dmmlib/src/custom_malloc.c

/*
 *   Copyright 2011 Institute of Communication and Computer Systems (ICCS) 
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 *
 */

#include <dmmlib/dmmlib.h>
#include "dmm_config.h"
#ifdef HAVE_LOCKS
#include "posix_lock.h"
#endif /* HAVE_LOCKS */
#if defined (SPLITTING_FIXED) || defined (SPLITTING_VARIABLE)
#include "split.h"
#endif /* SPLITTING_FIXED || SPLITTING_VARIABLE */
#include "other.h"
#include "linked_lists/linked_lists.h"
#include "linked_lists/search_algorithms.h"
#include "sys_alloc.h"
#include "block_header.h"
#ifdef WITH_ADAPTIVITY
#include "dmm_adaptor.h"
#endif /* WITH_ADAPTIVITY */

#if defined (BEST_FIT)
#define search_on_free(size) best_fit_on_freelist(heap, size)
#elif defined (GOOD_FIT)
#define search_on_free(size) good_fit_on_freelist(heap, size)
#elif defined (EXACT_FIT)
#define search_on_free(size) exact_fit_on_freelist(heap, size)
#elif defined (FIRST_FIT)
#define search_on_free(size) first_fit_on_freelist(heap, size)
#endif /* BEST_FIT */

void * custom_ahmalloc(allocator_t* allocator, heap_t* heap, size_t size) {
    void *ptr;
#if defined (SPLITTING_FIXED) || defined (SPLITTING_VARIABLE)
    size_t new_size;
    size_t min_split_size;
#endif /* (SPLITTING_FIXED) || (SPLITTING_VARIABLE) */

    ptr = NULL;

#ifdef HAVE_LOCKS
    posix_lock(heap);
#endif /* HAVE_LOCKS */

#ifdef COUNT_HOPS
    /* Initialize the hops counter */
    heap->dmm_stats.total_hops = 0;
#endif /* COUNT_HOPS */

#ifdef WITH_FIXED_LISTS
    ptr = search_on_fixed(heap, req_padding(size));

    if(ptr == NULL) {
#endif /* WITH_FIXED_LISTS */
#ifdef ALLOC_VAR_FIT
        ptr = (*allocator->search_policy)(heap, req_padding(size));
#elif defined (HEAP_VAR_FIT)
        ptr = (*heap->dmm_knobs.search_policy)(heap, req_padding(size));
#else /* ALLOC_VAR_FIT */
        ptr = search_on_free(size);
#endif /* ALLOC_VAR_FIT */
#ifdef WITH_FIXED_LISTS
    }
#endif /* WITH_FIXED_LISTS */

    if(ptr != NULL) {

#ifdef REQUEST_SIZE_INFO
        set_requested_size(ptr, size);
#endif /* REQUEST_SIZE_INFO */

        /* Try to split */
#if defined (SPLITTING_FIXED) || defined (SPLITTING_VARIABLE)
        /* Check what would be the size of the new block if we split the current
         * one.
         * Note: new_size is a size_t, so compare first in order to prevent an
         * underflow.
         */
        if(get_size(ptr) > size + HEADER_SIZE) {
            new_size = get_size(ptr) - size - HEADER_SIZE;
        } else {
            new_size = 0;
        }

#ifdef SPLITTING_FIXED
        min_split_size = MIN_SPLITTING_SIZE;
#endif /* SPLITTING_FIXED */
#ifdef SPLITTING_VARIABLE
        min_split_size = heap->dmm_knobs.min_split_size;
#endif /* SPLITTING_VARIABLE */

        if(new_size >= min_split_size) {
            split(allocator, heap, ptr, size);
        }
#endif /* (SPLITTING_FIXED) || (SPLITTING_VARIABLE) */

        mark_used(allocator, ptr);

#ifdef FUTURE_FEATURES
        /* Update the used blocks list */
        push_block(&ptr, &heap->used_blocks_head);
#endif /* FUTURE_FEATURES */

#ifdef WITH_STATS
        /* Update statistics */
#ifdef REQUEST_SIZE_INFO
        heap->dmm_stats.mem_requested += size;
#endif /* REQUEST_SIZE_INFO */
        heap->dmm_stats.mem_used += HEADER_SIZE + get_size(ptr);
        heap->dmm_stats.live_objects += 1;
        heap->dmm_stats.num_malloc += 1;
#endif /* WITH_STATS */

        /* FIXME To be refactored - END */

    } else {
        ptr = sys_alloc(allocator, heap, size);
    }

#ifdef WITH_ADAPTIVITY
    /* Refresh the state of the heap allocator if a certain number of
     * malloc's has been served already
     */
    /* TODO Define 50 as a constant */
    if(heap->dmm_stats.num_malloc % 50) {
        malloc_state_refresh(heap);
    }
#endif /* WITH_ADAPTIVITY */

#ifdef HAVE_LOCKS
    posix_unlock(heap);
#endif /* HAVE_LOCKS */

    return ptr;
}