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eo ptr ind: pack memory, use in mmap fifo as recycle trash 

- pack active flag and generation nbr in an _Eo_Id_Entry struct
  - replace Eina_Trash with a fifo which lives in mmaped memory owned by eo_id.
  - fifo uses indexes instead of pointers to spare memory
  - never used entries are served first, then those in the fifo
    are reused, thus we ensure that a freed entry won't soon be reused.
This commit is contained in:
Jérémy Zurcher 2013-05-03 21:28:32 +02:00
parent 88cf0cf460
commit f769128dca
1 changed files with 94 additions and 60 deletions
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154
src/lib/eo/eo_ptr_indirection.c
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@ -3,6 +3,7 @@
#endif
#include "eo_ptr_indirection.h"
#include <assert.h>
#ifdef __linux__
#include <sys/types.h>
#include <sys/stat.h>
@ -32,22 +33,27 @@
* occur when accessing with the old id.
*
* Each table is composed of:
* - entries composed of
* - an index 'start' indicating which entry is the next one to use.
* - 2 indexes 'queue_head' and 'queue_tail' defining a queue (fifo),
* that will help us to store the entries to be reused. It stores only the
* entries that have been used at least one time. The entries that have
* never been used are "pointed" by the start parameter.
* - entries composed of:
* - a pointer to the object
* - a flag indicating if the entry is active
* - a generation assigned to the object
* - an index 'start' indicating which entry is the next one to use.
* - a queue that will help us to store the unused entries. It stores only the
* entries that have been used at least one time. The entries that have
* never been used are "pointed" by the start parameter.
* When an entry is searched into a table, we first try to pop from the
* queue. If a NULL value is returned, we have to use one of the entries that
* have never been used. If a such entry doesn't exist, we pass to the next
* table. Otherwise, we reserve this entry to the object pointer and create
* - an index 'next_in_queue' used to chain the entries in the queue
* When an entry is searched into a table, we first use one of the entries that
* has never been used. If there is none, we try to pop from the queue.
* If a such entry doesn't exist, we pass to the next table.
* When an entry is found, we reserve it to the object pointer and create
* the id with the table id, the intermediate table id, the entry and a
* generation.
* When an object is freed, the entry into the table is released by pushing
* it into the queue.
* When an object is freed, the entry into the table is released by appending
* it to the queue.
* Assigning all the entries of a table before trying to reuse them from
* the fifo ensures that we are not going to soon recycle a released entry,
* thus minimize the risks of an aggressive del() then use() on a single entry.
*/
#if SIZEOF_UINTPTR_T == 4
@ -56,16 +62,18 @@
# define BITS_FOR_IDS_INTER_TABLE 5
# define BITS_FOR_ID_IN_TABLE 12
# define BITS_FOR_GENERATION_COUNTER 10
typedef int16_t Table_Index;
typedef uint16_t Generation_Counter;
#else
/* 64 bits */
# define BITS_FOR_IDS_TABLE 11
# define BITS_FOR_IDS_INTER_TABLE 11
# define BITS_FOR_ID_IN_TABLE 12
# define BITS_FOR_GENERATION_COUNTER 30
typedef int16_t Table_Index;
typedef uint32_t Generation_Counter;
#endif
typedef uintptr_t Table_Index;
/* Shifts macros to manipulate the Eo id */
#define SHIFT_FOR_IDS_TABLE \
(BITS_FOR_IDS_INTER_TABLE + BITS_FOR_ID_IN_TABLE + BITS_FOR_GENERATION_COUNTER)
@ -152,6 +160,9 @@ typedef struct
unsigned int active : 1;
/* Generation */
unsigned int generation : BITS_FOR_GENERATION_COUNTER;
/* Indicates where to find the next entry to recycle */
Table_Index next_in_queue;
} _Eo_Id_Entry;
/* Table */
@ -159,31 +170,33 @@ typedef struct
{
/* Entries of the table holding real pointers and generations */
_Eo_Id_Entry entries[MAX_IDS_PER_TABLE];
/* Queue to handle free entries */
Eina_Trash *queue;
/* Indicates where start the "never used" entries */
Table_Index start;
/* Indicates where to find the next entry to recycle */
Table_Index queue_head;
/* Indicates where to add an entry to recycle */
Table_Index queue_tail;
} _Eo_Ids_Table;
/* Tables handling pointers indirection */
_Eo_Ids_Table **_eo_ids_tables[MAX_IDS_TABLES] = { NULL };
/* Next generation to use when assigning a new entry to a Eo pointer */
Table_Index _eo_generation_counter;
Generation_Counter _eo_generation_counter;
/* Macro used to compose an Eo id */
#define EO_COMPOSE_ID(TABLE, INTER_TABLE, ENTRY, GENERATION) \
(Eo_Id)(((TABLE & (MAX_IDS_TABLES - 1)) << SHIFT_FOR_IDS_TABLE) | \
((INTER_TABLE & (MAX_IDS_INTER_TABLES - 1)) << SHIFT_FOR_IDS_INTER_TABLE) |\
((ENTRY & (MAX_IDS_PER_TABLE - 1)) << SHIFT_FOR_ID_IN_TABLE) | \
(GENERATION & (MAX_GENERATIONS - 1) ))
#define EO_COMPOSE_ID(TABLE, INTER_TABLE, ENTRY, GENERATION) \
(((Eo_Id)(TABLE & (MAX_IDS_TABLES - 1)) << SHIFT_FOR_IDS_TABLE) | \
((Eo_Id)(INTER_TABLE & (MAX_IDS_INTER_TABLES - 1)) << SHIFT_FOR_IDS_INTER_TABLE) | \
((ENTRY & (MAX_IDS_PER_TABLE - 1)) << SHIFT_FOR_ID_IN_TABLE) | \
(GENERATION & (MAX_GENERATIONS - 1) ))
/* Macro to extract from an Eo id the indexes of the tables */
#define EO_DECOMPOSE_ID(ID, TABLE, INTER_TABLE, ENTRY, GENERATION) \
TABLE = (ID >> SHIFT_FOR_IDS_TABLE) & (MAX_IDS_TABLES - 1); \
#define EO_DECOMPOSE_ID(ID, TABLE, INTER_TABLE, ENTRY, GENERATION) \
TABLE = (ID >> SHIFT_FOR_IDS_TABLE) & (MAX_IDS_TABLES - 1); \
INTER_TABLE = (ID >> SHIFT_FOR_IDS_INTER_TABLE) & (MAX_IDS_INTER_TABLES - 1); \
ENTRY = (ID >> SHIFT_FOR_ID_IN_TABLE) & (MAX_IDS_PER_TABLE - 1); \
GENERATION = ID & (MAX_GENERATIONS - 1); \
ENTRY = (ID >> SHIFT_FOR_ID_IN_TABLE) & (MAX_IDS_PER_TABLE - 1); \
GENERATION = ID & (MAX_GENERATIONS - 1); \
/* Macro used for readability */
#define ID_TABLE _eo_ids_tables[table_id][int_table_id]
@ -193,9 +206,10 @@ _eo_obj_pointer_get(const Eo_Id obj_id)
{
#ifdef HAVE_EO_ID
_Eo_Id_Entry *entry;
Table_Index table_id, int_table_id, entry_id, generation;
Generation_Counter generation;
Table_Index table_id, int_table_id, entry_id;
EO_DECOMPOSE_ID((Table_Index) obj_id, table_id, int_table_id, entry_id, generation);
EO_DECOMPOSE_ID(obj_id, table_id, int_table_id, entry_id, generation);
/* Checking the validity of the entry */
if (_eo_ids_tables[table_id] && ID_TABLE)
@ -218,50 +232,59 @@ Eo_Id
_eo_id_allocate(const _Eo *obj)
{
#ifdef HAVE_EO_ID
_Eo_Ids_Table *table;
_Eo_Id_Entry *entry = NULL;
for (Table_Index table_id = 1; table_id < MAX_IDS_TABLES; table_id++)
{
if (!_eo_ids_tables[table_id])
{
/* We allocate a new table */
/* We allocate a new intermediate table */
_eo_ids_tables[table_id] = _eo_id_mem_calloc(MAX_IDS_INTER_TABLES, sizeof(_Eo_Ids_Table*));
}
for (Table_Index int_table_id = 0; int_table_id < MAX_IDS_INTER_TABLES; int_table_id++)
{
if (!ID_TABLE)
table = ID_TABLE;
if (!table)
{
/* We allocate a new intermediate table */
ID_TABLE = _eo_id_mem_calloc(1, sizeof(_Eo_Ids_Table));
eina_trash_init(&(ID_TABLE->queue));
/* We allocate a new table */
table = _eo_id_mem_calloc(1, sizeof(_Eo_Ids_Table));
table->start = 1;
table->queue_head = table->queue_tail = -1;
ID_TABLE = table;
/* We select directly the first entry of the new table */
entry = &(ID_TABLE->entries[0]);
ID_TABLE->start = 1;
entry = &(table->entries[0]);
}
else if (table->start < MAX_IDS_PER_TABLE)
{
/* We use an empty entries in the table */
entry = &(table->entries[table->start]);
table->start++;
}
else if (table->queue_head != -1)
{
/* We pop an unused entry from the queue */
entry = &(table->entries[table->queue_head]);
if (entry->next_in_queue == -1)
table->queue_head = table->queue_tail = -1;
else
table->queue_head = entry->next_in_queue;
}
else
{
/* We try to pop from the queue an unused entry */
entry = (_Eo_Id_Entry *)eina_trash_pop(&(ID_TABLE->queue));
/* Table is full of actives entries */
continue;
}
if (!entry && ID_TABLE->start < MAX_IDS_PER_TABLE)
{
/* No more unused entries in the trash but still empty entries in the table */
entry = &(ID_TABLE->entries[ID_TABLE->start]);
ID_TABLE->start++;
}
if (entry)
{
/* An entry was found - need to find the entry id and fill it */
entry->ptr = (_Eo *)obj;
entry->active = 1;
entry->generation = _eo_generation_counter;
_eo_generation_counter++;
_eo_generation_counter %= MAX_GENERATIONS;
return EO_COMPOSE_ID(table_id, int_table_id,
(entry - ID_TABLE->entries),
entry->generation);
}
assert(entry);
/* An entry was found - need to find the entry id and fill it */
entry->ptr = (_Eo *)obj;
entry->active = 1;
entry->generation = _eo_generation_counter;
_eo_generation_counter++;
_eo_generation_counter %= MAX_GENERATIONS;
return EO_COMPOSE_ID(table_id, int_table_id,
(entry - table->entries),
entry->generation);
}
}
return 0;
@ -274,20 +297,31 @@ void
_eo_id_release(const Eo_Id obj_id)
{
#ifdef HAVE_EO_ID
_Eo_Ids_Table *table;
_Eo_Id_Entry *entry;
Table_Index table_id, int_table_id, entry_id, generation;
EO_DECOMPOSE_ID((Table_Index) obj_id, table_id, int_table_id, entry_id, generation);
Generation_Counter generation;
Table_Index table_id, int_table_id, entry_id;
EO_DECOMPOSE_ID(obj_id, table_id, int_table_id, entry_id, generation);
/* Checking the validity of the entry */
if (_eo_ids_tables[table_id] && ID_TABLE)
if (_eo_ids_tables[table_id] && (table = ID_TABLE))
{
entry = &(ID_TABLE->entries[entry_id]);
entry = &(table->entries[entry_id]);
if (entry && entry->active && (entry->generation == generation))
{
/* Disable the entry */
entry->active = 0;
entry->next_in_queue = -1;
/* Push the entry into the queue */
eina_trash_push(&(ID_TABLE->queue), entry);
if (table->queue_tail == -1)
{
table->queue_head = table->queue_tail = entry_id;
}
else
{
table->entries[table->queue_tail].next_in_queue = entry_id;
table->queue_tail = entry_id;
}
return;
}
}