Moving BeefMem

BeefTools/BeefMem/gperftools/src/base/spinlock_linux-inl.h

@@ -0,0 +1,103 @@
+/* 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.
+#ifdef __arm__
+    // ARM linux doesn't support sys_futex1(void*, int, int, struct timespec*);
+    have_futex = 0;
+#else
+    have_futex = (sizeof (Atomic32) == sizeof (int) &&
+                  sys_futex(&x, FUTEX_WAKE, 1, 0) >= 0);
+#endif
+    if (have_futex &&
+        sys_futex(&x, FUTEX_WAKE | futex_private_flag, 1, 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));
+    } 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, 0);
+  }
+}
+
+} // namespace internal
+} // namespace base