dmmlib/include/dmmlib/heap.h

/*
 *   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.
 *
 */

/**
 * \file 	heap.h
 * \author 	Ioannis Koutras (joko@microlab.ntua.gr)
 * \date 	September, 2011
 * 	Basic structures needed for the dmmlib allocator.
 */

#ifndef HEAP_H
#define HEAP_H

#include "dmm_config.h"

#include <stdbool.h>
#ifndef LEON3
#include <stdint.h>
#include <stddef.h> /* For size_t support */
#else
#include <sys/types.h>
#endif

#ifdef HAVE_LOCKS
#include <pthread.h>
#endif /* HAVE_LOCKS */

#ifdef WITH_KNOBS
/**
 * A structure for knobs states (currently 5)
 * 
 * FIXME Have to check them
 *
 * */
typedef uint8_t knob_state_t;
#endif /* WITH_KNOBS */

/** A structure to represent a maptable node.
 *  This is a single-linked list holoding blocks of specific size, thus acting
 *  as a fixed list within the allocator.
 */
typedef struct maptable_node_s {
	unsigned int size; /**< The size of the blocks of the fixed list. */
	void *fixed_list_head; /**< Pointer to the head node of the fixed list. */
	struct maptable_node_s *next; /**< Pointer to the next node of the
					maptable. */
} maptable_node_t;

#ifdef WITH_STATS
/** Statistics data structure. */
typedef struct dmmstats_s {
	size_t max_mem_allocated; /**< Maximum total memory allocated. */
	size_t max_mem_requested; /**< Maximum total memory requested. */
	size_t mem_allocated; /**< Total memory currently allocated. */
	size_t mem_requested; /**< Total memory currently requested. */
	uint32_t live_objects; /**< Number of the currently used blocks. */
	uint32_t read_mem_accesses; /**< Number of read accesses. */
	uint32_t write_mem_accesses; /**< Number of write accesses. */
	uint32_t num_malloc; /**< Number of malloc()'s served. */
	uint32_t num_free; /**< Number of free()'s served. */
} dmmstats_t;
#endif /* WITH_STATS */

#ifdef WITH_KNOBS
/** A structure to represent tunable parameters of a heap */
typedef struct dmmknobs_s {
	float frag_threshold; /**< Fragmentation threshold to enable coalescing
				or not. */ 
	uint32_t mem_threshold; /**< Memory size threshold. */
#ifdef GOOD_FIT
	float fit_percentage; /**< Fit percentage for good-fit searches. */
#endif  /* GOOD_FIT */
#ifdef HEAP_VAR_FIT
	/** Current search policy on the allocator's free lists. */
	void *(*search_policy)(heap_t * heap, size_t requested_size);
#endif /* HEAP_VAR_FIT */
#ifdef COALESCING_VARIABLE
	size_t max_coalesce_size; /**< Maximum coalesce size; -1 if coalescing
				     is not supported */
#endif /* COALESCING_VARIABLE */
#ifdef SPLITTING_VARIABLE
	size_t min_split_size; /**< Minimum split size. */
#endif /* SPLITTING_VARIABLE */
	/* FIXME Need to find explanation */
	float empty_threshold; /**< Empty Threshold */
	uint32_t percentage; /**< Percentage value */
	knob_state_t frag_state; /**< The current state of fragmentation. */
	knob_state_t foot_state; /**< The current state of footprint. */
} dmmknobs_t;
#endif /* WITH_KNOBS */

/** A structure to store heap information. */
typedef struct heap_s {
#ifdef WITH_FIXED_LISTS
	maptable_node_t *maptable_head; /**< The head of the maptable list. */
#endif /* WITH_FIXED_LISTS */
	void *free_list_head; /**< The head of the free list. */
#ifdef FUTURE_FEATURES
	void *used_blocks_head; /**< The head of the used blocks list. */
	void *rov_ptr; /**< Roving pointer. */
#endif /* FUTURE_FEATURES */
#ifndef LEON3
	uint64_t num_objects; /**< Number of objects in the heap. */
#else
	unsigned long num_objects; /**< Number of objects in the heap. */
#endif /* LEON3 */
#ifdef WITH_STATS
	dmmstats_t dmm_stats; /**< Statistics of the heap. */
#endif /* WITH_STATS */
#ifdef WITH_KNOBS
	dmmknobs_t dmm_knobs; /**< Tunable parameters of the heap. */
#endif /* WITH_KNOBS */
#ifdef HAVE_LOCKS
	pthread_mutex_t mutex;/**< Mutex when POSIX Threads are used. */
#endif /* HAVE_LOCKS */
} heap_t;

/** The allocator structure of dmmlib. */
typedef struct allocator_s {
	heap_t heaps[NUM_HEAPS]; /**< The heaps that the allocator manages. */
	bool initialized; /**< Initialization flag of the allocator. */
	void *border_ptr; /**< Border pointer of the allocator. */
	size_t remaining_size; /**< The size of the remaining free space which
				 is handled by the allocator. */
#ifdef ALLOC_VAR_FIT
	/** Current search policy on the allocator's free lists. */
	void *(*search_policy)(heap_t * heap, size_t requested_size);
#endif /* ALLOC_VAR_FIT */
} allocator_t;

#endif /* HEAP_H */