2  * Copyright 2013-2015 Samy Al Bahra.
33  * non-TSO architectures with TM support.
41  * skip_-prefixed counters represent the number of consecutive
42  * elisions to forfeit. retry_-prefixed counters represent the
45  *     _busy: Lock was busy
97     unsigned int status)  in _ck_elide_fallback()  argument
100 	st->n_fallback++;  in _ck_elide_fallback()
104 	if (st->skip != 0)  in _ck_elide_fallback()
107 	if (status & CK_PR_RTM_EXPLICIT) {  in _ck_elide_fallback()
108 		if (CK_PR_RTM_CODE(status) == CK_ELIDE_LOCK_BUSY) {  in _ck_elide_fallback()
109 			st->skip = c->skip_busy;  in _ck_elide_fallback()
110 			*retry = c->retry_busy;  in _ck_elide_fallback()
114 		st->skip = c->skip_other;  in _ck_elide_fallback()
118 	if ((status & CK_PR_RTM_RETRY) &&  in _ck_elide_fallback()
119 	    (status & CK_PR_RTM_CONFLICT)) {  in _ck_elide_fallback()
120 		st->skip = c->skip_conflict;  in _ck_elide_fallback()
121 		*retry = c->retry_conflict;  in _ck_elide_fallback()
130 	st->skip = USHRT_MAX;  in _ck_elide_fallback()
136  *     N - Namespace of elision implementation.
137  *     T - Typename of mutex.
138  *   L_P - Lock predicate, returns false if resource is available.
139  *     L - Function to call if resource is unavailable of transaction aborts.
140  *   U_P - Unlock predicate, returns false if elision failed.
141  *     U - Function to call if transaction failed.
145 	ck_elide_##N##_lock_adaptive(T *lock,						\
152 		if (CK_CC_UNLIKELY(st->skip != 0)) {					\
153 			st->skip--;							\
157 		retry = c->retry_conflict;						\
159 			unsigned int status = ck_pr_rtm_begin();			\
160 			if (status == CK_PR_RTM_STARTED) {				\
161 				if (L_P(lock) == true)					\
167 			hint = _ck_elide_fallback(&retry, st, c, status);		\
172 				while (--retry != 0) {					\
173 					if (L_P(lock) == false)				\
184 		} while (CK_CC_LIKELY(--retry > 0));					\
187 		L(lock);								\
191 	ck_elide_##N##_unlock_adaptive(struct ck_elide_stat *st, T *lock)		\
194 		if (U_P(lock) == false) {						\
196 			st->skip = 0;							\
197 			st->n_elide++;							\
199 			U(lock);							\
205 	ck_elide_##N##_lock(T *lock)							\
209 			L(lock);							\
213 		if (L_P(lock) == true)							\
219 	ck_elide_##N##_unlock(T *lock)							\
222 		if (U_P(lock) == false) {						\
225 			U(lock);							\
233 	ck_elide_##N##_trylock(T *lock)					\
239 		if (TL_P(lock) == true)					\
247  * elision wrappers directly calls into the user-specified lock operations.
249  * are paid (typically a storage cost that is a function of lock objects and
254 	ck_elide_##N##_lock_adaptive(T *lock,				\
261 		L(lock);						\
266 	    T *lock)							\
270 		U(lock);						\
274 	ck_elide_##N##_lock(T *lock)					\
277 		L(lock);						\
281 	ck_elide_##N##_unlock(T *lock)					\
284 		U(lock);						\
290 	ck_elide_##N##_trylock(T *lock)					\
293 		return TL_P(lock);					\
298  * Best-effort elision lock operations. First argument is name (N)
306 #define CK_ELIDE_LOCK(NAME, LOCK)	ck_elide_##NAME##_lock(LOCK)  argument
307 #define CK_ELIDE_UNLOCK(NAME, LOCK)	ck_elide_##NAME##_unlock(LOCK)  argument
308 #define CK_ELIDE_TRYLOCK(NAME, LOCK)	ck_elide_##NAME##_trylock(LOCK)  argument
311  * Adaptive elision lock operations. In addition to name and pointer
312  * to the lock, you must pass in a pointer to an initialized
313  * ck_elide_config structure along with a per-thread stat structure.
315 #define CK_ELIDE_LOCK_ADAPTIVE(NAME, STAT, CONFIG, LOCK) \  argument
316 	ck_elide_##NAME##_lock_adaptive(LOCK, STAT, CONFIG)
318 #define CK_ELIDE_UNLOCK_ADAPTIVE(NAME, STAT, LOCK) \  argument
319 	ck_elide_##NAME##_unlock_adaptive(STAT, LOCK)