/************************************************************************
Writes a page asynchronously from the buffer buf_pool to a file, if it can be
found in the buf_pool and it is in a flushable state. NOTE: in simulated aio
we must call os_aio_simulated_wake_handler_threads after we have posted a batch
of writes! */
static
ulint
buf_flush_try_page(
/*===============*/
/* out: 1 if a page was flushed, 0 otherwise */
ulint space, /* in: space id */
ulint offset, /* in: page offset */
ulint flush_type) /* in: BUF_FLUSH_LRU, BUF_FLUSH_LIST, or
BUF_FLUSH_SINGLE_PAGE */
{
buf_block_t* block;
ibool locked;
ut_ad(flush_type == BUF_FLUSH_LRU || flush_type == BUF_FLUSH_LIST
|| flush_type == BUF_FLUSH_SINGLE_PAGE);
mutex_enter(&(buf_pool->mutex));
block = buf_page_hash_get(space, offset);
ut_a(!block || block->state == BUF_BLOCK_FILE_PAGE);
if (!block) {
mutex_exit(&(buf_pool->mutex));
return(0);
}
mutex_enter(&block->mutex);
if (flush_type == BUF_FLUSH_LIST
&& buf_flush_ready_for_flush(block, flush_type)) {
block->io_fix = BUF_IO_WRITE;
/* If AWE is enabled and the page is not mapped to a frame,
then map it */
if (block->frame == NULL) {
ut_a(srv_use_awe);
/* We set second parameter TRUE because the block is
in the LRU list and we must put it to
awe_LRU_free_mapped list once mapped to a frame */
buf_awe_map_page_to_frame(block, TRUE);
}
block->flush_type = flush_type;
if (buf_pool->n_flush[flush_type] == 0) {
os_event_reset(buf_pool->no_flush[flush_type]);
}
(buf_pool->n_flush[flush_type])++;
locked = FALSE;
/* If the simulated aio thread is not running, we must
not wait for any latch, as we may end up in a deadlock:
if buf_fix_count == 0, then we know we need not wait */
if (block->buf_fix_count == 0) {
rw_lock_s_lock_gen(&(block->lock), BUF_IO_WRITE);
locked = TRUE;
}
mutex_exit(&block->mutex);
mutex_exit(&(buf_pool->mutex));
if (!locked) {
buf_flush_buffered_writes();
rw_lock_s_lock_gen(&(block->lock), BUF_IO_WRITE);
}
#ifdef UNIV_DEBUG
if (buf_debug_prints) {
fprintf(stderr,
"Flushing page space %lu, page no %lu \n",
(ulong) block->space, (ulong) block->offset);
}
#endif /* UNIV_DEBUG */
buf_flush_write_block_low(block);
return(1);
} else if (flush_type == BUF_FLUSH_LRU
&& buf_flush_ready_for_flush(block, flush_type)) {
/* VERY IMPORTANT:
Because any thread may call the LRU flush, even when owning
locks on pages, to avoid deadlocks, we must make sure that the
s-lock is acquired on the page without waiting: this is
accomplished because in the if-condition above we require
the page not to be bufferfixed (in function
..._ready_for_flush). */
block->io_fix = BUF_IO_WRITE;
/* If AWE is enabled and the page is not mapped to a frame,
then map it */
if (block->frame == NULL) {
ut_a(srv_use_awe);
/* We set second parameter TRUE because the block is
in the LRU list and we must put it to
awe_LRU_free_mapped list once mapped to a frame */
buf_awe_map_page_to_frame(block, TRUE);
}
block->flush_type = flush_type;
if (buf_pool->n_flush[flush_type] == 0) {
os_event_reset(buf_pool->no_flush[flush_type]);
}
(buf_pool->n_flush[flush_type])++;
rw_lock_s_lock_gen(&(block->lock), BUF_IO_WRITE);
/* Note that the s-latch is acquired before releasing the
buf_pool mutex: this ensures that the latch is acquired
immediately. */
mutex_exit(&block->mutex);
mutex_exit(&(buf_pool->mutex));
buf_flush_write_block_low(block);
return(1);
} else if (flush_type == BUF_FLUSH_SINGLE_PAGE
&& buf_flush_ready_for_flush(block, flush_type)) {
block->io_fix = BUF_IO_WRITE;
/* If AWE is enabled and the page is not mapped to a frame,
then map it */
if (block->frame == NULL) {
ut_a(srv_use_awe);
/* We set second parameter TRUE because the block is
in the LRU list and we must put it to
awe_LRU_free_mapped list once mapped to a frame */
buf_awe_map_page_to_frame(block, TRUE);
}
block->flush_type = flush_type;
if (buf_pool->n_flush[block->flush_type] == 0) {
os_event_reset(buf_pool->no_flush[block->flush_type]);
}
(buf_pool->n_flush[flush_type])++;
mutex_exit(&block->mutex);
mutex_exit(&(buf_pool->mutex));
rw_lock_s_lock_gen(&(block->lock), BUF_IO_WRITE);
#ifdef UNIV_DEBUG
if (buf_debug_prints) {
fprintf(stderr,
"Flushing single page space %lu,"
" page no %lu \n",
(ulong) block->space,
(ulong) block->offset);
}
#endif /* UNIV_DEBUG */
buf_flush_write_block_low(block);
return(1);
}
mutex_exit(&block->mutex);
mutex_exit(&(buf_pool->mutex));
return(0);
}
buf_block_t*
buf_LRU_get_free_block(void)
/*========================*/
/* out: the free control block; also if AWE is
used, it is guaranteed that the block has its
page mapped to a frame when we return */
{
buf_block_t* block = NULL;
ibool freed;
ulint n_iterations = 1;
ibool mon_value_was = FALSE;
ibool started_monitor = FALSE;
loop:
mutex_enter(&(buf_pool->mutex));
if (!recv_recovery_on && UT_LIST_GET_LEN(buf_pool->free)
+ UT_LIST_GET_LEN(buf_pool->LRU) < buf_pool->max_size / 20) {
ut_print_timestamp(stderr);
fprintf(stderr,
" InnoDB: ERROR: over 95 percent of the buffer pool"
" is occupied by\n"
"InnoDB: lock heaps or the adaptive hash index!"
" Check that your\n"
"InnoDB: transactions do not set too many row locks.\n"
"InnoDB: Your buffer pool size is %lu MB."
" Maybe you should make\n"
"InnoDB: the buffer pool bigger?\n"
"InnoDB: We intentionally generate a seg fault"
" to print a stack trace\n"
"InnoDB: on Linux!\n",
(ulong) (buf_pool->curr_size
/ (1024 * 1024 / UNIV_PAGE_SIZE)));
ut_error;
} else if (!recv_recovery_on && UT_LIST_GET_LEN(buf_pool->free)
+ UT_LIST_GET_LEN(buf_pool->LRU) < buf_pool->max_size / 3) {
if (!buf_lru_switched_on_innodb_mon) {
/* Over 67 % of the buffer pool is occupied by lock
heaps or the adaptive hash index. This may be a memory
leak! */
ut_print_timestamp(stderr);
fprintf(stderr,
" InnoDB: WARNING: over 67 percent of"
" the buffer pool is occupied by\n"
"InnoDB: lock heaps or the adaptive"
" hash index! Check that your\n"
"InnoDB: transactions do not set too many"
" row locks.\n"
"InnoDB: Your buffer pool size is %lu MB."
" Maybe you should make\n"
"InnoDB: the buffer pool bigger?\n"
"InnoDB: Starting the InnoDB Monitor to print"
" diagnostics, including\n"
"InnoDB: lock heap and hash index sizes.\n",
(ulong) (buf_pool->curr_size
/ (1024 * 1024 / UNIV_PAGE_SIZE)));
buf_lru_switched_on_innodb_mon = TRUE;
srv_print_innodb_monitor = TRUE;
os_event_set(srv_lock_timeout_thread_event);
}
} else if (buf_lru_switched_on_innodb_mon) {
/* Switch off the InnoDB Monitor; this is a simple way
to stop the monitor if the situation becomes less urgent,
but may also surprise users if the user also switched on the
monitor! */
buf_lru_switched_on_innodb_mon = FALSE;
srv_print_innodb_monitor = FALSE;
}
/* If there is a block in the free list, take it */
if (UT_LIST_GET_LEN(buf_pool->free) > 0) {
block = UT_LIST_GET_FIRST(buf_pool->free);
ut_a(block->in_free_list);
UT_LIST_REMOVE(free, buf_pool->free, block);
block->in_free_list = FALSE;
ut_a(block->state != BUF_BLOCK_FILE_PAGE);
ut_a(!block->in_LRU_list);
if (srv_use_awe) {
if (block->frame) {
/* Remove from the list of mapped pages */
UT_LIST_REMOVE(awe_LRU_free_mapped,
buf_pool->awe_LRU_free_mapped,
block);
} else {
/* We map the page to a frame; second param
FALSE below because we do not want it to be
added to the awe_LRU_free_mapped list */
buf_awe_map_page_to_frame(block, FALSE);
}
}
mutex_enter(&block->mutex);
block->state = BUF_BLOCK_READY_FOR_USE;
UNIV_MEM_ALLOC(block->frame, UNIV_PAGE_SIZE);
mutex_exit(&block->mutex);
mutex_exit(&(buf_pool->mutex));
if (started_monitor) {
srv_print_innodb_monitor = mon_value_was;
}
return(block);
}
/* If no block was in the free list, search from the end of the LRU
list and try to free a block there */
mutex_exit(&(buf_pool->mutex));
freed = buf_LRU_search_and_free_block(n_iterations);
if (freed > 0) {
goto loop;
}
if (n_iterations > 30) {
ut_print_timestamp(stderr);
fprintf(stderr,
"InnoDB: Warning: difficult to find free blocks from\n"
"InnoDB: the buffer pool (%lu search iterations)!"
" Consider\n"
"InnoDB: increasing the buffer pool size.\n"
"InnoDB: It is also possible that"
" in your Unix version\n"
"InnoDB: fsync is very slow, or"
" completely frozen inside\n"
"InnoDB: the OS kernel. Then upgrading to"
" a newer version\n"
"InnoDB: of your operating system may help."
" Look at the\n"
"InnoDB: number of fsyncs in diagnostic info below.\n"
"InnoDB: Pending flushes (fsync) log: %lu;"
" buffer pool: %lu\n"
"InnoDB: %lu OS file reads, %lu OS file writes,"
" %lu OS fsyncs\n"
"InnoDB: Starting InnoDB Monitor to print further\n"
"InnoDB: diagnostics to the standard output.\n",
(ulong) n_iterations,
(ulong) fil_n_pending_log_flushes,
(ulong) fil_n_pending_tablespace_flushes,
(ulong) os_n_file_reads, (ulong) os_n_file_writes,
(ulong) os_n_fsyncs);
mon_value_was = srv_print_innodb_monitor;
started_monitor = TRUE;
srv_print_innodb_monitor = TRUE;
os_event_set(srv_lock_timeout_thread_event);
}
/* No free block was found: try to flush the LRU list */
buf_flush_free_margin();
++srv_buf_pool_wait_free;
os_aio_simulated_wake_handler_threads();
mutex_enter(&(buf_pool->mutex));
if (buf_pool->LRU_flush_ended > 0) {
/* We have written pages in an LRU flush. To make the insert
buffer more efficient, we try to move these pages to the free
list. */
mutex_exit(&(buf_pool->mutex));
buf_LRU_try_free_flushed_blocks();
} else {
mutex_exit(&(buf_pool->mutex));
}
if (n_iterations > 10) {
os_thread_sleep(500000);
}
n_iterations++;
goto loop;
}
