MDEV-7962 wsrep_on() takes 0.14% in OLTP RO

The reason why we have wsrep_on() at all is that the macro WSREP(thd)
depends on the definition of THD, and that is intentionally an opaque
data type for InnoDB. So, we cannot avoid invoking wsrep_on(), but
we can evaluate the less expensive conditions thd && WSREP_ON before
calling the function.

Global_read_lock: Use WSREP_NNULL(thd) instead of wsrep_on(thd)
because we not only know the definition of THD but also that
the pointer is not null.

wsrep_open(): Use WSREP(thd) instead of wsrep_on(thd).

InnoDB: Replace thd && wsrep_on(thd) with wsrep_on(thd), now that
the condition has been merged to the definition of the macro
wsrep_on().

include/mysql/service_wsrep.h

@@ -97,7 +97,7 @@ extern struct wsrep_service_st {
 #define wsrep_is_wsrep_xid(X) wsrep_service->wsrep_is_wsrep_xid_func(X)
 #define wsrep_xid_seqno(X) wsrep_service->wsrep_xid_seqno_func(X)
 #define wsrep_xid_uuid(X) wsrep_service->wsrep_xid_uuid_func(X)
-#define wsrep_on(X) WSREP_ON && wsrep_service->wsrep_on_func(X)
+#define wsrep_on(thd) (thd) && WSREP_ON && wsrep_service->wsrep_on_func(thd)
 #define wsrep_prepare_key_for_innodb(A,B,C,D,E,F,G) wsrep_service->wsrep_prepare_key_for_innodb_func(A,B,C,D,E,F,G)
 #define wsrep_thd_LOCK(T) wsrep_service->wsrep_thd_LOCK_func(T)
 #define wsrep_thd_UNLOCK(T) wsrep_service->wsrep_thd_UNLOCK_func(T)

sql/lock.cc

 /*
    Copyright (c) 2000, 2011, Oracle and/or its affiliates.
+   Copyright (c) 2020, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -1102,13 +1103,15 @@ void Global_read_lock::unlock_global_read_lock(THD *thd)
   {
     Wsrep_server_state& server_state= Wsrep_server_state::instance();
     if (server_state.state() == Wsrep_server_state::s_donor ||
-        (wsrep_on(thd) && server_state.state() != Wsrep_server_state::s_synced))
+        (WSREP_NNULL(thd) &&
+         server_state.state() != Wsrep_server_state::s_synced))
     {
       /* TODO: maybe redundant here?: */
       wsrep_locked_seqno= WSREP_SEQNO_UNDEFINED;
       server_state.resume();
     }
-    else if (wsrep_on(thd) && server_state.state() == Wsrep_server_state::s_synced)
+    else if (WSREP_NNULL(thd) &&
+             server_state.state() == Wsrep_server_state::s_synced)
     {
       server_state.resume_and_resync();
     }
@@ -1164,11 +1167,13 @@ bool Global_read_lock::make_global_read_lock_block_commit(THD *thd)
   Wsrep_server_state& server_state= Wsrep_server_state::instance();
   wsrep::seqno paused_seqno;
   if (server_state.state() == Wsrep_server_state::s_donor ||
-      (wsrep_on(thd) && server_state.state() != Wsrep_server_state::s_synced))
+      (WSREP_NNULL(thd) &&
+       server_state.state() != Wsrep_server_state::s_synced))
   {
     paused_seqno= server_state.pause();
   }
-  else if (wsrep_on(thd) && server_state.state() == Wsrep_server_state::s_synced)
+  else if (WSREP_NNULL(thd) &&
+           server_state.state() == Wsrep_server_state::s_synced)
   {
     paused_seqno= server_state.desync_and_pause();
   }

sql/wsrep_trans_observer.h

@@ -405,7 +405,7 @@ static inline void wsrep_after_apply(THD* thd)
 static inline void wsrep_open(THD* thd)
 {
   DBUG_ENTER("wsrep_open");
-  if (wsrep_on(thd))
+  if (WSREP(thd))
   {
     thd->wsrep_cs().open(wsrep::client_id(thd->thread_id));
     thd->wsrep_cs().debug_log_level(wsrep_debug);

storage/innobase/dict/dict0stats_bg.cc

@@ -179,8 +179,7 @@ void dict_stats_update_if_needed_func(dict_table_t* table)
 			generated row locks and allow BF thread
 			lock waits to be enqueued at head of waiting
 			queue. */
-			if (thd
-			    && wsrep_on(thd)
+			if (wsrep_on(thd)
 			    && !wsrep_thd_is_applying(thd)
 			    && wsrep_thd_is_BF(thd, 0)) {
 				WSREP_DEBUG("Avoiding background statistics"

storage/innobase/handler/ha_innodb.cc

@@ -4366,7 +4366,7 @@ innobase_commit_low(
 #ifdef WITH_WSREP
 	THD* thd = (THD*)trx->mysql_thd;
 	const char* tmp = 0;
-	if (thd && wsrep_on(thd)) {
+	if (wsrep_on(thd)) {
 #ifdef WSREP_PROC_INFO
 		char info[64];
 		info[sizeof(info) - 1] = '\0';
@@ -4386,7 +4386,7 @@ innobase_commit_low(
 	}
 	trx->will_lock = 0;
 #ifdef WITH_WSREP
-	if (thd && wsrep_on(thd)) { thd_proc_info(thd, tmp); }
+	if (wsrep_on(thd)) { thd_proc_info(thd, tmp); }
 #endif /* WITH_WSREP */
 }