Ubuntu Linux kernel memory leak, cache memory trouble

[佐伯 浩]

As soon as I start Ubuntu 12.04.4 LTS with i386 PAE kernel, 8GB memory, GNU/Linux 3.2.0-64-generic-pae i686,
cache memory area increases a little by a little, and It consumes at last, a few hours later, 5GB memory. User memory left will become 200MB.

I release cache memory by issuing a shell script, cache_release.sh. It is like that :

#!/bin/bash

/bin/sync
/bin/sync
/bin/sync
/bin/sync
/bin/sync

/sbin/sysctl -w vm.drop_caches=1
/sbin/sysctl -w vm.drop_caches=2
/sbin/sysctl -w vm.drop_caches=3

I registered this shell script to crontab and I issue this script command once a ten minutes.

Maybe kernel requires patches.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.2.0-64-generic-pae 3.2.0-64.97
ProcVersionSignature: Ubuntu 3.2.0-64.97-generic-pae 3.2.59
Uname: Linux 3.2.0-64-generic-pae i686
NonfreeKernelModules: nvidia
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC665 Analog [ALC665 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: hiroshi 4448 F.... pulseaudio
 /dev/snd/controlC0: hiroshi 4448 F.... pulseaudio
 /dev/snd/pcmC0D0p: hiroshi 4448 F...m pulseaudio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf0a00000 irq 57'
   Mixer name : 'Realtek ALC665'
   Components : 'HDA:10ec0665,1028046e,00100003'
   Controls : 26
   Simple ctrls : 13
Card1.Amixer.info:
 Card hw:1 'NVidia'/'HDA NVidia at 0xcdefc000 irq 17'
   Mixer name : 'Nvidia GPU 14 HDMI/DP'
   Components : 'HDA:10de0014,10de0101,00100100'
   Controls : 24
   Simple ctrls : 4
Date: Wed Jun 18 05:27:20 2014
HibernationDevice: RESUME=UUID=02e8790f-b82d-416f-8a25-de64b1bac6e9
InstallationMedia: Ubuntu 12.04 "Precise" - Build i386 LIVE Binary 20120501-03:27
MachineType: Dell Inc. XPS L501X
MarkForUpload: True
ProcFB:

ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.2.0-64-generic-pae root=UUID=1dff47dd-b881-4de7-b290-b74b48753d63 ro quiet splash
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-64-generic-pae N/A
 linux-backports-modules-3.2.0-64-generic-pae N/A
 linux-firmware 1.79.15
SourcePackage: linux
StagingDrivers: mei
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/26/2011
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A08
dmi.board.vendor: Dell Inc.
dmi.board.version: A08
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: A08
dmi.modalias: dmi:bvnDellInc.:bvrA08:bd07/26/2011:svnDellInc.:pnXPSL501X:pvrA08:rvnDellInc.:rn:rvrA08:cvnDellInc.:ct8:cvrA08:
dmi.product.name: XPS L501X
dmi.product.version: A08
dmi.sys.vendor: Dell Inc.

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.16 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.16-rc1-utopic/

[佐伯 浩 (h-saeki)]

Tag : 'kernel-fixed-upstream'

Hi, Joseph Salisbury (jsalisbury).

I tested with Ver. 3.16 kernel.

I test ran for fourty minutes.

To see with 'top' command, the kernel consumes as cache memory 700MB.

First it consumed 500MB and after thirty minutes, 700MB was consumed.
To release cache memory with 'cache_release.sh', cosumed cache memory became 100MB.
It seems to me, as for Ver. 3.16 kernel, cache memory management bug is already fixed.