Do not disable parallel mark for WRAP_MARK_SOME

Issue #179 (bdwgc).

Now, if there is a chance of unmapping of root segments, the latter
ones are scanned immediately by GC_push_roots thus preventing memory
protection faults in GC_mark_local.

* include/private/gc_priv.h (GC_PUSH_CONDITIONAL): Move definition to
mark_rts.c.
* include/private/gcconfig.h [WRAP_MARK_SOME && PARALLEL_MARK]
(PARALLEL_MARK): Do not undefine; remove TODO item.
* mark.c [WRAP_MARK_SOME && PARALLEL_MARK] (GC_push_conditional_eager):
New internal function; add TODO item.
* mark_rts.c [WRAP_MARK_SOME && PARALLEL_MARK]
(GC_push_conditional_eager): Declare function.
* mark_rts.c [WRAP_MARK_SOME && PARALLEL_MARK] (GC_PUSH_CONDITIONAL):
Define to GC_push_conditional_eager if GC_parallel.

diff --git a/include/private/gc_priv.h b/include/private/gc_priv.h
index 3a6eca6..215a6fa 100644 (file)
--- a/include/private/gc_priv.h
+++ b/include/private/gc_priv.h
@@ -1657,15 +1657,6 @@ GC_INNER void GC_initiate_gc(void);
 GC_INNER GC_bool GC_collection_in_progress(void);
                         /* Collection is in progress, or was abandoned. */
 
-#ifndef GC_DISABLE_INCREMENTAL
-# define GC_PUSH_CONDITIONAL(b, t, all) \
-                GC_push_conditional((ptr_t)(b), (ptr_t)(t), all)
-                        /* Do either of GC_push_all or GC_push_selected */
-                        /* depending on the third arg.                  */
-#else
-# define GC_PUSH_CONDITIONAL(b, t, all) GC_push_all((ptr_t)(b), (ptr_t)(t))
-#endif
-
 #define GC_PUSH_ALL_SYM(sym) \
                 GC_push_all((ptr_t)&(sym), (ptr_t)&(sym) + sizeof(sym))
 

diff --git a/include/private/gcconfig.h b/include/private/gcconfig.h
index e217d9a..33b482c 100644 (file)
--- a/include/private/gcconfig.h
+++ b/include/private/gcconfig.h
@@ -3007,11 +3007,6 @@
 # define WRAP_MARK_SOME
 #endif
 
-#if defined(WRAP_MARK_SOME) && defined(PARALLEL_MARK)
-  /* TODO: GC_mark_local does not handle memory protection faults yet.  */
-# undef PARALLEL_MARK
-#endif
-
 #if defined(PARALLEL_MARK) && !defined(DEFAULT_STACK_MAYBE_SMALL) \
     && (defined(HPUX) || defined(GC_DGUX386_THREADS) \
         || defined(NO_GETCONTEXT) /* e.g. musl */)

diff --git a/mark.c b/mark.c
index 28fea0e..abdb9a2 100644 (file)
--- a/mark.c
+++ b/mark.c
@@ -1628,6 +1628,35 @@ GC_INNER void GC_push_all_stack(ptr_t bottom, ptr_t top)
 # endif
 }
 
+#if defined(WRAP_MARK_SOME) && defined(PARALLEL_MARK)
+  /* Similar to GC_push_conditional but scans the whole region immediately. */
+  GC_INNER void GC_push_conditional_eager(ptr_t bottom, ptr_t top,
+                                          GC_bool all)
+                        GC_ATTR_NO_SANITIZE_ADDR GC_ATTR_NO_SANITIZE_MEMORY
+  {
+    word * b = (word *)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
+    word * t = (word *)(((word) top) & ~(ALIGNMENT-1));
+    register word *p;
+    register word *lim;
+    register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
+    register ptr_t least_ha = GC_least_plausible_heap_addr;
+#   define GC_greatest_plausible_heap_addr greatest_ha
+#   define GC_least_plausible_heap_addr least_ha
+
+    if (top == NULL)
+      return;
+    (void)all; /* TODO: If !all then scan only dirty pages. */
+
+    lim = t - 1;
+    for (p = b; (word)p <= (word)lim; p = (word *)((ptr_t)p + ALIGNMENT)) {
+      register word q = *p;
+      GC_PUSH_ONE_HEAP(q, p, GC_mark_stack_top);
+    }
+#   undef GC_greatest_plausible_heap_addr
+#   undef GC_least_plausible_heap_addr
+  }
+#endif /* WRAP_MARK_SOME && PARALLEL_MARK */
+
 #if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES) && \
     defined(MARK_BIT_PER_GRANULE)
 # if GC_GRANULE_WORDS == 1

diff --git a/mark_rts.c b/mark_rts.c
index eb2e0e9..00d5450 100644 (file)
--- a/mark_rts.c
+++ b/mark_rts.c
@@ -497,6 +497,24 @@ GC_API void GC_CALL GC_exclude_static_roots(void *b, void *e)
     UNLOCK();
 }
 
+#if defined(WRAP_MARK_SOME) && defined(PARALLEL_MARK)
+  /* GC_mark_local does not handle memory protection faults yet.  So,   */
+  /* the static data regions are scanned immediately by GC_push_roots.  */
+  GC_INNER void GC_push_conditional_eager(ptr_t bottom, ptr_t top,
+                                          GC_bool all);
+# define GC_PUSH_CONDITIONAL(b, t, all) \
+                (GC_parallel \
+                    ? GC_push_conditional_eager(b, t, all) \
+                    : GC_push_conditional((ptr_t)(b), (ptr_t)(t), all))
+#elif defined(GC_DISABLE_INCREMENTAL)
+# define GC_PUSH_CONDITIONAL(b, t, all) GC_push_all((ptr_t)(b), (ptr_t)(t))
+#else
+# define GC_PUSH_CONDITIONAL(b, t, all) \
+                GC_push_conditional((ptr_t)(b), (ptr_t)(t), all)
+                        /* Do either of GC_push_all or GC_push_selected */
+                        /* depending on the third arg.                  */
+#endif
+
 /* Invoke push_conditional on ranges that are not excluded. */
 STATIC void GC_push_conditional_with_exclusions(ptr_t bottom, ptr_t top,
                                                 GC_bool all GC_ATTR_UNUSED)