Revert the kernel mutex split phase I patch. Some artefacts have been left

in the code but they have nothing to do with the kernel mutex split code.
Some subsequent commits use the new functions. This patch has been tested
with: ./mtr --suite=innodb with UNIV_DEBUG and UNIV_SYNC_DEBUG enabled.
All tests were successful.

storage/innobase/include/que0que.h

@@ -381,9 +381,6 @@ struct que_thr_struct{
 					thus far */
 	ulint		lock_state;	/*!< lock state of thread (table or
 					row) */
-	struct srv_slot_struct*
-			slot;		/* The thread slot in the wait
-					array in srv_sys_t */
 };
 
 #define QUE_THR_MAGIC_N		8476583

storage/innobase/include/srv0srv.h

@@ -239,6 +239,7 @@ extern	ibool	srv_print_latch_waits;
 # define srv_print_latch_waits		FALSE
 #endif /* UNIV_DEBUG */
 
+extern ulint	srv_activity_count;
 extern ulint	srv_fatal_semaphore_wait_threshold;
 extern ulint	srv_dml_needed_delay;
 
@@ -313,6 +314,12 @@ typedef struct export_var_struct export_struc;
 /** Status variables to be passed to MySQL */
 extern export_struc export_vars;
 
+/** The server system */
+typedef struct srv_sys_struct	srv_sys_t;
+
+/** The server system */
+extern srv_sys_t*	srv_sys;
+
 # ifdef UNIV_PFS_THREAD
 /* Keys to register InnoDB threads with performance schema */
 extern mysql_pfs_key_t	trx_rollback_clean_thread_key;
@@ -414,8 +421,6 @@ enum srv_thread_type {
 			be biggest) */
 };
 
-struct srv_slot_struct;
-
 /*********************************************************************//**
 Boots Innobase server.
 @return	DB_SUCCESS or error code */
@@ -466,6 +471,17 @@ srv_set_io_thread_op_info(
 	const char*	str);	/*!< in: constant char string describing the
 				state */
 /*********************************************************************//**
+Releases threads of the type given from suspension in the thread table.
+NOTE! The server mutex has to be reserved by the caller!
+@return number of threads released: this may be less than n if not
+enough threads were suspended at the moment */
+UNIV_INTERN
+ulint
+srv_release_threads(
+/*================*/
+	enum srv_thread_type	type,	/*!< in: thread type */
+	ulint			n);	/*!< in: number of threads to release */
+/*********************************************************************//**
 The master thread controlling the server.
 @return	a dummy parameter */
 UNIV_INTERN
@@ -612,13 +628,6 @@ void
 srv_export_innodb_status(void);
 /*==========================*/
 
-/******************************************************************//**
-Increment the server activity counter. */
-UNIV_INTERN
-void
-srv_inc_activity_count(void);
-/*=========================*/
-
 /*********************************************************************//**
 Asynchronous purge thread.
 @return	a dummy parameter */
@@ -700,6 +709,20 @@ struct export_var_struct{
 	ulint innodb_rows_deleted;		/*!< srv_n_rows_deleted */
 };
 
+/** Thread slot in the thread table */
+typedef struct srv_slot_struct	srv_slot_t;
+  
+/** Thread table is an array of slots */
+typedef srv_slot_t	srv_table_t;
+
+/** The server system struct */
+struct srv_sys_struct{
+	srv_table_t*	threads;	/*!< server thread table */
+	UT_LIST_BASE_NODE_T(que_thr_t)
+			tasks;		/*!< task queue */
+};
+
+extern ulint	srv_n_threads_active[];
 #else /* !UNIV_HOTBACKUP */
 # define srv_use_adaptive_hash_indexes		FALSE
 # define srv_use_checksums			TRUE

storage/innobase/include/sync0sync.h

@@ -105,7 +105,6 @@ extern mysql_pfs_key_t	rw_lock_mutex_key;
 extern mysql_pfs_key_t	srv_dict_tmpfile_mutex_key;
 extern mysql_pfs_key_t	srv_innodb_monitor_mutex_key;
 extern mysql_pfs_key_t	srv_misc_tmpfile_mutex_key;
-extern mysql_pfs_key_t	srv_threads_mutex_key;
 extern mysql_pfs_key_t	srv_monitor_file_mutex_key;
 extern mysql_pfs_key_t	syn_arr_mutex_key;
 # ifdef UNIV_SYNC_DEBUG
@@ -588,9 +587,6 @@ Kernel mutex				If a kernel operation needs a file
 |					fsp x-latch before acquiring the kernel
 |					mutex.
 V
-Threads mutex				Thread scheduling mutex
-|
-V
 Search system mutex
 |
 V
@@ -661,9 +657,8 @@ or row lock! */
 /*------------------------------------- MySQL binlog mutex */
 /*-------------------------------*/
 #define	SYNC_KERNEL		300
-#define SYNC_THREADS		299
-#define SYNC_REC_LOCK		298
-#define	SYNC_TRX_LOCK_HEAP	297
+#define SYNC_REC_LOCK		299
+#define	SYNC_TRX_LOCK_HEAP	298
 #define SYNC_TRX_SYS_HEADER	290
 #define SYNC_LOG		170
 #define SYNC_LOG_FLUSH_ORDER	147

storage/innobase/include/univ.i

@@ -245,6 +245,9 @@ by one. */
 #define UNIV_SET_MEM_TO_ZERO
 #endif
 
+#define UNIV_DEBUG
+#define UNIV_SYNC_DEBUG
+
 /*
 #define UNIV_SQL_DEBUG
 #define UNIV_LOG_DEBUG

storage/innobase/que/que0que.c

@@ -29,6 +29,7 @@ Created 5/27/1996 Heikki Tuuri
 #include "que0que.ic"
 #endif
 
+#include "srv0que.h"
 #include "usr0sess.h"
 #include "trx0trx.h"
 #include "trx0roll.h"
@@ -225,8 +226,6 @@ que_thr_create(
 	thr->resource = 0;
 	thr->lock_state = QUE_THR_LOCK_NOLOCK;
 
-	thr->slot = NULL;
-
 	UT_LIST_ADD_LAST(thrs, parent->thrs, thr);
 
 	return(thr);
@@ -312,9 +311,7 @@ que_thr_end_wait_no_next_thr(
 	/* In MySQL we let the OS thread (not just the query thread) to wait
 	for the lock to be released: */
 
-	if (thr != NULL) {
 	srv_release_mysql_thread_if_suspended(thr);
-	}
 
 	/* srv_que_task_enqueue_low(thr); */
 }

storage/innobase/row/row0undo.c

@@ -341,7 +341,7 @@ row_undo_step(
 
 	ut_ad(thr);
 
-	srv_inc_activity_count();
+	srv_activity_count++;
 
 	trx = thr_get_trx(thr);
 

storage/innobase/sync/sync0sync.c

@@ -1167,7 +1167,6 @@ sync_thread_add_level(
 	case SYNC_SEARCH_SYS_CONF:
 	case SYNC_TRX_LOCK_HEAP:
 	case SYNC_KERNEL:
-	case SYNC_THREADS:
 	case SYNC_IBUF_BITMAP_MUTEX:
 	case SYNC_RSEG:
 	case SYNC_TRX_UNDO:

storage/innobase/trx/trx0roll.c

@@ -37,6 +37,7 @@ Created 3/26/1996 Heikki Tuuri
 #include "trx0rec.h"
 #include "que0que.h"
 #include "usr0sess.h"
+#include "srv0que.h"
 #include "srv0start.h"
 #include "row0undo.h"
 #include "row0mysql.h"