sys/sys/serialize.h

   1 /*
   2  * Provides a fast serialization facility that will serialize across blocking
   3  * conditions.  This facility is very similar to a lock but much faster for
   4  * the common case.  It utilizes the atomic_intr_*() functions to acquire
   5  * and release the serializer and token functions to block.
   6  *
   7  * This API is designed to be used whenever low level serialization is
   8  * required.  Unlike tokens this serialization is not safe from deadlocks
   9  * nor is it recursive, and care must be taken when using it.
  10  *
  11  * $DragonFly: src/sys/sys/serialize.h,v 1.9 2008/05/14 11:59:24 sephe Exp $
  12  */
  13
  14 #ifndef _SYS_SERIALIZE_H_
  15 #define _SYS_SERIALIZE_H_
  16
  17 #ifndef _MACHINE_STDINT_H_
  18 #include <machine/stdint.h>
  19 #endif
  20
  21 struct thread;
  22
  23 struct lwkt_serialize {
  24     __atomic_intr_t     interlock;
  25     struct thread       *last_td;
  26     unsigned int        sleep_cnt;
  27     unsigned int        tryfail_cnt;
  28     unsigned int        enter_cnt;
  29     unsigned int        try_cnt;
  30 };
  31
  32 #ifdef INVARIANTS
  33 /*
  34  * Note that last_td is only maintained when INVARIANTS is turned on,
  35  * so this check is only useful as part of a [K]KASSERT.
  36  */
  37 #define IS_SERIALIZED(ss)               ((ss)->last_td == curthread)
  38 #endif
  39
  40 #define ASSERT_SERIALIZED(ss)           KKASSERT(IS_SERIALIZED((ss)))
  41 #define ASSERT_NOT_SERIALIZED(ss)       KKASSERT(!IS_SERIALIZED((ss)))
  42
  43 typedef struct lwkt_serialize *lwkt_serialize_t;
  44
  45 void lwkt_serialize_init(lwkt_serialize_t);
  46 void lwkt_serialize_enter(lwkt_serialize_t);
  47 #ifdef SMP
  48 void lwkt_serialize_adaptive_enter(lwkt_serialize_t);
  49 #endif
  50 int lwkt_serialize_try(lwkt_serialize_t);
  51 void lwkt_serialize_exit(lwkt_serialize_t);
  52 void lwkt_serialize_handler_disable(lwkt_serialize_t);
  53 void lwkt_serialize_handler_enable(lwkt_serialize_t);
  54 void lwkt_serialize_handler_call(lwkt_serialize_t, void (*)(void *, void *), void *, void *);
  55 int lwkt_serialize_handler_try(lwkt_serialize_t, void (*)(void *, void *), void *, void *);
  56
  57 #endif  /* !_SYS_SERIALIZE_H_ */