue-data-address
+ :structure waitqueue
+ :slot data)
(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 MUTEX and return to the caller."
+time we reacquire MUTEX and return to the caller.
+
+Note that if CONDITION-WAIT unwinds (due to eg. a timeout) instead of
+returning normally, it may do so without holding the mutex."
#!-sb-thread (declare (ignore queue))
(assert mutex)
#!-sb-thread (error "Not supported in unithread builds.")
#!+sb-thread
- (let ((value (mutex-value mutex)))
- (unwind-protect
- (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
- (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 mutex value))))
+ (let ((me *current-thread*))
+ (assert (eq me (mutex-%owner mutex)))
+ (/show0 "CONDITION-WAITing")
+ #!+sb-lutex
+ ;; Need to disable interrupts so that we don't miss setting the
+ ;; owner on our way out. (pthread_cond_wait handles the actual
+ ;; re-acquisition.)
+ (without-interrupts
+ (unwind-protect
+ (progn
+ (setf (mutex-%owner mutex) nil)
+ (with-lutex-address (queue-lutex-address (waitqueue-lutex queue))
+ (with-lutex-address (mutex-lutex-address (mutex-lutex mutex))
+ (with-local-interrupts
+ (%lutex-wait queue-lutex-address mutex-lutex-address)))))
+ (setf (mutex-%owner mutex) me)))
+ #!-sb-lutex
+ ;; Need to disable interrupts so that we don't miss grabbing the
+ ;; mutex on our way out.
+ (without-interrupts
+ (let ((me nil))
+ ;; This setf becomes visible to other CPUS due to the usual
+ ;; memory barrier semantics of lock acquire/release. This must
+ ;; not be moved into the loop else wakeups may be lost upon
+ ;; continuing after a deadline or EINTR.
+ (setf (waitqueue-data queue) me)
+ (loop
+ (multiple-value-bind (to-sec to-usec)
+ (allow-with-interrupts (decode-timeout nil))
+ (case (unwind-protect
+ (with-pinned-objects (queue me)
+ ;; RELEASE-MUTEX is purposefully as close to
+ ;; FUTEX-WAIT as possible to reduce the size
+ ;; of the window where WAITQUEUE-DATA may be
+ ;; set by a notifier.
+ (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. We may get spurious
+ ;; wakeups, but that's ok.
+ (allow-with-interrupts
+ (futex-wait (waitqueue-data-address queue)
+ (get-lisp-obj-address me)
+ ;; our way of saying "no
+ ;; timeout":
+ (or to-sec -1)
+ (or to-usec 0))))
+ ;; 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.
+ (allow-with-interrupts (get-mutex mutex)))
+ ;; ETIMEDOUT; we know it was a timeout, yet we cannot
+ ;; signal a deadline unconditionally here because the
+ ;; call to GET-MUTEX may already have signaled it.
+ ((1))
+ ;; EINTR
+ ((2))
+ ;; EWOULDBLOCK, -1 here, is the possible spurious wakeup
+ ;; case. 0 is the normal wakeup.
+ (otherwise (return)))))))))
(defun condition-notify (queue &optional (n 1))
#!+sb-doc
- "Notify N threads waiting on QUEUE."
+ "Notify N threads waiting on QUEUE. The same mutex that is used in
+the corresponding CONDITION-WAIT must be held by this thread during
+this call."
#!-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
- (let ((me *current-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) n)))
+ #!-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)
#!+sb-doc
"Notify all threads waiting on QUEUE."
- (condition-notify queue most-positive-fixnum))
+ (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)))
+\f
-;;;; semaphores
+;;;; 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))
+ (waitcount 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))
-
-(setf (sb!kernel:fdocumentation 'semaphore-name 'function)
- "The name of the semaphore. Setfable.")
+ "Create a semaphore with the supplied COUNT and NAME."
+ (%make-semaphore name count))
-(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."
- ;; 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))
+ "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.
+ ;;
+ ;; We need to disable interrupts so that we don't forget to
+ ;; decrement the waitcount (which would happen if an asynch
+ ;; interrupt should catch us on our way out from the loop.)
+ (with-system-mutex ((semaphore-mutex semaphore) :allow-with-interrupts t)
+ ;; Quick check: is it positive? If not, enter the wait loop.
+ (let ((count (semaphore-%count semaphore)))
+ (if (plusp count)
+ (setf (semaphore-%count semaphore) (1- count))
+ (unwind-protect
+ (progn
+ (incf (semaphore-waitcount semaphore))
+ (loop until (plusp (setf count (semaphore-%count semaphore)))
+ do (condition-wait (semaphore-queue semaphore)
+ (semaphore-mutex semaphore)))
+ (setf (semaphore-%count semaphore) (1- count)))
+ ;; Need to use ATOMIC-DECF instead of DECF, as CONDITION-WAIT
+ ;; may unwind without the lock being held due to timeouts.
+ (atomic-decf (semaphore-waitcount semaphore)))))))
+
+(defun try-semaphore (semaphore)
#!+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
+ "Try to decrement the count of SEMAPHORE if the count would not be
+negative. Else return NIL."
+ ;; No need for disabling interrupts; the mutex prevents interleaved
+ ;; modifications, and we don't leave temporarily inconsistent state
+ ;; around.
+ (with-mutex ((semaphore-mutex semaphore))
+ (let ((count (semaphore-%count semaphore)))
+ (when (plusp count)
+ (setf (semaphore-%count semaphore) (1- count))))))
+
+(defun signal-semaphore (semaphore &optional (n 1))
+ #!+sb-doc
+ "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))
+ ;; Need to disable interrupts so that we don't lose a wakeup after
+ ;; we have incremented the count.
+ (with-system-mutex ((semaphore-mutex semaphore))
+ (let ((waitcount (semaphore-waitcount semaphore))
+ (count (incf (semaphore-%count semaphore) n)))
+ (when (plusp waitcount)
+ (condition-notify (semaphore-queue semaphore) (min waitcount count))))))
+\f
+
+;;;; Job control, independent listeners
(defstruct session
(lock (make-mutex :name "session lock"))
(defvar *session* nil)
-;;; the debugger itself tries to acquire the session lock, don't let
+;;; The debugger itself tries to acquire the session lock, don't let
;;; funny situations (like getting a sigint while holding the session
-;;; lock) occur
+;;; lock) occur. At the same time we need to allow interrupts while
+;;; *waiting* for the session lock for things like GET-FOREGROUND to
+;;; be interruptible.
+;;;
+;;; Take care: we sometimes need to obtain the session lock while
+;;; holding on to *ALL-THREADS-LOCK*, so we must _never_ obtain it
+;;; _after_ getting a session lock! (Deadlock risk.)
+;;;
+;;; FIXME: It would be good to have ordered locks to ensure invariants
+;;; like the above.
(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)))
+ `(with-system-mutex ((session-lock ,session) :allow-with-interrupts t)
+ ,@body))
(defun new-session ()
(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 (thread session)
(with-session-lock (session)
;;; Remove thread from its session, if it has one.
#!+sb-thread
(defun handle-thread-exit (thread)
- (with-mutex (*all-threads-lock*)
- (setq *all-threads* (delete thread *all-threads*)))
- (when *session*
- (%delete-thread-from-session thread *session*)))
+ (/show0 "HANDLING THREAD EXIT")
+ ;; 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 ()
#!+sb-doc
#!+sb-thread
(let ((was-foreground t))
(loop
+ (/show0 "Looping in GET-FOREGROUND")
(with-session-lock (*session*)
(let ((int-t (session-interactive-threads *session*)))
(when (eq (car int-t) *current-thread*)
(sb!unix::unix-setsid)
(let* ((sb!impl::*stdin*
(make-fd-stream in :input t :buffering :line
- :dual-channel-p t))
+ :dual-channel-p t))
(sb!impl::*stdout*
(make-fd-stream out :output t :buffering :line
:dual-channel-p t))
(sb!impl::toplevel-repl nil)
(sb!int:flush-standard-output-streams))))))
(make-thread #'thread-repl))))
+\f
-;;;; the beef
+;;;; 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."
+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
(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
- (let ((*current-thread* thread)
- (sb!kernel::*restart-clusters* nil)
- (sb!kernel::*handler-clusters* nil)
- (sb!kernel::*condition-restarts* nil)
- (sb!impl::*descriptor-handlers* nil)) ; serve-event
- (setf (thread-os-thread thread) (current-thread-sap-id))
- (with-mutex (*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)
- (funcall real-function))
- ;; we're going down, can't handle
- ;; interrupts sanely anymore
- (let ((sb!impl::*gc-inhibit* t))
- (block-blockable-signals)
- (setf (thread-%alive-p thread) nil)
- (setf (thread-os-thread thread) nil)
- ;; and remove what can be the last
- ;; reference to this thread
- (handle-thread-exit thread)))))))
+ (named-lambda initial-thread-function ()
+ ;; 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
+ ;;
+ ;; As it is, this lambda must not cons until we are ready
+ ;; to run GC. Be very careful.
+ (let* ((*current-thread* thread)
+ (*restart-clusters* nil)
+ (*handler-clusters* (sb!kernel::initial-handler-clusters))
+ (*condition-restarts* nil)
+ (sb!impl::*deadline* nil)
+ (sb!impl::*step-out* nil)
+ ;; internal printer variables
+ (sb!impl::*previous-case* nil)
+ (sb!impl::*previous-readtable-case* nil)
+ (sb!impl::*internal-symbol-output-fun* nil)
+ (sb!impl::*descriptor-handlers* nil)) ; serve-event
+ ;; Binding from C
+ (setf sb!vm:*alloc-signal* *default-alloc-signal*)
+ (setf (thread-os-thread thread) (current-thread-os-thread))
+ (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*))
+ (without-interrupts
+ (unwind-protect
+ (with-local-interrupts
+ ;; Now that most things have a chance
+ ;; to work properly without messing up
+ ;; other threads, it's time to enable
+ ;; signals.
+ (sb!unix::unblock-deferrable-signals)
+ (setf (thread-result thread)
+ (cons t
+ (multiple-value-list
+ (funcall real-function))))
+ ;; Try to block deferrables. An
+ ;; interrupt may unwind it, but for a
+ ;; normal exit it prevents interrupt
+ ;; loss.
+ (block-deferrable-signals))
+ ;; We're going down, can't handle interrupts
+ ;; sanely anymore. GC remains enabled.
+ (block-deferrable-signals)
+ ;; We don't want to run interrupts in a dead
+ ;; thread when we leave WITHOUT-INTERRUPTS.
+ ;; This potentially causes important
+ ;; interupts to be lost: SIGINT comes to
+ ;; mind.
+ (setq *interrupt-pending* nil)
+ (handle-thread-exit thread))))))))
(values))))
- (with-pinned-objects (initial-function)
- (let ((os-thread
- ;; don't let the child inherit *CURRENT-THREAD* because that
- ;; can prevent gc'ing this thread while the child runs
- (let ((*current-thread* nil))
+ ;; If the starting thread is stopped for gc before it signals the
+ ;; semaphore then we'd be stuck.
+ (assert (not *gc-inhibit*))
+ ;; Keep INITIAL-FUNCTION pinned until the child thread is
+ ;; initialized properly. Wrap the whole thing in
+ ;; WITHOUT-INTERRUPTS because we pass INITIAL-FUNCTION to another
+ ;; thread.
+ (without-interrupts
+ (with-pinned-objects (initial-function)
+ (let ((os-thread
(%create-thread
- (sb!kernel:get-lisp-obj-address initial-function)))))
- (when (zerop os-thread)
- (error "Can't create a new thread"))
- (wait-on-semaphore setup-sem)
- thread))))
+ (get-lisp-obj-address initial-function))))
+ (when (zerop os-thread)
+ (error "Can't create a new thread"))
+ (wait-on-semaphore setup-sem)
+ thread)))))
+
+(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-system-mutex ((thread-result-lock thread) :allow-with-interrupts t)
+ (cond ((car (thread-result thread))
+ (return-from join-thread
+ (values-list (cdr (thread-result thread)))))
+ (defaultp
+ (return-from join-thread default))))
+ (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 (sb!kernel: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)))
+ `(with-system-mutex ((thread-interruptions-lock ,thread))
+ ,@body))
-;; Called from the signal handler.
+;;; Called from the signal handler.
+#!-win32
(defun run-interruption ()
- (in-interruption ()
- (let ((interruption (with-interruptions-lock (*current-thread*)
- (pop (thread-interruptions *current-thread*)))))
- (with-interrupts
- (funcall interruption)))))
-
-;; 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.
+ (let ((interruption (with-interruptions-lock (*current-thread*)
+ (pop (thread-interruptions *current-thread*)))))
+ ;; If there is more to do, then resignal and let the normal
+ ;; interrupt deferral mechanism take care of the rest. From the
+ ;; OS's point of view the signal we are in the handler for is no
+ ;; longer pending, so the signal will not be lost.
+ (when (thread-interruptions *current-thread*)
+ (kill-safely (thread-os-thread *current-thread*) sb!unix:sigpipe))
+ (when interruption
+ (funcall interruption))))
+
(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)))))))
+won't like the effect. FUNCTION runs with interrupts disabled, but
+WITH-INTERRUPTS is allowed in it. Keep in mind that many things may
+enable interrupts (GET-MUTEX when contended, for instance) so the
+first thing to do is usually a WITH-INTERRUPTS or a
+WITHOUT-INTERRUPTS. Within a thread interrupts are queued, they are
+run in same the order they were sent."
+ #!+win32
+ (declare (ignore thread))
+ #!+win32
+ (with-interrupt-bindings
+ (with-interrupts (funcall function)))
+ #!-win32
+ (let ((os-thread (thread-os-thread thread)))
+ (cond ((not os-thread)
+ (error 'interrupt-thread-error :thread thread))
+ (t
+ (with-interruptions-lock (thread)
+ ;; Append to the end of the interruptions queue. It's
+ ;; O(N), but it does not hurt to slow interruptors down a
+ ;; bit when the queue gets long.
+ (setf (thread-interruptions thread)
+ (append (thread-interruptions thread)
+ (list (lambda ()
+ (without-interrupts
+ (allow-with-interrupts
+ (funcall function))))))))
+ (when (minusp (kill-safely os-thread sb!unix:sigpipe))
+ (error 'interrupt-thread-error :thread thread))))))
(defun terminate-thread (thread)
#!+sb-doc
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
+(define-alien-routine "thread_yield" int)
+
+#!+sb-doc
+(setf (fdocumentation 'thread-yield 'function)
+ "Yield the processor to other threads.")
+
+;;; internal use only. If you think you need to use these, 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))))
- (print os-thread)
- (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)
- (sb!kernel:make-lisp-obj tl-val))))
+(progn
+ (defun %thread-sap (thread)
+ (let ((thread-sap (alien-sap (extern-alien "all_threads" (* t))))
+ (target (thread-os-thread thread)))
+ (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 target) (return thread-sap))
+ (setf thread-sap
+ (sap-ref-sap thread-sap (* sb!vm:n-word-bytes
+ sb!vm::thread-next-slot)))))))
+
+ (defun %symbol-value-in-thread (symbol thread)
+ ;; Prevent the thread from dying completely while we look for the TLS
+ ;; area...
+ (with-all-threads-lock
+ (loop
+ (if (thread-alive-p thread)
+ (let* ((epoch sb!kernel::*gc-epoch*)
+ (offset (* sb!vm:n-word-bytes
+ (sb!vm::symbol-tls-index symbol)))
+ (tl-val (sap-ref-word (%thread-sap thread) offset)))
+ (cond ((zerop offset)
+ (return (values nil :no-tls-value)))
+ ((or (eql tl-val sb!vm:no-tls-value-marker-widetag)
+ (eql tl-val sb!vm:unbound-marker-widetag))
+ (return (values nil :unbound-in-thread)))
+ (t
+ (multiple-value-bind (obj ok) (make-lisp-obj tl-val nil)
+ ;; The value we constructed may be invalid if a GC has
+ ;; occurred. That is harmless, though, since OBJ is
+ ;; either in a register or on stack, and we are
+ ;; conservative on both on GENCGC -- so a bogus object
+ ;; is safe here as long as we don't return it. If we
+ ;; ever port threads to a non-conservative GC we must
+ ;; pin the TL-VAL address before constructing OBJ, or
+ ;; make WITH-ALL-THREADS-LOCK imply WITHOUT-GCING.
+ ;;
+ ;; The reason we don't just rely on TL-VAL pinning the
+ ;; object is that the call to MAKE-LISP-OBJ may cause
+ ;; bignum allocation, at which point TL-VAL might not
+ ;; be alive anymore -- hence the epoch check.
+ (when (eq epoch sb!kernel::*gc-epoch*)
+ (if ok
+ (return (values obj :ok))
+ (return (values obj :invalid-tls-value))))))))
+ (return (values nil :thread-dead))))))
+
+ (defun %set-symbol-value-in-thread (symbol thread value)
+ (with-pinned-objects (value)
+ ;; Prevent the thread from dying completely while we look for the TLS
+ ;; area...
+ (with-all-threads-lock
+ (if (thread-alive-p thread)
+ (let ((offset (* sb!vm:n-word-bytes
+ (sb!vm::symbol-tls-index symbol))))
+ (cond ((zerop offset)
+ (values nil :no-tls-value))
+ (t
+ (setf (sap-ref-word (%thread-sap thread) offset)
+ (get-lisp-obj-address value))
+ (values value :ok))))
+ (values nil :thread-dead))))))
+
+(defun symbol-value-in-thread (symbol thread &optional (errorp t))
+ "Return the local value of SYMBOL in THREAD, and a secondary value of T
+on success.
+
+If the value cannot be retrieved (because the thread has exited or because it
+has no local binding for NAME) and ERRORP is true signals an error of type
+SYMBOL-VALUE-IN-THREAD-ERROR; if ERRORP is false returns a primary value of
+NIL, and a secondary value of NIL.
+
+Can also be used with SETF to change the thread-local value of SYMBOL.
+
+SYMBOL-VALUE-IN-THREAD is primarily intended as a debugging tool, and not as a
+mechanism for inter-thread communication."
+ (declare (symbol symbol) (thread thread))
+ #!+sb-thread
+ (multiple-value-bind (res status) (%symbol-value-in-thread symbol thread)
+ (if (eq :ok status)
+ (values res t)
+ (if errorp
+ (error 'symbol-value-in-thread-error
+ :name symbol
+ :thread thread
+ :info (list :read status))
+ (values nil nil))))
+ #!-sb-thread
+ (if (boundp symbol)
+ (values (symbol-value symbol) t)
+ (if errorp
+ (error 'symbol-value-in-thread-error
+ :name symbol
+ :thread thread
+ :info (list :read :unbound-in-thread))
+ (values nil nil))))
+
+(defun (setf symbol-value-in-thread) (value symbol thread &optional (errorp t))
+ (declare (symbol symbol) (thread thread))
+ #!+sb-thread
+ (multiple-value-bind (res status) (%set-symbol-value-in-thread symbol thread value)
+ (if (eq :ok status)
+ (values res t)
+ (if errorp
+ (error 'symbol-value-in-thread-error
+ :name symbol
+ :thread thread
+ :info (list :write status))
+ (values nil nil))))
+ #!-sb-thread
+ (if (boundp symbol)
+ (values (setf (symbol-value symbol) value) t)
+ (if errorp
+ (error 'symbol-value-in-thread-error
+ :name symbol
+ :thread thread
+ :info (list :write :unbound-in-thread))
+ (values nil nil))))
+
+(defun sb!vm::locked-symbol-global-value-add (symbol-name delta)
+ (sb!vm::locked-symbol-global-value-add symbol-name delta))
+\f
+
+;;;; 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)))
projects / sbcl.git / blobdiff