MDEV-16264 Use threadpool for Innodb background work.

Almost all threads have gone
- the "ticking" threads, that sleep a while then do some work)
(srv_monitor_thread, srv_error_monitor_thread, srv_master_thread)
were replaced with timers. Some timers are periodic,
e.g the "master" timer.

- The btr_defragment_thread is also replaced by a timer , which
reschedules it self when current defragment "item" needs throttling

- the buf_resize_thread and buf_dump_threads are substitutes with tasks
Ditto with page cleaner workers.

- purge workers threads are not tasks as well, and purge cleaner
coordinator is a combination of a task and timer.

- All AIO is outsourced to tpool, Innodb just calls thread_pool::submit_io()
and provides the callback.

- The srv_slot_t was removed, and innodb_debug_sync used in purge
is currently not working, and needs reimplementation.

1 files changed, 0 insertions, 20 deletions

diff --git a/storage/innobase/row/row0purge.cc b/storage/innobase/row/row0purge.cc
index 4dee8de5aad..41731ed17a0 100644
--- a/storage/innobase/row/row0purge.cc
+++ b/storage/innobase/row/row0purge.cc
@@ -1311,26 +1311,6 @@ row_purge_step(
 
 	node->start();
 
-#ifdef UNIV_DEBUG
-	srv_slot_t *slot = thr->thread_slot;
-	ut_ad(slot);
-
-	rw_lock_x_lock(&slot->debug_sync_lock);
-	while (UT_LIST_GET_LEN(slot->debug_sync)) {
-		srv_slot_t::debug_sync_t *sync =
-					UT_LIST_GET_FIRST(slot->debug_sync);
-		const char* sync_str = reinterpret_cast<char*>(&sync[1]);
-		bool result = debug_sync_set_action(current_thd,
-						    sync_str,
-						    strlen(sync_str));
-		ut_a(!result);
-
-		UT_LIST_REMOVE(slot->debug_sync, sync);
-		ut_free(sync);
-	}
-	rw_lock_x_unlock(&slot->debug_sync_lock);
-#endif
-
 	if (!(node->undo_recs == NULL || ib_vector_is_empty(node->undo_recs))) {
 		trx_purge_rec_t*purge_rec;