Function SpinLockWait

be/src/gutil/spinlock_internal.cc:61–78

See spinlock_internal.h for spec.

// See spinlock_internal.h for spec.
int32 SpinLockWait(volatile Atomic32 *w, int n,
                   const SpinLockWaitTransition trans[]) {
  int32 v;
  bool done = false;
  for (int loop = 0; !done; loop++) {
    v = base::subtle::Acquire_Load(w);
    int i;
    for (i = 0; i != n && v != trans[i].from; i++) {
    }
    if (i == n) {
      SpinLockDelay(w, v, loop);     // no matching transition
    } else if (trans[i].to == v ||   // null transition
               base::subtle::Acquire_CompareAndSwap(w, v, trans[i].to) == v) {
      done = trans[i].done;
    }
  }
  return v;
}

// Return a suggested delay in nanoseconds for iteration number "loop"
static int SuggestedDelayNS(int loop) {