(let* ((cookie (list thread))
(info (if (thread-alive-p thread)
:running
- (multiple-value-list (join-thread thread :default cookie))))
+ (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~^, ~}~]~]"
+ (format stream
+ "~@[~S ~]~:[~A~;~A~:[ no values~; values: ~:*~{~S~^, ~}~]~]"
(thread-name thread)
(eq :finished state)
state
;; 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
#!+sb-thread
(progn
(defun sb!vm::current-thread-offset-sap (n)
(declare (type (unsigned-byte 27) n))
(sb!vm::current-thread-offset-sap n))
+\f
+
+;;;; Spinlocks
(declaim (inline get-spinlock release-spinlock))
-;; Should always be called with interrupts disabled.
+;;; Should always be called with interrupts disabled.
(defun get-spinlock (spinlock)
(declare (optimize (speed 3) (safety 0)))
(let* ((new *current-thread*)
(sb!ext:compare-and-swap (spinlock-value spinlock)
*current-thread* nil))
(error "Only the owner can release the spinlock ~S." spinlock)))
+\f
-;;;; mutexes
+;;;; Mutexes
#!+sb-doc
(setf (fdocumentation 'make-mutex 'function)
(with-pinned-objects (mutex)
(futex-wake (mutex-state-address mutex) 1))))
nil))
+\f
-;;;; waitqueues/condition variables
+;;;; Waitqueues/condition variables
(defstruct (waitqueue (:constructor %make-waitqueue))
#!+sb-doc
(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.)
+ ;; 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
(%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.
+ ;; 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?
+ ;; This setf becomes visible to other CPUS due to the
+ ;; usual memory barrier semantics of lock
+ ;; acquire/release.
(setf (waitqueue-data queue) me)
(release-mutex mutex)
- ;; Now we go to sleep using futex-wait. If anyone else
+ ;; 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.
+ ;; 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"
+ ;; our way if saying "no
+ ;; timeout":
+ (or to-sec -1)
(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.
+ ;; 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
- "Notify N threads waiting on QUEUE."
+ "Notify N threads waiting on QUEUE. The same mutex that is used in
+the correspoinding 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
#!+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.
+ ;; 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 (name %count)))
#!+sb-doc
;; 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.)
+ ;; 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)))
(progn
(incf (semaphore-waitcount semaphore))
(loop until (plusp (setf count (semaphore-%count semaphore)))
- do (condition-wait (semaphore-queue semaphore) (semaphore-mutex semaphore)))
+ do (condition-wait (semaphore-queue semaphore)
+ (semaphore-mutex semaphore)))
(setf (semaphore-%count semaphore) (1- count)))
(decf (semaphore-waitcount semaphore)))))))
"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.
+ ;; 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
+;;;; Job control, independent listeners
(defstruct session
(lock (make-mutex :name "session lock"))
;;; The debugger itself tries to acquire the session lock, don't let
;;; funny situations (like getting a sigint while holding the session
;;; 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.
+;;; *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.)
+;;; 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.
+;;; FIXME: It would be good to have ordered locks to ensure invariants
+;;; like the above.
(defmacro with-session-lock ((session) &body body)
`(with-system-mutex ((session-lock ,session) :allow-with-interrupts t)
,@body))
#!+sb-thread
(defun handle-thread-exit (thread)
(/show0 "HANDLING THREAD EXIT")
- ;; We're going down, can't handle interrupts sanely anymore.
- ;; GC remains enabled.
+ ;; We're going down, can't handle interrupts sanely anymore. GC
+ ;; remains enabled.
(block-deferrable-signals)
;; Lisp-side cleanup
(with-all-threads-lock
(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
`(with-system-mutex ((thread-interruptions-lock ,thread))
,@body))
-;; Called from the signal handler in C.
+;;; Called from the signal handler in C.
(defun run-interruption ()
(in-interruption ()
(loop
(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.
+;;; 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
(defun %symbol-value-in-thread (symbol thread)
(tagbody
- ;; Prevent the dead from dying completely while we look for the TLS area...
+ ;; 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)))
+ (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 (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)))
+ (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...
+ ;; 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)))
+ (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)))
+ (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))))
+ (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))
+\f
-;;; Stepping
+;;;; Stepping
(defun thread-stepping ()
(make-lisp-obj
projects / sbcl.git / commitdiff