src/vppinfra/lock.h

   1 /*
   2  * Copyright (c) 2017 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #ifndef included_clib_lock_h
  17 #define included_clib_lock_h
  18
  19 #include <vppinfra/clib.h>
  20
  21 #if __x86_64__
  22 #define CLIB_PAUSE() __builtin_ia32_pause ()
  23 #else
  24 #define CLIB_PAUSE()
  25 #endif
  26
  27 #if CLIB_DEBUG > 1
  28 #define CLIB_LOCK_DBG(_p)                               \
  29 do {                                                    \
  30     (*_p)->frame_address = __builtin_frame_address (0); \
  31     (*_p)->pid = getpid ();                             \
  32     (*_p)->thread_index = os_get_thread_index ();       \
  33 } while (0)
  34 #define CLIB_LOCK_DBG_CLEAR(_p)                         \
  35 do {                                                    \
  36     (*_p)->frame_address = 0;                           \
  37     (*_p)->pid = 0;                                     \
  38     (*_p)->thread_index = 0;                            \
  39 } while (0)
  40 #else
  41 #define CLIB_LOCK_DBG(_p)
  42 #define CLIB_LOCK_DBG_CLEAR(_p)
  43 #endif
  44
  45 #define CLIB_SPINLOCK_IS_LOCKED(_p) (*(_p))->lock
  46 #define CLIB_SPINLOCK_ASSERT_LOCKED(_p) ASSERT(CLIB_SPINLOCK_IS_LOCKED((_p)))
  47
  48 typedef struct
  49 {
  50   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  51   u32 lock;
  52 #if CLIB_DEBUG > 0
  53   pid_t pid;
  54   uword thread_index;
  55   void *frame_address;
  56 #endif
  57 } *clib_spinlock_t;
  58
  59 static inline void
  60 clib_spinlock_init (clib_spinlock_t * p)
  61 {
  62   *p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
  63   clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
  64 }
  65
  66 static inline void
  67 clib_spinlock_free (clib_spinlock_t * p)
  68 {
  69   if (*p)
  70     {
  71       clib_mem_free ((void *) *p);
  72       *p = 0;
  73     }
  74 }
  75
  76 static_always_inline void
  77 clib_spinlock_lock (clib_spinlock_t * p)
  78 {
  79   while (clib_atomic_test_and_set (&(*p)->lock))
  80     CLIB_PAUSE ();
  81   CLIB_LOCK_DBG (p);
  82 }
  83
  84 static_always_inline void
  85 clib_spinlock_lock_if_init (clib_spinlock_t * p)
  86 {
  87   if (PREDICT_FALSE (*p != 0))
  88     clib_spinlock_lock (p);
  89 }
  90
  91 static_always_inline void
  92 clib_spinlock_unlock (clib_spinlock_t * p)
  93 {
  94   CLIB_LOCK_DBG_CLEAR (p);
  95   /* Make sure all reads/writes are complete before releasing the lock */
  96   clib_atomic_release (&(*p)->lock);
  97 }
  98
  99 static_always_inline void
 100 clib_spinlock_unlock_if_init (clib_spinlock_t * p)
 101 {
 102   if (PREDICT_FALSE (*p != 0))
 103     clib_spinlock_unlock (p);
 104 }
 105
 106 /*
 107  * Readers-Writer Lock
 108  */
 109
 110 typedef struct clib_rw_lock_
 111 {
 112   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
 113   volatile u32 n_readers;
 114   volatile u32 n_readers_lock;
 115   volatile u32 writer_lock;
 116 #if CLIB_DEBUG > 0
 117   pid_t pid;
 118   uword thread_index;
 119   void *frame_address;
 120 #endif
 121 } *clib_rwlock_t;
 122
 123 always_inline void
 124 clib_rwlock_init (clib_rwlock_t * p)
 125 {
 126   *p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
 127   clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
 128 }
 129
 130 always_inline void
 131 clib_rwlock_free (clib_rwlock_t * p)
 132 {
 133   if (*p)
 134     {
 135       clib_mem_free ((void *) *p);
 136       *p = 0;
 137     }
 138 }
 139
 140 always_inline void
 141 clib_rwlock_reader_lock (clib_rwlock_t * p)
 142 {
 143   while (clib_atomic_test_and_set (&(*p)->n_readers_lock))
 144     CLIB_PAUSE ();
 145
 146   (*p)->n_readers += 1;
 147   if ((*p)->n_readers == 1)
 148     {
 149       while (clib_atomic_test_and_set (&(*p)->writer_lock))
 150         CLIB_PAUSE ();
 151     }
 152   clib_atomic_release (&(*p)->n_readers_lock);
 153   CLIB_LOCK_DBG (p);
 154 }
 155
 156 always_inline void
 157 clib_rwlock_reader_unlock (clib_rwlock_t * p)
 158 {
 159   ASSERT ((*p)->n_readers > 0);
 160   CLIB_LOCK_DBG_CLEAR (p);
 161
 162   while (clib_atomic_test_and_set (&(*p)->n_readers_lock))
 163     CLIB_PAUSE ();
 164
 165   (*p)->n_readers -= 1;
 166   if ((*p)->n_readers == 0)
 167     {
 168       clib_atomic_release (&(*p)->writer_lock);
 169     }
 170   clib_atomic_release (&(*p)->n_readers_lock);
 171 }
 172
 173 always_inline void
 174 clib_rwlock_writer_lock (clib_rwlock_t * p)
 175 {
 176   while (clib_atomic_test_and_set (&(*p)->writer_lock))
 177     CLIB_PAUSE ();
 178   CLIB_LOCK_DBG (p);
 179 }
 180
 181 always_inline void
 182 clib_rwlock_writer_unlock (clib_rwlock_t * p)
 183 {
 184   CLIB_LOCK_DBG_CLEAR (p);
 185   clib_atomic_release (&(*p)->writer_lock);
 186 }
 187
 188 #endif
 189
 190 /*
 191  * fd.io coding-style-patch-verification: ON
 192  *
 193  * Local Variables:
 194  * eval: (c-set-style "gnu")
 195  * End:
 196  */