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36 #include <sys/queue.h>
38 #include <rte_memory.h>
39 #include <rte_memzone.h>
40 #include <rte_tailq.h>
42 #include <rte_launch.h>
43 #include <rte_per_lcore.h>
44 #include <rte_lcore.h>
45 #include <rte_debug.h>
46 #include <rte_common.h>
47 #include <rte_spinlock.h>
49 #include "malloc_elem.h"
50 #include "malloc_heap.h"
52 #define MIN_DATA_SIZE (CACHE_LINE_SIZE * 2)
55 * initialise a general malloc_elem header structure
58 malloc_elem_init(struct malloc_elem *elem,
59 struct malloc_heap *heap, size_t size)
62 elem->prev = elem->next_free = NULL;
63 elem->state = ELEM_FREE;
71 * initialise a dummy malloc_elem header for the end-of-memzone marker
74 malloc_elem_mkend(struct malloc_elem *elem, struct malloc_elem *prev)
76 malloc_elem_init(elem, prev->heap, 0);
78 elem->state = ELEM_BUSY; /* mark busy so its never merged */
82 * calculate the starting point of where data of the requested size
83 * and alignment would fit in the current element. If the data doesn't
87 elem_start_pt(struct malloc_elem *elem, size_t size, unsigned align)
89 const uintptr_t end_pt = (uintptr_t)elem +
90 elem->size - MALLOC_ELEM_TRAILER_LEN;
91 const uintptr_t new_data_start = rte_align_floor_int((end_pt - size),align);
92 const uintptr_t new_elem_start = new_data_start - MALLOC_ELEM_HEADER_LEN;
94 /* if the new start point is before the exist start, it won't fit */
95 return (new_elem_start < (uintptr_t)elem) ? NULL : (void *)new_elem_start;
99 * use elem_start_pt to determine if we get meet the size and
100 * alignment request from the current element
103 malloc_elem_can_hold(struct malloc_elem *elem, size_t size, unsigned align)
105 return elem_start_pt(elem, size, align) != NULL;
109 * split an existing element into two smaller elements at the given
110 * split_pt parameter.
113 split_elem(struct malloc_elem *elem, struct malloc_elem *split_pt)
115 struct malloc_elem *next_elem = RTE_PTR_ADD(elem, elem->size);
116 const unsigned old_elem_size = (uintptr_t)split_pt - (uintptr_t)elem;
117 const unsigned new_elem_size = elem->size - old_elem_size;
119 malloc_elem_init(split_pt, elem->heap, new_elem_size);
120 split_pt->prev = elem;
121 next_elem->prev = split_pt;
122 elem->size = old_elem_size;
127 * reserve a block of data in an existing malloc_elem. If the malloc_elem
128 * is much larger than the data block requested, we split the element in two.
129 * This function is only called from malloc_heap_alloc so parameter checking
130 * is not done here, as it's done there previously.
133 malloc_elem_alloc(struct malloc_elem *elem, size_t size,
134 unsigned align, struct malloc_elem *prev_free)
136 struct malloc_elem *new_elem = elem_start_pt(elem, size, align);
137 const unsigned old_elem_size = (uintptr_t)new_elem - (uintptr_t)elem;
139 if (old_elem_size <= MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE){
140 /* don't split it, pad the element instead */
141 elem->state = ELEM_BUSY;
142 elem->pad = old_elem_size;
144 /* put a dummy header in padding, to point to real element header */
145 if (elem->pad > 0){ /* pad will be at least 64-bytes, as everything
146 * is cache-line aligned */
147 new_elem->pad = elem->pad;
148 new_elem->state = ELEM_PAD;
149 new_elem->size = elem->size - elem->pad;
150 set_header(new_elem);
152 /* remove element from free list */
153 if (prev_free == NULL)
154 elem->heap->free_head = elem->next_free;
156 prev_free->next_free = elem->next_free;
161 /* we are going to split the element in two. The original element
162 * remains free, and the new element is the one allocated, so no free list
163 * changes need to be made.
165 split_elem(elem, new_elem);
166 new_elem->state = ELEM_BUSY;
172 * joing two struct malloc_elem together. elem1 and elem2 must
173 * be contiguous in memory.
176 join_elem(struct malloc_elem *elem1, struct malloc_elem *elem2)
178 struct malloc_elem *next = RTE_PTR_ADD(elem2, elem2->size);
179 elem1->size += elem2->size;
184 * scan the free list, and remove the request element from that
185 * free list. (Free list to scan is got from heap pointer in element)
188 remove_from_free_list(struct malloc_elem *elem)
190 if (elem == elem->heap->free_head)
191 elem->heap->free_head = elem->next_free;
193 struct malloc_elem *prev_free = elem->heap->free_head;
194 while (prev_free && prev_free->next_free != elem)
195 prev_free = prev_free->next_free;
197 rte_panic("Corrupted free list\n");
198 prev_free->next_free = elem->next_free;
203 * free a malloc_elem block by adding it to the free list. If the
204 * blocks either immediately before or immediately after newly freed block
205 * are also free, the blocks are merged together.
208 malloc_elem_free(struct malloc_elem *elem)
210 if (!malloc_elem_cookies_ok(elem) || elem->state != ELEM_BUSY)
213 rte_spinlock_lock(&(elem->heap->lock));
214 struct malloc_elem *next = RTE_PTR_ADD(elem, elem->size);
215 if (next->state == ELEM_FREE){
216 /* join to this one, and remove from free list */
217 join_elem(elem, next);
218 remove_from_free_list(next);
221 /* check if previous element is free, if so join with it and return,
222 * no need to update free list, as that element is already there
224 if (elem->prev != NULL && elem->prev->state == ELEM_FREE)
225 join_elem(elem->prev, elem);
226 /* otherwise add ourselves to the free list */
228 elem->next_free = elem->heap->free_head;
229 elem->heap->free_head = elem;
230 elem->state = ELEM_FREE;
233 /* decrease heap's count of allocated elements */
234 elem->heap->alloc_count--;
235 rte_spinlock_unlock(&(elem->heap->lock));
241 * attempt to resize a malloc_elem by expanding into any free space
242 * immediately after it in memory.
245 malloc_elem_resize(struct malloc_elem *elem, size_t size)
247 const size_t new_size = size + MALLOC_ELEM_OVERHEAD;
248 /* if we request a smaller size, then always return ok */
249 const size_t current_size = elem->size - elem->pad;
250 if (current_size >= new_size)
253 struct malloc_elem *next = RTE_PTR_ADD(elem, elem->size);
254 rte_spinlock_lock(&elem->heap->lock);
255 if (next ->state != ELEM_FREE)
257 if (current_size + next->size < new_size)
260 /* we now know the element fits, so join the two, then remove from free
263 join_elem(elem, next);
264 remove_from_free_list(next);
266 if (elem->size - new_size > MIN_DATA_SIZE + MALLOC_ELEM_OVERHEAD){
267 /* now we have a big block together. Lets cut it down a bit, by splitting */
268 struct malloc_elem *split_pt = RTE_PTR_ADD(elem, new_size);
269 split_pt = RTE_PTR_ALIGN_CEIL(split_pt, CACHE_LINE_SIZE);
270 split_elem(elem, split_pt);
271 split_pt->state = ELEM_FREE;
272 split_pt->next_free = elem->heap->free_head;
273 elem->heap->free_head = split_pt;
275 rte_spinlock_unlock(&elem->heap->lock);
279 rte_spinlock_unlock(&elem->heap->lock);