vppinfra: add readers-writer lock

Change-Id: I606fd89c410369cbd9ce9dcaaaa9dc58796e7c0e
Signed-off-by: Florin Coras <fcoras@cisco.com>
This commit is contained in:
Florin Coras
2018-01-23 18:17:44 -08:00
committed by Dave Barach
parent b384b54331
commit 1f9600e50f

View File

@ -18,6 +18,30 @@
#include <vppinfra/clib.h>
#if __x86_64__
#define CLIB_PAUSE() __builtin_ia32_pause ()
#else
#define CLIB_PAUSE()
#endif
#if CLIB_DEBUG > 1
#define CLIB_LOCK_DBG(_p) \
do { \
(*_p)->frame_address = __builtin_frame_address (0); \
(*_p)->pid = getpid (); \
(*_p)->thread_index = os_get_thread_index (); \
} while (0)
#define CLIB_LOCK_DBG_CLEAR(_p) \
do { \
(*_p)->frame_address = 0; \
(*_p)->pid = 0; \
(*_p)->thread_index = 0; \
} while (0)
#else
#define CLIB_LOCK_DBG(_p)
#define CLIB_LOCK_DBG_CLEAR(_p)
#endif
typedef struct
{
CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
@ -50,15 +74,8 @@ static_always_inline void
clib_spinlock_lock (clib_spinlock_t * p)
{
while (__sync_lock_test_and_set (&(*p)->lock, 1))
#if __x86_64__
__builtin_ia32_pause ()
#endif
;
#if CLIB_DEBUG > 0
(*p)->frame_address = __builtin_frame_address (0);
(*p)->pid = getpid ();
(*p)->thread_index = os_get_thread_index ();
#endif
CLIB_PAUSE ();
CLIB_LOCK_DBG (p);
}
static_always_inline void
@ -71,11 +88,7 @@ clib_spinlock_lock_if_init (clib_spinlock_t * p)
static_always_inline void
clib_spinlock_unlock (clib_spinlock_t * p)
{
#if CLIB_DEBUG > 0
(*p)->frame_address = 0;
(*p)->pid = 0;
(*p)->thread_index = 0;
#endif
CLIB_LOCK_DBG_CLEAR (p);
/* Make sure all writes are complete before releasing the lock */
CLIB_MEMORY_BARRIER ();
(*p)->lock = 0;
@ -88,6 +101,77 @@ clib_spinlock_unlock_if_init (clib_spinlock_t * p)
clib_spinlock_unlock (p);
}
/*
* Readers-Writer Lock
*/
typedef struct clib_rw_lock_
{
CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
volatile u32 n_readers;
volatile u32 writer_lock;
#if CLIB_DEBUG > 0
pid_t pid;
uword thread_index;
void *frame_address;
#endif
} *clib_rwlock_t;
always_inline void
clib_rwlock_init (clib_rwlock_t * p)
{
*p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
}
always_inline void
clib_rwlock_free (clib_rwlock_t * p)
{
if (*p)
{
clib_mem_free ((void *) *p);
*p = 0;
}
}
always_inline void
clib_rwlock_reader_lock (clib_rwlock_t * p)
{
if (__sync_fetch_and_add (&(*p)->n_readers, 1) == 0)
{
while (__sync_lock_test_and_set (&(*p)->writer_lock, 1))
CLIB_PAUSE ();
}
CLIB_LOCK_DBG (p);
}
always_inline void
clib_rwlock_reader_unlock (clib_rwlock_t * p)
{
CLIB_LOCK_DBG_CLEAR (p);
if (__sync_fetch_and_sub (&(*p)->n_readers, 1) == 1)
{
CLIB_MEMORY_BARRIER ();
(*p)->writer_lock = 0;
}
}
always_inline void
clib_rwlock_writer_lock (clib_rwlock_t * p)
{
while (__sync_lock_test_and_set (&(*p)->writer_lock, 1))
CLIB_PAUSE ();
CLIB_LOCK_DBG (p);
}
always_inline void
clib_rwlock_writer_unlock (clib_rwlock_t * p)
{
CLIB_LOCK_DBG_CLEAR (p);
CLIB_MEMORY_BARRIER ();
(*p)->writer_lock = 0;
}
#endif
/*