bk commit into 5.1 tree (gkodinov:1.2572) BUG#28284

[kgeorge]

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ChangeSet@stripped, 2007-08-24 18:06:44+03:00, gkodinov@stripped +3 -0
  Bug #28284: Test "mysqlslap" reports "out of memory"
  
  When locking a "fast" mutex a static variable cpu_count 
  was used as a flag to initialize itself on the first usage 
  by calling sysconf() and setting non-zero value.
  This is not thread and optimization safe on some 
  platforms. That's why the global initialization needs 
  to be done once in a designated function.
  This will also speed up the usage (by a small bit) 
  because it won't have to check if it's initialized on
  every call.
  
  Fixed by moving the fast mutexes initialization out of 
  my_pthread_fastmutex_lock() to fastmutex_global_init()
  and call it from my_init()

  include/my_pthread.h@stripped, 2007-08-24 18:06:42+03:00, gkodinov@stripped +1 -0
    Bug #28284: move the fast mutexes initialization out of 
    my_pthread_fastmutex_lock() to fastmutex_global_init()
    and call it from my_init()

  mysys/my_init.c@stripped, 2007-08-24 18:06:42+03:00, gkodinov@stripped +3 -0
    Bug #28284: move the fast mutexes initialization out of 
    my_pthread_fastmutex_lock() to fastmutex_global_init()
    and call it from my_init()

  mysys/thr_mutex.c@stripped, 2007-08-24 18:06:42+03:00, gkodinov@stripped +11 -6
    Bug #28284: move the fast mutexes initialization out of 
    my_pthread_fastmutex_lock() to fastmutex_global_init()
    and call it from my_init()

diff -Nrup a/include/my_pthread.h b/include/my_pthread.h
--- a/include/my_pthread.h	2007-06-25 19:21:16 +03:00
+++ b/include/my_pthread.h	2007-08-24 18:06:42 +03:00
@@ -538,6 +538,7 @@ typedef struct st_my_pthread_fastmutex_t
   pthread_mutex_t mutex;
   uint spins;
 } my_pthread_fastmutex_t;
+void fastmutex_global_init(void);
 
 int my_pthread_fastmutex_init(my_pthread_fastmutex_t *mp, 
                               const pthread_mutexattr_t *attr);
diff -Nrup a/mysys/my_init.c b/mysys/my_init.c
--- a/mysys/my_init.c	2007-08-02 07:49:24 +03:00
+++ b/mysys/my_init.c	2007-08-24 18:06:42 +03:00
@@ -79,6 +79,9 @@ my_bool my_init(void)
 #if defined(THREAD) && defined(SAFE_MUTEX)
   safe_mutex_global_init();		/* Must be called early */
 #endif
+#if defined(THREAD) && defined(MY_PTHREAD_FASTMUTEX) && !defined(SAFE_MUTEX)
+  fastmutex_global_init();              /* Must be called early */
+#endif
   netware_init();
 #ifdef THREAD
 #if defined(HAVE_PTHREAD_INIT)
diff -Nrup a/mysys/thr_mutex.c b/mysys/thr_mutex.c
--- a/mysys/thr_mutex.c	2007-02-23 13:13:48 +02:00
+++ b/mysys/thr_mutex.c	2007-08-24 18:06:42 +03:00
@@ -394,15 +394,11 @@ ulong mutex_delay(ulong delayloops)
 #define MY_PTHREAD_FASTMUTEX_SPINS 8
 #define MY_PTHREAD_FASTMUTEX_DELAY 4
 
+static int cpu_count= 0;
+
 int my_pthread_fastmutex_init(my_pthread_fastmutex_t *mp,
                               const pthread_mutexattr_t *attr)
 {
-  static int cpu_count= 0;
-#ifdef _SC_NPROCESSORS_CONF
-  if (!cpu_count && (attr == MY_MUTEX_INIT_FAST))
-    cpu_count= sysconf(_SC_NPROCESSORS_CONF);
-#endif
-  
   if ((cpu_count > 1) && (attr == MY_MUTEX_INIT_FAST))
     mp->spins= MY_PTHREAD_FASTMUTEX_SPINS; 
   else
@@ -432,4 +428,13 @@ int my_pthread_fastmutex_lock(my_pthread
   }
   return pthread_mutex_lock(&mp->mutex);
 }
+
+
+void fastmutex_global_init(void)
+{
+#ifdef _SC_NPROCESSORS_CONF
+  cpu_count= sysconf(_SC_NPROCESSORS_CONF);
+#endif
+}
+  
 #endif /* defined(THREAD) && defined(MY_PTHREAD_FASTMUTEX) && !defined(SAFE_MUTEX) */