If MaxMemFree is set, limit the number of recycled pools that is kept

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1137262 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/CHANGES b/CHANGES
index 1a3a0d6f2ec9cce7cf22b055f5855a8c6ef49a5a..346513884413e5be665a1a691f0b41947edacc29 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -2,6 +2,9 @@
 
 Changes with Apache 2.3.13
 
+  *) mpm_event: If MaxMemFree is set, limit the number of pools that is kept
+     around. [Stefan Fritsch]
+
   *) mpm_event: Fix graceful restart aborting connections. PR 43359.
      [Takashi Sato <takashi lans-tv com>]
 

diff --git a/server/mpm/event/event.c b/server/mpm/event/event.c
index 83ebcff71f90863dc661bd02bc60edd51db04cfe..b002f56910c19b3e063951d33964ec0c12b9b251 100644 (file)
--- a/server/mpm/event/event.c
+++ b/server/mpm/event/event.c
@@ -1558,6 +1558,7 @@ static void *APR_THREAD_FUNC start_threads(apr_thread_t * thd, void *dummy)
     int listener_started = 0;
     int loops;
     int prev_threads_created;
+    int max_recycled_pools = -1;
 
     /* We must create the fd queues before we start up the listener
      * and worker threads. */
@@ -1569,8 +1570,15 @@ static void *APR_THREAD_FUNC start_threads(apr_thread_t * thd, void *dummy)
         clean_child_exit(APEXIT_CHILDFATAL);
     }
 
+    if (ap_max_mem_free != APR_ALLOCATOR_MAX_FREE_UNLIMITED) {
+        /* If we want to conserve memory, let's not keep an unlimited number of
+         * pools & allocators.
+         * XXX: This should probably be a separate config directive
+         */
+        max_recycled_pools = threads_per_child * 3 / 4 ;
+    }
     rv = ap_queue_info_create(&worker_queue_info, pchild,
-                              threads_per_child);
+                              threads_per_child, max_recycled_pools);
     if (rv != APR_SUCCESS) {
         ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
                      "ap_queue_info_create() failed");

diff --git a/server/mpm/event/fdqueue.c b/server/mpm/event/fdqueue.c
index c1dbda1ee526d4296f3b12c707feb4549bf75467..26b5906d22bb9881381d02480a62f144a3046045 100644 (file)
--- a/server/mpm/event/fdqueue.c
+++ b/server/mpm/event/fdqueue.c
@@ -34,6 +34,8 @@ struct fd_queue_info_t
     apr_thread_cond_t *wait_for_idler;
     int terminated;
     int max_idlers;
+    int max_recycled_pools;
+    apr_uint32_t recycled_pools_count;
     recycled_pool *recycled_pools;
 };
 
@@ -60,7 +62,8 @@ static apr_status_t queue_info_cleanup(void *data_)
 }
 
 apr_status_t ap_queue_info_create(fd_queue_info_t ** queue_info,
-                                  apr_pool_t * pool, int max_idlers)
+                                  apr_pool_t * pool, int max_idlers,
+                                  int max_recycled_pools)
 {
     apr_status_t rv;
     fd_queue_info_t *qi;
@@ -77,6 +80,7 @@ apr_status_t ap_queue_info_create(fd_queue_info_t ** queue_info,
         return rv;
     }
     qi->recycled_pools = NULL;
+    qi->max_recycled_pools = max_recycled_pools;
     qi->max_idlers = max_idlers;
     apr_pool_cleanup_register(pool, qi, queue_info_cleanup,
                               apr_pool_cleanup_null);
@@ -191,29 +195,36 @@ apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t * queue_info)
 void ap_push_pool(fd_queue_info_t * queue_info,
                                     apr_pool_t * pool_to_recycle)
 {
+    struct recycled_pool *new_recycle;
     /* If we have been given a pool to recycle, atomically link
      * it into the queue_info's list of recycled pools
      */
-    if (pool_to_recycle) {
-        struct recycled_pool *new_recycle;
-        new_recycle = (struct recycled_pool *) apr_palloc(pool_to_recycle,
-                                                          sizeof
-                                                          (*new_recycle));
-        new_recycle->pool = pool_to_recycle;
-        for (;;) {
-            /*
-             * Save queue_info->recycled_pool in local variable next because
-             * new_recycle->next can be changed after apr_atomic_casptr
-             * function call. For gory details see PR 44402.
-             */
-            struct recycled_pool *next = queue_info->recycled_pools;
-            new_recycle->next = next;
-            if (apr_atomic_casptr
-                ((void*) &(queue_info->recycled_pools),
-                 new_recycle, next) == next) {
-                break;
-            }
+    if (!pool_to_recycle)
+        return;
+
+    if (queue_info->max_recycled_pools >= 0) {
+        apr_uint32_t cnt = apr_atomic_read32(&queue_info->recycled_pools_count);
+        if (cnt >= queue_info->max_recycled_pools) {
+            apr_pool_destroy(pool_to_recycle);
+            return;
         }
+        apr_atomic_inc32(&queue_info->recycled_pools_count);
+    }
+
+    new_recycle = (struct recycled_pool *) apr_palloc(pool_to_recycle,
+                                                      sizeof (*new_recycle));
+    new_recycle->pool = pool_to_recycle;
+    for (;;) {
+        /*
+         * Save queue_info->recycled_pool in local variable next because
+         * new_recycle->next can be changed after apr_atomic_casptr
+         * function call. For gory details see PR 44402.
+         */
+        struct recycled_pool *next = queue_info->recycled_pools;
+        new_recycle->next = next;
+        if (apr_atomic_casptr((void*) &(queue_info->recycled_pools),
+                              new_recycle, next) == next)
+            break;
     }
 }
 
@@ -241,6 +252,8 @@ void ap_pop_pool(apr_pool_t ** recycled_pool, fd_queue_info_t * queue_info)
             ((void*) &(queue_info->recycled_pools),
              first_pool->next, first_pool) == first_pool) {
             *recycled_pool = first_pool->pool;
+            if (queue_info->max_recycled_pools >= 0)
+                apr_atomic_dec32(&queue_info->recycled_pools_count);
             break;
         }
     }

diff --git a/server/mpm/event/fdqueue.h b/server/mpm/event/fdqueue.h
index fbe120b8db8a4f69d2bdf80912dee3302970705d..9c1deb6441b366a36494c757c6aa041b7e5c27fd 100644 (file)
--- a/server/mpm/event/fdqueue.h
+++ b/server/mpm/event/fdqueue.h
@@ -42,7 +42,8 @@
 typedef struct fd_queue_info_t fd_queue_info_t;
 
 apr_status_t ap_queue_info_create(fd_queue_info_t ** queue_info,
-                                  apr_pool_t * pool, int max_idlers);
+                                  apr_pool_t * pool, int max_idlers,
+                                  int max_recycled_pools);
 apr_status_t ap_queue_info_set_idle(fd_queue_info_t * queue_info,
                                     apr_pool_t * pool_to_recycle);
 apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t * queue_info);