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net-snmp/SOURCES/net-snmp-5.8-memavailable.p...

144 lines
5.6 KiB

From 5b8bf5d4130761c3374f9ad618e8a76bb75eb634 Mon Sep 17 00:00:00 2001
From: Yuwei Ba <i@xiaoba.me>
Date: Fri, 21 Aug 2020 15:06:10 +0800
Subject: [PATCH] snmpd: support MemAvailable on Linux
See also https://github.com/net-snmp/net-snmp/pull/167 .
[bvanassche: modified the behavior of this patch]
---
agent/mibgroup/hardware/memory/memory_linux.c | 20 ++++++++++++++++++-
agent/mibgroup/ucd-snmp/memory.c | 12 ++++++++++-
agent/mibgroup/ucd-snmp/memory.h | 1 +
include/net-snmp/agent/hardware/memory.h | 1 +
mibs/UCD-SNMP-MIB.txt | 16 +++++++++++++++
5 files changed, 48 insertions(+), 2 deletions(-)
diff --git a/agent/mibgroup/hardware/memory/memory_linux.c b/agent/mibgroup/hardware/memory/memory_linux.c
index 6d5e86cde4..4ae235c2d0 100644
--- a/agent/mibgroup/hardware/memory/memory_linux.c
+++ b/agent/mibgroup/hardware/memory/memory_linux.c
@@ -24,7 +24,8 @@ int netsnmp_mem_arch_load( netsnmp_cache *cache, void *magic ) {
static int first = 1;
ssize_t bytes_read;
char *b;
- unsigned long memtotal = 0, memfree = 0, memshared = 0,
+ int have_memavail = 0;
+ unsigned long memtotal = 0, memavail = 0, memfree = 0, memshared = 0,
buffers = 0, cached = 0, sreclaimable = 0,
swaptotal = 0, swapfree = 0;
@@ -81,6 +82,11 @@ int netsnmp_mem_arch_load( netsnmp_cache *cache, void *magic ) {
if (first)
snmp_log(LOG_ERR, "No MemTotal line in /proc/meminfo\n");
}
+ b = strstr(buff, "MemAvailable: ");
+ if (b) {
+ have_memavail = 1;
+ sscanf(b, "MemAvailable: %lu", &memavail);
+ }
b = strstr(buff, "MemFree: ");
if (b)
sscanf(b, "MemFree: %lu", &memfree);
@@ -151,6 +157,18 @@ int netsnmp_mem_arch_load( netsnmp_cache *cache, void *magic ) {
mem->other = -1;
}
+ if (have_memavail) {
+ mem = netsnmp_memory_get_byIdx(NETSNMP_MEM_TYPE_AVAILMEM, 1);
+ if (mem) {
+ if (!mem->descr)
+ mem->descr = strdup("Available memory");
+ mem->units = 1024;
+ mem->size = memavail;
+ mem->free = memavail;
+ mem->other = -1;
+ }
+ }
+
mem = netsnmp_memory_get_byIdx( NETSNMP_MEM_TYPE_VIRTMEM, 1 );
if (!mem) {
snmp_log_perror("No Virtual Memory info entry");
diff --git a/agent/mibgroup/ucd-snmp/memory.c b/agent/mibgroup/ucd-snmp/memory.c
index 371a77e9a5..158b28e67b 100644
--- a/agent/mibgroup/ucd-snmp/memory.c
+++ b/agent/mibgroup/ucd-snmp/memory.c
@@ -26,7 +26,7 @@ init_memory(void)
netsnmp_create_handler_registration("memory", handle_memory,
memory_oid, OID_LENGTH(memory_oid),
HANDLER_CAN_RONLY),
- 1, 26);
+ 1, 27);
netsnmp_register_scalar(
netsnmp_create_handler_registration("memSwapError", handle_memory,
memSwapError_oid, OID_LENGTH(memSwapError_oid),
@@ -272,6 +272,16 @@ handle_memory(netsnmp_mib_handler *handler,
c64.low = val & 0xFFFFFFFF;
c64.high = val >>32;
break;
+ case MEMORY_SYS_AVAIL:
+ type = ASN_COUNTER64;
+ mem_info = netsnmp_memory_get_byIdx(NETSNMP_MEM_TYPE_AVAILMEM, 0);
+ if (!mem_info)
+ goto NOSUCH;
+ val = mem_info->size; /* memavail */
+ val *= (mem_info->units/1024);
+ c64.low = val & 0xFFFFFFFF;
+ c64.high = val >> 32;
+ break;
case MEMORY_SWAP_ERROR:
mem_info = netsnmp_memory_get_byIdx( NETSNMP_MEM_TYPE_SWAP, 0 );
if (!mem_info)
diff --git a/agent/mibgroup/ucd-snmp/memory.h b/agent/mibgroup/ucd-snmp/memory.h
index ded2140227..54a56a2fdb 100644
--- a/agent/mibgroup/ucd-snmp/memory.h
+++ b/agent/mibgroup/ucd-snmp/memory.h
@@ -41,6 +41,7 @@ Netsnmp_Node_Handler handle_memory;
#define MEMORY_SHARED_X 24
#define MEMORY_BUFFER_X 25
#define MEMORY_CACHED_X 26
+#define MEMORY_SYS_AVAIL 27
#define MEMORY_SWAP_ERROR 100
#define MEMORY_SWAP_ERRMSG 101
#endif /* MEMORY_H */
diff --git a/include/net-snmp/agent/hardware/memory.h b/include/net-snmp/agent/hardware/memory.h
index 54265cf22a..aca3a4d00d 100644
--- a/include/net-snmp/agent/hardware/memory.h
+++ b/include/net-snmp/agent/hardware/memory.h
@@ -10,6 +10,7 @@ typedef struct netsnmp_memory_info_s netsnmp_memory_info;
#define NETSNMP_MEM_TYPE_SHARED 8
#define NETSNMP_MEM_TYPE_SHARED2 9
#define NETSNMP_MEM_TYPE_SWAP 10
+#define NETSNMP_MEM_TYPE_AVAILMEM 11
/* Leave space for individual swap devices */
#define NETSNMP_MEM_TYPE_MAX 30
diff --git a/mibs/UCD-SNMP-MIB.txt b/mibs/UCD-SNMP-MIB.txt
index cde67feb50..d360bad025 100644
--- a/mibs/UCD-SNMP-MIB.txt
+++ b/mibs/UCD-SNMP-MIB.txt
@@ -746,6 +746,22 @@ memCachedX OBJECT-TYPE
memory as specifically reserved for this purpose."
::= { memory 26 }
+memSysAvail OBJECT-TYPE
+ SYNTAX CounterBasedGauge64
+ UNITS "kB"
+ MAX-ACCESS read-only
+ STATUS current
+ DESCRIPTION
+ "The total amount of available memory, which is an estimate
+ of how much memory is available for starting new applications,
+ without swapping.
+
+ This object will not be implemented on hosts where the
+ underlying operating system does not explicitly identify
+ memory as specifically reserved for this purpose."
+ ::= { memory 27 }
+
+
memSwapError OBJECT-TYPE
SYNTAX UCDErrorFlag
MAX-ACCESS read-only