1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _PERF_RESORT_RB_H_
3 #define _PERF_RESORT_RB_H_
4 /*
5 * Template for creating a class to resort an existing rb_tree according to
6 * a new sort criteria, that must be present in the entries of the source
7 * rb_tree.
8 *
9 * (c) 2016 Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Quick example, resorting threads by its shortname:
12 *
13 * First define the prefix (threads) to be used for the functions and data
14 * structures created, and provide an expression for the sorting, then the
15 * fields to be present in each of the entries in the new, sorted, rb_tree.
16 *
17 * The body of the init function should collect the fields, maybe
18 * pre-calculating them from multiple entries in the original 'entry' from
19 * the rb_tree used as a source for the entries to be sorted:
20
21 DEFINE_RB_RESORT_RB(threads, strcmp(a->thread->shortname,
22 b->thread->shortname) < 0,
23 struct thread *thread;
24 )
25 {
26 entry->thread = rb_entry(nd, struct thread, rb_node);
27 }
28
29 * After this it is just a matter of instantiating it and iterating it,
30 * for a few data structures with existing rb_trees, such as 'struct machine',
31 * helpers are available to get the rb_root and the nr_entries:
32
33 DECLARE_RESORT_RB_MACHINE_THREADS(threads, machine_ptr);
34
35 * This will instantiate the new rb_tree and a cursor for it, that can be used as:
36
37 struct rb_node *nd;
38
39 resort_rb__for_each_entry(nd, threads) {
40 struct thread *t = threads_entry;
41 printf("%s: %d\n", t->shortname, t->tid);
42 }
43
44 * Then delete it:
45
46 resort_rb__delete(threads);
47
48 * The name of the data structures and functions will have a _sorted suffix
49 * right before the method names, i.e. will look like:
50 *
51 * struct threads_sorted_entry {}
52 * threads_sorted__insert()
53 */
54
55 #define DEFINE_RESORT_RB(__name, __comp, ...) \
56 struct __name##_sorted_entry { \
57 struct rb_node rb_node; \
58 __VA_ARGS__ \
59 }; \
60 static void __name##_sorted__init_entry(struct rb_node *nd, \
61 struct __name##_sorted_entry *entry); \
62 \
63 static int __name##_sorted__cmp(struct rb_node *nda, struct rb_node *ndb) \
64 { \
65 struct __name##_sorted_entry *a, *b; \
66 a = rb_entry(nda, struct __name##_sorted_entry, rb_node); \
67 b = rb_entry(ndb, struct __name##_sorted_entry, rb_node); \
68 return __comp; \
69 } \
70 \
71 struct __name##_sorted { \
72 struct rb_root entries; \
73 struct __name##_sorted_entry nd[0]; \
74 }; \
75 \
76 static void __name##_sorted__insert(struct __name##_sorted *sorted, \
77 struct rb_node *sorted_nd) \
78 { \
79 struct rb_node **p = &sorted->entries.rb_node, *parent = NULL; \
80 while (*p != NULL) { \
81 parent = *p; \
82 if (__name##_sorted__cmp(sorted_nd, parent)) \
83 p = &(*p)->rb_left; \
84 else \
85 p = &(*p)->rb_right; \
86 } \
87 rb_link_node(sorted_nd, parent, p); \
88 rb_insert_color(sorted_nd, &sorted->entries); \
89 } \
90 \
91 static void __name##_sorted__sort(struct __name##_sorted *sorted, \
92 struct rb_root *entries) \
93 { \
94 struct rb_node *nd; \
95 unsigned int i = 0; \
96 for (nd = rb_first(entries); nd; nd = rb_next(nd)) { \
97 struct __name##_sorted_entry *snd = &sorted->nd[i++]; \
98 __name##_sorted__init_entry(nd, snd); \
99 __name##_sorted__insert(sorted, &snd->rb_node); \
100 } \
101 } \
102 \
103 static struct __name##_sorted *__name##_sorted__new(struct rb_root *entries, \
104 int nr_entries) \
105 { \
106 struct __name##_sorted *sorted; \
107 sorted = malloc(sizeof(*sorted) + sizeof(sorted->nd[0]) * nr_entries); \
108 if (sorted) { \
109 sorted->entries = RB_ROOT; \
110 __name##_sorted__sort(sorted, entries); \
111 } \
112 return sorted; \
113 } \
114 \
115 static void __name##_sorted__delete(struct __name##_sorted *sorted) \
116 { \
117 free(sorted); \
118 } \
119 \
120 static void __name##_sorted__init_entry(struct rb_node *nd, \
121 struct __name##_sorted_entry *entry)
122
123 #define DECLARE_RESORT_RB(__name) \
124 struct __name##_sorted_entry *__name##_entry; \
125 struct __name##_sorted *__name = __name##_sorted__new
126
127 #define resort_rb__for_each_entry(__nd, __name) \
128 for (__nd = rb_first(&__name->entries); \
129 __name##_entry = rb_entry(__nd, struct __name##_sorted_entry, \
130 rb_node), __nd; \
131 __nd = rb_next(__nd))
132
133 #define resort_rb__delete(__name) \
134 __name##_sorted__delete(__name), __name = NULL
135
136 /*
137 * Helpers for other classes that contains both an rbtree and the
138 * number of entries in it:
139 */
140
141 /* For 'struct intlist' */
142 #define DECLARE_RESORT_RB_INTLIST(__name, __ilist) \
143 DECLARE_RESORT_RB(__name)(&__ilist->rblist.entries.rb_root, \
144 __ilist->rblist.nr_entries)
145
146 #endif /* _PERF_RESORT_RB_H_ */
147
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