X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=rts%2FSTM.c;h=b9be955f55dfb5e8ebb94ee03e40ec03d1b40f3f;hp=c271a25d3cf6bbfe0c2ccd6729a7e7956bf1fe76;hb=9ecd4a3e69829f4c4ca6207043256cd40146556d;hpb=067ec969bb0bdc4c88582e53b040fa2925cbcc56

diff --git a/rts/STM.c b/rts/STM.c
index c271a25..b9be955 100644
--- a/rts/STM.c
+++ b/rts/STM.c
@@ -306,7 +306,7 @@ static StgClosure *lock_tvar(StgTRecHeader *trec,
   do {
     do {
       result = s -> current_value;
-    } while (GET_INFO(result) == &stg_TREC_HEADER_info);
+    } while (GET_INFO(UNTAG_CLOSURE(result)) == &stg_TREC_HEADER_info);
   } while (cas((void *)&(s -> current_value),
 	       (StgWord)result, (StgWord)trec) != (StgWord)result);
   return result;
@@ -388,10 +388,18 @@ static void unpark_tso(Capability *cap, StgTSO *tso) {
 
 static void unpark_waiters_on(Capability *cap, StgTVar *s) {
   StgTVarWatchQueue *q;
+  StgTVarWatchQueue *trail;
   TRACE("unpark_waiters_on tvar=%p", s);
-  for (q = s -> first_watch_queue_entry; 
-       q != END_STM_WATCH_QUEUE; 
+  // unblock TSOs in reverse order, to be a bit fairer (#2319)
+  for (q = s -> first_watch_queue_entry, trail = q;
+       q != END_STM_WATCH_QUEUE;
        q = q -> next_queue_entry) {
+    trail = q;
+  }
+  q = trail;
+  for (;
+       q != END_STM_WATCH_QUEUE; 
+       q = q -> prev_queue_entry) {
     if (watcher_is_tso(q)) {
       unpark_tso(cap, (StgTSO *)(q -> closure));
     }
@@ -1565,7 +1573,7 @@ static StgClosure *read_current_value(StgTRecHeader *trec STG_UNUSED, StgTVar *t
   result = tvar -> current_value;
 
 #if defined(STM_FG_LOCKS)
-  while (GET_INFO(result) == &stg_TREC_HEADER_info) {
+  while (GET_INFO(UNTAG_CLOSURE(result)) == &stg_TREC_HEADER_info) {
     TRACE("%p : read_current_value(%p) saw %p", trec, tvar, result);
     result = tvar -> current_value;
   }