src/hotspot/share/gc/x/xMark.inline.hpp

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#ifndef SHARE_GC_X_XMARK_INLINE_HPP
#define SHARE_GC_X_XMARK_INLINE_HPP

#include "gc/x/xMark.hpp"

#include "gc/x/xAddress.inline.hpp"
#include "gc/x/xMarkStack.inline.hpp"
#include "gc/x/xPage.inline.hpp"
#include "gc/x/xPageTable.inline.hpp"
#include "gc/x/xThreadLocalData.hpp"
#include "runtime/javaThread.hpp"
#include "utilities/debug.hpp"

// Marking before pushing helps reduce mark stack memory usage. However,
// we only mark before pushing in GC threads to avoid burdening Java threads
// with writing to, and potentially first having to clear, mark bitmaps.
//
// It's also worth noting that while marking an object can be done at any
// time in the marking phase, following an object can only be done after
// root processing has called ClassLoaderDataGraph::clear_claimed_marks(),
// since it otherwise would interact badly with claiming of CLDs.

template <bool gc_thread, bool follow, bool finalizable, bool publish>
inline void XMark::mark_object(uintptr_t addr) {
  assert(XAddress::is_marked(addr), "Should be marked");

  XPage* const page = _page_table->get(addr);
  if (page->is_allocating()) {
    // Already implicitly marked
    return;
  }

  const bool mark_before_push = gc_thread;
  bool inc_live = false;

  if (mark_before_push) {
    // Try mark object
    if (!page->mark_object(addr, finalizable, inc_live)) {
      // Already marked
      return;
    }
  } else {
    // Don't push if already marked
    if (page->is_object_marked<finalizable>(addr)) {
      // Already marked
      return;
    }
  }

  // Push
  XMarkThreadLocalStacks* const stacks = XThreadLocalData::stacks(Thread::current());
  XMarkStripe* const stripe = _stripes.stripe_for_addr(addr);
  XMarkStackEntry entry(addr, !mark_before_push, inc_live, follow, finalizable);
  stacks->push(&_allocator, &_stripes, stripe, entry, publish);
}

#endif // SHARE_GC_X_XMARK_INLINE_HPP