"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)
+ (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
(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)
- `(call-with-system-mutex (lambda () ,@body) *all-threads-lock*))
+ `(with-system-mutex (*all-threads-lock*)
+ ,@body))
(defun list-all-threads ()
#!+sb-doc
(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 ()
+(declaim (inline current-thread-os-thread))
+(defun current-thread-os-thread ()
(sap-int
(sb!vm::current-thread-offset-sap sb!vm::thread-os-thread-slot)))
(/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
(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 (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 enabled, but we are allowed to enabled them,
;; check for pending interrupts every once in a while.
(assert mutex)
#!-sb-thread (error "Not supported in unithread builds.")
#!+sb-thread
- (let ((owner (mutex-%owner mutex)))
+ (let ((me *current-thread*))
+ (assert (eq me (mutex-%owner mutex)))
(/show0 "CONDITION-WAITing")
#!+sb-lutex
- (progn
- ;; 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-%owner mutex) owner))
+ ;; 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
- (unwind-protect
- (let ((me *current-thread*))
- ;; 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. 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 owner))))
+ ;; Need to disable interrupts so that we don't miss grabbing the mutex
+ ;; on our way out.
+ (without-interrupts
+ (unwind-protect
+ (let ((me *current-thread*))
+ ;; 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. 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)
+ (allow-with-interrupts
+ (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)))))
(defun condition-notify (queue &optional (n 1))
#!+sb-doc
future."
(name nil :type (or null simple-string))
(%count 0 :type (integer 0))
+ (waitcount 0 :type (integer 0))
(mutex (make-mutex))
(queue (make-waitqueue)))
#!+sb-doc
"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 semaphore))
- (loop until (> (semaphore-%count semaphore) 0)
- do (condition-wait (semaphore-queue semaphore) (semaphore-mutex semaphore))
- finally (decf (semaphore-%count semaphore)))))
+ ;; 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)))
+ (decf (semaphore-waitcount semaphore)))))))
(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))
- (with-mutex ((semaphore-mutex semaphore))
- (when (= n (incf (semaphore-%count semaphore) n))
- (condition-notify (semaphore-queue semaphore) 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))))))
;;;; job control, independent listeners
(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)
- `(call-with-system-mutex (lambda () ,@body) (session-lock ,session)))
+ `(with-system-mutex ((session-lock ,session) :allow-with-interrupts t)
+ ,@body))
(defun new-session ()
(make-session :threads (list *current-thread*)
;; 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))
+ (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)
+ (empty (vector))
+ (sb!impl::*merge-sort-temp-vector* empty)
+ (sb!impl::*zap-array-data-temp* empty)
+ (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*))
"The thread that was not interrupted.")
(defmacro with-interruptions-lock ((thread) &body body)
- `(call-with-system-mutex (lambda () ,@body) (thread-interruptions-lock ,thread)))
+ `(with-system-mutex ((thread-interruptions-lock ,thread))
+ ,@body))
;; Called from the signal handler in C.
(defun run-interruption ()
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))))
- (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))))
+(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)
+ (tagbody
+ ;; Prevent the dead 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)))
+ (tl-val (sap-ref-word (%thread-sap thread) offset)))
+ (if (eql tl-val sb!vm::no-tls-value-marker-widetag)
+ (go :unbound)
+ (return-from %symbol-value-in-thread (values (make-lisp-obj tl-val) t))))
+ (return-from %symbol-value-in-thread (values nil nil))))
+ :unbound
+ (error "Cannot read thread-local symbol value: ~S unbound in ~S" symbol thread)))
+
+ (defun %set-symbol-value-in-thread (symbol thread value)
+ (tagbody
+ (with-pinned-objects (value)
+ ;; Prevent the dead 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)))
+ (sap (%thread-sap thread))
+ (tl-val (sap-ref-word sap offset)))
+ (if (eql tl-val sb!vm::no-tls-value-marker-widetag)
+ (go :unbound)
+ (setf (sap-ref-word sap offset) (get-lisp-obj-address value)))
+ (return-from %set-symbol-value-in-thread (values value t)))
+ (return-from %set-symbol-value-in-thread (values nil nil)))))
+ :unbound
+ (error "Cannot set thread-local symbol value: ~S unbound in ~S" symbol thread))))
(defun sb!vm::locked-symbol-global-value-add (symbol-name delta)
(sb!vm::locked-symbol-global-value-add symbol-name delta))
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