PERFORCE change 12066 for review

[Arthur Bergman]

Change 12066 by sky@sky-titanic on 2001/09/18 10:24:31

        Changed how ownership of mutexes are held. We never hold a mutex only a slot 
indicating that we own the lock.

Affected files ...

... //depot/perl/sharedsv.c#5 edit
... //depot/perl/sharedsv.h#3 edit

Differences ...

==== //depot/perl/sharedsv.c#5 (text) ====
Index: perl/sharedsv.c
--- perl/sharedsv.c.~1~ Tue Sep 18 04:30:05 2001
+++ perl/sharedsv.c     Tue Sep 18 04:30:05 2001
@@ -63,6 +63,8 @@
     New(2555,ssv,1,shared_sv);
     MUTEX_INIT(&ssv->mutex);
     COND_INIT(&ssv->cond);
+    COND_INIT(&ssv->user_cond);
+    ssv->owner = 0;
     ssv->locks = 0;
     return ssv;
 }
@@ -97,15 +99,19 @@
 {
     if(!ssv)
         return;
+    MUTEX_LOCK(&ssv->mutex);
     if(ssv->owner && ssv->owner == my_perl) {
         ssv->locks++;
+       MUTEX_UNLOCK(&ssv->mutex);
         return;
     }
-    MUTEX_LOCK(&ssv->mutex);
+    while(ssv->owner) 
+      COND_WAIT(&ssv->cond,&ssv->mutex);
     ssv->locks++;
     ssv->owner = my_perl;
     if(ssv->locks == 1)
         SAVEDESTRUCTOR_X(Perl_sharedsv_unlock_scope,ssv);
+    MUTEX_UNLOCK(&ssv->mutex);
 }
 
 /*
@@ -119,22 +125,31 @@
 void
 Perl_sharedsv_unlock(pTHX_ shared_sv* ssv)
 {
-    if(ssv->owner != my_perl)
+    MUTEX_LOCK(&ssv->mutex);
+    if(ssv->owner != my_perl) {
+        Perl_croak(aTHX_ "panic: Perl_sharedsv_unlock unlocking mutex that we don't 
+own");
+        MUTEX_UNLOCK(&ssv->mutex); 
         return;
+    } 
 
     if(--ssv->locks == 0) {
         ssv->owner = NULL;
-        MUTEX_UNLOCK(&ssv->mutex);
+       COND_SIGNAL(&ssv->cond);
     }
+    MUTEX_UNLOCK(&ssv->mutex);
  }
 
 void
 Perl_sharedsv_unlock_scope(pTHX_ shared_sv* ssv)
 {
-    if(ssv->owner != my_perl)
+    MUTEX_LOCK(&ssv->mutex);
+    if(ssv->owner != my_perl) {
+        MUTEX_UNLOCK(&ssv->mutex);
         return;
+    }
     ssv->locks = 0;
     ssv->owner = NULL;
+    COND_SIGNAL(&ssv->cond);
     MUTEX_UNLOCK(&ssv->mutex);
 }
 
@@ -199,3 +214,4 @@
 }
 
 #endif /* USE_ITHREADS */
+

==== //depot/perl/sharedsv.h#3 (text) ====
Index: perl/sharedsv.h
--- perl/sharedsv.h.~1~ Tue Sep 18 04:30:05 2001
+++ perl/sharedsv.h     Tue Sep 18 04:30:05 2001
@@ -5,6 +5,7 @@
     SV*              sv;    /* The actual data */
     perl_mutex       mutex; /* Our mutex */
     perl_cond        cond;  /* Our condition variable */
+    perl_cond        user_cond;  /* For user level conditions */
     IV               locks; /* Number of locks held */
     PerlInterpreter* owner; /* who owns the lock */
 } shared_sv;
End of Patch.