Squashed 'third_party/gperftools/' content from commit 54505f1
Change-Id: Id02e833828732b0efe7dac722b8485279e67c5fa
git-subtree-dir: third_party/gperftools
git-subtree-split: 54505f1d50c2d1f4676f5e87090b64a117fd980e
diff --git a/src/base/spinlock_linux-inl.h b/src/base/spinlock_linux-inl.h
new file mode 100644
index 0000000..aadf62a
--- /dev/null
+++ b/src/base/spinlock_linux-inl.h
@@ -0,0 +1,101 @@
+// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
+/* 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
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * 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
+
+static bool have_futex;
+static int futex_private_flag = FUTEX_PRIVATE_FLAG;
+
+namespace {
+static struct InitModule {
+ InitModule() {
+ int x = 0;
+ // futexes are ints, so we can use them only when
+ // that's the same size as the lockword_ in SpinLock.
+ have_futex = (sizeof (Atomic32) == sizeof (int) &&
+ sys_futex(&x, FUTEX_WAKE, 1, NULL, NULL, 0) >= 0);
+ if (have_futex &&
+ sys_futex(&x, FUTEX_WAKE | futex_private_flag, 1, NULL, NULL, 0) < 0) {
+ futex_private_flag = 0;
+ }
+ }
+} init_module;
+
+} // anonymous namespace
+
+
+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 = 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
+ sys_futex(reinterpret_cast<int *>(const_cast<Atomic32 *>(w)),
+ FUTEX_WAIT | futex_private_flag,
+ value, reinterpret_cast<struct kernel_timespec *>(&tm),
+ NULL, 0);
+ } else {
+ nanosleep(&tm, NULL);
+ }
+ errno = save_errno;
+ }
+}
+
+void SpinLockWake(volatile Atomic32 *w, bool all) {
+ if (have_futex) {
+ sys_futex(reinterpret_cast<int *>(const_cast<Atomic32 *>(w)),
+ FUTEX_WAKE | futex_private_flag, all? INT_MAX : 1,
+ NULL, NULL, 0);
+ }
+}
+
+} // namespace internal
+} // namespace base