(defun get-spinlock (lock offset new-value)
(declare (optimize (speed 3) (safety 0)))
+ ;; %instance-set-conditional can test for 0 (which is a fixnum) and
+ ;; store any value
(loop until
- (eql (sb!vm::%instance-set-conditional lock offset 0 new-value) 0)))
+ (eql (sb!vm::%instance-set-conditional lock offset 0 new-value) 0)))
-;; this should do nothing if we didn't own the lock, so safe to use in
-;; unwind-protect cleanups when lock acquisition failed for some reason
-(defun release-spinlock (lock offset our-value)
+(defun release-spinlock (lock offset)
(declare (optimize (speed 3) (safety 0)))
- (sb!vm::%instance-set-conditional lock offset our-value 0))
+ ;; %instance-set-conditional cannot compare arbitrary objects
+ ;; meaningfully, so
+ ;; (sb!vm::%instance-set-conditional lock offset our-value 0)
+ ;; does not work for bignum thread ids.
+ (sb!vm::%instance-set lock offset 0))
(defmacro with-spinlock ((queue) &body body)
(with-unique-names (pid)
(progn
(get-spinlock ,queue 2 ,pid)
,@body)
- (release-spinlock ,queue 2 ,pid)))))
+ (release-spinlock ,queue 2)))))
;;;; the higher-level locking operations are based on waitqueues