MDEV-24334 make monitor_set_tbl global variable thread-safe

Atomic_relaxed<T>: add fetch_or() and fetch_and()

innodb_init(): rely on a zero-initialization of a global variable

monitor_set_tbl: make Atomic_relaxed<ulint> array and use proper operations
for setting bit, unsetting bit and reading bit

Reviewed by: Marko Mäkelä

4 files changed, 18 insertions, 16 deletions

diff --git a/include/my_atomic_wrapper.h b/include/my_atomic_wrapper.h
index 64835e30ca7..c574fba4a8e 100644
--- a/include/my_atomic_wrapper.h
+++ b/include/my_atomic_wrapper.h
@@ -13,6 +13,7 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
 
+#pragma once
 #ifdef __cplusplus
 #include <atomic>
 /**
@@ -50,6 +51,10 @@ public:
   { return m.fetch_sub(i, o); }
   Type fetch_xor(const Type i, std::memory_order o= std::memory_order_relaxed)
   { return m.fetch_xor(i, o); }
+  Type fetch_and(const Type i, std::memory_order o= std::memory_order_relaxed)
+  { return m.fetch_and(i, o); }
+  Type fetch_or(const Type i, std::memory_order o= std::memory_order_relaxed)
+  { return m.fetch_or(i, o); }
   bool compare_exchange_strong(Type& i1, const Type i2,
                                std::memory_order o1= std::memory_order_relaxed,
                                std::memory_order o2= std::memory_order_relaxed)
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index a9206df377c..345f2a37d5d 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -4245,9 +4245,6 @@ static int innodb_init(void* p)
 	}
 #endif /* MYSQL_DYNAMIC_PLUGIN */
 
-	/* Currently, monitor counter information are not persistent. */
-	memset(monitor_set_tbl, 0, sizeof monitor_set_tbl);
-
 	memset(innodb_counter_value, 0, sizeof innodb_counter_value);
 
 	/* Do this as late as possible so server is fully starts up,
diff --git a/storage/innobase/include/srv0mon.h b/storage/innobase/include/srv0mon.h
index 45f9ae3d5e9..58e36676398 100644
--- a/storage/innobase/include/srv0mon.h
+++ b/storage/innobase/include/srv0mon.h
@@ -498,23 +498,23 @@ enum mon_option_t {
 
 /** This "monitor_set_tbl" is a bitmap records whether a particular monitor
 counter has been turned on or off */
-extern ulint		monitor_set_tbl[(NUM_MONITOR + NUM_BITS_ULINT - 1) /
-					NUM_BITS_ULINT];
+extern Atomic_relaxed<ulint>
+    monitor_set_tbl[(NUM_MONITOR + NUM_BITS_ULINT - 1) / NUM_BITS_ULINT];
 
 /** Macros to turn on/off the control bit in monitor_set_tbl for a monitor
 counter option. */
-#define MONITOR_ON(monitor)					\
-	(monitor_set_tbl[unsigned(monitor) / NUM_BITS_ULINT] |=	\
-	 (ulint(1) << (unsigned(monitor) % NUM_BITS_ULINT)))
+#define MONITOR_ON(monitor)                                                   \
+  (monitor_set_tbl[unsigned(monitor) / NUM_BITS_ULINT].fetch_or(              \
+      (ulint(1) << (unsigned(monitor) % NUM_BITS_ULINT))))
 
-#define MONITOR_OFF(monitor)					\
-	(monitor_set_tbl[unsigned(monitor) / NUM_BITS_ULINT] &=	\
-	 ~(ulint(1) << (unsigned(monitor) % NUM_BITS_ULINT)))
+#define MONITOR_OFF(monitor)                                                  \
+  (monitor_set_tbl[unsigned(monitor) / NUM_BITS_ULINT].fetch_and(             \
+      ~(ulint(1) << (unsigned(monitor) % NUM_BITS_ULINT))))
 
 /** Check whether the requested monitor is turned on/off */
-#define MONITOR_IS_ON(monitor)					\
-	(monitor_set_tbl[unsigned(monitor) / NUM_BITS_ULINT] &	\
-	 (ulint(1) << (unsigned(monitor) % NUM_BITS_ULINT)))
+#define MONITOR_IS_ON(monitor)                                                \
+  (monitor_set_tbl[unsigned(monitor) / NUM_BITS_ULINT] &                      \
+   (ulint(1) << (unsigned(monitor) % NUM_BITS_ULINT)))
 
 /** The actual monitor counter array that records each monintor counter
 value */
diff --git a/storage/innobase/srv/srv0mon.cc b/storage/innobase/srv/srv0mon.cc
index c759a5b75fe..e64d3b9f426 100644
--- a/storage/innobase/srv/srv0mon.cc
+++ b/storage/innobase/srv/srv0mon.cc
@@ -1424,8 +1424,8 @@ monitor_value_t	innodb_counter_value[NUM_MONITOR];
 
 /* monitor_set_tbl is used to record and determine whether a monitor
 has been turned on/off. */
-ulint		monitor_set_tbl[(NUM_MONITOR + NUM_BITS_ULINT
-						- 1) / NUM_BITS_ULINT];
+Atomic_relaxed<ulint>
+    monitor_set_tbl[(NUM_MONITOR + NUM_BITS_ULINT - 1) / NUM_BITS_ULINT];
 
 /****************************************************************//**
 Get a monitor's "monitor_info" by its monitor id (index into the