Add support for kernel memory limit

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>

sysinfo/sysinfo.go

@@ -36,6 +36,9 @@ type cgroupMemInfo struct {
 
 	// Whether memory swappiness is supported or not
 	MemorySwappiness bool
+
+	// Whether kernel memory limit is supported or not
+	KernelMemory bool
 }
 
 type cgroupCPUInfo struct {

sysinfo/sysinfo_linux.go

@@ -57,12 +57,17 @@ func checkCgroupMem(quiet bool) cgroupMemInfo {
 	if !quiet && !memorySwappiness {
 		logrus.Warnf("Your kernel does not support memory swappiness.")
 	}
+	kernelMemory := cgroupEnabled(mountPoint, "memory.kmem.limit_in_bytes")
+	if !quiet && !kernelMemory {
+		logrus.Warnf("Your kernel does not support kernel memory limit.")
+	}
 
 	return cgroupMemInfo{
 		MemoryLimit:      true,
 		SwapLimit:        swapLimit,
 		OomKillDisable:   oomKillDisable,
 		MemorySwappiness: memorySwappiness,
+		KernelMemory:     kernelMemory,
 	}
 }