;; 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))
+ (setf (spinlock-value spinlock) nil)
+
+ ;; FIXME: Is a :memory barrier too strong here? Can we use a :write
+ ;; barrier instead?
+ #!+(not (or x86 x86-64))
+ (barrier (:memory)))
\f
;;;; Mutexes
#!+sb-doc
"Deprecated in favor of GRAB-MUTEX."
(declare (type mutex mutex) (optimize (speed 3))
- #!-sb-thread (ignore waitp timeout)
- #!+sb-lutex (ignore timeout))
+ #!-sb-thread (ignore waitp timeout))
(unless new-owner
(setq new-owner *current-thread*))
+ (barrier (:read))
(let ((old (mutex-%owner mutex)))
(when (eq new-owner old)
(error "Recursive lock attempt ~S." mutex))
;; 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)
+ (progn
+ (when timeout
+ (error "Mutex timeouts not supported on this platform."))
+ (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)
+ (barrier (:write))
+ t))
#!-sb-lutex
;; This is a direct translation of the Mutex 2 algorithm from
;; "Futexes are Tricky" by Ulrich Drepper.
(waitp
(bug "Failed to acquire lock with WAITP."))))))
-(defun grab-mutex (mutex &key (new-owner *current-thread*)
- (waitp t) (timeout nil))
+(defun grab-mutex (mutex &key (waitp t) (timeout nil))
#!+sb-doc
- "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.
+ "Acquire MUTEX for the current thread. If WAITP is true (the default) and
+the mutex is not immediately available, sleep until it is available.
If TIMEOUT is given, it specifies a relative timeout, in seconds, on
how long GRAB-MUTEX should try to acquire the lock in the contested
-case.
+case. Unsupported on :SB-LUTEX platforms (eg. Darwin), where a non-NIL
+TIMEOUT signals an error.
If GRAB-MUTEX returns T, the lock acquisition was successful. In case
of WAITP being NIL, or an expired TIMEOUT, GRAB-MUTEX may also return
Notes:
- - Using the NEW-OWNER parameter to assign a MUTEX to another thread
- than the current one is not recommended, and liable to be
- deprecated.
-
- GRAB-MUTEX is not interrupt safe. The correct way to call it is:
(WITHOUT-INTERRUPTS
ALLOW-WITH-INTERRUPTS allows the call to be interrupted from
sleep.
- - The TIMEOUT parameter is currently only supported on non-SB-LUTEX
- platforms like Linux or BSD.
-
- (GRAB-MUTEX <mutex> :timeout 0.0) differs from
(GRAB-MUTEX <mutex> :waitp nil) in that the former may signal a
DEADLINE-TIMEOUT if the global deadline was due already on
- It is recommended that you use WITH-MUTEX instead of calling
GRAB-MUTEX directly.
"
- (get-mutex mutex new-owner waitp timeout))
+ (get-mutex mutex nil waitp timeout))
(defun release-mutex (mutex &key (if-not-owner :punt))
#!+sb-doc
#!-sb-thread (error "Not supported in unithread builds.")
#!+sb-thread
(let ((me *current-thread*))
+ (barrier (:read))
(assert (eq me (mutex-%owner mutex)))
(/show0 "CONDITION-WAITing")
#!+sb-lutex
(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)))
+ (barrier (:write)
+ (setf (mutex-%owner mutex) me))))
#!-sb-lutex
;; Need to disable interrupts so that we don't miss grabbing the
;; mutex on our way out.
projects / sbcl.git / blobdiff