Mark/compact: use a dynamically-sized mark stack, and don't do linear scan

[ghc-hetmet.git] / rts / sm / Scav.c

diff --git a/rts/sm/Scav.c b/rts/sm/Scav.c
index 4c75ed2..5e38777 100644 (file)
--- a/rts/sm/Scav.c
+++ b/rts/sm/Scav.c
@@ -19,6 +19,7 @@
 #include "GCThread.h"
 #include "GCUtils.h"
 #include "Compact.h"
+#include "MarkStack.h"
 #include "Evac.h"
 #include "Scav.h"
 #include "Apply.h"
@@ -740,9 +741,7 @@ scavenge_mark_stack(void)
     gct->evac_step = &oldest_gen->steps[0];
     saved_evac_step = gct->evac_step;
 
-linear_scan:
-    while (!mark_stack_empty()) {
-       p = pop_mark_stack();
+    while ((p = pop_mark_stack())) {
 
        ASSERT(LOOKS_LIKE_CLOSURE_PTR(p));
        info = get_itbl((StgClosure *)p);
@@ -1055,49 +1054,7 @@ linear_scan:
                recordMutableGen_GC((StgClosure *)q, gct->evac_step->gen_no);
            }
        }
-       
-       // mark the next bit to indicate "scavenged"
-       mark(q+1, Bdescr(q));
-
-    } // while (!mark_stack_empty())
-
-    // start a new linear scan if the mark stack overflowed at some point
-    if (mark_stack_overflowed && oldgen_scan_bd == NULL) {
-       debugTrace(DEBUG_gc, "scavenge_mark_stack: starting linear scan");
-       mark_stack_overflowed = rtsFalse;
-       oldgen_scan_bd = oldest_gen->steps[0].old_blocks;
-       oldgen_scan = oldgen_scan_bd->start;
-    }
-
-    if (oldgen_scan_bd) {
-       // push a new thing on the mark stack
-    loop:
-       // find a closure that is marked but not scavenged, and start
-       // from there.
-       while (oldgen_scan < oldgen_scan_bd->free 
-              && !is_marked(oldgen_scan,oldgen_scan_bd)) {
-           oldgen_scan++;
-       }
-
-       if (oldgen_scan < oldgen_scan_bd->free) {
-
-           // already scavenged?
-           if (is_marked(oldgen_scan+1,oldgen_scan_bd)) {
-               oldgen_scan += sizeofW(StgHeader) + MIN_PAYLOAD_SIZE;
-               goto loop;
-           }
-           push_mark_stack(oldgen_scan);
-           // ToDo: bump the linear scan by the actual size of the object
-           oldgen_scan += sizeofW(StgHeader) + MIN_PAYLOAD_SIZE;
-           goto linear_scan;
-       }
-
-       oldgen_scan_bd = oldgen_scan_bd->link;
-       if (oldgen_scan_bd != NULL) {
-           oldgen_scan = oldgen_scan_bd->start;
-           goto loop;
-       }
-    }
+    } // while (p = pop_mark_stack())
 }
 
 /* -----------------------------------------------------------------------------
@@ -1964,8 +1921,7 @@ loop:
     }
     
     // scavenge objects in compacted generation
-    if (mark_stack_overflowed || oldgen_scan_bd != NULL ||
-       (mark_stack_bdescr != NULL && !mark_stack_empty())) {
+    if (mark_stack_bd != NULL && !mark_stack_empty()) {
        scavenge_mark_stack();
        work_to_do = rtsTrue;
     }