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> |
48f5e0b5 | 29 | #include <wrapper/vmalloc.h> |
f3bc08c5 | 30 | |
0b6d2ab3 | 31 | #ifdef DEBUG_HEAP |
a88db018 | 32 | void lttng_check_heap(const struct lttng_ptr_heap *heap) |
0b6d2ab3 MD |
33 | { |
34 | size_t i; | |
35 | ||
36 | if (!heap->len) | |
37 | return; | |
38 | ||
39 | for (i = 1; i < heap->len; i++) | |
40 | WARN_ON_ONCE(!heap->gt(heap->ptrs[i], heap->ptrs[0])); | |
41 | } | |
42 | #endif | |
43 | ||
a29e892a | 44 | static |
7369e702 | 45 | size_t parent(size_t i) |
c9891db2 | 46 | { |
0b6d2ab3 | 47 | return (i -1) >> 1; |
7369e702 MD |
48 | } |
49 | ||
50 | static | |
51 | size_t left(size_t i) | |
52 | { | |
0b6d2ab3 | 53 | return (i << 1) + 1; |
7369e702 MD |
54 | } |
55 | ||
56 | static | |
57 | size_t right(size_t i) | |
58 | { | |
0b6d2ab3 | 59 | return (i << 1) + 2; |
7369e702 MD |
60 | } |
61 | ||
a29e892a MD |
62 | /* |
63 | * Copy of heap->ptrs pointer is invalid after heap_grow. | |
64 | */ | |
7369e702 | 65 | static |
a88db018 | 66 | int heap_grow(struct lttng_ptr_heap *heap, size_t new_len) |
7369e702 MD |
67 | { |
68 | void **new_ptrs; | |
69 | ||
70 | if (heap->alloc_len >= new_len) | |
71 | return 0; | |
72 | ||
73 | heap->alloc_len = max_t(size_t, new_len, heap->alloc_len << 1); | |
48f5e0b5 | 74 | new_ptrs = lttng_kvmalloc(heap->alloc_len * sizeof(void *), heap->gfpmask); |
7369e702 | 75 | if (!new_ptrs) |
c9891db2 | 76 | return -ENOMEM; |
7369e702 MD |
77 | if (heap->ptrs) |
78 | memcpy(new_ptrs, heap->ptrs, heap->len * sizeof(void *)); | |
48f5e0b5 | 79 | lttng_kvfree(heap->ptrs); |
7369e702 MD |
80 | heap->ptrs = new_ptrs; |
81 | return 0; | |
82 | } | |
83 | ||
84 | static | |
a88db018 | 85 | int heap_set_len(struct lttng_ptr_heap *heap, size_t new_len) |
7369e702 MD |
86 | { |
87 | int ret; | |
88 | ||
89 | ret = heap_grow(heap, new_len); | |
90 | if (ret) | |
91 | return ret; | |
92 | heap->len = new_len; | |
c9891db2 MD |
93 | return 0; |
94 | } | |
95 | ||
a88db018 | 96 | int lttng_heap_init(struct lttng_ptr_heap *heap, size_t alloc_len, |
7369e702 MD |
97 | gfp_t gfpmask, int gt(void *a, void *b)) |
98 | { | |
99 | heap->ptrs = NULL; | |
100 | heap->len = 0; | |
101 | heap->alloc_len = 0; | |
102 | heap->gt = gt; | |
ff77b142 | 103 | heap->gfpmask = gfpmask; |
7369e702 MD |
104 | /* |
105 | * Minimum size allocated is 1 entry to ensure memory allocation | |
106 | * never fails within heap_replace_max. | |
107 | */ | |
c8d547f0 | 108 | return heap_grow(heap, max_t(size_t, 1, alloc_len)); |
7369e702 MD |
109 | } |
110 | ||
a88db018 | 111 | void lttng_heap_free(struct lttng_ptr_heap *heap) |
c9891db2 | 112 | { |
48f5e0b5 | 113 | lttng_kvfree(heap->ptrs); |
c9891db2 | 114 | } |
f3bc08c5 | 115 | |
a88db018 | 116 | static void heapify(struct lttng_ptr_heap *heap, size_t i) |
f3bc08c5 | 117 | { |
7369e702 MD |
118 | void **ptrs = heap->ptrs; |
119 | size_t l, r, largest; | |
120 | ||
121 | for (;;) { | |
0b6d2ab3 MD |
122 | void *tmp; |
123 | ||
7369e702 MD |
124 | l = left(i); |
125 | r = right(i); | |
0b6d2ab3 | 126 | if (l < heap->len && heap->gt(ptrs[l], ptrs[i])) |
7369e702 MD |
127 | largest = l; |
128 | else | |
129 | largest = i; | |
0b6d2ab3 | 130 | if (r < heap->len && heap->gt(ptrs[r], ptrs[largest])) |
7369e702 | 131 | largest = r; |
0b6d2ab3 | 132 | if (largest == i) |
7369e702 | 133 | break; |
0b6d2ab3 MD |
134 | tmp = ptrs[i]; |
135 | ptrs[i] = ptrs[largest]; | |
136 | ptrs[largest] = tmp; | |
137 | i = largest; | |
7369e702 | 138 | } |
a88db018 | 139 | lttng_check_heap(heap); |
f3bc08c5 MD |
140 | } |
141 | ||
a88db018 | 142 | void *lttng_heap_replace_max(struct lttng_ptr_heap *heap, void *p) |
f3bc08c5 MD |
143 | { |
144 | void *res; | |
f3bc08c5 | 145 | |
7369e702 MD |
146 | if (!heap->len) { |
147 | (void) heap_set_len(heap, 1); | |
a29e892a | 148 | heap->ptrs[0] = p; |
a88db018 | 149 | lttng_check_heap(heap); |
f3bc08c5 MD |
150 | return NULL; |
151 | } | |
152 | ||
153 | /* Replace the current max and heapify */ | |
a29e892a MD |
154 | res = heap->ptrs[0]; |
155 | heap->ptrs[0] = p; | |
f3bc08c5 MD |
156 | heapify(heap, 0); |
157 | return res; | |
158 | } | |
159 | ||
a88db018 | 160 | int lttng_heap_insert(struct lttng_ptr_heap *heap, void *p) |
c9891db2 | 161 | { |
a29e892a MD |
162 | void **ptrs; |
163 | size_t pos; | |
7369e702 | 164 | int ret; |
c9891db2 | 165 | |
7369e702 MD |
166 | ret = heap_set_len(heap, heap->len + 1); |
167 | if (ret) | |
168 | return ret; | |
a29e892a | 169 | ptrs = heap->ptrs; |
a29e892a | 170 | pos = heap->len - 1; |
0b6d2ab3 MD |
171 | while (pos > 0 && heap->gt(p, ptrs[parent(pos)])) { |
172 | /* Move parent down until we find the right spot */ | |
173 | ptrs[pos] = ptrs[parent(pos)]; | |
174 | pos = parent(pos); | |
a29e892a | 175 | } |
0b6d2ab3 | 176 | ptrs[pos] = p; |
a88db018 | 177 | lttng_check_heap(heap); |
7369e702 | 178 | return 0; |
c9891db2 MD |
179 | } |
180 | ||
a88db018 | 181 | void *lttng_heap_remove(struct lttng_ptr_heap *heap) |
f3bc08c5 | 182 | { |
7369e702 | 183 | switch (heap->len) { |
f3bc08c5 MD |
184 | case 0: |
185 | return NULL; | |
186 | case 1: | |
7369e702 | 187 | (void) heap_set_len(heap, 0); |
a29e892a | 188 | return heap->ptrs[0]; |
f3bc08c5 | 189 | } |
f3bc08c5 | 190 | /* Shrink, replace the current max by previous last entry and heapify */ |
7369e702 | 191 | heap_set_len(heap, heap->len - 1); |
0b6d2ab3 | 192 | /* len changed. previous last entry is at heap->len */ |
a88db018 | 193 | return lttng_heap_replace_max(heap, heap->ptrs[heap->len]); |
f3bc08c5 MD |
194 | } |
195 | ||
a88db018 | 196 | void *lttng_heap_cherrypick(struct lttng_ptr_heap *heap, void *p) |
f3bc08c5 | 197 | { |
7369e702 | 198 | size_t pos, len = heap->len; |
f3bc08c5 | 199 | |
7369e702 | 200 | for (pos = 0; pos < len; pos++) |
a29e892a | 201 | if (heap->ptrs[pos] == p) |
f3bc08c5 MD |
202 | goto found; |
203 | return NULL; | |
204 | found: | |
7369e702 MD |
205 | if (heap->len == 1) { |
206 | (void) heap_set_len(heap, 0); | |
a88db018 | 207 | lttng_check_heap(heap); |
a29e892a | 208 | return heap->ptrs[0]; |
f3bc08c5 | 209 | } |
7369e702 MD |
210 | /* Replace p with previous last entry and heapify. */ |
211 | heap_set_len(heap, heap->len - 1); | |
0b6d2ab3 MD |
212 | /* len changed. previous last entry is at heap->len */ |
213 | heap->ptrs[pos] = heap->ptrs[heap->len]; | |
f3bc08c5 MD |
214 | heapify(heap, pos); |
215 | return p; | |
216 | } |