X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FThreadPaused.c;h=4882ab2374b148c603661378a8c58c9b2c989816;hb=4adc53ff5eb66b6beef9b38e18f23d00de2d56b4;hp=e76d70fbd5f52b986b3e1fcf9077ebbdea4f6c37;hpb=b33fa57b919b0b315a64662b72203de68958e0a4;p=ghc-hetmet.git

diff --git a/rts/ThreadPaused.c b/rts/ThreadPaused.c
index e76d70f..4882ab2 100644
--- a/rts/ThreadPaused.c
+++ b/rts/ThreadPaused.c
@@ -50,7 +50,7 @@ stackSqueeze(StgTSO *tso, StgPtr bottom)
     current_gap_size = 0;
     gap = (struct stack_gap *) (tso->sp - sizeofW(StgUpdateFrame));
 
-    while (frame < bottom) {
+    while (frame <= bottom) {
 	
 	info = get_ret_itbl((StgClosure *)frame);
 	switch (info->i.type) {
@@ -74,7 +74,7 @@ stackSqueeze(StgTSO *tso, StgPtr bottom)
 		 * screw us up if we don't check.
 		 */
 		if (upd->updatee != updatee && !closure_IND(upd->updatee)) {
-		    UPD_IND_NOLOCK(upd->updatee, updatee);
+		    UPD_IND(upd->updatee, updatee);
 		}
 
 		// now mark this update frame as a stack gap.  The gap
@@ -178,6 +178,8 @@ threadPaused(Capability *cap, StgTSO *tso)
 {
     StgClosure *frame;
     StgRetInfoTable *info;
+    const StgInfoTable *bh_info;
+    const StgInfoTable *cur_bh_info USED_IF_THREADS;
     StgClosure *bh;
     StgPtr stack_end;
     nat words_to_squeeze = 0;
@@ -193,6 +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;
@@ -200,6 +206,11 @@ threadPaused(Capability *cap, StgTSO *tso)
     while (1) {
 	// If we've already marked this frame, then stop here.
 	if (frame->header.info == (StgInfoTable *)&stg_marked_upd_frame_info) {
+	    if (prev_was_update_frame) {
+		words_to_squeeze += sizeofW(StgUpdateFrame);
+		weight += weight_pending;
+		weight_pending = 0;
+	    }
 	    goto end;
 	}
 
@@ -212,15 +223,22 @@ threadPaused(Capability *cap, StgTSO *tso)
 	    SET_INFO(frame, (StgInfoTable *)&stg_marked_upd_frame_info);
 
 	    bh = ((StgUpdateFrame *)frame)->updatee;
+            bh_info = bh->header.info;
 
-	    if (closure_IND(bh) || bh->header.info == &stg_BLACKHOLE_info) {
+#ifdef THREADED_RTS
+        retry:
+#endif
+	    if (closure_flags[INFO_PTR_TO_STRUCT(bh_info)->type] & _IND
+                || bh_info == &stg_BLACKHOLE_info) {
 		debugTrace(DEBUG_squeeze,
 			   "suspending duplicate work: %ld words of stack",
 			   (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:
@@ -230,14 +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);
@@ -246,7 +262,20 @@ 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, 
+                        (StgWord)bh_info, 
+                        (StgWord)&stg_BLACKHOLE_info);
+
+                if (cur_bh_info != bh_info) {
+                    bh_info = cur_bh_info;
+                    goto retry;
+                }
+#else
 		SET_INFO(bh,&stg_BLACKHOLE_info);
+#endif
 
 		// We pretend that bh has just been created.
 		LDV_RECORD_CREATE(bh);
@@ -285,7 +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 < words_to_squeeze) {
+	((weight <= 5 && words_to_squeeze > 0) || weight < words_to_squeeze)) {
 	stackSqueeze(tso, (StgPtr)frame);
     }
 }