LLVM OpenMP* Runtime Library
kmp_taskdeps.h
1 /*
2  * kmp_taskdeps.h
3  */
4 
5 
6 //===----------------------------------------------------------------------===//
7 //
8 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
9 // See https://llvm.org/LICENSE.txt for license information.
10 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
11 //
12 //===----------------------------------------------------------------------===//
13 
14 
15 #ifndef KMP_TASKDEPS_H
16 #define KMP_TASKDEPS_H
17 
18 #include "kmp.h"
19 
20 #define KMP_ACQUIRE_DEPNODE(gtid, n) __kmp_acquire_lock(&(n)->dn.lock, (gtid))
21 #define KMP_RELEASE_DEPNODE(gtid, n) __kmp_release_lock(&(n)->dn.lock, (gtid))
22 
23 static inline void __kmp_node_deref(kmp_info_t *thread, kmp_depnode_t *node) {
24  if (!node)
25  return;
26 
27  kmp_int32 n = KMP_ATOMIC_DEC(&node->dn.nrefs) - 1;
28  if (n == 0) {
29  KMP_ASSERT(node->dn.nrefs == 0);
30 #if USE_FAST_MEMORY
31  __kmp_fast_free(thread, node);
32 #else
33  __kmp_thread_free(thread, node);
34 #endif
35  }
36 }
37 
38 static inline void __kmp_depnode_list_free(kmp_info_t *thread,
39  kmp_depnode_list *list) {
40  kmp_depnode_list *next;
41 
42  for (; list; list = next) {
43  next = list->next;
44 
45  __kmp_node_deref(thread, list->node);
46 #if USE_FAST_MEMORY
47  __kmp_fast_free(thread, list);
48 #else
49  __kmp_thread_free(thread, list);
50 #endif
51  }
52 }
53 
54 static inline void __kmp_dephash_free_entries(kmp_info_t *thread,
55  kmp_dephash_t *h) {
56  for (size_t i = 0; i < h->size; i++) {
57  if (h->buckets[i]) {
58  kmp_dephash_entry_t *next;
59  for (kmp_dephash_entry_t *entry = h->buckets[i]; entry; entry = next) {
60  next = entry->next_in_bucket;
61  __kmp_depnode_list_free(thread, entry->last_ins);
62  __kmp_depnode_list_free(thread, entry->last_mtxs);
63  __kmp_node_deref(thread, entry->last_out);
64  if (entry->mtx_lock) {
65  __kmp_destroy_lock(entry->mtx_lock);
66  __kmp_free(entry->mtx_lock);
67  }
68 #if USE_FAST_MEMORY
69  __kmp_fast_free(thread, entry);
70 #else
71  __kmp_thread_free(thread, entry);
72 #endif
73  }
74  h->buckets[i] = 0;
75  }
76  }
77 }
78 
79 static inline void __kmp_dephash_free(kmp_info_t *thread, kmp_dephash_t *h) {
80  __kmp_dephash_free_entries(thread, h);
81 #if USE_FAST_MEMORY
82  __kmp_fast_free(thread, h);
83 #else
84  __kmp_thread_free(thread, h);
85 #endif
86 }
87 
88 static inline void __kmp_release_deps(kmp_int32 gtid, kmp_taskdata_t *task) {
89  kmp_info_t *thread = __kmp_threads[gtid];
90  kmp_depnode_t *node = task->td_depnode;
91 
92  if (task->td_dephash) {
93  KA_TRACE(
94  40, ("__kmp_release_deps: T#%d freeing dependencies hash of task %p.\n",
95  gtid, task));
96  __kmp_dephash_free(thread, task->td_dephash);
97  task->td_dephash = NULL;
98  }
99 
100  if (!node)
101  return;
102 
103  KA_TRACE(20, ("__kmp_release_deps: T#%d notifying successors of task %p.\n",
104  gtid, task));
105 
106  KMP_ACQUIRE_DEPNODE(gtid, node);
107  node->dn.task =
108  NULL; // mark this task as finished, so no new dependencies are generated
109  KMP_RELEASE_DEPNODE(gtid, node);
110 
111  kmp_depnode_list_t *next;
112  for (kmp_depnode_list_t *p = node->dn.successors; p; p = next) {
113  kmp_depnode_t *successor = p->node;
114  kmp_int32 npredecessors = KMP_ATOMIC_DEC(&successor->dn.npredecessors) - 1;
115 
116  // successor task can be NULL for wait_depends or because deps are still
117  // being processed
118  if (npredecessors == 0) {
119  KMP_MB();
120  if (successor->dn.task) {
121  KA_TRACE(20, ("__kmp_release_deps: T#%d successor %p of %p scheduled "
122  "for execution.\n",
123  gtid, successor->dn.task, task));
124  __kmp_omp_task(gtid, successor->dn.task, false);
125  }
126  }
127 
128  next = p->next;
129  __kmp_node_deref(thread, p->node);
130 #if USE_FAST_MEMORY
131  __kmp_fast_free(thread, p);
132 #else
133  __kmp_thread_free(thread, p);
134 #endif
135  }
136 
137  __kmp_node_deref(thread, node);
138 
139  KA_TRACE(
140  20,
141  ("__kmp_release_deps: T#%d all successors of %p notified of completion\n",
142  gtid, task));
143 }
144 
145 #endif // KMP_TASKDEPS_H