Bug#374767: vm.memory.size[available] functionality

[Krzysztof Raczkowski]

Package: zabbix
Severity: wishlist

Function vm.memory.size[free] shows free system memory which is calculated 
like this:
free = total - (buffers + cached +used)
So, it shows real free memory during short period after system start only.
Here's my system:

[EMAIL PROTECTED]:~ $ free -m
             total       used       free     shared    buffers     cached
Mem:          2026       1976         50          0        269       1382
-/+ buffers/cache:        324       1702
Swap:         2047          0       2047

vm.memory.size[free] shows, that I've got only 50 MB of free memory, and 
zabbix activates warning trigger.

I found a patch on Zabbix Forum 
(http://www.zabbix.com/forum/showthread.php?t=2405), which add 
new 'available' functionality to vm.memory.size[] function. It calculates 
available memory as below:
avaliable = total - used
omitting buffers and cached.

Now I've got 1702 MB of available memory, and no triggers activated.

It applies cleanly to zabbix-1.1. Can it be applied to Debian version too?

-- 
Krzysztof Raczkowski
Rzeszow University of Technology
System Administrator of CZ RMSK
tel.: (017) 865-13-93; e-mail: [EMAIL PROTECTED]

--- zabbix-1.1beta7.orig/src/libs/zbxsysinfo/linux/memory.c     2005-12-15 
03:11:02.000000000 -0600
+++ zabbix-1.1beta7/src/libs/zbxsysinfo/linux/memory.c  2006-03-14 
16:13:47.000000000 -0600
@@ -22,17 +22,13 @@
 #include "common.h"
 #include "sysinfo.h"
 
-static int     VM_MEMORY_CACHED(const char *cmd, const char *param, unsigned 
flags, AGENT_RESULT *result)
+zbx_uint64_t   vm_cached_internal(void)
 {
        FILE    *f;
        char    *t;
        char    c[MAX_STRING_LEN];
        zbx_uint64_t    res = 0;
 
-       assert(result);
-
-        init_result(result);
-               
        f=fopen("/proc/meminfo","r");
        if(NULL == f)
        {
@@ -56,8 +52,39 @@
                }
        }
        fclose(f);
+       return res;
+}
+
+static int     VM_MEMORY_AVAILABLE(const char *cmd, const char *param, 
unsigned flags, AGENT_RESULT *result)
+{
+       struct sysinfo info;
+
+       assert(result);
+
+        init_result(result);
+               
+       if( 0 == sysinfo(&info))
+       {
+#ifdef HAVE_SYSINFO_MEM_UNIT
+               SET_UI64_RESULT(result, ((zbx_uint64_t)(info.freeram + 
info.bufferram) * (zbx_uint64_t)info.mem_unit) + vm_cached_internal());
+#else
+               SET_UI64_RESULT(result, (info.freeram + info.sharedram + 
vm_cached_internal()));
+#endif
+               return SYSINFO_RET_OK;
+       }
+       else
+       {
+               return SYSINFO_RET_FAIL;
+       }
+}
+
+static int     VM_MEMORY_CACHED(const char *cmd, const char *param, unsigned 
flags, AGENT_RESULT *result)
+{
+       assert(result);
+
+        init_result(result);
 
-       SET_UI64_RESULT(result, res);
+       SET_UI64_RESULT(result, vm_cached_internal());
        return SYSINFO_RET_OK;
 }
 
@@ -169,6 +196,7 @@
                {"total",       VM_MEMORY_TOTAL},
                {"buffers",     VM_MEMORY_BUFFERS},
                {"cached",      VM_MEMORY_CACHED},
+               {"available",   VM_MEMORY_AVAILABLE},
                {0,     0}
        };
         char    mode[MAX_STRING_LEN];