Commit | Line | Data |
---|---|---|
f3bc08c5 | 1 | /* |
a88db018 | 2 | * lttng_prio_heap.c |
162769ef | 3 | * |
7369e702 | 4 | * Priority heap containing pointers. Based on CLRS, chapter 6. |
162769ef MD |
5 | * |
6 | * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
7 | * | |
8 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
9 | * of this software and associated documentation files (the "Software"), to deal | |
10 | * in the Software without restriction, including without limitation the rights | |
11 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
12 | * copies of the Software, and to permit persons to whom the Software is | |
13 | * furnished to do so, subject to the following conditions: | |
14 | * | |
15 | * The above copyright notice and this permission notice shall be included in | |
16 | * all copies or substantial portions of the Software. | |
5fd8c00a MD |
17 | * |
18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
20 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
21 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
22 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
23 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
24 | * SOFTWARE. | |
f3bc08c5 MD |
25 | */ |
26 | ||
27 | #include <linux/slab.h> | |
5671a661 | 28 | #include <lib/prio_heap/lttng_prio_heap.h> |
f3bc08c5 | 29 | |
0b6d2ab3 | 30 | #ifdef DEBUG_HEAP |
a88db018 | 31 | void lttng_check_heap(const struct lttng_ptr_heap *heap) |
0b6d2ab3 MD |
32 | { |
33 | size_t i; | |
34 | ||
35 | if (!heap->len) | |
36 | return; | |
37 | ||
38 | for (i = 1; i < heap->len; i++) | |
39 | WARN_ON_ONCE(!heap->gt(heap->ptrs[i], heap->ptrs[0])); | |
40 | } | |
41 | #endif | |
42 | ||
a29e892a | 43 | static |
7369e702 | 44 | size_t parent(size_t i) |
c9891db2 | 45 | { |
0b6d2ab3 | 46 | return (i -1) >> 1; |
7369e702 MD |
47 | } |
48 | ||
49 | static | |
50 | size_t left(size_t i) | |
51 | { | |
0b6d2ab3 | 52 | return (i << 1) + 1; |
7369e702 MD |
53 | } |
54 | ||
55 | static | |
56 | size_t right(size_t i) | |
57 | { | |
0b6d2ab3 | 58 | return (i << 1) + 2; |
7369e702 MD |
59 | } |
60 | ||
a29e892a MD |
61 | /* |
62 | * Copy of heap->ptrs pointer is invalid after heap_grow. | |
63 | */ | |
7369e702 | 64 | static |
a88db018 | 65 | int heap_grow(struct lttng_ptr_heap *heap, size_t new_len) |
7369e702 MD |
66 | { |
67 | void **new_ptrs; | |
68 | ||
69 | if (heap->alloc_len >= new_len) | |
70 | return 0; | |
71 | ||
72 | heap->alloc_len = max_t(size_t, new_len, heap->alloc_len << 1); | |
73 | new_ptrs = kmalloc(heap->alloc_len * sizeof(void *), heap->gfpmask); | |
74 | if (!new_ptrs) | |
c9891db2 | 75 | return -ENOMEM; |
7369e702 MD |
76 | if (heap->ptrs) |
77 | memcpy(new_ptrs, heap->ptrs, heap->len * sizeof(void *)); | |
78 | kfree(heap->ptrs); | |
79 | heap->ptrs = new_ptrs; | |
80 | return 0; | |
81 | } | |
82 | ||
83 | static | |
a88db018 | 84 | int heap_set_len(struct lttng_ptr_heap *heap, size_t new_len) |
7369e702 MD |
85 | { |
86 | int ret; | |
87 | ||
88 | ret = heap_grow(heap, new_len); | |
89 | if (ret) | |
90 | return ret; | |
91 | heap->len = new_len; | |
c9891db2 MD |
92 | return 0; |
93 | } | |
94 | ||
a88db018 | 95 | int lttng_heap_init(struct lttng_ptr_heap *heap, size_t alloc_len, |
7369e702 MD |
96 | gfp_t gfpmask, int gt(void *a, void *b)) |
97 | { | |
98 | heap->ptrs = NULL; | |
99 | heap->len = 0; | |
100 | heap->alloc_len = 0; | |
101 | heap->gt = gt; | |
ff77b142 | 102 | heap->gfpmask = gfpmask; |
7369e702 MD |
103 | /* |
104 | * Minimum size allocated is 1 entry to ensure memory allocation | |
105 | * never fails within heap_replace_max. | |
106 | */ | |
c8d547f0 | 107 | return heap_grow(heap, max_t(size_t, 1, alloc_len)); |
7369e702 MD |
108 | } |
109 | ||
a88db018 | 110 | void lttng_heap_free(struct lttng_ptr_heap *heap) |
c9891db2 MD |
111 | { |
112 | kfree(heap->ptrs); | |
113 | } | |
f3bc08c5 | 114 | |
a88db018 | 115 | static void heapify(struct lttng_ptr_heap *heap, size_t i) |
f3bc08c5 | 116 | { |
7369e702 MD |
117 | void **ptrs = heap->ptrs; |
118 | size_t l, r, largest; | |
119 | ||
120 | for (;;) { | |
0b6d2ab3 MD |
121 | void *tmp; |
122 | ||
7369e702 MD |
123 | l = left(i); |
124 | r = right(i); | |
0b6d2ab3 | 125 | if (l < heap->len && heap->gt(ptrs[l], ptrs[i])) |
7369e702 MD |
126 | largest = l; |
127 | else | |
128 | largest = i; | |
0b6d2ab3 | 129 | if (r < heap->len && heap->gt(ptrs[r], ptrs[largest])) |
7369e702 | 130 | largest = r; |
0b6d2ab3 | 131 | if (largest == i) |
7369e702 | 132 | break; |
0b6d2ab3 MD |
133 | tmp = ptrs[i]; |
134 | ptrs[i] = ptrs[largest]; | |
135 | ptrs[largest] = tmp; | |
136 | i = largest; | |
7369e702 | 137 | } |
a88db018 | 138 | lttng_check_heap(heap); |
f3bc08c5 MD |
139 | } |
140 | ||
a88db018 | 141 | void *lttng_heap_replace_max(struct lttng_ptr_heap *heap, void *p) |
f3bc08c5 MD |
142 | { |
143 | void *res; | |
f3bc08c5 | 144 | |
7369e702 MD |
145 | if (!heap->len) { |
146 | (void) heap_set_len(heap, 1); | |
a29e892a | 147 | heap->ptrs[0] = p; |
a88db018 | 148 | lttng_check_heap(heap); |
f3bc08c5 MD |
149 | return NULL; |
150 | } | |
151 | ||
152 | /* Replace the current max and heapify */ | |
a29e892a MD |
153 | res = heap->ptrs[0]; |
154 | heap->ptrs[0] = p; | |
f3bc08c5 MD |
155 | heapify(heap, 0); |
156 | return res; | |
157 | } | |
158 | ||
a88db018 | 159 | int lttng_heap_insert(struct lttng_ptr_heap *heap, void *p) |
c9891db2 | 160 | { |
a29e892a MD |
161 | void **ptrs; |
162 | size_t pos; | |
7369e702 | 163 | int ret; |
c9891db2 | 164 | |
7369e702 MD |
165 | ret = heap_set_len(heap, heap->len + 1); |
166 | if (ret) | |
167 | return ret; | |
a29e892a | 168 | ptrs = heap->ptrs; |
a29e892a | 169 | pos = heap->len - 1; |
0b6d2ab3 MD |
170 | while (pos > 0 && heap->gt(p, ptrs[parent(pos)])) { |
171 | /* Move parent down until we find the right spot */ | |
172 | ptrs[pos] = ptrs[parent(pos)]; | |
173 | pos = parent(pos); | |
a29e892a | 174 | } |
0b6d2ab3 | 175 | ptrs[pos] = p; |
a88db018 | 176 | lttng_check_heap(heap); |
7369e702 | 177 | return 0; |
c9891db2 MD |
178 | } |
179 | ||
a88db018 | 180 | void *lttng_heap_remove(struct lttng_ptr_heap *heap) |
f3bc08c5 | 181 | { |
7369e702 | 182 | switch (heap->len) { |
f3bc08c5 MD |
183 | case 0: |
184 | return NULL; | |
185 | case 1: | |
7369e702 | 186 | (void) heap_set_len(heap, 0); |
a29e892a | 187 | return heap->ptrs[0]; |
f3bc08c5 | 188 | } |
f3bc08c5 | 189 | /* Shrink, replace the current max by previous last entry and heapify */ |
7369e702 | 190 | heap_set_len(heap, heap->len - 1); |
0b6d2ab3 | 191 | /* len changed. previous last entry is at heap->len */ |
a88db018 | 192 | return lttng_heap_replace_max(heap, heap->ptrs[heap->len]); |
f3bc08c5 MD |
193 | } |
194 | ||
a88db018 | 195 | void *lttng_heap_cherrypick(struct lttng_ptr_heap *heap, void *p) |
f3bc08c5 | 196 | { |
7369e702 | 197 | size_t pos, len = heap->len; |
f3bc08c5 | 198 | |
7369e702 | 199 | for (pos = 0; pos < len; pos++) |
a29e892a | 200 | if (heap->ptrs[pos] == p) |
f3bc08c5 MD |
201 | goto found; |
202 | return NULL; | |
203 | found: | |
7369e702 MD |
204 | if (heap->len == 1) { |
205 | (void) heap_set_len(heap, 0); | |
a88db018 | 206 | lttng_check_heap(heap); |
a29e892a | 207 | return heap->ptrs[0]; |
f3bc08c5 | 208 | } |
7369e702 MD |
209 | /* Replace p with previous last entry and heapify. */ |
210 | heap_set_len(heap, heap->len - 1); | |
0b6d2ab3 MD |
211 | /* len changed. previous last entry is at heap->len */ |
212 | heap->ptrs[pos] = heap->ptrs[heap->len]; | |
f3bc08c5 MD |
213 | heapify(heap, pos); |
214 | return p; | |
215 | } |