third_party/tcmalloc/chromium/src/base/spinlock_posix-inl.h

   1 /* Copyright (c) 2009, Google Inc.
   2  * All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  *     * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
  13  * distribution.
  14  *     * Neither the name of Google Inc. nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * ---
  31  * This file is a Posix-specific part of spinlock_internal.cc
  32  */
  33
  34 #include <config.h>
  35 #include <errno.h>
  36 #ifdef HAVE_SCHED_H
  37 #include <sched.h>      /* For sched_yield() */
  38 #endif
  39 #include <time.h>       /* For nanosleep() */
  40
  41 namespace base {
  42 namespace internal {
  43
  44 void SpinLockDelay(volatile Atomic32 *w, int32 value, int loop) {
  45   int save_errno = errno;
  46   if (loop == 0) {
  47   } else if (loop == 1) {
  48     sched_yield();
  49   } else {
  50     struct timespec tm;
  51     tm.tv_sec = 0;
  52     tm.tv_nsec = base::internal::SuggestedDelayNS(loop);
  53     nanosleep(&tm, NULL);
  54   }
  55   errno = save_errno;
  56 }
  57
  58 void SpinLockWake(volatile Atomic32 *w, bool all) {
  59 }
  60
  61 } // namespace internal
  62 } // namespace base