4c62782f36552eb9905264193d0e4309ff4e82e3
1 /* SPDX-License-Identifier: MIT
5 * Priority heap containing pointers. Based on CLRS, chapter 6.
7 * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 #include <linux/slab.h>
11 #include <lib/prio_heap/lttng_prio_heap.h>
15 void lttng_check_heap(const struct lttng_ptr_heap
*heap
)
22 for (i
= 1; i
< heap
->len
; i
++)
23 WARN_ON_ONCE(!heap
->gt(heap
->ptrs
[i
], heap
->ptrs
[0]));
28 size_t parent(size_t i
)
40 size_t right(size_t i
)
46 * Copy of heap->ptrs pointer is invalid after heap_grow.
49 int heap_grow(struct lttng_ptr_heap
*heap
, size_t new_len
)
53 if (heap
->alloc_len
>= new_len
)
56 heap
->alloc_len
= max_t(size_t, new_len
, heap
->alloc_len
<< 1);
57 new_ptrs
= kvmalloc_node(heap
->alloc_len
* sizeof(void *), heap
->gfpmask
,
62 memcpy(new_ptrs
, heap
->ptrs
, heap
->len
* sizeof(void *));
64 heap
->ptrs
= new_ptrs
;
69 int heap_set_len(struct lttng_ptr_heap
*heap
, size_t new_len
)
73 ret
= heap_grow(heap
, new_len
);
80 int lttng_heap_init(struct lttng_ptr_heap
*heap
, size_t alloc_len
,
81 gfp_t gfpmask
, int gt(void *a
, void *b
))
87 heap
->gfpmask
= gfpmask
;
89 * Minimum size allocated is 1 entry to ensure memory allocation
90 * never fails within heap_replace_max.
92 return heap_grow(heap
, max_t(size_t, 1, alloc_len
));
95 void lttng_heap_free(struct lttng_ptr_heap
*heap
)
100 static void heapify(struct lttng_ptr_heap
*heap
, size_t i
)
102 void **ptrs
= heap
->ptrs
;
103 size_t l
, r
, largest
;
110 if (l
< heap
->len
&& heap
->gt(ptrs
[l
], ptrs
[i
]))
114 if (r
< heap
->len
&& heap
->gt(ptrs
[r
], ptrs
[largest
]))
119 ptrs
[i
] = ptrs
[largest
];
123 lttng_check_heap(heap
);
126 void *lttng_heap_replace_max(struct lttng_ptr_heap
*heap
, void *p
)
131 (void) heap_set_len(heap
, 1);
133 lttng_check_heap(heap
);
137 /* Replace the current max and heapify */
144 int lttng_heap_insert(struct lttng_ptr_heap
*heap
, void *p
)
150 ret
= heap_set_len(heap
, heap
->len
+ 1);
155 while (pos
> 0 && heap
->gt(p
, ptrs
[parent(pos
)])) {
156 /* Move parent down until we find the right spot */
157 ptrs
[pos
] = ptrs
[parent(pos
)];
161 lttng_check_heap(heap
);
165 void *lttng_heap_remove(struct lttng_ptr_heap
*heap
)
171 (void) heap_set_len(heap
, 0);
172 return heap
->ptrs
[0];
174 /* Shrink, replace the current max by previous last entry and heapify */
175 heap_set_len(heap
, heap
->len
- 1);
176 /* len changed. previous last entry is at heap->len */
177 return lttng_heap_replace_max(heap
, heap
->ptrs
[heap
->len
]);
180 void *lttng_heap_cherrypick(struct lttng_ptr_heap
*heap
, void *p
)
182 size_t pos
, len
= heap
->len
;
184 for (pos
= 0; pos
< len
; pos
++)
185 if (heap
->ptrs
[pos
] == p
)
189 if (heap
->len
== 1) {
190 (void) heap_set_len(heap
, 0);
191 lttng_check_heap(heap
);
192 return heap
->ptrs
[0];
194 /* Replace p with previous last entry and heapify. */
195 heap_set_len(heap
, heap
->len
- 1);
196 /* len changed. previous last entry is at heap->len */
197 heap
->ptrs
[pos
] = heap
->ptrs
[heap
->len
];
This page took 0.033255 seconds and 3 git commands to generate.