LLVM OpenMP* Runtime Library
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kmp_taskdeps.h
1/*
2 * kmp_taskdeps.h
3 */
4
5//===----------------------------------------------------------------------===//
6//
7// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
8// See https://llvm.org/LICENSE.txt for license information.
9// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef KMP_TASKDEPS_H
14#define KMP_TASKDEPS_H
15
16#include "kmp.h"
17
18#define KMP_ACQUIRE_DEPNODE(gtid, n) __kmp_acquire_lock(&(n)->dn.lock, (gtid))
19#define KMP_RELEASE_DEPNODE(gtid, n) __kmp_release_lock(&(n)->dn.lock, (gtid))
20
21static inline void __kmp_node_deref(kmp_info_t *thread, kmp_depnode_t *node) {
22 if (!node)
23 return;
24
25 kmp_int32 n = KMP_ATOMIC_DEC(&node->dn.nrefs) - 1;
26 KMP_DEBUG_ASSERT(n >= 0);
27 if (n == 0) {
28 KMP_ASSERT(node->dn.nrefs == 0);
29#if USE_FAST_MEMORY
30 __kmp_fast_free(thread, node);
31#else
32 __kmp_thread_free(thread, node);
33#endif
34 }
35}
36
37static inline void __kmp_depnode_list_free(kmp_info_t *thread,
38 kmp_depnode_list *list) {
39 kmp_depnode_list *next;
40
41 for (; list; list = next) {
42 next = list->next;
43
44 __kmp_node_deref(thread, list->node);
45#if USE_FAST_MEMORY
46 __kmp_fast_free(thread, list);
47#else
48 __kmp_thread_free(thread, list);
49#endif
50 }
51}
52
53static inline void __kmp_dephash_free_entries(kmp_info_t *thread,
54 kmp_dephash_t *h) {
55 for (size_t i = 0; i < h->size; i++) {
56 if (h->buckets[i]) {
57 kmp_dephash_entry_t *next;
58 for (kmp_dephash_entry_t *entry = h->buckets[i]; entry; entry = next) {
59 next = entry->next_in_bucket;
60 __kmp_depnode_list_free(thread, entry->last_set);
61 __kmp_depnode_list_free(thread, entry->prev_set);
62 __kmp_node_deref(thread, entry->last_out);
63 if (entry->mtx_lock) {
64 __kmp_destroy_lock(entry->mtx_lock);
65 __kmp_free(entry->mtx_lock);
66 }
67#if USE_FAST_MEMORY
68 __kmp_fast_free(thread, entry);
69#else
70 __kmp_thread_free(thread, entry);
71#endif
72 }
73 h->buckets[i] = 0;
74 }
75 }
76}
77
78static inline void __kmp_dephash_free(kmp_info_t *thread, kmp_dephash_t *h) {
79 __kmp_dephash_free_entries(thread, h);
80#if USE_FAST_MEMORY
81 __kmp_fast_free(thread, h);
82#else
83 __kmp_thread_free(thread, h);
84#endif
85}
86
87extern void __kmpc_give_task(kmp_task_t *ptask, kmp_int32 start);
88
89static inline void __kmp_release_deps(kmp_int32 gtid, kmp_taskdata_t *task) {
90 kmp_info_t *thread = __kmp_threads[gtid];
91 kmp_depnode_t *node = task->td_depnode;
92
93 // Check mutexinoutset dependencies, release locks
94 if (UNLIKELY(node && (node->dn.mtx_num_locks < 0))) {
95 // negative num_locks means all locks were acquired
96 node->dn.mtx_num_locks = -node->dn.mtx_num_locks;
97 for (int i = node->dn.mtx_num_locks - 1; i >= 0; --i) {
98 KMP_DEBUG_ASSERT(node->dn.mtx_locks[i] != NULL);
99 __kmp_release_lock(node->dn.mtx_locks[i], gtid);
100 }
101 }
102
103 if (task->td_dephash) {
104 KA_TRACE(
105 40, ("__kmp_release_deps: T#%d freeing dependencies hash of task %p.\n",
106 gtid, task));
107 __kmp_dephash_free(thread, task->td_dephash);
108 task->td_dephash = NULL;
109 }
110
111 if (!node)
112 return;
113
114 KA_TRACE(20, ("__kmp_release_deps: T#%d notifying successors of task %p.\n",
115 gtid, task));
116
117 KMP_ACQUIRE_DEPNODE(gtid, node);
118 node->dn.task =
119 NULL; // mark this task as finished, so no new dependencies are generated
120 KMP_RELEASE_DEPNODE(gtid, node);
121
122 kmp_depnode_list_t *next;
123 kmp_taskdata_t *next_taskdata;
124 for (kmp_depnode_list_t *p = node->dn.successors; p; p = next) {
125 kmp_depnode_t *successor = p->node;
126 kmp_int32 npredecessors = KMP_ATOMIC_DEC(&successor->dn.npredecessors) - 1;
127
128 // successor task can be NULL for wait_depends or because deps are still
129 // being processed
130 if (npredecessors == 0) {
131 KMP_MB();
132 if (successor->dn.task) {
133 KA_TRACE(20, ("__kmp_release_deps: T#%d successor %p of %p scheduled "
134 "for execution.\n",
135 gtid, successor->dn.task, task));
136 // If a regular task depending on a hidden helper task, when the
137 // hidden helper task is done, the regular task should be executed by
138 // its encountering team.
139 if (KMP_HIDDEN_HELPER_THREAD(gtid)) {
140 // Hidden helper thread can only execute hidden helper tasks
141 KMP_ASSERT(task->td_flags.hidden_helper);
142 next_taskdata = KMP_TASK_TO_TASKDATA(successor->dn.task);
143 // If the dependent task is a regular task, we need to push to its
144 // encountering thread's queue; otherwise, it can be pushed to its own
145 // queue.
146 if (!next_taskdata->td_flags.hidden_helper) {
147 __kmpc_give_task(
148 successor->dn.task,
149 __kmp_tid_from_gtid(next_taskdata->encountering_gtid));
150 } else {
151 __kmp_omp_task(gtid, successor->dn.task, false);
152 }
153 } else {
154 __kmp_omp_task(gtid, successor->dn.task, false);
155 }
156 }
157 }
158
159 next = p->next;
160 __kmp_node_deref(thread, p->node);
161#if USE_FAST_MEMORY
162 __kmp_fast_free(thread, p);
163#else
164 __kmp_thread_free(thread, p);
165#endif
166 }
167
168 __kmp_node_deref(thread, node);
169
170 KA_TRACE(
171 20,
172 ("__kmp_release_deps: T#%d all successors of %p notified of completion\n",
173 gtid, task));
174}
175
176#endif // KMP_TASKDEPS_H