code.grnet.gr Git - archipelago/blob - xseg/xq/xq_lock.h

   1 #ifndef _XQ_LOCK_H
   2 #define _XQ_LOCK_H
   3
   4 #define MFENCE() __sync_synchronize()
   5 #define BARRIER() __asm__ __volatile__ ("" : "memory")
   6 #define __pause() __asm__ __volatile__ ("pause\n");
   7 #undef __pause
   8 #define __pause()
   9
  10 struct xq_lock {
  11         long lock;
  12         unsigned long serial;
  13 } __attribute__ ((aligned (32))); /* support up to 128bit longs */
  14
  15 static inline unsigned long xq_acquire(struct xq_lock *lock, unsigned long nr)
  16 {
  17         unsigned long __serial;
  18         for (;;) {
  19                 for (; *(volatile unsigned long *)(&lock->lock); )
  20                         __pause();
  21
  22                 if (!__sync_fetch_and_sub(&lock->lock, 1))
  23                         break;
  24         }
  25
  26         __serial = lock->serial;
  27         lock->serial += nr;
  28         return __serial;
  29 }
  30
  31 static inline void xq_release(struct xq_lock *lock)
  32 {
  33         lock->lock = 0L;
  34 }
  35
  36 #endif