[NOT TO COMMIT!] Replace third_party/tcmalloc/chromium with tcmalloc r136 (the latest).

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

Index: third_party/tcmalloc/chromium/src/base/spinlock_linux-inl.h
diff --git a/third_party/tcmalloc/chromium/src/base/spinlock_linux-inl.h b/third_party/tcmalloc/chromium/src/base/spinlock_linux-inl.h
index dc2c6bac4d8c5384e065587fd7277dd8a9bb8ee4..bee2d4cedb123ecd61889fc18775a8e60d804e5c 100644
--- a/third_party/tcmalloc/chromium/src/base/spinlock_linux-inl.h
+++ b/third_party/tcmalloc/chromium/src/base/spinlock_linux-inl.h
@@ -31,6 +31,7 @@
  * This file is a Linux-specific part of spinlock_internal.cc
  */
 
+#include <errno.h>
 #include <sched.h>
 #include <time.h>
 #include <limits.h>
@@ -40,17 +41,6 @@
 #define FUTEX_WAKE 1
 #define FUTEX_PRIVATE_FLAG 128
 
-// Note: Instead of making direct system calls that are inlined, we rely
-//       on the syscall() function in glibc to do the right thing. This
-//       is necessary to make the code compatible with the seccomp sandbox,
-//       which needs to be able to find and patch all places where system
-//       calls are made. Scanning through and patching glibc is fast, but
-//       doing so on the entire Chrome binary would be prohibitively
-//       expensive.
-//       This is a notable change from the upstream version of tcmalloc,
-//       which prefers direct system calls in order to improve compatibility
-//       with older toolchains and runtime libraries.
-
 static bool have_futex;
 static int futex_private_flag = FUTEX_PRIVATE_FLAG;
 
@@ -64,11 +54,11 @@ static struct InitModule {
     // ARM linux doesn't support sys_futex1(void*, int, int, struct timespec*);
     have_futex = 0;
 #else
-    have_futex = (sizeof (Atomic32) == sizeof (int) && 
-                  syscall(__NR_futex, &x, FUTEX_WAKE, 1, 0) >= 0);
+    have_futex = (sizeof (Atomic32) == sizeof (int) &&
+                  sys_futex(&x, FUTEX_WAKE, 1, 0) >= 0);
 #endif
     if (have_futex &&
-        syscall(__NR_futex, &x, FUTEX_WAKE | futex_private_flag, 1, 0) < 0) {
+        sys_futex(&x, FUTEX_WAKE | futex_private_flag, 1, 0) < 0) {
       futex_private_flag = 0;
     }
   }
@@ -86,13 +76,13 @@ void SpinLockDelay(volatile Atomic32 *w, int32 value, int loop) {
     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) {
-      syscall(__NR_futex, reinterpret_cast<int *>(const_cast<Atomic32 *>(w)),
+      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 {
@@ -104,8 +94,8 @@ void SpinLockDelay(volatile Atomic32 *w, int32 value, int loop) {
 
 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);
+    sys_futex(reinterpret_cast<int *>(const_cast<Atomic32 *>(w)),
+              FUTEX_WAKE | futex_private_flag, all? INT_MAX : 1, 0);
   }
 }