Experiment for updating the tcmalloc chromium branch to r144 (gperftools 2.0).

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

 /* Copyright (c) 2009, Google Inc.
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  * 
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * ---
  * This file is a Linux-specific part of spinlock_internal.cc
  */
 
+#include <errno.h>
 #include <sched.h>
 #include <time.h>
 #include <limits.h>
 #include "base/linux_syscall_support.h"
 
 #define FUTEX_WAIT 0
 #define FUTEX_WAKE 1
 #define FUTEX_PRIVATE_FLAG 128
 
 // Note: Instead of making direct system calls that are inlined, we rely
@@ skipping 35 matching lines @@
 
 namespace base {
 namespace internal {
 
 void SpinLockDelay(volatile Atomic32 *w, int32 value, int loop) {
   if (loop != 0) {
     int save_errno = errno;
     struct timespec tm;
     tm.tv_sec = 0;
     if (have_futex) {
-      tm.tv_nsec = 1000000;   // 1ms; really we're trying to sleep for one
-                              // kernel clock tick
+      tm.tv_nsec = base::internal::SuggestedDelayNS(loop);
     } else {
       tm.tv_nsec = 2000001;   // above 2ms so linux 2.4 doesn't spin
     }
     if (have_futex) {
+      tm.tv_nsec *= 16;  // increase the delay; we expect explicit wakeups
       syscall(__NR_futex, reinterpret_cast<int *>(const_cast<Atomic32 *>(w)),
                 FUTEX_WAIT | futex_private_flag,
                 value, reinterpret_cast<struct kernel_timespec *>(&tm));
     } else {
       nanosleep(&tm, NULL);
     }
     errno = save_errno;
   }
 }
 
 void SpinLockWake(volatile Atomic32 *w, bool all) {
   if (have_futex) {
     syscall(__NR_futex, reinterpret_cast<int *>(const_cast<Atomic32 *>(w)),
               FUTEX_WAKE | futex_private_flag, 1, 0);
   }
 }
 
 } // namespace internal
 } // namespace base