[Sbcl-commits] CVS: sbcl/src/code target-thread.lisp,1.110,1.111

[Gabor M. <me...@us...>]

Update of /cvsroot/sbcl/sbcl/src/code
In directory fdv4jf1.ch3.sourceforge.com:/tmp/cvs-serv11975/src/code

Modified Files:
	target-thread.lisp 
Log Message:
1.0.26.4: less pessimal waitqueues

Readers calling CONDITION-WAIT don't interfere with each other.
CONDITION-WAIT used to set WAITQUEUE-DATA to *CURRENT-THREAD* causing
other readers entering FUTEX-WAIT to return with EWOULDBLOCK.

Set WAITQUEUE-DATA to NIL in readers, and to *CURRENT-THREAD* in
writers.

Also, fix a warning in :SEMAPHORE-MULTIPLE-WAITERS test.


Index: target-thread.lisp
===================================================================
RCS file: /cvsroot/sbcl/sbcl/src/code/target-thread.lisp,v
retrieving revision 1.110
retrieving revision 1.111
diff -u -d -r1.110 -r1.111
--- target-thread.lisp	1 Mar 2009 15:57:08 -0000	1.110
+++ target-thread.lisp	16 Mar 2009 15:59:03 -0000	1.111
@@ -328,7 +328,7 @@
       (setf (mutex-%owner mutex) new-owner)
       t)
     #!-sb-lutex
-    ;; This is a direct tranlation of the Mutex 2 algorithm from
+    ;; This is a direct translation of the Mutex 2 algorithm from
     ;; "Futexes are Tricky" by Ulrich Drepper.
     (let ((old (sb!ext:compare-and-swap (mutex-state mutex)
                                         +lock-free+
@@ -463,7 +463,7 @@
     ;; mutex on our way out.
     (without-interrupts
       (unwind-protect
-           (let ((me *current-thread*))
+           (let ((me nil))
              ;; This setf becomes visible to other CPUS due to the
              ;; usual memory barrier semantics of lock
              ;; acquire/release.
@@ -487,6 +487,8 @@
                                       (or to-usec 0))))
                   ((1) (signal-deadline))
                   ((2))
+                  ;; EWOULDBLOCK, -1 here, is the possible spurious
+                  ;; wakeup case. 0 is the normal wakeup.
                   (otherwise (return))))))
         ;; If we are interrupted while waiting, we should do these
         ;; things before returning. Ideally, in the case of an
@@ -497,7 +499,7 @@
 (defun condition-notify (queue &optional (n 1))
   #!+sb-doc
   "Notify N threads waiting on QUEUE. The same mutex that is used in
-the correspoinding condition-wait must be held by this thread during
+the corresponding 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.")