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#if USE_ITT_BUILD && USE_ITT_NOTIFY
29 __itt_sync_destroy(node);
30#endif
31 KMP_ASSERT(node->dn.nrefs == 0);
32#if USE_FAST_MEMORY
33 __kmp_fast_free(thread, node);
34#else
35 __kmp_thread_free(thread, node);
36#endif
37 }
38}
39
40static inline void __kmp_depnode_list_free(kmp_info_t *thread,
41 kmp_depnode_list *list) {
42 kmp_depnode_list *next;
43
44 for (; list; list = next) {
45 next = list->next;
46
47 __kmp_node_deref(thread, node: list->node);
48#if USE_FAST_MEMORY
49 __kmp_fast_free(thread, list);
50#else
51 __kmp_thread_free(thread, list);
52#endif
53 }
54}
55
56static inline void __kmp_dephash_free_entries(kmp_info_t *thread,
57 kmp_dephash_t *h) {
58 for (size_t i = 0; i < h->size; i++) {
59 if (h->buckets[i]) {
60 kmp_dephash_entry_t *next;
61 for (kmp_dephash_entry_t *entry = h->buckets[i]; entry; entry = next) {
62 next = entry->next_in_bucket;
63 __kmp_depnode_list_free(thread, list: entry->last_set);
64 __kmp_depnode_list_free(thread, list: entry->prev_set);
65 __kmp_node_deref(thread, node: entry->last_out);
66 if (entry->mtx_lock) {
67 __kmp_destroy_lock(lck: entry->mtx_lock);
68 __kmp_free(entry->mtx_lock);
69 }
70#if USE_FAST_MEMORY
71 __kmp_fast_free(thread, entry);
72#else
73 __kmp_thread_free(thread, entry);
74#endif
75 }
76 h->buckets[i] = 0;
77 }
78 }
79 __kmp_node_deref(thread, node: h->last_all);
80 h->last_all = NULL;
81}
82
83static inline void __kmp_dephash_free(kmp_info_t *thread, kmp_dephash_t *h) {
84 __kmp_dephash_free_entries(thread, h);
85#if USE_FAST_MEMORY
86 __kmp_fast_free(thread, h);
87#else
88 __kmp_thread_free(thread, h);
89#endif
90}
91
92extern void __kmpc_give_task(kmp_task_t *ptask, kmp_int32 start);
93
94static inline void __kmp_release_deps(kmp_int32 gtid, kmp_taskdata_t *task) {
95
96#if OMPX_TASKGRAPH
97 if (task->is_taskgraph && !(__kmp_tdg_is_recording(task->tdg->tdg_status))) {
98 kmp_node_info_t *TaskInfo = &(task->tdg->record_map[task->td_task_id]);
99
100 for (int i = 0; i < TaskInfo->nsuccessors; i++) {
101 kmp_int32 successorNumber = TaskInfo->successors[i];
102 kmp_node_info_t *successor = &(task->tdg->record_map[successorNumber]);
103 kmp_int32 npredecessors = KMP_ATOMIC_DEC(&successor->npredecessors_counter) - 1;
104 if (successor->task != nullptr && npredecessors == 0) {
105 __kmp_omp_task(gtid, successor->task, false);
106 }
107 }
108 return;
109 }
110#endif
111
112 kmp_info_t *thread = __kmp_threads[gtid];
113 kmp_depnode_t *node = task->td_depnode;
114
115 // Check mutexinoutset dependencies, release locks
116 if (UNLIKELY(node && (node->dn.mtx_num_locks < 0))) {
117 // negative num_locks means all locks were acquired
118 node->dn.mtx_num_locks = -node->dn.mtx_num_locks;
119 for (int i = node->dn.mtx_num_locks - 1; i >= 0; --i) {
120 KMP_DEBUG_ASSERT(node->dn.mtx_locks[i] != NULL);
121 __kmp_release_lock(lck: node->dn.mtx_locks[i], gtid);
122 }
123 }
124
125 if (task->td_dephash) {
126 KA_TRACE(
127 40, ("__kmp_release_deps: T#%d freeing dependencies hash of task %p.\n",
128 gtid, task));
129 __kmp_dephash_free(thread, h: task->td_dephash);
130 task->td_dephash = NULL;
131 }
132
133 if (!node)
134 return;
135
136 KA_TRACE(20, ("__kmp_release_deps: T#%d notifying successors of task %p.\n",
137 gtid, task));
138
139 KMP_ACQUIRE_DEPNODE(gtid, node);
140#if OMPX_TASKGRAPH
141 if (!task->is_taskgraph ||
142 (task->is_taskgraph && !__kmp_tdg_is_recording(task->tdg->tdg_status)))
143#endif
144 node->dn.task =
145 NULL; // mark this task as finished, so no new dependencies are generated
146 KMP_RELEASE_DEPNODE(gtid, node);
147
148 kmp_depnode_list_t *next;
149 kmp_taskdata_t *next_taskdata;
150 for (kmp_depnode_list_t *p = node->dn.successors; p; p = next) {
151 kmp_depnode_t *successor = p->node;
152#if USE_ITT_BUILD && USE_ITT_NOTIFY
153 __itt_sync_releasing(successor);
154#endif
155 kmp_int32 npredecessors = KMP_ATOMIC_DEC(&successor->dn.npredecessors) - 1;
156
157 // successor task can be NULL for wait_depends or because deps are still
158 // being processed
159 if (npredecessors == 0) {
160#if USE_ITT_BUILD && USE_ITT_NOTIFY
161 __itt_sync_acquired(successor);
162#endif
163 KMP_MB();
164 if (successor->dn.task) {
165 KA_TRACE(20, ("__kmp_release_deps: T#%d successor %p of %p scheduled "
166 "for execution.\n",
167 gtid, successor->dn.task, task));
168 // If a regular task depending on a hidden helper task, when the
169 // hidden helper task is done, the regular task should be executed by
170 // its encountering team.
171 if (KMP_HIDDEN_HELPER_THREAD(gtid)) {
172 // Hidden helper thread can only execute hidden helper tasks
173 KMP_ASSERT(task->td_flags.hidden_helper);
174 next_taskdata = KMP_TASK_TO_TASKDATA(successor->dn.task);
175 // If the dependent task is a regular task, we need to push to its
176 // encountering thread's queue; otherwise, it can be pushed to its own
177 // queue.
178 if (!next_taskdata->td_flags.hidden_helper) {
179 kmp_int32 encountering_gtid =
180 next_taskdata->td_alloc_thread->th.th_info.ds.ds_gtid;
181 kmp_int32 encountering_tid = __kmp_tid_from_gtid(gtid: encountering_gtid);
182 __kmpc_give_task(ptask: successor->dn.task, start: encountering_tid);
183 } else {
184 __kmp_omp_task(gtid, new_task: successor->dn.task, serialize_immediate: false);
185 }
186 } else {
187 __kmp_omp_task(gtid, new_task: successor->dn.task, serialize_immediate: false);
188 }
189 }
190 }
191
192 next = p->next;
193 __kmp_node_deref(thread, node: p->node);
194#if USE_FAST_MEMORY
195 __kmp_fast_free(thread, p);
196#else
197 __kmp_thread_free(thread, p);
198#endif
199 }
200
201 __kmp_node_deref(thread, node);
202
203 KA_TRACE(
204 20,
205 ("__kmp_release_deps: T#%d all successors of %p notified of completion\n",
206 gtid, task));
207}
208
209#endif // KMP_TASKDEPS_H
210

source code of openmp/runtime/src/kmp_taskdeps.h