Patch submitted to qpid-dev by ksmith@redhat.com. Fixes concurrency issues arising from previous move to use singleton apr pool.

"My patch does three things:

1) Modifies the APRPool class to use alloc/free semantics for APR memory pools. Each time a caller calls APRPool::get() they'll their own pool reference. I've fixed up all the call sites I can find to also call APRPool::free() at the appropriate time.

2) Caches freed APR memory pools in a STL stack. This cuts down on the number of memory pools created overall.

3) As a result of doing #1 and #2 I've introduced a guard mutex around APRPool::get() and APRPool::free(). This is to prevent concurrent access to the memory pool cache. If it's too heavyweight, the mutex along with the caching mechanism could be removed entirely."



git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/branches/M2@540511 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 7 insertions, 3 deletions

diff --git a/cpp/lib/common/sys/Mutex.h b/cpp/lib/common/sys/Mutex.h
index 4022da2f6e..9b1412aa09 100644
--- a/cpp/lib/common/sys/Mutex.h
+++ b/cpp/lib/common/sys/Mutex.h
@@ -21,8 +21,9 @@
 
 #ifdef USE_APR
 #  include <apr_thread_mutex.h>
-#  include <apr/APRBase.h>
-#  include <apr/APRPool.h>
+#  include <apr_pools.h>
+#  include "apr/APRBase.h"
+#  include "apr/APRPool.h"
 #else
 #  include <pthread.h>
 #  include <posix/check.h>
@@ -62,6 +63,7 @@ class Mutex : private boost::noncopyable {
   protected:
 #ifdef USE_APR
     apr_thread_mutex_t* mutex;
+    apr_pool_t* pool;
 #else
     pthread_mutex_t mutex;
 #endif
@@ -71,11 +73,13 @@ class Mutex : private boost::noncopyable {
 // APR ================================================================
 
 Mutex::Mutex() {
-    CHECK_APR_SUCCESS(apr_thread_mutex_create(&mutex, APR_THREAD_MUTEX_NESTED, APRPool::get()));
+    pool = APRPool::get();
+    CHECK_APR_SUCCESS(apr_thread_mutex_create(&mutex, APR_THREAD_MUTEX_NESTED, pool));
 }
 
 Mutex::~Mutex(){
     CHECK_APR_SUCCESS(apr_thread_mutex_destroy(mutex));
+    APRPool::free(pool);    
 }
 
 void Mutex::lock() {