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37 #include <sys/queue.h>
39 #include <rte_memory.h>
41 #include <rte_launch.h>
42 #include <rte_per_lcore.h>
43 #include <rte_lcore.h>
44 #include <rte_debug.h>
45 #include <rte_common.h>
46 #include <rte_spinlock.h>
48 #include "malloc_elem.h"
49 #include "malloc_heap.h"
51 #define MIN_DATA_SIZE (RTE_CACHE_LINE_SIZE)
54 * initialise a general malloc_elem header structure
57 malloc_elem_init(struct malloc_elem *elem,
58 struct malloc_heap *heap, const struct rte_memseg *ms, size_t size)
63 memset(&elem->free_list, 0, sizeof(elem->free_list));
64 elem->state = ELEM_FREE;
72 * initialise a dummy malloc_elem header for the end-of-memseg marker
75 malloc_elem_mkend(struct malloc_elem *elem, struct malloc_elem *prev)
77 malloc_elem_init(elem, prev->heap, prev->ms, 0);
79 elem->state = ELEM_BUSY; /* mark busy so its never merged */
83 * calculate the starting point of where data of the requested size
84 * and alignment would fit in the current element. If the data doesn't
88 elem_start_pt(struct malloc_elem *elem, size_t size, unsigned align,
91 const size_t bmask = ~(bound - 1);
92 uintptr_t end_pt = (uintptr_t)elem +
93 elem->size - MALLOC_ELEM_TRAILER_LEN;
94 uintptr_t new_data_start = RTE_ALIGN_FLOOR((end_pt - size), align);
95 uintptr_t new_elem_start;
98 if ((new_data_start & bmask) != ((end_pt - 1) & bmask)) {
99 end_pt = RTE_ALIGN_FLOOR(end_pt, bound);
100 new_data_start = RTE_ALIGN_FLOOR((end_pt - size), align);
101 if (((end_pt - 1) & bmask) != (new_data_start & bmask))
105 new_elem_start = new_data_start - MALLOC_ELEM_HEADER_LEN;
107 /* if the new start point is before the exist start, it won't fit */
108 return (new_elem_start < (uintptr_t)elem) ? NULL : (void *)new_elem_start;
112 * use elem_start_pt to determine if we get meet the size and
113 * alignment request from the current element
116 malloc_elem_can_hold(struct malloc_elem *elem, size_t size, unsigned align,
119 return elem_start_pt(elem, size, align, bound) != NULL;
123 * split an existing element into two smaller elements at the given
124 * split_pt parameter.
127 split_elem(struct malloc_elem *elem, struct malloc_elem *split_pt)
129 struct malloc_elem *next_elem = RTE_PTR_ADD(elem, elem->size);
130 const size_t old_elem_size = (uintptr_t)split_pt - (uintptr_t)elem;
131 const size_t new_elem_size = elem->size - old_elem_size;
133 malloc_elem_init(split_pt, elem->heap, elem->ms, new_elem_size);
134 split_pt->prev = elem;
135 next_elem->prev = split_pt;
136 elem->size = old_elem_size;
141 * Given an element size, compute its freelist index.
142 * We free an element into the freelist containing similarly-sized elements.
143 * We try to allocate elements starting with the freelist containing
144 * similarly-sized elements, and if necessary, we search freelists
145 * containing larger elements.
147 * Example element size ranges for a heap with five free lists:
148 * heap->free_head[0] - (0 , 2^8]
149 * heap->free_head[1] - (2^8 , 2^10]
150 * heap->free_head[2] - (2^10 ,2^12]
151 * heap->free_head[3] - (2^12, 2^14]
152 * heap->free_head[4] - (2^14, MAX_SIZE]
155 malloc_elem_free_list_index(size_t size)
157 #define MALLOC_MINSIZE_LOG2 8
158 #define MALLOC_LOG2_INCREMENT 2
163 if (size <= (1UL << MALLOC_MINSIZE_LOG2))
166 /* Find next power of 2 >= size. */
167 log2 = sizeof(size) * 8 - __builtin_clzl(size-1);
169 /* Compute freelist index, based on log2(size). */
170 index = (log2 - MALLOC_MINSIZE_LOG2 + MALLOC_LOG2_INCREMENT - 1) /
171 MALLOC_LOG2_INCREMENT;
173 return index <= RTE_HEAP_NUM_FREELISTS-1?
174 index: RTE_HEAP_NUM_FREELISTS-1;
178 * Add the specified element to its heap's free list.
181 malloc_elem_free_list_insert(struct malloc_elem *elem)
185 idx = malloc_elem_free_list_index(elem->size - MALLOC_ELEM_HEADER_LEN);
186 elem->state = ELEM_FREE;
187 LIST_INSERT_HEAD(&elem->heap->free_head[idx], elem, free_list);
191 * Remove the specified element from its heap's free list.
194 elem_free_list_remove(struct malloc_elem *elem)
196 LIST_REMOVE(elem, free_list);
200 * reserve a block of data in an existing malloc_elem. If the malloc_elem
201 * is much larger than the data block requested, we split the element in two.
202 * This function is only called from malloc_heap_alloc so parameter checking
203 * is not done here, as it's done there previously.
206 malloc_elem_alloc(struct malloc_elem *elem, size_t size, unsigned align,
209 struct malloc_elem *new_elem = elem_start_pt(elem, size, align, bound);
210 const size_t old_elem_size = (uintptr_t)new_elem - (uintptr_t)elem;
211 const size_t trailer_size = elem->size - old_elem_size - size -
212 MALLOC_ELEM_OVERHEAD;
214 elem_free_list_remove(elem);
216 if (trailer_size > MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
217 /* split it, too much free space after elem */
218 struct malloc_elem *new_free_elem =
219 RTE_PTR_ADD(new_elem, size + MALLOC_ELEM_OVERHEAD);
221 split_elem(elem, new_free_elem);
222 malloc_elem_free_list_insert(new_free_elem);
225 if (old_elem_size < MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
226 /* don't split it, pad the element instead */
227 elem->state = ELEM_BUSY;
228 elem->pad = old_elem_size;
230 /* put a dummy header in padding, to point to real element header */
231 if (elem->pad > 0){ /* pad will be at least 64-bytes, as everything
232 * is cache-line aligned */
233 new_elem->pad = elem->pad;
234 new_elem->state = ELEM_PAD;
235 new_elem->size = elem->size - elem->pad;
236 set_header(new_elem);
242 /* we are going to split the element in two. The original element
243 * remains free, and the new element is the one allocated.
244 * Re-insert original element, in case its new size makes it
245 * belong on a different list.
247 split_elem(elem, new_elem);
248 new_elem->state = ELEM_BUSY;
249 malloc_elem_free_list_insert(elem);
255 * joing two struct malloc_elem together. elem1 and elem2 must
256 * be contiguous in memory.
259 join_elem(struct malloc_elem *elem1, struct malloc_elem *elem2)
261 struct malloc_elem *next = RTE_PTR_ADD(elem2, elem2->size);
262 elem1->size += elem2->size;
267 * free a malloc_elem block by adding it to the free list. If the
268 * blocks either immediately before or immediately after newly freed block
269 * are also free, the blocks are merged together.
272 malloc_elem_free(struct malloc_elem *elem)
274 if (!malloc_elem_cookies_ok(elem) || elem->state != ELEM_BUSY)
277 rte_spinlock_lock(&(elem->heap->lock));
278 struct malloc_elem *next = RTE_PTR_ADD(elem, elem->size);
279 if (next->state == ELEM_FREE){
280 /* remove from free list, join to this one */
281 elem_free_list_remove(next);
282 join_elem(elem, next);
285 /* check if previous element is free, if so join with it and return,
286 * need to re-insert in free list, as that element's size is changing
288 if (elem->prev != NULL && elem->prev->state == ELEM_FREE) {
289 elem_free_list_remove(elem->prev);
290 join_elem(elem->prev, elem);
291 malloc_elem_free_list_insert(elem->prev);
293 /* otherwise add ourselves to the free list */
295 malloc_elem_free_list_insert(elem);
298 /* decrease heap's count of allocated elements */
299 elem->heap->alloc_count--;
300 rte_spinlock_unlock(&(elem->heap->lock));
306 * attempt to resize a malloc_elem by expanding into any free space
307 * immediately after it in memory.
310 malloc_elem_resize(struct malloc_elem *elem, size_t size)
312 const size_t new_size = size + MALLOC_ELEM_OVERHEAD;
313 /* if we request a smaller size, then always return ok */
314 const size_t current_size = elem->size - elem->pad;
315 if (current_size >= new_size)
318 struct malloc_elem *next = RTE_PTR_ADD(elem, elem->size);
319 rte_spinlock_lock(&elem->heap->lock);
320 if (next ->state != ELEM_FREE)
322 if (current_size + next->size < new_size)
325 /* we now know the element fits, so remove from free list,
328 elem_free_list_remove(next);
329 join_elem(elem, next);
331 if (elem->size - new_size >= MIN_DATA_SIZE + MALLOC_ELEM_OVERHEAD){
332 /* now we have a big block together. Lets cut it down a bit, by splitting */
333 struct malloc_elem *split_pt = RTE_PTR_ADD(elem, new_size);
334 split_pt = RTE_PTR_ALIGN_CEIL(split_pt, RTE_CACHE_LINE_SIZE);
335 split_elem(elem, split_pt);
336 malloc_elem_free_list_insert(split_pt);
338 rte_spinlock_unlock(&elem->heap->lock);
342 rte_spinlock_unlock(&elem->heap->lock);