/usr/include/ck_cohort.h is in libck-dev 0.4.4-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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* Copyright 2013-2014 Samy Al Bahra.
* Copyright 2013 Brendon Scheinman.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _CK_COHORT_H
#define _CK_COHORT_H
/*
* This is an implementation of lock cohorts as described in:
* Dice, D.; Marathe, V.; and Shavit, N. 2012.
* Lock Cohorting: A General Technique for Designing NUMA Locks
*/
#include <ck_cc.h>
#include <ck_pr.h>
#include <stddef.h>
enum ck_cohort_state {
CK_COHORT_STATE_GLOBAL = 0,
CK_COHORT_STATE_LOCAL = 1
};
#define CK_COHORT_DEFAULT_LOCAL_PASS_LIMIT 10
#define CK_COHORT_NAME(N) ck_cohort_##N
#define CK_COHORT_INSTANCE(N) struct CK_COHORT_NAME(N)
#define CK_COHORT_INIT(N, C, GL, LL, P) ck_cohort_##N##_init(C, GL, LL, P)
#define CK_COHORT_LOCK(N, C, GC, LC) ck_cohort_##N##_lock(C, GC, LC)
#define CK_COHORT_UNLOCK(N, C, GC, LC) ck_cohort_##N##_unlock(C, GC, LC)
#define CK_COHORT_TRYLOCK(N, C, GLC, LLC, LUC) ck_cohort_##N##_trylock(C, GLC, LLC, LUC)
#define CK_COHORT_LOCKED(N, C, GC, LC) ck_cohort_##N##_locked(C, GC, LC)
#define CK_COHORT_PROTOTYPE(N, GL, GU, GI, LL, LU, LI) \
CK_COHORT_INSTANCE(N) { \
void *global_lock; \
void *local_lock; \
enum ck_cohort_state release_state; \
unsigned int waiting_threads; \
unsigned int acquire_count; \
unsigned int local_pass_limit; \
}; \
\
CK_CC_INLINE static void \
ck_cohort_##N##_init(struct ck_cohort_##N *cohort, \
void *global_lock, void *local_lock, unsigned int pass_limit) \
{ \
cohort->global_lock = global_lock; \
cohort->local_lock = local_lock; \
cohort->release_state = CK_COHORT_STATE_GLOBAL; \
cohort->waiting_threads = 0; \
cohort->acquire_count = 0; \
cohort->local_pass_limit = pass_limit; \
ck_pr_barrier(); \
return; \
} \
\
CK_CC_INLINE static void \
ck_cohort_##N##_lock(CK_COHORT_INSTANCE(N) *cohort, \
void *global_context, void *local_context) \
{ \
\
ck_pr_inc_uint(&cohort->waiting_threads); \
LL(cohort->local_lock, local_context); \
ck_pr_dec_uint(&cohort->waiting_threads); \
\
if (cohort->release_state == CK_COHORT_STATE_GLOBAL) { \
GL(cohort->global_lock, global_context); \
} \
\
++cohort->acquire_count; \
return; \
} \
\
CK_CC_INLINE static void \
ck_cohort_##N##_unlock(CK_COHORT_INSTANCE(N) *cohort, \
void *global_context, void *local_context) \
{ \
\
if (ck_pr_load_uint(&cohort->waiting_threads) > 0 \
&& cohort->acquire_count < cohort->local_pass_limit) { \
cohort->release_state = CK_COHORT_STATE_LOCAL; \
} else { \
GU(cohort->global_lock, global_context); \
cohort->release_state = CK_COHORT_STATE_GLOBAL; \
cohort->acquire_count = 0; \
} \
\
ck_pr_fence_release(); \
LU(cohort->local_lock, local_context); \
\
return; \
} \
\
CK_CC_INLINE static bool \
ck_cohort_##N##_locked(CK_COHORT_INSTANCE(N) *cohort, \
void *global_context, void *local_context) \
{ \
return GI(cohort->local_lock, local_context) || \
LI(cohort->global_lock, global_context); \
}
#define CK_COHORT_TRYLOCK_PROTOTYPE(N, GL, GU, GI, GTL, LL, LU, LI, LTL) \
CK_COHORT_PROTOTYPE(N, GL, GU, GI, LL, LU, LI) \
CK_CC_INLINE static bool \
ck_cohort_##N##_trylock(CK_COHORT_INSTANCE(N) *cohort, \
void *global_context, void *local_context, \
void *local_unlock_context) \
{ \
\
bool trylock_result; \
\
ck_pr_inc_uint(&cohort->waiting_threads); \
trylock_result = LTL(cohort->local_lock, local_context); \
ck_pr_dec_uint(&cohort->waiting_threads); \
if (trylock_result == false) { \
return false; \
} \
\
if (cohort->release_state == CK_COHORT_STATE_GLOBAL && \
GTL(cohort->global_lock, global_context) == false) { \
LU(cohort->local_lock, local_unlock_context); \
return false; \
} \
\
++cohort->acquire_count; \
return true; \
}
#define CK_COHORT_INITIALIZER { \
.global_lock = NULL, \
.local_lock = NULL, \
.release_state = CK_COHORT_STATE_GLOBAL, \
.waiting_threads = 0, \
.acquire_count = 0, \
.local_pass_limit = CK_COHORT_DEFAULT_LOCAL_PASS_LIMIT \
}
#endif /* _CK_COHORT_H */
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