X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Ftarget-thread.lisp;h=67ef209c7ab662ec63836ed3f47e6e9e712f48e2;hb=ad3beba970fab6e451a461c9f9b14faf4ef17718;hp=dd25ecbbce9595f49501c954a98ded9342935dfe;hpb=bb756e3d4b19c30d4a9cd4250b606c5969613ad9;p=sbcl.git

diff --git a/src/code/target-thread.lisp b/src/code/target-thread.lisp
index dd25ecb..67ef209 100644
--- a/src/code/target-thread.lisp
+++ b/src/code/target-thread.lisp
@@ -1,5 +1,4 @@
-;;;; support for threads in the target machine common to uni- and
-;;;; multithread systems
+;;;; support for threads in the target machine
 
 ;;;; This software is part of the SBCL system. See the README file for
 ;;;; more information.
@@ -12,10 +11,23 @@
 
 (in-package "SB!THREAD")
 
+;;; set the doc here because in early-thread FDOCUMENTATION is not
+;;; available, yet
+#!+sb-doc
+(setf (sb!kernel: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
   %sap)
 
+#!+sb-doc
+(setf (sb!kernel:fdocumentation 'thread-name 'function)
+      "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)
@@ -50,6 +62,8 @@
 	    (:dead #.(sb!vm:fixnumize 3))))))
 
 (defun thread-alive-p (thread)
+  #!+sb-doc
+  "Check if THREAD is running."
   (not (eq :dead (thread-state thread))))
 
 ;; A thread is eligible for gc iff it has finished and there are no
@@ -59,6 +73,8 @@
 (defvar *all-threads-lock* (make-mutex :name "all threads lock"))
 
 (defun list-all-threads ()
+  #!+sb-doc
+  "Return a list of the live threads."
   (with-mutex (*all-threads-lock*)
     (copy-list *all-threads*)))
 
@@ -79,3 +95,497 @@
     ;; in case we are in reinit since saving core with multiple
     ;; threads doesn't work.
     (setq *all-threads* (list initial-thread))))
+
+;;;;
+
+#!+sb-thread
+(progn
+  (define-alien-routine ("create_thread" %create-thread)
+      system-area-pointer
+    (lisp-fun-address unsigned-long))
+
+  (define-alien-routine reap-dead-thread void
+    (thread-sap system-area-pointer))
+
+  (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)))
+
+;;; used by debug-int.lisp to access interrupt contexts
+#!-(and 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))
+  (sb!sys:sap-ref-sap (alien-sap (extern-alien "all_threads" (* t)))
+               (* n sb!vm:n-word-bytes)))
+
+;;;; spinlocks
+
+(defstruct spinlock
+  #!+sb-doc
+  "Spinlock type."
+  (name nil :type (or null simple-string))
+  (value 0))
+  
+(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)))
+
+(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))
+
+#!+sb-doc
+(setf (sb!kernel: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.")
+
+#!+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 (wait-p 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 (setf 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)
+  #!+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)
+  #!+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))
+
+;;;; waitqueues/condition variables
+
+(defstruct (waitqueue (:constructor %make-waitqueue))
+  #!+sb-doc
+  "Waitqueue type."
+  (name nil :type (or null simple-string))
+  (data nil))
+
+(defun make-waitqueue (&key name)
+  #!+sb-doc
+  "Create a waitqueue."
+  (%make-waitqueue :name name))
+
+#!+sb-doc
+(setf (sb!kernel: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))))
+
+(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."
+  #!-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))))
+
+(defun condition-notify (queue)
+  #!+sb-doc
+  "Notify one of the threads waiting on QUEUE."
+  #!-sb-thread (declare (ignore queue))
+  #!-sb-thread (error "Not supported in unithread builds.")
+  #!+sb-thread
+  (let ((me *current-thread*))
+    ;; 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) 1)))
+
+(defun condition-broadcast (queue)
+  #!+sb-doc
+  "Notify all threads waiting on QUEUE."
+  #!-sb-thread (declare (ignore queue))
+  #!-sb-thread (error "Not supported in unithread builds.")
+  #!+sb-thread
+  (let ((me *current-thread*))
+    (setf (waitqueue-data queue) me)
+    (futex-wake (waitqueue-data-address queue) (ash 1 30))))
+
+;;;; job control, independent listeners
+
+(defstruct session
+  (lock (make-mutex :name "session lock"))
+  (threads nil)
+  (interactive-threads nil)
+  (interactive-threads-queue (make-waitqueue)))
+
+(defvar *session* nil)
+
+;;; the debugger itself tries to acquire the session lock, don't let
+;;; 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
+  `(sb!sys:without-interrupts
+    (with-mutex ((session-lock ,session))
+      ,@body)))
+
+(defun new-session ()
+  (make-session :threads (list *current-thread*)
+                :interactive-threads (list *current-thread*)))
+
+(defun init-job-control ()
+  (setf *session* (new-session)))
+
+(defun %delete-thread-from-session (thread session)
+  (with-session-lock (session)
+    (setf (session-threads session)
+          (delete thread (session-threads session))
+          (session-interactive-threads session)
+          (delete thread (session-interactive-threads session)))))
+
+(defun call-with-new-session (fn)
+  (%delete-thread-from-session *current-thread* *session*)
+  (let ((*session* (new-session)))
+    (funcall fn)))
+
+(defmacro with-new-session (args &body forms)
+  (declare (ignore args))               ;for extensibility
+  (sb!int:with-unique-names (fb-name)
+    `(labels ((,fb-name () ,@forms))
+      (call-with-new-session (function ,fb-name)))))
+
+;;; 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*)))
+
+(defun terminate-session ()
+  #!+sb-doc
+  "Kill all threads in session except for this one.  Does nothing if current
+thread is not the foreground thread."
+  ;; FIXME: threads created in other threads may escape termination
+  (let ((to-kill
+         (with-session-lock (*session*)
+           (and (eq *current-thread*
+                    (car (session-interactive-threads *session*)))
+                (session-threads *session*)))))
+    ;; do the kill after dropping the mutex; unwind forms in dying
+    ;; threads may want to do session things
+    (dolist (thread to-kill)
+      (unless (eq thread *current-thread*)
+        ;; terminate the thread but don't be surprised if it has
+        ;; exited in the meantime
+        (handler-case (terminate-thread thread)
+          (interrupt-thread-error ()))))))
+
+;;; called from top of invoke-debugger
+(defun debugger-wait-until-foreground-thread (stream)
+  "Returns T if thread had been running in background, NIL if it was
+interactive."
+  (declare (ignore stream))
+  #!-sb-thread nil
+  #!+sb-thread
+  (prog1
+      (with-session-lock (*session*)
+        (not (member *current-thread*
+                     (session-interactive-threads *session*))))
+    (get-foreground)))
+
+(defun get-foreground ()
+  #!-sb-thread t
+  #!+sb-thread
+  (let ((was-foreground t))
+    (loop
+     (with-session-lock (*session*)
+       (let ((int-t (session-interactive-threads *session*)))
+         (when (eq (car int-t) *current-thread*)
+           (unless was-foreground
+             (format *query-io* "Resuming thread ~A~%" *current-thread*))
+           (return-from get-foreground t))
+         (setf was-foreground nil)
+         (unless (member *current-thread* int-t)
+           (setf (cdr (last int-t))
+                 (list *current-thread*)))
+         (condition-wait
+          (session-interactive-threads-queue *session*)
+          (session-lock *session*)))))))
+
+(defun release-foreground (&optional next)
+  #!+sb-doc
+  "Background this thread.  If NEXT is supplied, arrange for it to
+have the foreground next"
+  #!-sb-thread (declare (ignore next))
+  #!-sb-thread nil
+  #!+sb-thread
+  (with-session-lock (*session*)
+    (setf (session-interactive-threads *session*)
+          (delete *current-thread* (session-interactive-threads *session*)))
+    (when next
+      (setf (session-interactive-threads *session*)
+            (list* next
+                   (delete next (session-interactive-threads *session*)))))
+    (condition-broadcast (session-interactive-threads-queue *session*))))
+
+(defun foreground-thread ()
+  (car (session-interactive-threads *session*)))
+
+(defun make-listener-thread (tty-name)
+  (assert (probe-file tty-name))
+  (let* ((in (sb!unix:unix-open (namestring tty-name) sb!unix:o_rdwr #o666))
+         (out (sb!unix:unix-dup in))
+         (err (sb!unix:unix-dup in)))
+    (labels ((thread-repl ()
+               (sb!unix::unix-setsid)
+               (let* ((sb!impl::*stdin*
+                       (sb!sys:make-fd-stream in :input t :buffering :line
+                                              :dual-channel-p t))
+                      (sb!impl::*stdout*
+                       (sb!sys:make-fd-stream out :output t :buffering :line
+                                              :dual-channel-p t))
+                      (sb!impl::*stderr*
+                       (sb!sys:make-fd-stream err :output t :buffering :line
+                                              :dual-channel-p t))
+                      (sb!impl::*tty*
+                       (sb!sys:make-fd-stream err :input t :output t
+                                              :buffering :line
+                                              :dual-channel-p t))
+                      (sb!impl::*descriptor-handlers* nil))
+                 (with-new-session ()
+                   (unwind-protect
+                        (sb!impl::toplevel-repl nil)
+                     (sb!int:flush-standard-output-streams))))))
+      (make-thread #'thread-repl))))
+
+;;;; 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."
+  #!-sb-thread (declare (ignore function name))
+  #!-sb-thread (error "Not supported in unithread builds.")
+  #!+sb-thread
+  (let* ((thread (%make-thread :name name))
+         (setup-p nil)
+         (real-function (coerce function 'function))
+         (thread-sap
+          (%create-thread
+           (sb!kernel:get-lisp-obj-address
+            (lambda ()
+              ;; FIXME: use semaphores?
+              (loop until setup-p)
+              ;; 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
+                    (sb!impl::*available-buffers* nil)) ;for fd-stream
+                ;; 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)
+                (unwind-protect
+                     (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*))
+                           ;; 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)
+                           (unwind-protect
+                                (funcall real-function)
+                             ;; we're going down, can't handle
+                             ;; interrupts sanely anymore
+                             (sb!unix::block-blockable-signals)))))
+                  ;; mark the thread dead, so that the gc does not
+                  ;; wait for it to handle sig-stop-for-gc
+                  (%set-thread-state thread :dead)
+                  ;; and remove what can be the last reference to
+                  ;; the thread object
+                  (handle-thread-exit thread)
+                  0))
+              (values))))))
+    (when (sb!sys:sap= thread-sap (sb!sys:int-sap 0))
+      (error "Can't create a new thread"))
+    (setf (thread-%sap thread) thread-sap)
+    (with-mutex (*all-threads-lock*)
+      (push thread *all-threads*))
+    (with-session-lock (*session*)
+      (push thread (session-threads *session*)))
+    (setq setup-p t)
+    (sb!impl::finalize thread (lambda () (reap-dead-thread thread-sap)))
+    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)
+   (errno :reader interrupt-thread-error-errno :initarg :errno))
+  #!+sb-doc
+  (:documentation "Interrupting thread failed.")
+  (:report (lambda (c s)
+             (format s "interrupt thread ~A failed (~A: ~A)"
+                     (interrupt-thread-error-thread c)
+                     (interrupt-thread-error-errno c)
+                     (strerror (interrupt-thread-error-errno c))))))
+
+#!+sb-doc
+(setf (sb!kernel:fdocumentation 'interrupt-thread-error-thread 'function)
+      "The thread that was not interrupted."
+      (sb!kernel:fdocumentation 'interrupt-thread-error-errno 'function)
+      "The reason why the interruption failed.")
+
+(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
+  (let ((function (coerce function 'function)))
+    (multiple-value-bind (res err)
+        (sb!unix::syscall ("interrupt_thread"
+                           system-area-pointer sb!alien:unsigned-long)
+                          thread
+                          (thread-%sap thread)
+                          (sb!kernel:get-lisp-obj-address function))
+      (unless res
+        (error 'interrupt-thread-error :thread thread :errno err)))))
+
+(defun terminate-thread (thread)
+  #!+sb-doc
+  "Terminate the thread identified by THREAD, by causing it to run
+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
+;;; 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 symbol-value-in-thread (symbol thread)
+  (let ((thread-sap (thread-%sap thread)))
+    (let* ((index (sb!vm::symbol-tls-index symbol))
+           (tl-val (sb!sys:sap-ref-word thread-sap
+                                        (* sb!vm:n-word-bytes index))))
+      (if (eql tl-val sb!vm::unbound-marker-widetag)
+          (sb!vm::symbol-global-value symbol)
+          (sb!kernel:make-lisp-obj tl-val)))))