From a35e25cf3a6ddb35e77a11b450b831d8feae87d4 Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 27 Apr 2022 16:36:49 +0900
Subject: [PATCH 01/16] feat: add slab metrics input plugin

---
 etc/telegraf.conf                         |  3 +
 plugins/inputs/all/all.go                 |  1 +
 plugins/inputs/slab/README.md             | 42 +++++++++++
 plugins/inputs/slab/slab.go               | 32 ++++++++
 plugins/inputs/slab/slab_linux.go         | 69 ++++++++++++++++++
 plugins/inputs/slab/slab_notlinux.go      | 15 ++++
 plugins/inputs/slab/slab_sample_config.go |  8 ++
 plugins/inputs/slab/slab_test.go          | 89 +++++++++++++++++++++++
 8 files changed, 259 insertions(+)
 create mode 100644 plugins/inputs/slab/README.md
 create mode 100644 plugins/inputs/slab/slab.go
 create mode 100644 plugins/inputs/slab/slab_linux.go
 create mode 100644 plugins/inputs/slab/slab_notlinux.go
 create mode 100644 plugins/inputs/slab/slab_sample_config.go
 create mode 100644 plugins/inputs/slab/slab_test.go

diff --git a/etc/telegraf.conf b/etc/telegraf.conf
index 4dd4021759557..11a9a16f54639 100644
--- a/etc/telegraf.conf
+++ b/etc/telegraf.conf
@@ -6918,6 +6918,9 @@
 #   #  	 key = "device_name"
 #   #  	 value = 'one_of("sda", "sdb")'
 
+# # Get slab statistics from procfs
+# [[inputs.slab]]
+#   # no configuration
 
 # # Get synproxy counter statistics from procfs
 # [[inputs.synproxy]]
diff --git a/plugins/inputs/all/all.go b/plugins/inputs/all/all.go
index d55bb98f18c76..549397d24d877 100644
--- a/plugins/inputs/all/all.go
+++ b/plugins/inputs/all/all.go
@@ -174,6 +174,7 @@ import (
 	_ "github.com/influxdata/telegraf/plugins/inputs/salesforce"
 	_ "github.com/influxdata/telegraf/plugins/inputs/sensors"
 	_ "github.com/influxdata/telegraf/plugins/inputs/sflow"
+	_ "github.com/influxdata/telegraf/plugins/inputs/slab"
 	_ "github.com/influxdata/telegraf/plugins/inputs/smart"
 	_ "github.com/influxdata/telegraf/plugins/inputs/snmp"
 	_ "github.com/influxdata/telegraf/plugins/inputs/snmp_legacy"
diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
new file mode 100644
index 0000000000000..f7e6b602ac6e9
--- /dev/null
+++ b/plugins/inputs/slab/README.md
@@ -0,0 +1,42 @@
+# Slab Input Plugin
+
+This plugin collects details on how much memory each entry in Slab cache is
+consuming. For example, it collects the consumption of `kmalloc-1024` and
+`xfs_inode`. Since this information is obtained by parsing `/proc/slabinfo`
+file, only Linux is supported. The specification of `/proc/slabinfo` has
+not changed since [Linux v2.6.12 (April 2005)](https://github.com/torvalds/linux/blob/1da177e4/mm/slab.c#L2848-L2861),
+so it can be regarded as sufficiently stable. The memory usage is
+equivalent to the `CACHE_SIZE` column of `slabtop` command.
+
+## Configuration
+
+```toml
+# Get slab statistics from procfs
+[[inputs.slab]]
+  # no configuration
+```
+
+## Metrics
+
+Metrics include generic ones such as `kmalloc-*` as well as those of kernel
+subsystems and drivers used by the system such as `xfs_inode`.
+
+- mem
+  - fields:
+    - kmalloc-8_size_in_bytes (integer)
+    - kmalloc-16_size_in_bytes (integer)
+    - kmalloc-32_size_in_bytes (integer)
+    - kmalloc-64_size_in_bytes (integer)
+    - kmalloc-96_size_in_bytes (integer)
+    - kmalloc-128_size_in_bytes (integer)
+    - kmalloc-256_size_in_bytes (integer)
+    - kmalloc-512_size_in_bytes (integer)
+    - xfs_ili_size_in_bytes (integer)
+    - xfs_inode_size_in_bytes (integer)
+
+## Example Output
+
+```shel
+slab
+kmalloc-1024_size_in_bytes=239927296i,kmalloc-512_size_in_bytes=5582848i 1651049129000000000
+```
diff --git a/plugins/inputs/slab/slab.go b/plugins/inputs/slab/slab.go
new file mode 100644
index 0000000000000..9c0a106ed07de
--- /dev/null
+++ b/plugins/inputs/slab/slab.go
@@ -0,0 +1,32 @@
+package slab
+
+import (
+	"os"
+	"path"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+type SlabStats struct {
+	Log telegraf.Logger `toml:"-"`
+
+	// slab stats filename (proc filesystem)
+	statFile string
+}
+
+func getHostProc() string {
+	procPath := "/proc"
+	if os.Getenv("HOST_PROC") != "" {
+		procPath = os.Getenv("HOST_PROC")
+	}
+	return procPath
+}
+
+func init() {
+	inputs.Add("slab", func() telegraf.Input {
+		return &SlabStats{
+			statFile: path.Join(getHostProc(), "/slabinfo"),
+		}
+	})
+}
diff --git a/plugins/inputs/slab/slab_linux.go b/plugins/inputs/slab/slab_linux.go
new file mode 100644
index 0000000000000..8cc01345cc0f6
--- /dev/null
+++ b/plugins/inputs/slab/slab_linux.go
@@ -0,0 +1,69 @@
+//go:build linux
+// +build linux
+
+package slab
+
+import (
+	"bufio"
+	"errors"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/influxdata/telegraf"
+)
+
+func (ss *SlabStats) Init() error {
+	return nil
+}
+
+func (ss *SlabStats) Gather(acc telegraf.Accumulator) error {
+	fields, err := ss.getSlabStats()
+	if err != nil {
+		return err
+	}
+
+	acc.AddGauge("slab", fields, nil)
+	return nil
+}
+
+func (ss *SlabStats) getSlabStats() (map[string]interface{}, error) {
+	fields := map[string]interface{}{}
+
+	file, err := os.Open(ss.statFile)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+
+	// Read header rows
+	scanner.Scan() // for "slabinfo - version: 2.1"
+	scanner.Scan() // for "# name <active_objs> <num_objs> <objsize> ..."
+
+	// Read data rows
+	for scanner.Scan() {
+		line := scanner.Text()
+		cols := strings.Fields(line)
+
+		if len(cols) < 4 {
+			return nil, errors.New("the content of /proc/slabinfo is invalid")
+		}
+
+		var numObj, sizObj int
+
+		numObj, err = strconv.Atoi(cols[2])
+		if err != nil {
+			return nil, err
+		}
+
+		sizObj, err = strconv.Atoi(cols[3])
+		if err != nil {
+			return nil, err
+		}
+
+		fields[cols[0]+"_size_in_bytes"] = numObj * sizObj
+	}
+	return fields, nil
+}
diff --git a/plugins/inputs/slab/slab_notlinux.go b/plugins/inputs/slab/slab_notlinux.go
new file mode 100644
index 0000000000000..95047ea2e5c86
--- /dev/null
+++ b/plugins/inputs/slab/slab_notlinux.go
@@ -0,0 +1,15 @@
+//go:build !linux
+// +build !linux
+
+package slab
+
+import "github.com/influxdata/telegraf"
+
+func (ss *SlabStats) Init() error {
+	ss.Log.Warn("Current platform is not supported")
+	return nil
+}
+
+func (ss *SlabStats) Gather(acc telegraf.Accumulator) error {
+	return nil
+}
diff --git a/plugins/inputs/slab/slab_sample_config.go b/plugins/inputs/slab/slab_sample_config.go
new file mode 100644
index 0000000000000..b45c9b259fc02
--- /dev/null
+++ b/plugins/inputs/slab/slab_sample_config.go
@@ -0,0 +1,8 @@
+//go:generate go run ../../../tools/generate_plugindata/main.go
+//go:generate go run ../../../tools/generate_plugindata/main.go --clean
+// DON'T EDIT; This file is used as a template by tools/generate_plugindata
+package slab
+
+func (ss *SlabStats) SampleConfig() string {
+	return `{{ .SampleConfig }}`
+}
diff --git a/plugins/inputs/slab/slab_test.go b/plugins/inputs/slab/slab_test.go
new file mode 100644
index 0000000000000..a09566abc6fed
--- /dev/null
+++ b/plugins/inputs/slab/slab_test.go
@@ -0,0 +1,89 @@
+//go:build linux
+// +build linux
+
+package slab
+
+import (
+	"os"
+	"testing"
+
+	"github.com/influxdata/telegraf/testutil"
+	"github.com/stretchr/testify/require"
+)
+
+func makeFakeStatFile(content []byte) string {
+	tmpfile, err := os.CreateTemp("", "slab_test")
+	if err != nil {
+		panic(err)
+	}
+
+	if _, err := tmpfile.Write(content); err != nil {
+		panic(err)
+	}
+	if err := tmpfile.Close(); err != nil {
+		panic(err)
+	}
+
+	return tmpfile.Name()
+}
+
+func TestSlab(t *testing.T) {
+	slabStats := SlabStats{
+		statFile: makeFakeStatFile([]byte(procSlabInfo)),
+	}
+
+	var acc testutil.Accumulator
+	err := acc.GatherError(slabStats.Gather)
+	require.NoError(t, err)
+
+	fields := map[string]interface{}{
+		"ext4_allocation_context_size_in_bytes": int(16384),
+		"ext4_extent_status_size_in_bytes":      int(8160),
+		"ext4_free_data_size_in_bytes":          int(0),
+		"ext4_inode_cache_size_in_bytes":        int(491520),
+		"ext4_io_end_size_in_bytes":             int(4032),
+		"ext4_xattr_size_in_bytes":              int(0),
+		"kmalloc-1024_size_in_bytes":            int(239927296),
+		"kmalloc-128_size_in_bytes":             int(5586944),
+		"kmalloc-16_size_in_bytes":              int(17002496),
+		"kmalloc-192_size_in_bytes":             int(4015872),
+		"kmalloc-2048_size_in_bytes":            int(3309568),
+		"kmalloc-256_size_in_bytes":             int(5423104),
+		"kmalloc-32_size_in_bytes":              int(3657728),
+		"kmalloc-4096_size_in_bytes":            int(2359296),
+		"kmalloc-512_size_in_bytes":             int(41435136),
+		"kmalloc-64_size_in_bytes":              int(8536064),
+		"kmalloc-8_size_in_bytes":               int(229376),
+		"kmalloc-8192_size_in_bytes":            int(1048576),
+		"kmalloc-96_size_in_bytes":              int(12378240),
+		"kmem_cache_size_in_bytes":              int(81920),
+		"kmem_cache_node_size_in_bytes":         int(36864),
+	}
+
+	acc.AssertContainsFields(t, "slab", fields)
+}
+
+var procSlabInfo = `slabinfo - version: 2.1
+# name            <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> : tunables <limit> <batchcount> <sharedfactor> : slabdata <active_slabs> <num_slabs> <sharedavail>
+ext4_inode_cache     480    480   1024   32    8 : tunables    0    0    0 : slabdata     15     15      0
+ext4_xattr             0      0     88   46    1 : tunables    0    0    0 : slabdata      0      0      0
+ext4_free_data         0      0     64   64    1 : tunables    0    0    0 : slabdata      0      0      0
+ext4_allocation_context    128    128    128   32    1 : tunables    0    0    0 : slabdata      4      4      0
+ext4_io_end           56     56     72   56    1 : tunables    0    0    0 : slabdata      1      1      0
+ext4_extent_status    204    204     40  102    1 : tunables    0    0    0 : slabdata      2      2      0
+kmalloc-8192         106    128   8192    4    8 : tunables    0    0    0 : slabdata     32     32      0
+kmalloc-4096         486    576   4096    8    8 : tunables    0    0    0 : slabdata     72     72      0
+kmalloc-2048        1338   1616   2048   16    8 : tunables    0    0    0 : slabdata    101    101      0
+kmalloc-1024      155845 234304   1024   32    8 : tunables    0    0    0 : slabdata   7329   7329      0
+kmalloc-512        18995  80928    512   32    4 : tunables    0    0    0 : slabdata   2529   2529      0
+kmalloc-256        16366  21184    256   32    2 : tunables    0    0    0 : slabdata    662    662      0
+kmalloc-192        18835  20916    192   21    1 : tunables    0    0    0 : slabdata    996    996      0
+kmalloc-128        23600  43648    128   32    1 : tunables    0    0    0 : slabdata   1364   1364      0
+kmalloc-96         95106 128940     96   42    1 : tunables    0    0    0 : slabdata   3070   3070      0
+kmalloc-64         82432 133376     64   64    1 : tunables    0    0    0 : slabdata   2084   2084      0
+kmalloc-32         78477 114304     32  128    1 : tunables    0    0    0 : slabdata    893    893      0
+kmalloc-16        885605 1062656     16  256    1 : tunables    0    0    0 : slabdata   4151   4151      0
+kmalloc-8          28672  28672      8  512    1 : tunables    0    0    0 : slabdata     56     56      0
+kmem_cache_node      576    576     64   64    1 : tunables    0    0    0 : slabdata      9      9      0
+kmem_cache           320    320    256   32    2 : tunables    0    0    0 : slabdata     10     10      0
+`

From a7aa43180f42a60bc160bbee6363aaa5cb2edd12 Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 11 May 2022 16:21:32 +0900
Subject: [PATCH 02/16] add use_sudo option

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/README.md     |  5 ++++-
 plugins/inputs/slab/slab.go       |  1 +
 plugins/inputs/slab/slab_linux.go | 33 +++++++++++++++++++++++--------
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index f7e6b602ac6e9..e5622c166e5e4 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -8,12 +8,15 @@ not changed since [Linux v2.6.12 (April 2005)](https://github.com/torvalds/linux
 so it can be regarded as sufficiently stable. The memory usage is
 equivalent to the `CACHE_SIZE` column of `slabtop` command.
 
+**Note: `/proc/slabinfo` is usually restricted to read as root user. Enable `use_sudo` option if necessary.**
+
 ## Configuration
 
 ```toml
 # Get slab statistics from procfs
 [[inputs.slab]]
-  # no configuration
+  ## Use sudo to run LVM commands
+  use_sudo = false
 ```
 
 ## Metrics
diff --git a/plugins/inputs/slab/slab.go b/plugins/inputs/slab/slab.go
index 9c0a106ed07de..e54ef0da4c1de 100644
--- a/plugins/inputs/slab/slab.go
+++ b/plugins/inputs/slab/slab.go
@@ -13,6 +13,7 @@ type SlabStats struct {
 
 	// slab stats filename (proc filesystem)
 	statFile string
+	UseSudo  bool `toml:"use_sudo"`
 }
 
 func getHostProc() string {
diff --git a/plugins/inputs/slab/slab_linux.go b/plugins/inputs/slab/slab_linux.go
index 8cc01345cc0f6..4c90694a7a477 100644
--- a/plugins/inputs/slab/slab_linux.go
+++ b/plugins/inputs/slab/slab_linux.go
@@ -5,12 +5,16 @@ package slab
 
 import (
 	"bufio"
+	"bytes"
 	"errors"
-	"os"
+	"fmt"
+	"os/exec"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/internal"
 )
 
 func (ss *SlabStats) Init() error {
@@ -30,13 +34,9 @@ func (ss *SlabStats) Gather(acc telegraf.Accumulator) error {
 func (ss *SlabStats) getSlabStats() (map[string]interface{}, error) {
 	fields := map[string]interface{}{}
 
-	file, err := os.Open(ss.statFile)
-	if err != nil {
-		return nil, err
-	}
-	defer file.Close()
-
-	scanner := bufio.NewScanner(file)
+	out, err := ss.runCmd("/bin/cat", []string{ss.statFile})
+	bytesReader := bytes.NewReader(out)
+	scanner := bufio.NewScanner(bytesReader)
 
 	// Read header rows
 	scanner.Scan() // for "slabinfo - version: 2.1"
@@ -67,3 +67,20 @@ func (ss *SlabStats) getSlabStats() (map[string]interface{}, error) {
 	}
 	return fields, nil
 }
+
+func (ss *SlabStats) runCmd(cmd string, args []string) ([]byte, error) {
+	execCmd := exec.Command(cmd, args...)
+	if ss.UseSudo {
+		execCmd = exec.Command("sudo", append([]string{"-n", cmd}, args...)...)
+	}
+
+	out, err := internal.StdOutputTimeout(execCmd, 5*time.Second)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"failed to run command %s: %s - %s",
+			strings.Join(execCmd.Args, " "), err, string(out),
+		)
+	}
+
+	return out, nil
+}

From fc8e88b05328b0d467c725442c94380a87f8909b Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 11 May 2022 16:22:36 +0900
Subject: [PATCH 03/16] remove unused comment

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/slab.go | 1 -
 1 file changed, 1 deletion(-)

diff --git a/plugins/inputs/slab/slab.go b/plugins/inputs/slab/slab.go
index e54ef0da4c1de..f502d401aa78f 100644
--- a/plugins/inputs/slab/slab.go
+++ b/plugins/inputs/slab/slab.go
@@ -11,7 +11,6 @@ import (
 type SlabStats struct {
 	Log telegraf.Logger `toml:"-"`
 
-	// slab stats filename (proc filesystem)
 	statFile string
 	UseSudo  bool `toml:"use_sudo"`
 }

From b35fb14dcb68365db6a2eff83497abcfb699a5e1 Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 11 May 2022 16:36:31 +0900
Subject: [PATCH 04/16] fix naming

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/README.md     | 25 +++++++++---------
 plugins/inputs/slab/slab_linux.go |  6 ++++-
 plugins/inputs/slab/slab_test.go  | 42 +++++++++++++++----------------
 3 files changed, 39 insertions(+), 34 deletions(-)

diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index e5622c166e5e4..ddbc15296286c 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -21,25 +21,26 @@ equivalent to the `CACHE_SIZE` column of `slabtop` command.
 
 ## Metrics
 
-Metrics include generic ones such as `kmalloc-*` as well as those of kernel
+Metrics include generic ones such as `kmalloc_*` as well as those of kernel
 subsystems and drivers used by the system such as `xfs_inode`.
+Each field with `_size` suffix indicates memory consumption in bytes.
 
 - mem
   - fields:
-    - kmalloc-8_size_in_bytes (integer)
-    - kmalloc-16_size_in_bytes (integer)
-    - kmalloc-32_size_in_bytes (integer)
-    - kmalloc-64_size_in_bytes (integer)
-    - kmalloc-96_size_in_bytes (integer)
-    - kmalloc-128_size_in_bytes (integer)
-    - kmalloc-256_size_in_bytes (integer)
-    - kmalloc-512_size_in_bytes (integer)
-    - xfs_ili_size_in_bytes (integer)
-    - xfs_inode_size_in_bytes (integer)
+    _ kmalloc_8_size (integer)
+    _ kmalloc_16_size (integer)
+    _ kmalloc_32_size (integer)
+    _ kmalloc_64_size (integer)
+    _ kmalloc_96_size (integer)
+    _ kmalloc_128_size (integer)
+    _ kmalloc_256_size (integer)
+    _ kmalloc_512_size (integer)
+    _ xfs_ili_size (integer)
+    _ xfs_inode_size (integer)
 
 ## Example Output
 
 ```shel
 slab
-kmalloc-1024_size_in_bytes=239927296i,kmalloc-512_size_in_bytes=5582848i 1651049129000000000
+kmalloc_1024_size=239927296i,kmalloc_512_size=5582848i 1651049129000000000
 ```
diff --git a/plugins/inputs/slab/slab_linux.go b/plugins/inputs/slab/slab_linux.go
index 4c90694a7a477..17056d96bcc53 100644
--- a/plugins/inputs/slab/slab_linux.go
+++ b/plugins/inputs/slab/slab_linux.go
@@ -63,7 +63,7 @@ func (ss *SlabStats) getSlabStats() (map[string]interface{}, error) {
 			return nil, err
 		}
 
-		fields[cols[0]+"_size_in_bytes"] = numObj * sizObj
+		fields[normalizeName(cols[0])] = numObj * sizObj
 	}
 	return fields, nil
 }
@@ -84,3 +84,7 @@ func (ss *SlabStats) runCmd(cmd string, args []string) ([]byte, error) {
 
 	return out, nil
 }
+
+func normalizeName(name string) string {
+	return strings.ReplaceAll(strings.ToLower(name), "-", "_") + "_size"
+}
diff --git a/plugins/inputs/slab/slab_test.go b/plugins/inputs/slab/slab_test.go
index a09566abc6fed..e5eda8f13666b 100644
--- a/plugins/inputs/slab/slab_test.go
+++ b/plugins/inputs/slab/slab_test.go
@@ -37,27 +37,27 @@ func TestSlab(t *testing.T) {
 	require.NoError(t, err)
 
 	fields := map[string]interface{}{
-		"ext4_allocation_context_size_in_bytes": int(16384),
-		"ext4_extent_status_size_in_bytes":      int(8160),
-		"ext4_free_data_size_in_bytes":          int(0),
-		"ext4_inode_cache_size_in_bytes":        int(491520),
-		"ext4_io_end_size_in_bytes":             int(4032),
-		"ext4_xattr_size_in_bytes":              int(0),
-		"kmalloc-1024_size_in_bytes":            int(239927296),
-		"kmalloc-128_size_in_bytes":             int(5586944),
-		"kmalloc-16_size_in_bytes":              int(17002496),
-		"kmalloc-192_size_in_bytes":             int(4015872),
-		"kmalloc-2048_size_in_bytes":            int(3309568),
-		"kmalloc-256_size_in_bytes":             int(5423104),
-		"kmalloc-32_size_in_bytes":              int(3657728),
-		"kmalloc-4096_size_in_bytes":            int(2359296),
-		"kmalloc-512_size_in_bytes":             int(41435136),
-		"kmalloc-64_size_in_bytes":              int(8536064),
-		"kmalloc-8_size_in_bytes":               int(229376),
-		"kmalloc-8192_size_in_bytes":            int(1048576),
-		"kmalloc-96_size_in_bytes":              int(12378240),
-		"kmem_cache_size_in_bytes":              int(81920),
-		"kmem_cache_node_size_in_bytes":         int(36864),
+		"ext4_allocation_context_size": int(16384),
+		"ext4_extent_status_size":      int(8160),
+		"ext4_free_data_size":          int(0),
+		"ext4_inode_cache_size":        int(491520),
+		"ext4_io_end_size":             int(4032),
+		"ext4_xattr_size":              int(0),
+		"kmalloc_1024_size":            int(239927296),
+		"kmalloc_128_size":             int(5586944),
+		"kmalloc_16_size":              int(17002496),
+		"kmalloc_192_size":             int(4015872),
+		"kmalloc_2048_size":            int(3309568),
+		"kmalloc_256_size":             int(5423104),
+		"kmalloc_32_size":              int(3657728),
+		"kmalloc_4096_size":            int(2359296),
+		"kmalloc_512_size":             int(41435136),
+		"kmalloc_64_size":              int(8536064),
+		"kmalloc_8_size":               int(229376),
+		"kmalloc_8192_size":            int(1048576),
+		"kmalloc_96_size":              int(12378240),
+		"kmem_cache_size":              int(81920),
+		"kmem_cache_node_size":         int(36864),
 	}
 
 	acc.AssertContainsFields(t, "slab", fields)

From 9cd9e1c62c4f6f8c83118940314f29a2897c2b4d Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 11 May 2022 16:43:07 +0900
Subject: [PATCH 05/16] fix doc

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 etc/telegraf.conf             | 4 +++-
 plugins/inputs/slab/README.md | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/etc/telegraf.conf b/etc/telegraf.conf
index 11a9a16f54639..ad35538803f59 100644
--- a/etc/telegraf.conf
+++ b/etc/telegraf.conf
@@ -6920,7 +6920,9 @@
 
 # # Get slab statistics from procfs
 # [[inputs.slab]]
-#   # no configuration
+#   ## /proc/slabinfo is usually restricted to read as root user.
+#   ## Enable `use_sudo` option if necessary.
+#   # use_sudo = false
 
 # # Get synproxy counter statistics from procfs
 # [[inputs.synproxy]]
diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index ddbc15296286c..12a304073f46f 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -15,7 +15,8 @@ equivalent to the `CACHE_SIZE` column of `slabtop` command.
 ```toml
 # Get slab statistics from procfs
 [[inputs.slab]]
-  ## Use sudo to run LVM commands
+  ## /proc/slabinfo is usually restricted to read as root user.
+  ## Enable `use_sudo` option if necessary.
   use_sudo = false
 ```
 

From 4c330b55632bdaaa3090f842f4c84d8276ed28fd Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 11 May 2022 16:44:31 +0900
Subject: [PATCH 06/16] fix typo

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/README.md | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index 12a304073f46f..50dd69e792602 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -28,16 +28,16 @@ Each field with `_size` suffix indicates memory consumption in bytes.
 
 - mem
   - fields:
-    _ kmalloc_8_size (integer)
-    _ kmalloc_16_size (integer)
-    _ kmalloc_32_size (integer)
-    _ kmalloc_64_size (integer)
-    _ kmalloc_96_size (integer)
-    _ kmalloc_128_size (integer)
-    _ kmalloc_256_size (integer)
-    _ kmalloc_512_size (integer)
-    _ xfs_ili_size (integer)
-    _ xfs_inode_size (integer)
+    - kmalloc_8_size (integer)
+    - kmalloc_16_size (integer)
+    - kmalloc_32_size (integer)
+    - kmalloc_64_size (integer)
+    - kmalloc_96_size (integer)
+    - kmalloc_128_size (integer)
+    - kmalloc_256_size (integer)
+    - kmalloc_512_size (integer)
+    - xfs_ili_size (integer)
+    - xfs_inode_size (integer)
 
 ## Example Output
 

From 3b88f109dd68f37c3f87e5814f3003ead7b81266 Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 11 May 2022 16:48:36 +0900
Subject: [PATCH 07/16] add err checking

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/slab_linux.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/plugins/inputs/slab/slab_linux.go b/plugins/inputs/slab/slab_linux.go
index 17056d96bcc53..8c7d9c3abaeca 100644
--- a/plugins/inputs/slab/slab_linux.go
+++ b/plugins/inputs/slab/slab_linux.go
@@ -35,6 +35,10 @@ func (ss *SlabStats) getSlabStats() (map[string]interface{}, error) {
 	fields := map[string]interface{}{}
 
 	out, err := ss.runCmd("/bin/cat", []string{ss.statFile})
+	if err != nil {
+		return nil, err
+	}
+
 	bytesReader := bytes.NewReader(out)
 	scanner := bufio.NewScanner(bytesReader)
 

From 2ac75380d9cb86cf7b7dc7381c681dc2377f95aa Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 11 May 2022 17:07:15 +0900
Subject: [PATCH 08/16] fix docs

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index 50dd69e792602..3f2b6146cd982 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -16,7 +16,7 @@ equivalent to the `CACHE_SIZE` column of `slabtop` command.
 # Get slab statistics from procfs
 [[inputs.slab]]
   ## /proc/slabinfo is usually restricted to read as root user.
-  ## Enable `use_sudo` option if necessary.
+  ## Enable use_sudo option if necessary.
   use_sudo = false
 ```
 

From 6a20b15b549eeddf8e6c00d042043832769dff57 Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Tue, 17 May 2022 10:25:35 +0900
Subject: [PATCH 09/16] add linux only build tags & remove unused files

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/slab.go               | 100 ++++++++++++++++++++--
 plugins/inputs/slab/slab_linux.go         |  94 --------------------
 plugins/inputs/slab/slab_nonlinux.go      |   4 +
 plugins/inputs/slab/slab_notlinux.go      |  15 ----
 plugins/inputs/slab/slab_sample_config.go |   3 +
 5 files changed, 101 insertions(+), 115 deletions(-)
 delete mode 100644 plugins/inputs/slab/slab_linux.go
 create mode 100644 plugins/inputs/slab/slab_nonlinux.go
 delete mode 100644 plugins/inputs/slab/slab_notlinux.go

diff --git a/plugins/inputs/slab/slab.go b/plugins/inputs/slab/slab.go
index f502d401aa78f..06352dd52d2f4 100644
--- a/plugins/inputs/slab/slab.go
+++ b/plugins/inputs/slab/slab.go
@@ -1,13 +1,33 @@
+//go:build linux
+// +build linux
+
 package slab
 
 import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
 	"os"
+	"os/exec"
 	"path"
+	"strconv"
+	"strings"
+	"time"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/plugins/inputs"
 )
 
+func init() {
+	inputs.Add("slab", func() telegraf.Input {
+		return &SlabStats{
+			statFile: path.Join(getHostProc(), "/slabinfo"),
+		}
+	})
+}
+
 type SlabStats struct {
 	Log telegraf.Logger `toml:"-"`
 
@@ -15,6 +35,78 @@ type SlabStats struct {
 	UseSudo  bool `toml:"use_sudo"`
 }
 
+func (ss *SlabStats) Init() error {
+	return nil
+}
+
+func (ss *SlabStats) Gather(acc telegraf.Accumulator) error {
+	fields, err := ss.getSlabStats()
+	if err != nil {
+		return err
+	}
+
+	acc.AddGauge("slab", fields, nil)
+	return nil
+}
+
+func (ss *SlabStats) getSlabStats() (map[string]interface{}, error) {
+	fields := map[string]interface{}{}
+
+	out, err := ss.runCmd("/bin/cat", []string{ss.statFile})
+	if err != nil {
+		return nil, err
+	}
+
+	bytesReader := bytes.NewReader(out)
+	scanner := bufio.NewScanner(bytesReader)
+
+	// Read header rows
+	scanner.Scan() // for "slabinfo - version: 2.1"
+	scanner.Scan() // for "# name <active_objs> <num_objs> <objsize> ..."
+
+	// Read data rows
+	for scanner.Scan() {
+		line := scanner.Text()
+		cols := strings.Fields(line)
+
+		if len(cols) < 4 {
+			return nil, errors.New("the content of /proc/slabinfo is invalid")
+		}
+
+		var numObj, sizObj int
+
+		numObj, err = strconv.Atoi(cols[2])
+		if err != nil {
+			return nil, err
+		}
+
+		sizObj, err = strconv.Atoi(cols[3])
+		if err != nil {
+			return nil, err
+		}
+
+		fields[normalizeName(cols[0])] = numObj * sizObj
+	}
+	return fields, nil
+}
+
+func (ss *SlabStats) runCmd(cmd string, args []string) ([]byte, error) {
+	execCmd := exec.Command(cmd, args...)
+	if ss.UseSudo {
+		execCmd = exec.Command("sudo", append([]string{"-n", cmd}, args...)...)
+	}
+
+	out, err := internal.StdOutputTimeout(execCmd, 5*time.Second)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"failed to run command %s: %s - %s",
+			strings.Join(execCmd.Args, " "), err, string(out),
+		)
+	}
+
+	return out, nil
+}
+
 func getHostProc() string {
 	procPath := "/proc"
 	if os.Getenv("HOST_PROC") != "" {
@@ -23,10 +115,6 @@ func getHostProc() string {
 	return procPath
 }
 
-func init() {
-	inputs.Add("slab", func() telegraf.Input {
-		return &SlabStats{
-			statFile: path.Join(getHostProc(), "/slabinfo"),
-		}
-	})
+func normalizeName(name string) string {
+	return strings.ReplaceAll(strings.ToLower(name), "-", "_") + "_size"
 }
diff --git a/plugins/inputs/slab/slab_linux.go b/plugins/inputs/slab/slab_linux.go
deleted file mode 100644
index 8c7d9c3abaeca..0000000000000
--- a/plugins/inputs/slab/slab_linux.go
+++ /dev/null
@@ -1,94 +0,0 @@
-//go:build linux
-// +build linux
-
-package slab
-
-import (
-	"bufio"
-	"bytes"
-	"errors"
-	"fmt"
-	"os/exec"
-	"strconv"
-	"strings"
-	"time"
-
-	"github.com/influxdata/telegraf"
-	"github.com/influxdata/telegraf/internal"
-)
-
-func (ss *SlabStats) Init() error {
-	return nil
-}
-
-func (ss *SlabStats) Gather(acc telegraf.Accumulator) error {
-	fields, err := ss.getSlabStats()
-	if err != nil {
-		return err
-	}
-
-	acc.AddGauge("slab", fields, nil)
-	return nil
-}
-
-func (ss *SlabStats) getSlabStats() (map[string]interface{}, error) {
-	fields := map[string]interface{}{}
-
-	out, err := ss.runCmd("/bin/cat", []string{ss.statFile})
-	if err != nil {
-		return nil, err
-	}
-
-	bytesReader := bytes.NewReader(out)
-	scanner := bufio.NewScanner(bytesReader)
-
-	// Read header rows
-	scanner.Scan() // for "slabinfo - version: 2.1"
-	scanner.Scan() // for "# name <active_objs> <num_objs> <objsize> ..."
-
-	// Read data rows
-	for scanner.Scan() {
-		line := scanner.Text()
-		cols := strings.Fields(line)
-
-		if len(cols) < 4 {
-			return nil, errors.New("the content of /proc/slabinfo is invalid")
-		}
-
-		var numObj, sizObj int
-
-		numObj, err = strconv.Atoi(cols[2])
-		if err != nil {
-			return nil, err
-		}
-
-		sizObj, err = strconv.Atoi(cols[3])
-		if err != nil {
-			return nil, err
-		}
-
-		fields[normalizeName(cols[0])] = numObj * sizObj
-	}
-	return fields, nil
-}
-
-func (ss *SlabStats) runCmd(cmd string, args []string) ([]byte, error) {
-	execCmd := exec.Command(cmd, args...)
-	if ss.UseSudo {
-		execCmd = exec.Command("sudo", append([]string{"-n", cmd}, args...)...)
-	}
-
-	out, err := internal.StdOutputTimeout(execCmd, 5*time.Second)
-	if err != nil {
-		return nil, fmt.Errorf(
-			"failed to run command %s: %s - %s",
-			strings.Join(execCmd.Args, " "), err, string(out),
-		)
-	}
-
-	return out, nil
-}
-
-func normalizeName(name string) string {
-	return strings.ReplaceAll(strings.ToLower(name), "-", "_") + "_size"
-}
diff --git a/plugins/inputs/slab/slab_nonlinux.go b/plugins/inputs/slab/slab_nonlinux.go
new file mode 100644
index 0000000000000..77ec3e6e6a170
--- /dev/null
+++ b/plugins/inputs/slab/slab_nonlinux.go
@@ -0,0 +1,4 @@
+//go:build !linux
+// +build !linux
+
+package slab
diff --git a/plugins/inputs/slab/slab_notlinux.go b/plugins/inputs/slab/slab_notlinux.go
deleted file mode 100644
index 95047ea2e5c86..0000000000000
--- a/plugins/inputs/slab/slab_notlinux.go
+++ /dev/null
@@ -1,15 +0,0 @@
-//go:build !linux
-// +build !linux
-
-package slab
-
-import "github.com/influxdata/telegraf"
-
-func (ss *SlabStats) Init() error {
-	ss.Log.Warn("Current platform is not supported")
-	return nil
-}
-
-func (ss *SlabStats) Gather(acc telegraf.Accumulator) error {
-	return nil
-}
diff --git a/plugins/inputs/slab/slab_sample_config.go b/plugins/inputs/slab/slab_sample_config.go
index b45c9b259fc02..eb4da02542bf4 100644
--- a/plugins/inputs/slab/slab_sample_config.go
+++ b/plugins/inputs/slab/slab_sample_config.go
@@ -1,3 +1,6 @@
+//go:build linux
+// +build linux
+
 //go:generate go run ../../../tools/generate_plugindata/main.go
 //go:generate go run ../../../tools/generate_plugindata/main.go --clean
 // DON'T EDIT; This file is used as a template by tools/generate_plugindata

From 7f17585b191cd685fc33a6f44f871bdefdf87bcd Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Tue, 17 May 2022 10:31:54 +0900
Subject: [PATCH 10/16] fix typo

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/{slab_nonlinux.go => slab_notlinux.go} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename plugins/inputs/slab/{slab_nonlinux.go => slab_notlinux.go} (100%)

diff --git a/plugins/inputs/slab/slab_nonlinux.go b/plugins/inputs/slab/slab_notlinux.go
similarity index 100%
rename from plugins/inputs/slab/slab_nonlinux.go
rename to plugins/inputs/slab/slab_notlinux.go

From 4b9e2384c5ca55cca949f49c03f2e428da749a5d Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 18 May 2022 10:49:51 +0900
Subject: [PATCH 11/16] rm use_sudo flag

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 etc/telegraf.conf             | 4 +---
 plugins/inputs/slab/README.md | 6 ++----
 plugins/inputs/slab/slab.go   | 6 +-----
 3 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/etc/telegraf.conf b/etc/telegraf.conf
index ad35538803f59..11a9a16f54639 100644
--- a/etc/telegraf.conf
+++ b/etc/telegraf.conf
@@ -6920,9 +6920,7 @@
 
 # # Get slab statistics from procfs
 # [[inputs.slab]]
-#   ## /proc/slabinfo is usually restricted to read as root user.
-#   ## Enable `use_sudo` option if necessary.
-#   # use_sudo = false
+#   # no configuration
 
 # # Get synproxy counter statistics from procfs
 # [[inputs.synproxy]]
diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index 3f2b6146cd982..5fcceec9c86c9 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -8,16 +8,14 @@ not changed since [Linux v2.6.12 (April 2005)](https://github.com/torvalds/linux
 so it can be regarded as sufficiently stable. The memory usage is
 equivalent to the `CACHE_SIZE` column of `slabtop` command.
 
-**Note: `/proc/slabinfo` is usually restricted to read as root user. Enable `use_sudo` option if necessary.**
+**Note: `/proc/slabinfo` is usually restricted to read as root user. Make sure telegraf can execute `sudo` without password.**
 
 ## Configuration
 
 ```toml
 # Get slab statistics from procfs
 [[inputs.slab]]
-  ## /proc/slabinfo is usually restricted to read as root user.
-  ## Enable use_sudo option if necessary.
-  use_sudo = false
+  # no configuration
 ```
 
 ## Metrics
diff --git a/plugins/inputs/slab/slab.go b/plugins/inputs/slab/slab.go
index 06352dd52d2f4..1e0fda87d2081 100644
--- a/plugins/inputs/slab/slab.go
+++ b/plugins/inputs/slab/slab.go
@@ -32,7 +32,6 @@ type SlabStats struct {
 	Log telegraf.Logger `toml:"-"`
 
 	statFile string
-	UseSudo  bool `toml:"use_sudo"`
 }
 
 func (ss *SlabStats) Init() error {
@@ -91,10 +90,7 @@ func (ss *SlabStats) getSlabStats() (map[string]interface{}, error) {
 }
 
 func (ss *SlabStats) runCmd(cmd string, args []string) ([]byte, error) {
-	execCmd := exec.Command(cmd, args...)
-	if ss.UseSudo {
-		execCmd = exec.Command("sudo", append([]string{"-n", cmd}, args...)...)
-	}
+	execCmd := exec.Command("sudo", append([]string{"-n", cmd}, args...)...)
 
 	out, err := internal.StdOutputTimeout(execCmd, 5*time.Second)
 	if err != nil {

From 7c2294b4d0bfed3076e10702e4d085c645be4697 Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 18 May 2022 11:16:10 +0900
Subject: [PATCH 12/16] fix runCmd

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/slab.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/plugins/inputs/slab/slab.go b/plugins/inputs/slab/slab.go
index 1e0fda87d2081..a18513df98789 100644
--- a/plugins/inputs/slab/slab.go
+++ b/plugins/inputs/slab/slab.go
@@ -90,7 +90,10 @@ func (ss *SlabStats) getSlabStats() (map[string]interface{}, error) {
 }
 
 func (ss *SlabStats) runCmd(cmd string, args []string) ([]byte, error) {
-	execCmd := exec.Command("sudo", append([]string{"-n", cmd}, args...)...)
+	execCmd := exec.Command(cmd, args...)
+	if os.Geteuid() != 0 {
+		execCmd = exec.Command("sudo", append([]string{"-n", cmd}, args...)...)
+	}
 
 	out, err := internal.StdOutputTimeout(execCmd, 5*time.Second)
 	if err != nil {

From 3fd0a46b797f5a8e4bea79e10721026ca16d3ad3 Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nob@bobuhiro11.net>
Date: Wed, 18 May 2022 12:13:59 +0900
Subject: [PATCH 13/16] Update plugins/inputs/slab/README.md

Co-authored-by: reimda <reimda@users.noreply.github.com>
---
 plugins/inputs/slab/README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index 5fcceec9c86c9..9075654b9b310 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -7,6 +7,7 @@ file, only Linux is supported. The specification of `/proc/slabinfo` has
 not changed since [Linux v2.6.12 (April 2005)](https://github.com/torvalds/linux/blob/1da177e4/mm/slab.c#L2848-L2861),
 so it can be regarded as sufficiently stable. The memory usage is
 equivalent to the `CACHE_SIZE` column of `slabtop` command.
+If the HOST_PROC environment variable is set, Telegraf will use its value instead of `/proc`
 
 **Note: `/proc/slabinfo` is usually restricted to read as root user. Make sure telegraf can execute `sudo` without password.**
 

From 4034fadc741945aef70ddba640cdc090498eb5c2 Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nob@bobuhiro11.net>
Date: Wed, 18 May 2022 12:14:23 +0900
Subject: [PATCH 14/16] Update plugins/inputs/slab/README.md

Co-authored-by: reimda <reimda@users.noreply.github.com>
---
 plugins/inputs/slab/README.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index 9075654b9b310..f81caf08bbef0 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -18,7 +18,12 @@ If the HOST_PROC environment variable is set, Telegraf will use its value instea
 [[inputs.slab]]
   # no configuration
 ```
+## Sudo configuration
 
+Since the slabinfo file is only readable by root, the plugin runs `sudo /bin/cat` to read the file.
+
+Sudo can be configured to allow telegraf to run just the command needed to read the slabinfo file. For example, if telegraf is running as the user 'telegraf' and HOST_PROC is not used, add this to the sudoers file:
+`telegraf ALL = (root) NOPASSWD: /bin/cat /proc/slabinfo`
 ## Metrics
 
 Metrics include generic ones such as `kmalloc_*` as well as those of kernel

From d44ded479ed0c6ac1a09679701a1d8780ab30d67 Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Date: Wed, 18 May 2022 14:10:18 +0900
Subject: [PATCH 15/16] fix for markdownlint

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
 plugins/inputs/slab/README.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index f81caf08bbef0..8c3c2e11242c8 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -18,12 +18,14 @@ If the HOST_PROC environment variable is set, Telegraf will use its value instea
 [[inputs.slab]]
   # no configuration
 ```
+
 ## Sudo configuration
 
 Since the slabinfo file is only readable by root, the plugin runs `sudo /bin/cat` to read the file.
 
 Sudo can be configured to allow telegraf to run just the command needed to read the slabinfo file. For example, if telegraf is running as the user 'telegraf' and HOST_PROC is not used, add this to the sudoers file:
 `telegraf ALL = (root) NOPASSWD: /bin/cat /proc/slabinfo`
+
 ## Metrics
 
 Metrics include generic ones such as `kmalloc_*` as well as those of kernel

From fe8fd4bc59272266a60a80e201997d10b899cc4a Mon Sep 17 00:00:00 2001
From: Nobuhiro MIKI <nob@bobuhiro11.net>
Date: Thu, 19 May 2022 10:07:37 +0900
Subject: [PATCH 16/16] Update plugins/inputs/slab/README.md

Co-authored-by: Joshua Powers <powersj@fastmail.com>
---
 plugins/inputs/slab/README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/plugins/inputs/slab/README.md b/plugins/inputs/slab/README.md
index 8c3c2e11242c8..18512fbf42b86 100644
--- a/plugins/inputs/slab/README.md
+++ b/plugins/inputs/slab/README.md
@@ -16,7 +16,8 @@ If the HOST_PROC environment variable is set, Telegraf will use its value instea
 ```toml
 # Get slab statistics from procfs
 [[inputs.slab]]
-  # no configuration
+  # no configuration - please see the plugin's README for steps to configure
+  # sudo properly
 ```
 
 ## Sudo configuration