dmmlib/src/custom_free.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 <stdio.h>
#include <dmmlib/dmmlib.h>
#include "other.h"
#ifdef HAVE_LOCKS
#include "posix_lock.h"
#endif /* HAVE_LOCKS */
#if defined (COALESCING_FIXED) || defined (COALESCING_VARIABLE)
#include "coalesce.h"
#endif /* COALESCING_FIXED || COALESCING_VARIABLE */
#ifdef WITH_ADAPTIVITY
#include "dmm_adaptor.h"
#endif /* WITH_ADAPTIVITY */
#include "block_header.h"

void custom_ahfree(allocator_t *allocator, heap_t* heap, void *ptr) {
    size_t size;
#ifdef WITH_FIXED_LISTS
    int fixed_list_id, i;
    maptable_node_t *current_maptable_node;
#endif /* WITH_FIXED_LISTS */
#if defined (COALESCING_FIXED) || defined (COALESCING_VARIABLE)
    bool coalesced;
    size_t max_coal_size;
    void *next_block;
    size_t current_next_size;
    size_t previous_current_size;
    size_t three_blocks_size;
#endif /* COALESCING_FIXED || COALESCING_VARIABLE */

#ifndef WITH_MEMORY_SPACE_AWARENESS
    int heap_id;
    /* Currently all the memory space aware allocators are pre-initialized */
    if(allocator == NULL) {
        allocator = &systemallocator;
    }

    if(heap == NULL) {
        heap_id = map_thread_heap();
        heap = &allocator->heaps[heap_id];
    }
#endif /* WITH_MEMORY_SPACE_AWARENESS */

    size = get_size(ptr);

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

#ifdef FUTURE_FEATURES
    remove_block(&ptr, &heap->used_blocks_head);
#endif /* FUTURE_FEATURES */

#ifdef WITH_STATS
    heap->dmm_stats.mem_allocated -= size;
#ifdef FUTURE_FEATURES
    heap->dmm_stats.mem_requested -= get_requested_size(ptr);
#endif /* FUTURE_FEATURES */
#endif /* WITH_STATS */

#if defined (COALESCING_FIXED) || defined (COALESCING_VARIABLE)
    coalesced = false;
#ifdef COALESCING_FIXED
    max_coal_size = MAX_COALESCE_SIZE;
#endif /* COALESCING_FIXED */
#ifdef COALESCING_VARIABLE
    max_coal_size = heap->dmm_knobs.max_coalesce_size;
#endif /* COALESCING_VARIABLE */

    next_block = get_dlnext(allocator, ptr);
    if(next_block != NULL) {
        if(is_free(next_block) == true) {
#ifdef WITH_OWNERSHIP
            if(get_owner(next_block) == get_owner(ptr)) {
#endif /* WITH_OWNERSHIP */
                current_next_size = size + get_size(next_block) + HEADER_SIZE;
#ifdef WITH_OWNERSHIP
            }
#endif /* WITH_OWNERSHIP */
        } else {
            current_next_size = (size_t) -1; /* SIZE_MAX */
        }
    } else {
        current_next_size = (size_t) -1; /* SIZE_MAX */
    }

    if(is_previous_free(ptr) == true) {
#ifdef WITH_OWNERSHIP
        if(get_owner(ptr) == get_owner(get_dlprevious(ptr))) {
#endif /* WITH_OWNERSHIP */
            previous_current_size = size + get_previous_size(ptr) + HEADER_SIZE;
#ifdef WITH_OWNERSHIP
        }
#endif /* WITH_OWNERSHIP */
    } else {
        previous_current_size = (size_t) -1; /* SIZE_MAX */
    }

    if(next_block != NULL && is_previous_free(ptr)) {
#ifdef WITH_OWNERSHIP
        if(get_owner(ptr) == get_owner(get_dlprevious(ptr) &&
            get_owner(ptr) == get_owner(next_block))) {
#endif /* WITH_OWNERSHIP */
                three_blocks_size = get_previous_size(ptr) + size +
                    get_size(next_block) + 2 * HEADER_SIZE;
#ifdef WITH_OWNERSHIP
        }
#endif /* WITH_OWNERSHIP */
    } else {
        three_blocks_size = (size_t) -1; /* SIZE_MAX */
    }

    if(three_blocks_size <= max_coal_size) {
        ptr = coalesce(allocator, heap, ptr, three_blocks_size);
        remove_block_from_lists(&next_block, heap);
        if(allocator->border_ptr == next_block) {
            allocator->border_ptr = ptr;
        }
        coalesced = true;
        size = three_blocks_size;
    } else {
        if(previous_current_size <= max_coal_size) {
            ptr = coalesce(allocator, heap, ptr, previous_current_size);
            coalesced = true;
            size = previous_current_size;
        } else {
            if(current_next_size <= max_coal_size) {
                set_size_and_free(allocator, ptr, current_next_size);
                remove_block_from_lists(&next_block, heap);
                if(allocator->border_ptr == next_block) {
                    allocator->border_ptr = ptr;
                }
            } else {
                mark_free(allocator, ptr);
            }
        }
    }
#else
    mark_free(allocator, ptr);
#endif /* COALESCING_FIXED || COALESCING_VARIABLE */

#ifdef WITH_FIXED_LISTS
    /* Check if the block could be put in a fixed list */
    fixed_list_id = map_size_to_list(heap, size);

    if(fixed_list_id != -1) {
        current_maptable_node = heap->maptable_head;		
        if(fixed_list_id != 0) {
            for(i = 1; i < fixed_list_id; i++) {
                current_maptable_node = current_maptable_node->next;
            }
        }
        push_block(&ptr, &current_maptable_node->fixed_list_head);
    } else { /* put it in the free list */
#endif /* WITH_FIXED_LISTS */
#if defined (COALESCING_FIXED) || defined (COALESCING_VARIABLE)
        /* The block should be added to the free list only if it is not
         * coalesced
         */
        if(!coalesced) {
            push_block(&ptr, &heap->free_list_head);
        }
#else
        push_block(&ptr, &heap->free_list_head);
#endif /* COALESCING_FIXED || COALESCING_VARIABLE */
#ifdef WITH_FIXED_LISTS
    }
#endif /* WITH_FIXED_LISTS */

#ifdef WITH_STATS
    /* Update Stats */
    heap->dmm_stats.live_objects -= 1;
    heap->dmm_stats.num_free += 1;
    /* End of Stats */
#endif /* WITH_STATS */

#ifdef WITH_ADAPTIVITY
    /* Refresh the state of the heap allocator if a certain number of
     * free's has been served already
     */
    /* TODO Define 100 as a constant */
    if(heap->dmm_stats.num_free % 100) {
        free_state_refresh(heap);
    }
#endif /* WITH_ADAPTIVITY */

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

/* Currently all the memory space aware allocators are pre-initialized, so
 * we do not expect any custom_ahmalloc call without knowing which allocator
 * and heap are to be used.
 */
#ifndef WITH_MEMORY_SPACE_AWARENESS
void custom_free(void *ptr) {
    custom_ahfree(NULL, NULL, ptr);
}
#endif /* WITH_MEMORY_SPACE_AWARENESS */