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/*-
* BSD LICENSE
*
* Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <sys/queue.h>
#include <rte_memory.h>
#include <rte_eal.h>
#include <rte_launch.h>
#include <rte_per_lcore.h>
#include <rte_lcore.h>
#include <rte_debug.h>
#include <rte_common.h>
#include <rte_spinlock.h>
#include "malloc_elem.h"
#include "malloc_heap.h"
#define MIN_DATA_SIZE (RTE_CACHE_LINE_SIZE)
/*
* initialise a general malloc_elem header structure
*/
void
malloc_elem_init(struct malloc_elem *elem,
struct malloc_heap *heap, const struct rte_memseg *ms, size_t size)
{
elem->heap = heap;
elem->ms = ms;
elem->prev = NULL;
memset(&elem->free_list, 0, sizeof(elem->free_list));
elem->state = ELEM_FREE;
elem->size = size;
elem->pad = 0;
set_header(elem);
set_trailer(elem);
}
/*
* initialise a dummy malloc_elem header for the end-of-memseg marker
*/
void
malloc_elem_mkend(struct malloc_elem *elem, struct malloc_elem *prev)
{
malloc_elem_init(elem, prev->heap, prev->ms, 0);
elem->prev = prev;
elem->state = ELEM_BUSY; /* mark busy so its never merged */
}
/*
* calculate the starting point of where data of the requested size
* and alignment would fit in the current element. If the data doesn't
* fit, return NULL.
*/
static void *
elem_start_pt(struct malloc_elem *elem, size_t size, unsigned align,
size_t bound)
{
const size_t bmask = ~(bound - 1);
uintptr_t end_pt = (uintptr_t)elem +
elem->size - MALLOC_ELEM_TRAILER_LEN;
uintptr_t new_data_start = RTE_ALIGN_FLOOR((end_pt - size), align);
uintptr_t new_elem_start;
/* check boundary */
if ((new_data_start & bmask) != ((end_pt - 1) & bmask)) {
end_pt = RTE_ALIGN_FLOOR(end_pt, bound);
new_data_start = RTE_ALIGN_FLOOR((end_pt - size), align);
if (((end_pt - 1) & bmask) != (new_data_start & bmask))
return NULL;
}
new_elem_start = new_data_start - MALLOC_ELEM_HEADER_LEN;
/* if the new start point is before the exist start, it won't fit */
return (new_elem_start < (uintptr_t)elem) ? NULL : (void *)new_elem_start;
}
/*
* use elem_start_pt to determine if we get meet the size and
* alignment request from the current element
*/
int
malloc_elem_can_hold(struct malloc_elem *elem, size_t size, unsigned align,
size_t bound)
{
return elem_start_pt(elem, size, align, bound) != NULL;
}
/*
* split an existing element into two smaller elements at the given
* split_pt parameter.
*/
static void
split_elem(struct malloc_elem *elem, struct malloc_elem *split_pt)
{
struct malloc_elem *next_elem = RTE_PTR_ADD(elem, elem->size);
const size_t old_elem_size = (uintptr_t)split_pt - (uintptr_t)elem;
const size_t new_elem_size = elem->size - old_elem_size;
malloc_elem_init(split_pt, elem->heap, elem->ms, new_elem_size);
split_pt->prev = elem;
next_elem->prev = split_pt;
elem->size = old_elem_size;
set_trailer(elem);
}
/*
* Given an element size, compute its freelist index.
* We free an element into the freelist containing similarly-sized elements.
* We try to allocate elements starting with the freelist containing
* similarly-sized elements, and if necessary, we search freelists
* containing larger elements.
*
* Example element size ranges for a heap with five free lists:
* heap->free_head[0] - (0 , 2^8]
* heap->free_head[1] - (2^8 , 2^10]
* heap->free_head[2] - (2^10 ,2^12]
* heap->free_head[3] - (2^12, 2^14]
* heap->free_head[4] - (2^14, MAX_SIZE]
*/
size_t
malloc_elem_free_list_index(size_t size)
{
#define MALLOC_MINSIZE_LOG2 8
#define MALLOC_LOG2_INCREMENT 2
size_t log2;
size_t index;
if (size <= (1UL << MALLOC_MINSIZE_LOG2))
return 0;
/* Find next power of 2 >= size. */
log2 = sizeof(size) * 8 - __builtin_clzl(size-1);
/* Compute freelist index, based on log2(size). */
index = (log2 - MALLOC_MINSIZE_LOG2 + MALLOC_LOG2_INCREMENT - 1) /
MALLOC_LOG2_INCREMENT;
return index <= RTE_HEAP_NUM_FREELISTS-1?
index: RTE_HEAP_NUM_FREELISTS-1;
}
/*
* Add the specified element to its heap's free list.
*/
void
malloc_elem_free_list_insert(struct malloc_elem *elem)
{
size_t idx;
idx = malloc_elem_free_list_index(elem->size - MALLOC_ELEM_HEADER_LEN);
elem->state = ELEM_FREE;
LIST_INSERT_HEAD(&elem->heap->free_head[idx], elem, free_list);
}
/*
* Remove the specified element from its heap's free list.
*/
static void
elem_free_list_remove(struct malloc_elem *elem)
{
LIST_REMOVE(elem, free_list);
}
/*
* reserve a block of data in an existing malloc_elem. If the malloc_elem
* is much larger than the data block requested, we split the element in two.
* This function is only called from malloc_heap_alloc so parameter checking
* is not done here, as it's done there previously.
*/
struct malloc_elem *
malloc_elem_alloc(struct malloc_elem *elem, size_t size, unsigned align,
size_t bound)
{
struct malloc_elem *new_elem = elem_start_pt(elem, size, align, bound);
const size_t old_elem_size = (uintptr_t)new_elem - (uintptr_t)elem;
const size_t trailer_size = elem->size - old_elem_size - size -
MALLOC_ELEM_OVERHEAD;
elem_free_list_remove(elem);
if (trailer_size > MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
/* split it, too much free space after elem */
struct malloc_elem *new_free_elem =
RTE_PTR_ADD(new_elem, size + MALLOC_ELEM_OVERHEAD);
split_elem(elem, new_free_elem);
malloc_elem_free_list_insert(new_free_elem);
}
if (old_elem_size < MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
/* don't split it, pad the element instead */
elem->state = ELEM_BUSY;
elem->pad = old_elem_size;
/* put a dummy header in padding, to point to real element header */
if (elem->pad > 0){ /* pad will be at least 64-bytes, as everything
* is cache-line aligned */
new_elem->pad = elem->pad;
new_elem->state = ELEM_PAD;
new_elem->size = elem->size - elem->pad;
set_header(new_elem);
}
return new_elem;
}
/* we are going to split the element in two. The original element
* remains free, and the new element is the one allocated.
* Re-insert original element, in case its new size makes it
* belong on a different list.
*/
split_elem(elem, new_elem);
new_elem->state = ELEM_BUSY;
malloc_elem_free_list_insert(elem);
return new_elem;
}
/*
* joing two struct malloc_elem together. elem1 and elem2 must
* be contiguous in memory.
*/
static inline void
join_elem(struct malloc_elem *elem1, struct malloc_elem *elem2)
{
struct malloc_elem *next = RTE_PTR_ADD(elem2, elem2->size);
elem1->size += elem2->size;
next->prev = elem1;
}
/*
* free a malloc_elem block by adding it to the free list. If the
* blocks either immediately before or immediately after newly freed block
* are also free, the blocks are merged together.
*/
int
malloc_elem_free(struct malloc_elem *elem)
{
if (!malloc_elem_cookies_ok(elem) || elem->state != ELEM_BUSY)
return -1;
rte_spinlock_lock(&(elem->heap->lock));
size_t sz = elem->size - sizeof(*elem) - MALLOC_ELEM_TRAILER_LEN;
uint8_t *ptr = (uint8_t *)&elem[1];
struct malloc_elem *next = RTE_PTR_ADD(elem, elem->size);
if (next->state == ELEM_FREE){
/* remove from free list, join to this one */
elem_free_list_remove(next);
join_elem(elem, next);
sz += (sizeof(*elem) + MALLOC_ELEM_TRAILER_LEN);
}
/* check if previous element is free, if so join with it and return,
* need to re-insert in free list, as that element's size is changing
*/
if (elem->prev != NULL && elem->prev->state == ELEM_FREE) {
elem_free_list_remove(elem->prev);
join_elem(elem->prev, elem);
sz += (sizeof(*elem) + MALLOC_ELEM_TRAILER_LEN);
ptr -= (sizeof(*elem) + MALLOC_ELEM_TRAILER_LEN);
elem = elem->prev;
}
malloc_elem_free_list_insert(elem);
/* decrease heap's count of allocated elements */
elem->heap->alloc_count--;
memset(ptr, 0, sz);
rte_spinlock_unlock(&(elem->heap->lock));
return 0;
}
/*
* attempt to resize a malloc_elem by expanding into any free space
* immediately after it in memory.
*/
int
malloc_elem_resize(struct malloc_elem *elem, size_t size)
{
const size_t new_size = size + elem->pad + MALLOC_ELEM_OVERHEAD;
/* if we request a smaller size, then always return ok */
if (elem->size >= new_size)
return 0;
struct malloc_elem *next = RTE_PTR_ADD(elem, elem->size);
rte_spinlock_lock(&elem->heap->lock);
if (next ->state != ELEM_FREE)
goto err_return;
if (elem->size + next->size < new_size)
goto err_return;
/* we now know the element fits, so remove from free list,
* join the two
*/
elem_free_list_remove(next);
join_elem(elem, next);
if (elem->size - new_size >= MIN_DATA_SIZE + MALLOC_ELEM_OVERHEAD) {
/* now we have a big block together. Lets cut it down a bit, by splitting */
struct malloc_elem *split_pt = RTE_PTR_ADD(elem, new_size);
split_pt = RTE_PTR_ALIGN_CEIL(split_pt, RTE_CACHE_LINE_SIZE);
split_elem(elem, split_pt);
malloc_elem_free_list_insert(split_pt);
}
rte_spinlock_unlock(&elem->heap->lock);
return 0;
err_return:
rte_spinlock_unlock(&elem->heap->lock);
return -1;
}
|