src/share/vm/code/codeCache.cpp

rev 10188 : [mq]: scavenge_nmethods_auto_prune

@@ -635,20 +635,23 @@
     }
   }
 }
 
 // Walk the list of methods which might contain non-perm oops.
-void CodeCache::scavenge_root_nmethods_do(CodeBlobClosure* f) {
+void CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure* f) {
   assert_locked_or_safepoint(CodeCache_lock);
 
   if (UseG1GC) {
     return;
   }
 
+  const bool fix_relocations = f->fix_relocations();
   debug_only(mark_scavenge_root_nmethods());
 
-  for (nmethod* cur = scavenge_root_nmethods(); cur != NULL; cur = cur->scavenge_root_link()) {
+  nmethod* prev = NULL;
+  nmethod* cur = scavenge_root_nmethods();
+  while (cur != NULL) {
     debug_only(cur->clear_scavenge_root_marked());
     assert(cur->scavenge_root_not_marked(), "");
     assert(cur->on_scavenge_root_list(), "else shouldn't be on this list");
 
     bool is_live = (!cur->is_zombie() && !cur->is_unloaded());

@@ -657,10 +660,22 @@
     }
     if (is_live) {
       // Perform cur->oops_do(f), maybe just once per nmethod.
       f->do_code_blob(cur);
     }
+    nmethod* const next = cur->scavenge_root_link();
+    // The scavengable nmethod list must contain all methods with scavengable
+    // oops. It is safe to include more nmethod on the list, but we do not
+    // expect any live non-scavengable nmethods on the list.
+    if (fix_relocations) {
+      if (!is_live || !cur->detect_scavenge_root_oops()) {
+        unlink_scavenge_root_nmethod(cur, prev);
+      } else {
+        prev = cur;
+      }
+    }
+    cur = next;
   }
 
   // Check for stray marks.
   debug_only(verify_perm_nmethods(NULL));
 }

@@ -676,32 +691,43 @@
   nm->set_scavenge_root_link(_scavenge_root_nmethods);
   set_scavenge_root_nmethods(nm);
   print_trace("add_scavenge_root", nm);
 }
 
+void CodeCache::unlink_scavenge_root_nmethod(nmethod* nm, nmethod* prev) {
+  assert_locked_or_safepoint(CodeCache_lock);
+
+  assert((prev == NULL && scavenge_root_nmethods() == nm) ||
+         (prev != NULL && prev->scavenge_root_link() == nm), "precondition");
+
+  assert(!UseG1GC, "G1 does not use the scavenge_root_nmethods list");
+
+  print_trace("unlink_scavenge_root", nm);
+  if (prev == NULL) {
+    set_scavenge_root_nmethods(nm->scavenge_root_link());
+  } else {
+    prev->set_scavenge_root_link(nm->scavenge_root_link());
+  }
+  nm->set_scavenge_root_link(NULL);
+  nm->clear_on_scavenge_root_list();
+}
+
 void CodeCache::drop_scavenge_root_nmethod(nmethod* nm) {
   assert_locked_or_safepoint(CodeCache_lock);
 
   if (UseG1GC) {
     return;
   }
 
   print_trace("drop_scavenge_root", nm);
-  nmethod* last = NULL;
-  nmethod* cur = scavenge_root_nmethods();
-  while (cur != NULL) {
-    nmethod* next = cur->scavenge_root_link();
+  nmethod* prev = NULL;
+  for (nmethod* cur = scavenge_root_nmethods(); cur != NULL; cur = cur->scavenge_root_link()) {
     if (cur == nm) {
-      if (last != NULL)
-            last->set_scavenge_root_link(next);
-      else  set_scavenge_root_nmethods(next);
-      nm->set_scavenge_root_link(NULL);
-      nm->clear_on_scavenge_root_list();
+      unlink_scavenge_root_nmethod(cur, prev);
       return;
     }
-    last = cur;
-    cur = next;
+    prev = cur;
   }
   assert(false, "should have been on list");
 }
 
 void CodeCache::prune_scavenge_root_nmethods() {

@@ -726,15 +752,11 @@
       // Keep it.  Advance 'last' to prevent deletion.
       last = cur;
     } else {
       // Prune it from the list, so we don't have to look at it any more.
       print_trace("prune_scavenge_root", cur);
-      cur->set_scavenge_root_link(NULL);
-      cur->clear_on_scavenge_root_list();
-      if (last != NULL)
-            last->set_scavenge_root_link(next);
-      else  set_scavenge_root_nmethods(next);
+      unlink_scavenge_root_nmethod(cur, last);
     }
     cur = next;
   }
 
   // Check for stray marks.