third_party/tcmalloc/chromium/src/base/spinlock_internal.h

   1 /* Copyright (c) 2010, Google Inc.
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   4  * Redistribution and use in source and binary forms, with or without
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  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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  29  *
  30  * ---
  31  * This file is an internal part spinlock.cc and once.cc
  32  * It may not be used directly by code outside of //base.
  33  */
  34
  35 #ifndef BASE_SPINLOCK_INTERNAL_H_
  36 #define BASE_SPINLOCK_INTERNAL_H_
  37
  38 #include <config.h>
  39 #include "base/basictypes.h"
  40 #include "base/atomicops.h"
  41
  42 namespace base {
  43 namespace internal {
  44
  45 // SpinLockWait() waits until it can perform one of several transitions from
  46 // "from" to "to".  It returns when it performs a transition where done==true.
  47 struct SpinLockWaitTransition {
  48   int32 from;
  49   int32 to;
  50   bool done;
  51 };
  52
  53 // Wait until *w can transition from trans[i].from to trans[i].to for some i
  54 // satisfying 0<=i<n && trans[i].done, atomically make the transition,
  55 // then return the old value of *w.   Make any other atomic tranistions
  56 // where !trans[i].done, but continue waiting.
  57 int32 SpinLockWait(volatile Atomic32 *w, int n,
  58                    const SpinLockWaitTransition trans[]);
  59 void SpinLockWake(volatile Atomic32 *w, bool all);
  60 void SpinLockDelay(volatile Atomic32 *w, int32 value, int loop);
  61
  62 } // namespace internal
  63 } // namespace base
  64 #endif