vppinfra: add readers-writer lock
Change-Id: I606fd89c410369cbd9ce9dcaaaa9dc58796e7c0e Signed-off-by: Florin Coras <fcoras@cisco.com>
This commit is contained in:
Florin Coras
committed by
Dave Barach
parent
b384b54331
commit
1f9600e50f
@ -18,6 +18,30 @@
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#include <vppinfra/clib.h>
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#if __x86_64__
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#define CLIB_PAUSE() __builtin_ia32_pause ()
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#else
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#define CLIB_PAUSE()
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#endif
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#if CLIB_DEBUG > 1
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#define CLIB_LOCK_DBG(_p) \
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do { \
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(*_p)->frame_address = __builtin_frame_address (0); \
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(*_p)->pid = getpid (); \
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(*_p)->thread_index = os_get_thread_index (); \
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} while (0)
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#define CLIB_LOCK_DBG_CLEAR(_p) \
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do { \
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(*_p)->frame_address = 0; \
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(*_p)->pid = 0; \
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(*_p)->thread_index = 0; \
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} while (0)
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#else
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#define CLIB_LOCK_DBG(_p)
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#define CLIB_LOCK_DBG_CLEAR(_p)
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#endif
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typedef struct
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{
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CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
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@ -50,15 +74,8 @@ static_always_inline void
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clib_spinlock_lock (clib_spinlock_t * p)
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{
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while (__sync_lock_test_and_set (&(*p)->lock, 1))
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#if __x86_64__
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__builtin_ia32_pause ()
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#endif
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;
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#if CLIB_DEBUG > 0
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(*p)->frame_address = __builtin_frame_address (0);
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(*p)->pid = getpid ();
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(*p)->thread_index = os_get_thread_index ();
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#endif
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CLIB_PAUSE ();
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CLIB_LOCK_DBG (p);
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}
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static_always_inline void
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@ -71,11 +88,7 @@ clib_spinlock_lock_if_init (clib_spinlock_t * p)
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static_always_inline void
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clib_spinlock_unlock (clib_spinlock_t * p)
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{
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#if CLIB_DEBUG > 0
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(*p)->frame_address = 0;
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(*p)->pid = 0;
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(*p)->thread_index = 0;
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#endif
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CLIB_LOCK_DBG_CLEAR (p);
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/* Make sure all writes are complete before releasing the lock */
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CLIB_MEMORY_BARRIER ();
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(*p)->lock = 0;
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@ -88,6 +101,77 @@ clib_spinlock_unlock_if_init (clib_spinlock_t * p)
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clib_spinlock_unlock (p);
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}
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/*
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* Readers-Writer Lock
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*/
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typedef struct clib_rw_lock_
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{
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CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
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volatile u32 n_readers;
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volatile u32 writer_lock;
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#if CLIB_DEBUG > 0
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pid_t pid;
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uword thread_index;
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void *frame_address;
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#endif
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} *clib_rwlock_t;
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always_inline void
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clib_rwlock_init (clib_rwlock_t * p)
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{
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*p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
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memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
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}
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always_inline void
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clib_rwlock_free (clib_rwlock_t * p)
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{
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if (*p)
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{
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clib_mem_free ((void *) *p);
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*p = 0;
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}
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}
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always_inline void
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clib_rwlock_reader_lock (clib_rwlock_t * p)
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{
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if (__sync_fetch_and_add (&(*p)->n_readers, 1) == 0)
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{
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while (__sync_lock_test_and_set (&(*p)->writer_lock, 1))
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CLIB_PAUSE ();
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}
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CLIB_LOCK_DBG (p);
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}
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always_inline void
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clib_rwlock_reader_unlock (clib_rwlock_t * p)
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{
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CLIB_LOCK_DBG_CLEAR (p);
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if (__sync_fetch_and_sub (&(*p)->n_readers, 1) == 1)
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{
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CLIB_MEMORY_BARRIER ();
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(*p)->writer_lock = 0;
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}
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}
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always_inline void
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clib_rwlock_writer_lock (clib_rwlock_t * p)
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{
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while (__sync_lock_test_and_set (&(*p)->writer_lock, 1))
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CLIB_PAUSE ();
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CLIB_LOCK_DBG (p);
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}
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always_inline void
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clib_rwlock_writer_unlock (clib_rwlock_t * p)
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{
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CLIB_LOCK_DBG_CLEAR (p);
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CLIB_MEMORY_BARRIER ();
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(*p)->writer_lock = 0;
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}
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#endif
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/*
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