usr/src/uts/common/sys/mutex.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #ifndef _SYS_MUTEX_H
  27 #define _SYS_MUTEX_H
  28
  29 #pragma ident   "%Z%%M% %I%     %E% SMI"
  30
  31 #ifndef _ASM
  32 #include <sys/types.h>
  33 #endif
  34
  35 #ifdef  __cplusplus
  36 extern "C" {
  37 #endif
  38
  39 #ifndef _ASM
  40
  41 /*
  42  * Public interface to mutual exclusion locks.  See mutex(9F) for details.
  43  *
  44  * The basic mutex type is MUTEX_ADAPTIVE, which is expected to be used
  45  * in almost all of the kernel.  MUTEX_SPIN provides interrupt blocking
  46  * and must be used in interrupt handlers above LOCK_LEVEL.  The iblock
  47  * cookie argument to mutex_init() encodes the interrupt level to block.
  48  * The iblock cookie must be NULL for adaptive locks.
  49  *
  50  * MUTEX_DEFAULT is the type usually specified (except in drivers) to
  51  * mutex_init().  It is identical to MUTEX_ADAPTIVE.
  52  *
  53  * MUTEX_DRIVER is always used by drivers.  mutex_init() converts this to
  54  * either MUTEX_ADAPTIVE or MUTEX_SPIN depending on the iblock cookie.
  55  *
  56  * Mutex statistics can be gathered on the fly, without rebooting or
  57  * recompiling the kernel, via the lockstat driver (lockstat(7D)).
  58  */
  59 typedef enum {
  60         MUTEX_ADAPTIVE = 0,     /* spin if owner is running, otherwise block */
  61         MUTEX_SPIN = 1,         /* block interrupts and spin */
  62         MUTEX_DRIVER = 4,       /* driver (DDI) mutex */
  63         MUTEX_DEFAULT = 6       /* kernel default mutex */
  64 } kmutex_type_t;
  65
  66 typedef struct mutex {
  67 #ifdef _LP64
  68         void    *_opaque[1];
  69 #else
  70         void    *_opaque[2];
  71 #endif
  72 } kmutex_t;
  73
  74 #ifdef _KERNEL
  75
  76 #define MUTEX_HELD(x)           (mutex_owned(x))
  77 #define MUTEX_NOT_HELD(x)       (!mutex_owned(x) || panicstr)
  78
  79 extern  void    mutex_init(kmutex_t *, char *, kmutex_type_t, void *);
  80 extern  void    mutex_destroy(kmutex_t *);
  81 extern  void    mutex_enter(kmutex_t *);
  82 extern  int     mutex_tryenter(kmutex_t *);
  83 extern  void    mutex_exit(kmutex_t *);
  84 extern  int     mutex_owned(const kmutex_t *);
  85 extern  struct _kthread *mutex_owner(const kmutex_t *);
  86
  87 extern  ushort_t mutex_backoff_base;
  88 extern  uint_t mutex_backoff_cap;
  89 extern  ushort_t mutex_cap_factor;
  90 extern  uchar_t mutex_backoff_shift;
  91 extern  void (*mutex_lock_delay)(uint_t);
  92 extern  uint_t (*mutex_lock_backoff)(uint_t);
  93 extern  void (*mutex_delay)(void);
  94 extern  void mutex_delay_default(void);
  95 extern  void mutex_sync(void);
  96
  97 extern  void default_lock_delay(uint_t);
  98 extern  uint_t default_lock_backoff(uint_t);
  99
 100 #endif  /* _KERNEL */
 101
 102 #endif  /* _ASM */
 103
 104 #ifdef  __cplusplus
 105 }
 106 #endif
 107
 108 #endif  /* _SYS_MUTEX_H */