From 0e78f62a6324a58de8a55aff13b490ffd2dd369f Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@newdream.net>
Date: Tue, 22 Jul 2008 12:26:24 -0700
Subject: [PATCH] use atomic_t to count threads

---
 src/common/Thread.h  | 9 +++++----
 src/config.cc        | 2 +-
 src/include/atomic.h | 1 +
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/common/Thread.h b/src/common/Thread.h
index b8b75bb57eec3..24876f7f12427 100644
--- a/src/common/Thread.h
+++ b/src/common/Thread.h
@@ -19,8 +19,9 @@
 #include <pthread.h>
 #include <signal.h>
 #include <errno.h>
+#include "include/atomic.h"
 
-extern int _num_threads;  // hack: in config.cc
+extern atomic_t _num_threads;  // hack: in config.cc
 
 class Thread {
  private:
@@ -36,7 +37,7 @@ class Thread {
  private:
   static void *_entry_func(void *arg) {
     void *r = ((Thread*)arg)->entry();
-    _num_threads--;
+    _num_threads.dec();
     return r;
   }
 
@@ -45,7 +46,7 @@ class Thread {
   bool is_started() { return thread_id != 0; }
   bool am_self() { return (pthread_self() == thread_id); }
 
-  static int get_num_threads() { return _num_threads; }
+  static int get_num_threads() { return _num_threads.test(); }
 
   int kill(int signal) {
     if (thread_id)
@@ -54,7 +55,7 @@ class Thread {
       return -EINVAL;
   }
   int create() {
-    _num_threads++;
+    _num_threads.inc();
     return pthread_create( &thread_id, NULL, _entry_func, (void*)this );
   }
   int join(void **prval = 0) {
diff --git a/src/config.cc b/src/config.cc
index 3369dde4656ad..121ee95f322b9 100644
--- a/src/config.cc
+++ b/src/config.cc
@@ -99,7 +99,7 @@ unsigned _page_size = sysconf(_SC_PAGESIZE);
 unsigned long _page_mask = ~(unsigned long)(_page_size - 1);
 unsigned _page_shift = _get_bits_of(_page_size);
 
-int _num_threads = 0;
+atomic_t _num_threads(0);
 
 // file layouts
 struct ceph_file_layout g_default_file_layout = {
diff --git a/src/include/atomic.h b/src/include/atomic.h
index 31a095d8ea95e..0fc65b0898233 100644
--- a/src/include/atomic.h
+++ b/src/include/atomic.h
@@ -47,6 +47,7 @@ class atomic_t {
   long nref;
 public:
   atomic_t(int i=0) : lock(false), nref(i) {}
+  atomic_t(const atomic_t& other);
   void inc() { 
     lock.Lock();
     ++nref;
-- 
2.39.5