meminfo: Fix the size mismatch in the swapTotal check mib for BSD. (#1345)

Signed-off-by: David O'Rourke <david.orourke@gmail.com>

CHANGELOG.md

@@ -7,7 +7,7 @@
 * [CHANGE]
 * [FEATURE]
 * [ENHANCEMENT]
-* [BUGFIX]
+* [BUGFIX] Fix incorrect sysctl call in BSD meminfo collector, resulting in broken swap metrics on FreeBSD #1345
 
 ## 0.18.0 / 2019-05-09
 

collector/memory_bsd.go

@@ -47,7 +47,7 @@ func NewMemoryCollector() (Collector, error) {
 
 	mibSwapTotal := "vm.swap_total"
 	/* swap_total is FreeBSD specific. Fall back to Dfly specific mib if not present. */
-	_, err = unix.SysctlUint32(mibSwapTotal)
+	_, err = unix.SysctlUint64(mibSwapTotal)
 	if err != nil {
 		mibSwapTotal = "vm.swap_size"
 	}