Source: vm.go in package github.com/prometheus/procfs

Copyright 2019 The Prometheus Authors Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

+build !windows


package procfs

import (
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"

	"github.com/prometheus/procfs/internal/util"
)

The VM interface is described at https://www.kernel.org/doc/Documentation/sysctl/vm.txt Each setting is exposed as a single file. Each file contains one line with a single numerical value, except lowmem_reserve_ratio which holds an array and numa_zonelist_order (deprecated) which is a string

type VM struct {
	AdminReserveKbytes        *int64   // /proc/sys/vm/admin_reserve_kbytes
	BlockDump                 *int64   // /proc/sys/vm/block_dump
	CompactUnevictableAllowed *int64   // /proc/sys/vm/compact_unevictable_allowed
	DirtyBackgroundBytes      *int64   // /proc/sys/vm/dirty_background_bytes
	DirtyBackgroundRatio      *int64   // /proc/sys/vm/dirty_background_ratio
	DirtyBytes                *int64   // /proc/sys/vm/dirty_bytes
	DirtyExpireCentisecs      *int64   // /proc/sys/vm/dirty_expire_centisecs
	DirtyRatio                *int64   // /proc/sys/vm/dirty_ratio
	DirtytimeExpireSeconds    *int64   // /proc/sys/vm/dirtytime_expire_seconds
	DirtyWritebackCentisecs   *int64   // /proc/sys/vm/dirty_writeback_centisecs
	DropCaches                *int64   // /proc/sys/vm/drop_caches
	ExtfragThreshold          *int64   // /proc/sys/vm/extfrag_threshold
	HugetlbShmGroup           *int64   // /proc/sys/vm/hugetlb_shm_group
	LaptopMode                *int64   // /proc/sys/vm/laptop_mode
	LegacyVaLayout            *int64   // /proc/sys/vm/legacy_va_layout
	LowmemReserveRatio        []*int64 // /proc/sys/vm/lowmem_reserve_ratio
	MaxMapCount               *int64   // /proc/sys/vm/max_map_count
	MemoryFailureEarlyKill    *int64   // /proc/sys/vm/memory_failure_early_kill
	MemoryFailureRecovery     *int64   // /proc/sys/vm/memory_failure_recovery
	MinFreeKbytes             *int64   // /proc/sys/vm/min_free_kbytes
	MinSlabRatio              *int64   // /proc/sys/vm/min_slab_ratio
	MinUnmappedRatio          *int64   // /proc/sys/vm/min_unmapped_ratio
	MmapMinAddr               *int64   // /proc/sys/vm/mmap_min_addr
	NrHugepages               *int64   // /proc/sys/vm/nr_hugepages
	NrHugepagesMempolicy      *int64   // /proc/sys/vm/nr_hugepages_mempolicy
	NrOvercommitHugepages     *int64   // /proc/sys/vm/nr_overcommit_hugepages
	NumaStat                  *int64   // /proc/sys/vm/numa_stat
	NumaZonelistOrder         string   // /proc/sys/vm/numa_zonelist_order
	OomDumpTasks              *int64   // /proc/sys/vm/oom_dump_tasks
	OomKillAllocatingTask     *int64   // /proc/sys/vm/oom_kill_allocating_task
	OvercommitKbytes          *int64   // /proc/sys/vm/overcommit_kbytes
	OvercommitMemory          *int64   // /proc/sys/vm/overcommit_memory
	OvercommitRatio           *int64   // /proc/sys/vm/overcommit_ratio
	PageCluster               *int64   // /proc/sys/vm/page-cluster
	PanicOnOom                *int64   // /proc/sys/vm/panic_on_oom
	PercpuPagelistFraction    *int64   // /proc/sys/vm/percpu_pagelist_fraction
	StatInterval              *int64   // /proc/sys/vm/stat_interval
	Swappiness                *int64   // /proc/sys/vm/swappiness
	UserReserveKbytes         *int64   // /proc/sys/vm/user_reserve_kbytes
	VfsCachePressure          *int64   // /proc/sys/vm/vfs_cache_pressure
	WatermarkBoostFactor      *int64   // /proc/sys/vm/watermark_boost_factor
	WatermarkScaleFactor      *int64   // /proc/sys/vm/watermark_scale_factor
	ZoneReclaimMode           *int64   // /proc/sys/vm/zone_reclaim_mode
}

VM reads the VM statistics from the specified `proc` filesystem.

func (fs FS) VM() (*VM, error) {
	path := fs.proc.Path("sys/vm")
	file, err := os.Stat(path)
	if err != nil {
		return nil, err
	}
	if !file.Mode().IsDir() {
		return nil, fmt.Errorf("%s is not a directory", path)
	}

	files, err := ioutil.ReadDir(path)
	if err != nil {
		return nil, err
	}

	var vm VM
	for _, f := range files {
		if f.IsDir() {
			continue
		}

ignore errors on read, as there are some write only in /proc/sys/vm

		value, err := util.SysReadFile(name)
		if err != nil {
			continue
		}
		vp := util.NewValueParser(value)

		switch f.Name() {
		case "admin_reserve_kbytes":
			vm.AdminReserveKbytes = vp.PInt64()
		case "block_dump":
			vm.BlockDump = vp.PInt64()
		case "compact_unevictable_allowed":
			vm.CompactUnevictableAllowed = vp.PInt64()
		case "dirty_background_bytes":
			vm.DirtyBackgroundBytes = vp.PInt64()
		case "dirty_background_ratio":
			vm.DirtyBackgroundRatio = vp.PInt64()
		case "dirty_bytes":
			vm.DirtyBytes = vp.PInt64()
		case "dirty_expire_centisecs":
			vm.DirtyExpireCentisecs = vp.PInt64()
		case "dirty_ratio":
			vm.DirtyRatio = vp.PInt64()
		case "dirtytime_expire_seconds":
			vm.DirtytimeExpireSeconds = vp.PInt64()
		case "dirty_writeback_centisecs":
			vm.DirtyWritebackCentisecs = vp.PInt64()
		case "drop_caches":
			vm.DropCaches = vp.PInt64()
		case "extfrag_threshold":
			vm.ExtfragThreshold = vp.PInt64()
		case "hugetlb_shm_group":
			vm.HugetlbShmGroup = vp.PInt64()
		case "laptop_mode":
			vm.LaptopMode = vp.PInt64()
		case "legacy_va_layout":
			vm.LegacyVaLayout = vp.PInt64()
		case "lowmem_reserve_ratio":
			stringSlice := strings.Fields(value)
			pint64Slice := make([]*int64, 0, len(stringSlice))
			for _, value := range stringSlice {
				vp := util.NewValueParser(value)
				pint64Slice = append(pint64Slice, vp.PInt64())
			}
			vm.LowmemReserveRatio = pint64Slice
		case "max_map_count":
			vm.MaxMapCount = vp.PInt64()
		case "memory_failure_early_kill":
			vm.MemoryFailureEarlyKill = vp.PInt64()
		case "memory_failure_recovery":
			vm.MemoryFailureRecovery = vp.PInt64()
		case "min_free_kbytes":
			vm.MinFreeKbytes = vp.PInt64()
		case "min_slab_ratio":
			vm.MinSlabRatio = vp.PInt64()
		case "min_unmapped_ratio":
			vm.MinUnmappedRatio = vp.PInt64()
		case "mmap_min_addr":
			vm.MmapMinAddr = vp.PInt64()
		case "nr_hugepages":
			vm.NrHugepages = vp.PInt64()
		case "nr_hugepages_mempolicy":
			vm.NrHugepagesMempolicy = vp.PInt64()
		case "nr_overcommit_hugepages":
			vm.NrOvercommitHugepages = vp.PInt64()
		case "numa_stat":
			vm.NumaStat = vp.PInt64()
		case "numa_zonelist_order":
			vm.NumaZonelistOrder = value
		case "oom_dump_tasks":
			vm.OomDumpTasks = vp.PInt64()
		case "oom_kill_allocating_task":
			vm.OomKillAllocatingTask = vp.PInt64()
		case "overcommit_kbytes":
			vm.OvercommitKbytes = vp.PInt64()
		case "overcommit_memory":
			vm.OvercommitMemory = vp.PInt64()
		case "overcommit_ratio":
			vm.OvercommitRatio = vp.PInt64()
		case "page-cluster":
			vm.PageCluster = vp.PInt64()
		case "panic_on_oom":
			vm.PanicOnOom = vp.PInt64()
		case "percpu_pagelist_fraction":
			vm.PercpuPagelistFraction = vp.PInt64()
		case "stat_interval":
			vm.StatInterval = vp.PInt64()
		case "swappiness":
			vm.Swappiness = vp.PInt64()
		case "user_reserve_kbytes":
			vm.UserReserveKbytes = vp.PInt64()
		case "vfs_cache_pressure":
			vm.VfsCachePressure = vp.PInt64()
		case "watermark_boost_factor":
			vm.WatermarkBoostFactor = vp.PInt64()
		case "watermark_scale_factor":
			vm.WatermarkScaleFactor = vp.PInt64()
		case "zone_reclaim_mode":
			vm.ZoneReclaimMode = vp.PInt64()
		}
		if err := vp.Err(); err != nil {
			return nil, err
		}
	}

	return &vm, nil