/** * Free the chunk */ void mem_pools_free (uint8_t *chunk_p) /**< pointer to the chunk */ { mem_pool_state_t *pool_state = mem_pools, *prev_pool_state_p = NULL; /** * Search for the pool containing specified chunk. */ while (!mem_pool_is_chunk_inside (pool_state, chunk_p)) { prev_pool_state_p = pool_state; pool_state = MEM_CP_GET_NON_NULL_POINTER (mem_pool_state_t, pool_state->next_pool_cp); } /** * Free the chunk */ mem_pool_free_chunk (pool_state, chunk_p); mem_free_chunks_number++; MEM_POOLS_STAT_FREE_CHUNK (); /** * If all chunks of the pool are free, free the pool itself. */ if (pool_state->free_chunks_number == MEM_POOL_CHUNKS_NUMBER) { if (prev_pool_state_p != NULL) { prev_pool_state_p->next_pool_cp = pool_state->next_pool_cp; } else { mem_pools = MEM_CP_GET_POINTER (mem_pool_state_t, pool_state->next_pool_cp); } mem_free_chunks_number -= MEM_POOL_CHUNKS_NUMBER; mem_heap_free_block ((uint8_t*) pool_state); MEM_POOLS_STAT_FREE_POOL (); } else if (mem_pools != pool_state) { JERRY_ASSERT (prev_pool_state_p != NULL); prev_pool_state_p->next_pool_cp = pool_state->next_pool_cp; MEM_CP_SET_NON_NULL_POINTER (pool_state->next_pool_cp, mem_pools); mem_pools = pool_state; } } /* mem_pools_free */
/** * Collect chunks from empty pools and free the pools */ void mem_pools_collect_empty (void) { /* * Hint magic number in header of pools with free pool-first chunks */ const uint16_t hint_magic_num_value = 0x7e89; /* * Collection-time chunk lists */ mem_pool_chunk_t *first_chunks_list_p = NULL; mem_pool_chunk_t *non_first_chunks_list_p = NULL; /* * At first stage collect free pool-first chunks to separate collection-time lists * and change their layout from mem_pool_chunk_t::u::free to mem_pool_chunk_t::u::pool_gc */ { mem_pool_chunk_t tmp_header; tmp_header.u.free.next_p = mem_free_chunk_p; for (mem_pool_chunk_t *free_chunk_iter_p = tmp_header.u.free.next_p, *prev_free_chunk_p = &tmp_header, *next_free_chunk_p; free_chunk_iter_p != NULL; free_chunk_iter_p = next_free_chunk_p) { mem_pool_chunk_t *pool_start_p = (mem_pool_chunk_t *) mem_heap_get_chunked_block_start (free_chunk_iter_p); VALGRIND_DEFINED_SPACE (free_chunk_iter_p, MEM_POOL_CHUNK_SIZE); next_free_chunk_p = free_chunk_iter_p->u.free.next_p; if (pool_start_p == free_chunk_iter_p) { /* * The chunk is first at its pool * * Remove the chunk from common list of free chunks */ prev_free_chunk_p->u.free.next_p = next_free_chunk_p; /* * Initialize pool-first chunk as pool header and it insert into list of free pool-first chunks */ free_chunk_iter_p->u.pool_gc.free_list_cp = MEM_CP_NULL; free_chunk_iter_p->u.pool_gc.free_chunks_num = 1; /* the first chunk */ free_chunk_iter_p->u.pool_gc.hint_magic_num = hint_magic_num_value; free_chunk_iter_p->u.pool_gc.traversal_check_flag = false; MEM_CP_SET_POINTER (free_chunk_iter_p->u.pool_gc.next_first_cp, first_chunks_list_p); first_chunks_list_p = free_chunk_iter_p; } else { prev_free_chunk_p = free_chunk_iter_p; } } mem_free_chunk_p = tmp_header.u.free.next_p; } if (first_chunks_list_p == NULL) { /* there are no empty pools */ return; } /* * At second stage we collect all free non-pool-first chunks, for which corresponding pool-first chunks are free, * and link them into the corresponding mem_pool_chunk_t::u::pool_gc::free_list_cp list, while also maintaining * the corresponding mem_pool_chunk_t::u::pool_gc::free_chunks_num: * - at first, for each non-pool-first free chunk we check whether traversal check flag is cleared in corresponding * first chunk in the same pool, and move those chunks, for which the condition is true, * to separate temporary list. * * - then, we flip the traversal check flags for each of free pool-first chunks. * * - at last, we perform almost the same as at first step, but check only non-pool-first chunks from the temporary * list, and send the chunks, for which the corresponding traversal check flag is cleared, back to the common list * of free chunks, and the rest chunks from the temporary list are linked to corresponding pool-first chunks. * Also, counter of the linked free chunks is maintained in every free pool-first chunk. */ { { mem_pool_chunk_t tmp_header; tmp_header.u.free.next_p = mem_free_chunk_p; for (mem_pool_chunk_t *free_chunk_iter_p = tmp_header.u.free.next_p, *prev_free_chunk_p = &tmp_header, *next_free_chunk_p; free_chunk_iter_p != NULL; free_chunk_iter_p = next_free_chunk_p) { mem_pool_chunk_t *pool_start_p = (mem_pool_chunk_t *) mem_heap_get_chunked_block_start (free_chunk_iter_p); next_free_chunk_p = free_chunk_iter_p->u.free.next_p; /* * The magic number doesn't guarantee that the chunk is actually a free pool-first chunk, * so we test the traversal check flag after flipping values of the flags in every * free pool-first chunk. */ uint16_t magic_num_field; bool traversal_check_flag; mem_pools_collect_read_magic_num_and_flag (pool_start_p, &magic_num_field, &traversal_check_flag); /* * During this traversal the flag in the free header chunks is in cleared state */ if (!traversal_check_flag && magic_num_field == hint_magic_num_value) { free_chunk_iter_p->u.free.next_p = non_first_chunks_list_p; non_first_chunks_list_p = free_chunk_iter_p; prev_free_chunk_p->u.free.next_p = next_free_chunk_p; } else { prev_free_chunk_p = free_chunk_iter_p; } } mem_free_chunk_p = tmp_header.u.free.next_p; } { /* * Now, flip the traversal check flag in free pool-first chunks */ for (mem_pool_chunk_t *first_chunks_iter_p = first_chunks_list_p; first_chunks_iter_p != NULL; first_chunks_iter_p = MEM_CP_GET_POINTER (mem_pool_chunk_t, first_chunks_iter_p->u.pool_gc.next_first_cp)) { JERRY_ASSERT (!first_chunks_iter_p->u.pool_gc.traversal_check_flag); first_chunks_iter_p->u.pool_gc.traversal_check_flag = true; } } { for (mem_pool_chunk_t *non_first_chunks_iter_p = non_first_chunks_list_p, *next_p; non_first_chunks_iter_p != NULL; non_first_chunks_iter_p = next_p) { next_p = non_first_chunks_iter_p->u.free.next_p; mem_pool_chunk_t *pool_start_p; pool_start_p = (mem_pool_chunk_t *) mem_heap_get_chunked_block_start (non_first_chunks_iter_p); uint16_t magic_num_field; bool traversal_check_flag; mem_pools_collect_read_magic_num_and_flag (pool_start_p, &magic_num_field, &traversal_check_flag); JERRY_ASSERT (magic_num_field == hint_magic_num_value); #ifndef JERRY_DISABLE_HEAVY_DEBUG bool is_occured = false; for (mem_pool_chunk_t *first_chunks_iter_p = first_chunks_list_p; first_chunks_iter_p != NULL; first_chunks_iter_p = MEM_CP_GET_POINTER (mem_pool_chunk_t, first_chunks_iter_p->u.pool_gc.next_first_cp)) { if (pool_start_p == first_chunks_iter_p) { is_occured = true; break; } } JERRY_ASSERT (is_occured == traversal_check_flag); #endif /* !JERRY_DISABLE_HEAVY_DEBUG */ /* * During this traversal the flag in the free header chunks is in set state * * If the flag is set, it is guaranteed that the pool-first chunk, * from the same pool, as the current non-pool-first chunk, is free * and is placed in the corresponding list of free pool-first chunks. */ if (traversal_check_flag) { pool_start_p->u.pool_gc.free_chunks_num++; non_first_chunks_iter_p->u.free.next_p = MEM_CP_GET_POINTER (mem_pool_chunk_t, pool_start_p->u.pool_gc.free_list_cp); MEM_CP_SET_NON_NULL_POINTER (pool_start_p->u.pool_gc.free_list_cp, non_first_chunks_iter_p); } else { non_first_chunks_iter_p->u.free.next_p = mem_free_chunk_p; mem_free_chunk_p = non_first_chunks_iter_p; } } } non_first_chunks_list_p = NULL; } /* * At third stage we check each free pool-first chunk in collection-time list for counted * number of free chunks in the pool, containing the chunk. * * If the number is equal to number of chunks in the pool - then the pool is empty, and so is freed, * otherwise - free chunks of the pool are returned to the common list of free chunks. */ for (mem_pool_chunk_t *first_chunks_iter_p = first_chunks_list_p, *next_p; first_chunks_iter_p != NULL; first_chunks_iter_p = next_p) { next_p = MEM_CP_GET_POINTER (mem_pool_chunk_t, first_chunks_iter_p->u.pool_gc.next_first_cp); JERRY_ASSERT (first_chunks_iter_p->u.pool_gc.hint_magic_num == hint_magic_num_value); JERRY_ASSERT (first_chunks_iter_p->u.pool_gc.traversal_check_flag); JERRY_ASSERT (first_chunks_iter_p->u.pool_gc.free_chunks_num <= MEM_POOL_CHUNKS_NUMBER); if (first_chunks_iter_p->u.pool_gc.free_chunks_num == MEM_POOL_CHUNKS_NUMBER) { #ifndef JERRY_NDEBUG mem_free_chunks_number -= MEM_POOL_CHUNKS_NUMBER; #endif /* !JERRY_NDEBUG */ MEM_HEAP_VALGRIND_FREYA_MEMPOOL_REQUEST (); mem_heap_free_block (first_chunks_iter_p); MEM_POOLS_STAT_FREE_POOL (); } else { mem_pool_chunk_t *first_chunk_p = first_chunks_iter_p; /* * Convert layout of first chunk from collection-time pool-first chunk's layout to the common free chunk layout */ first_chunk_p->u.free.next_p = MEM_CP_GET_POINTER (mem_pool_chunk_t, first_chunks_iter_p->u.pool_gc.free_list_cp); /* * Link local pool's list of free chunks into the common list of free chunks */ for (mem_pool_chunk_t *pool_chunks_iter_p = first_chunk_p; ; pool_chunks_iter_p = pool_chunks_iter_p->u.free.next_p) { JERRY_ASSERT (pool_chunks_iter_p != NULL); if (pool_chunks_iter_p->u.free.next_p == NULL) { pool_chunks_iter_p->u.free.next_p = mem_free_chunk_p; break; } } mem_free_chunk_p = first_chunk_p; } } #ifdef JERRY_VALGRIND /* * Valgrind-mode specific pass that marks all free chunks inaccessible */ for (mem_pool_chunk_t *free_chunk_iter_p = mem_free_chunk_p, *next_free_chunk_p; free_chunk_iter_p != NULL; free_chunk_iter_p = next_free_chunk_p) { next_free_chunk_p = free_chunk_iter_p->u.free.next_p; VALGRIND_NOACCESS_SPACE (free_chunk_iter_p, MEM_POOL_CHUNK_SIZE); } #endif /* JERRY_VALGRIND */ } /* mem_pools_collect_empty */
void mem_pools_collect_empty (void) { /* * Hint magic number in header of pools with free first chunks */ const uint16_t hint_magic_num_value = 0x7e89; /* * At first pass collect pointers to those of free chunks that are first at their pools * to separate lists (collection-time pool lists) and change them to headers of corresponding pools */ /* * Number of collection-time pool lists */ constexpr uint32_t pool_lists_number = 8; /* * Collection-time pool lists */ mem_pool_chunk_t *pool_lists_p[pool_lists_number]; for (uint32_t i = 0; i < pool_lists_number; i++) { pool_lists_p[i] = NULL; } /* * Number of the pools, included into the lists */ uint32_t pools_in_lists_number = 0; for (mem_pool_chunk_t *free_chunk_iter_p = mem_free_chunk_p, *prev_free_chunk_p = NULL, *next_free_chunk_p; free_chunk_iter_p != NULL; free_chunk_iter_p = next_free_chunk_p) { mem_pool_chunk_t *pool_start_p = (mem_pool_chunk_t *) mem_heap_get_chunked_block_start (free_chunk_iter_p); VALGRIND_DEFINED_SPACE (free_chunk_iter_p, MEM_POOL_CHUNK_SIZE); next_free_chunk_p = free_chunk_iter_p->u.free.next_p; if (pool_start_p == free_chunk_iter_p) { /* * The chunk is first at its pool * * Remove the chunk from common list of free chunks */ if (prev_free_chunk_p == NULL) { JERRY_ASSERT (mem_free_chunk_p == free_chunk_iter_p); mem_free_chunk_p = next_free_chunk_p; } else { prev_free_chunk_p->u.free.next_p = next_free_chunk_p; } pools_in_lists_number++; uint8_t list_id = pools_in_lists_number % pool_lists_number; /* * Initialize pool header and insert the pool into one of lists */ free_chunk_iter_p->u.pool_gc.free_list_cp = MEM_CP_NULL; free_chunk_iter_p->u.pool_gc.free_chunks_num = 1; /* the first chunk */ free_chunk_iter_p->u.pool_gc.hint_magic_num = hint_magic_num_value; free_chunk_iter_p->u.pool_gc.list_id = list_id; MEM_CP_SET_POINTER (free_chunk_iter_p->u.pool_gc.next_first_cp, pool_lists_p[list_id]); pool_lists_p[list_id] = free_chunk_iter_p; } else { prev_free_chunk_p = free_chunk_iter_p; } } if (pools_in_lists_number == 0) { /* there are no empty pools */ return; } /* * At second pass we check for all rest free chunks whether they are in pools that were included into * collection-time pool lists. * * For each of the chunk, try to find the corresponding pool through iterating the list. * * If pool is found in a list (so, first chunk of the pool is free) for a chunk, increment counter * of free chunks in the pools, and move the chunk from global free chunks list to collection-time * local list of corresponding pool's free chunks. */ for (mem_pool_chunk_t *free_chunk_iter_p = mem_free_chunk_p, *prev_free_chunk_p = NULL, *next_free_chunk_p; free_chunk_iter_p != NULL; free_chunk_iter_p = next_free_chunk_p) { mem_pool_chunk_t *pool_start_p = (mem_pool_chunk_t *) mem_heap_get_chunked_block_start (free_chunk_iter_p); next_free_chunk_p = free_chunk_iter_p->u.free.next_p; bool is_chunk_moved_to_local_list = false; #ifdef JERRY_VALGRIND /* * If the chunk is not free, there may be undefined bytes at hint_magic_num and list_id fields. * * Although, it is correct for the routine, valgrind issues warning about using uninitialized data * in conditional expression. To suppress the false-positive warning, the chunk is temporarily marked * as defined, and after reading hint magic number and list identifier, valgrind state of the chunk is restored. */ uint8_t vbits[MEM_POOL_CHUNK_SIZE]; unsigned status; status = VALGRIND_GET_VBITS (pool_start_p, vbits, MEM_POOL_CHUNK_SIZE); JERRY_ASSERT (status == 0 || status == 1); VALGRIND_DEFINED_SPACE (pool_start_p, MEM_POOL_CHUNK_SIZE); #endif /* JERRY_VALGRIND */ /* * The magic number doesn't guarantee that the chunk is actually a pool header, * so it is only optimization to reduce number of unnecessary iterations over * pool lists. */ uint16_t magic_num_field = pool_start_p->u.pool_gc.hint_magic_num; uint8_t id_to_search_in = pool_start_p->u.pool_gc.list_id; #ifdef JERRY_VALGRIND status = VALGRIND_SET_VBITS (pool_start_p, vbits, MEM_POOL_CHUNK_SIZE); JERRY_ASSERT (status == 0 || status == 1); #endif /* JERRY_VALGRIND */ if (magic_num_field == hint_magic_num_value) { /* * Maybe, the first chunk is free. * * If it is so, it is included in the list of pool's first free chunks. */ if (id_to_search_in < pool_lists_number) { for (mem_pool_chunk_t *pool_list_iter_p = pool_lists_p[id_to_search_in]; pool_list_iter_p != NULL; pool_list_iter_p = MEM_CP_GET_POINTER (mem_pool_chunk_t, pool_list_iter_p->u.pool_gc.next_first_cp)) { if (pool_list_iter_p == pool_start_p) { /* * The first chunk is actually free. * * So, incrementing free chunks counter in it. */ pool_start_p->u.pool_gc.free_chunks_num++; /* * It is possible that the corresponding pool is empty * * Moving current chunk from common list of free chunks to temporary list, local to the pool */ if (prev_free_chunk_p == NULL) { JERRY_ASSERT (mem_free_chunk_p == free_chunk_iter_p); mem_free_chunk_p = next_free_chunk_p; } else { prev_free_chunk_p->u.free.next_p = next_free_chunk_p; } free_chunk_iter_p->u.free.next_p = MEM_CP_GET_POINTER (mem_pool_chunk_t, pool_start_p->u.pool_gc.free_list_cp); MEM_CP_SET_NON_NULL_POINTER (pool_start_p->u.pool_gc.free_list_cp, free_chunk_iter_p); is_chunk_moved_to_local_list = true; break; } } } } if (!is_chunk_moved_to_local_list) { prev_free_chunk_p = free_chunk_iter_p; } } /* * At third pass we check each pool in collection-time pool lists free for counted * number of free chunks in the pool. * * If the number is equal to number of chunks in the pool - then the pool is empty, and so is freed, * otherwise - free chunks of the pool are returned to common list of free chunks. */ for (uint8_t list_id = 0; list_id < pool_lists_number; list_id++) { for (mem_pool_chunk_t *pool_list_iter_p = pool_lists_p[list_id], *next_p; pool_list_iter_p != NULL; pool_list_iter_p = next_p) { next_p = MEM_CP_GET_POINTER (mem_pool_chunk_t, pool_list_iter_p->u.pool_gc.next_first_cp); if (pool_list_iter_p->u.pool_gc.free_chunks_num == MEM_POOL_CHUNKS_NUMBER) { #ifndef JERRY_NDEBUG mem_free_chunks_number -= MEM_POOL_CHUNKS_NUMBER; #endif /* !JERRY_NDEBUG */ MEM_HEAP_VALGRIND_FREYA_MEMPOOL_REQUEST (); mem_heap_free_block (pool_list_iter_p); MEM_POOLS_STAT_FREE_POOL (); } else { mem_pool_chunk_t *first_chunk_p = pool_list_iter_p; /* * Convert layout of first chunk from collection-time pool header to common free chunk */ first_chunk_p->u.free.next_p = MEM_CP_GET_POINTER (mem_pool_chunk_t, pool_list_iter_p->u.pool_gc.free_list_cp); /* * Link local pool's list of free chunks into global list of free chunks */ for (mem_pool_chunk_t *pool_chunks_iter_p = first_chunk_p; ; pool_chunks_iter_p = pool_chunks_iter_p->u.free.next_p) { JERRY_ASSERT (pool_chunks_iter_p != NULL); if (pool_chunks_iter_p->u.free.next_p == NULL) { pool_chunks_iter_p->u.free.next_p = mem_free_chunk_p; break; } } mem_free_chunk_p = first_chunk_p; } } } #ifdef JERRY_VALGRIND /* * Valgrind-mode specific pass that marks all free chunks inaccessible */ for (mem_pool_chunk_t *free_chunk_iter_p = mem_free_chunk_p, *next_free_chunk_p; free_chunk_iter_p != NULL; free_chunk_iter_p = next_free_chunk_p) { next_free_chunk_p = free_chunk_iter_p->u.free.next_p; VALGRIND_NOACCESS_SPACE (free_chunk_iter_p, MEM_POOL_CHUNK_SIZE); } #endif /* JERRY_VALGRIND */ } /* mem_pools_collect_empty */