[sr-dev] git:master: memcached: fix crash during shutdown, make used memory manager configurable

Dragos Oancea droancea at yahoo.com
Tue Jul 2 16:46:09 CEST 2013


Hi Henning,


Thank you! This is good news.
I can confirm that the crash during the shutdown is fixed!
We are running now with the new module, I'll keep an eye on it.

Regards,
Dragos


________________________________
 From: Henning Westerholt <hw at kamailio.org>
To: sr-dev at lists.sip-router.org 
Sent: Sunday, June 30, 2013 3:46 PM
Subject: [sr-dev] git:master: memcached: fix crash during shutdown, make used memory manager configurable
 

Module: sip-router
Branch: master
Commit: df41d7f4e0cd8bd0c328f94360a6b3a3f3e9d59b
URL:    http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=df41d7f4e0cd8bd0c328f94360a6b3a3f3e9d59b

Author: Henning Westerholt <hw at kamailio.org>
Committer: Henning Westerholt <hw at kamailio.org>
Date:   Sun Jun 30 15:42:17 2013 +0200

memcached: fix crash during shutdown, make used memory manager configurable

* fix a crash during shutwdown, as reported from Dragos Oancea, droancea at yahoo dot com
* make memcache client library memory manager configurable, as default use
  the one from the system as this is probably the most tested configuration
  in the field
* the internal memory manager should provide a better performance in this case,
  but as the old library has some issues with the internal one, we better stay
  with this
* documentation will be provided in the next commit

---

modules/memcached/memcached.c |   45 ++++++++++++++++++++---------------------
modules/memcached/memcached.h |    4 ++-
test/unit/45.cfg              |    1 +
3 files changed, 26 insertions(+), 24 deletions(-)

diff --git a/modules/memcached/memcached.c b/modules/memcached/memcached.c
index 32852d9..86a08b3 100644
--- a/modules/memcached/memcached.c
+++ b/modules/memcached/memcached.c
@@ -43,7 +43,9 @@ unsigned int mcd_expire = 0;
/*! cache storage mode, set or add */
unsigned int mcd_mode = 0;
/*! server timeout in ms*/
-int mcd_timeout = 5000;
+unsigned int mcd_timeout = 5000;
+/*! Internal or system memory manager, default is system */
+unsigned int mcd_memory = 0;
/*! memcached handle */
struct memcached_st *memcached_h;
/*! memcached server list */
@@ -76,9 +78,10 @@ static pv_export_t mod_pvs[] = {
  */
static param_export_t params[] = {
    {"servers", STR_PARAM, &mcd_srv_str },
-    {"expire",   INT_PARAM, &mcd_expire },
+    {"expire",  INT_PARAM, &mcd_expire },
    {"timeout", INT_PARAM, &mcd_timeout },
    {"mode",    INT_PARAM, &mcd_mode },
+    {"memory",  INT_PARAM, &mcd_memory },
    {0, 0, 0}
};

@@ -105,10 +108,12 @@ struct module_exports exports = {
/*!
  * \brief Wrapper functions around our internal memory management
  * \param mem freed memory
+ * \note pkg_free does not allow NULL pointer as standard free, therefore we check it here
  * \see pkg_free
  */
static inline void mcd_free(memcached_st *ptr, void *mem, void *context) {
-    pkg_free(mem);
+        if (mem)
+            pkg_free(mem);
}


@@ -201,17 +206,21 @@ static int mod_init(void) {
    }
    LM_DBG("allocated new server handle at %p", memcached_h);

-    LM_DBG("set memory manager callbacks");
-    rc = memcached_set_memory_allocators(memcached_h, (memcached_malloc_fn)mcd_malloc,
+    if (mcd_memory == 1) {
+        LM_INFO("Use internal kamailio memory manager for memcached client library");
+        rc = memcached_set_memory_allocators(memcached_h, (memcached_malloc_fn)mcd_malloc,
                         (memcached_free_fn)mcd_free, (memcached_realloc_fn)mcd_realloc,
                         (memcached_calloc_fn)mcd_calloc, NULL);
-    if (rc == MEMCACHED_SUCCESS) {
-        LM_DBG("memory manager callbacks set");
+        if (rc == MEMCACHED_SUCCESS) {
+            LM_DBG("memory manager callbacks set");
+        } else {
+            LM_ERR("memory manager callbacks not set, returned %s.\n", memcached_strerror(memcached_h, rc));
+            return -1;
+        }
    } else {
-        LM_ERR("memory manager callbacks not set, returned %s.\n", memcached_strerror(memcached_h, rc));
-        return -1;
+        LM_INFO("Use system memory manager for memcached client library");
    }
-    
+
         servers = memcached_server_list_append(servers, server, atoi(port), &rc);
    
    if (memcached_behavior_set(memcached_h, MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT, mcd_timeout) != MEMCACHED_SUCCESS) {
@@ -241,20 +250,10 @@ static int mod_init(void) {
  * \brief Module shutdown function
  */
static void mod_destroy(void) {
-    memcached_return rc;
-    
    if (servers != NULL)
        memcached_server_list_free(servers);
    
-    /* unset custom memory manager to enable clean shutdown of in system memory allocated server structure */
-    LM_DBG("remove memory manager callbacks");
-    rc = memcached_set_memory_allocators(memcached_h, NULL, NULL, NULL, NULL, NULL);
-    if (rc == MEMCACHED_SUCCESS) {
-        LM_DBG("memory manager callbacks removed");
-    } else {
-        LM_ERR("memory manager callbacks not removed, returned %s but continue anyway.\n", memcached_strerror(memcached_h, rc));
-    }
-    
-    if (memcached_h != NULL)
-        memcached_free(memcached_h);
+    /* Crash on shutdown with internal memory manager, even if we disable the mm callbacks */
+    if (mcd_memory != 1 && memcached_h != NULL)
+                memcached_free(memcached_h);
}
diff --git a/modules/memcached/memcached.h b/modules/memcached/memcached.h
index 4d9a875..407d39f 100644
--- a/modules/memcached/memcached.h
+++ b/modules/memcached/memcached.h
@@ -35,7 +35,9 @@ extern unsigned int mcd_expire;
/*! cache storage mode, set or add */
extern unsigned int mcd_mode;
/*! server timeout */
-extern int mcd_timeout;
+extern unsigned int mcd_timeout;
+/*! Internal or system memory manager */
+extern unsigned int mcd_memory;
/*! memcached handle */
extern struct memcached_st* memcached_h;
/*! memcached server list */
diff --git a/test/unit/45.cfg b/test/unit/45.cfg
index f2b8c93..a170672 100644
--- a/test/unit/45.cfg
+++ b/test/unit/45.cfg
@@ -29,6 +29,7 @@ loadmodule "xlog/xlog.so"
modparam("mi_fifo", "fifo_name", "/tmp/kamailio_fifo")
modparam("usrloc", "db_mode", 3)
modparam("usrloc", "db_url", "mysql://kamailio:kamailiorw@localhost/kamailio")
+modparam("memcached", "memory", 0)

#-----------------------Routing configuration---------------------------------#
route{


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