X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FThreadPaused.c;h=2a3f3559966006b2435c526b93352a741ce75da5;hb=960a5edb6ac87c7d85e36f4b70be8da0175819f7;hp=3aa66edc191a858aef32056bb59860bada32b5b4;hpb=53a442f10d80cd85b33620a023c4a8749a7c0b20;p=ghc-hetmet.git

diff --git a/rts/ThreadPaused.c b/rts/ThreadPaused.c
index 3aa66ed..2a3f355 100644
--- a/rts/ThreadPaused.c
+++ b/rts/ThreadPaused.c
@@ -195,6 +195,10 @@ threadPaused(Capability *cap, StgTSO *tso)
     maybePerformBlockedException (cap, tso);
     if (tso->what_next == ThreadKilled) { return; }
 
+    // NB. Blackholing is *not* optional, we must either do lazy
+    // blackholing, or eager blackholing consistently.  See Note
+    // [upd-black-hole] in sm/Scav.c.
+
     stack_end = &tso->stack[tso->stack_size];
     
     frame = (StgClosure *)tso->sp;
@@ -231,8 +235,10 @@ threadPaused(Capability *cap, StgTSO *tso)
 			   (long)((StgPtr)frame - tso->sp));
 
 		// If this closure is already an indirection, then
-		// suspend the computation up to this point:
-		suspendComputation(cap,tso,(StgPtr)frame);
+		// suspend the computation up to this point.
+		// NB. check raiseAsync() to see what happens when
+		// we're in a loop (#2783).
+		suspendComputation(cap,tso,(StgUpdateFrame*)frame);
 
 		// Now drop the update frame, and arrange to return
 		// the value to the frame underneath:
@@ -242,14 +248,12 @@ threadPaused(Capability *cap, StgTSO *tso)
 
 		// And continue with threadPaused; there might be
 		// yet more computation to suspend.
-		threadPaused(cap,tso);
-		return;
+                frame = (StgClosure *)tso->sp + 2;
+                prev_was_update_frame = rtsFalse;
+                continue;
 	    }
 
 	    if (bh->header.info != &stg_CAF_BLACKHOLE_info) {
-#if (!defined(LAZY_BLACKHOLING)) && defined(DEBUG)
-		debugBelch("Unexpected lazy BHing required at 0x%04lx\n",(long)bh);
-#endif
 		// zero out the slop so that the sanity checker can tell
 		// where the next closure is.
 		DEBUG_FILL_SLOP(bh);
@@ -258,7 +262,7 @@ threadPaused(Capability *cap, StgTSO *tso)
 		// We pretend that bh is now dead.
 		LDV_recordDead_FILL_SLOP_DYNAMIC((StgClosure *)bh);
 #endif
-
+                // an EAGER_BLACKHOLE gets turned into a BLACKHOLE here.
 #ifdef THREADED_RTS
                 cur_bh_info = (const StgInfoTable *)
                     cas((StgVolatilePtr)&bh->header.info, 
@@ -310,7 +314,7 @@ end:
     // the number of words we have to shift down is less than the
     // number of stack words we squeeze away by doing so.
     if (RtsFlags.GcFlags.squeezeUpdFrames == rtsTrue &&
-	((weight <= 4 && words_to_squeeze > 0) || weight < words_to_squeeze)) {
+	((weight <= 5 && words_to_squeeze > 0) || weight < words_to_squeeze)) {
 	stackSqueeze(tso, (StgPtr)frame);
     }
 }