9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 
  27 #include "gc/shared/memset_with_concurrent_readers.hpp"
  28 #include "runtime/prefetch.inline.hpp"

  29 #include "utilities/debug.hpp"
  30 #include "utilities/globalDefinitions.hpp"
  31 #include "utilities/macros.hpp"
  32 
  33 #if INCLUDE_ALL_GCS
  34 
  35 // An implementation of memset, for use when there may be concurrent
  36 // readers of the region being stored into.
  37 //
  38 // We can't use the standard library memset if it is implemented using
  39 // block initializing stores.  Doing so can result in concurrent readers
  40 // seeing spurious zeros.
  41 //
  42 // We can't use the obvious C/C++ for-loop, because the compiler may
  43 // recognize the idiomatic loop and optimize it into a call to the
  44 // standard library memset; we've seen exactly this happen with, for
  45 // example, Solaris Studio 12.3.  Hence the use of inline assembly
  46 // code, hiding loops from the compiler's optimizer.
  47 //
  48 // We don't attempt to use the standard library memset when it is safe

   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 
  27 #include "gc/shared/memset_with_concurrent_readers.hpp"
  28 #include "runtime/prefetch.inline.hpp"
  29 #include "utilities/align.hpp"
  30 #include "utilities/debug.hpp"
  31 #include "utilities/globalDefinitions.hpp"
  32 #include "utilities/macros.hpp"
  33 
  34 #if INCLUDE_ALL_GCS
  35 
  36 // An implementation of memset, for use when there may be concurrent
  37 // readers of the region being stored into.
  38 //
  39 // We can't use the standard library memset if it is implemented using
  40 // block initializing stores.  Doing so can result in concurrent readers
  41 // seeing spurious zeros.
  42 //
  43 // We can't use the obvious C/C++ for-loop, because the compiler may
  44 // recognize the idiomatic loop and optimize it into a call to the
  45 // standard library memset; we've seen exactly this happen with, for
  46 // example, Solaris Studio 12.3.  Hence the use of inline assembly
  47 // code, hiding loops from the compiler's optimizer.
  48 //
  49 // We don't attempt to use the standard library memset when it is safe