Bug 53791

Summary:	vmalloc=xxxMB makes problems with oom
Product:	Memory Management	Reporter:	Dieter Ferdinand (dieter.ferdinand)
Component:	Other	Assignee:	Andrew Morton (akpm)
Status:	NEW ---
Severity:	normal	CC:	mohamad.abo.ras
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	3.2.37, 3.7.3	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	kernel log

Description Dieter Ferdinand 2013-02-13 14:27:36 UTC

hello,
i have installed a new linux-system and try to optimize the system.

but since three days, i have the problem, that much processes are killed by oom.

i try some different settings and if i start my system with kernel 3.7.3 and vmalloc=768M the system crash during initialisation/starting services with systemd while oom beginn to kill processes.

after i change to vmalloc=256M the system starts without activation of oom.

normaly, i use kernel 3.2.37 and with this kernel this problem happens every time, i make my systembackup (first backup with copy all files, more then 500 GB) with rsync.

my system have 16GB of ram, AMD FX(tm)-8120 Eight-Core Processor and since some days 6 harddisk (4 with 2 TB and 2 with 3 TB).

swapspace is not activated at this time, because i have same trouble with the harddisk some days before (i think problem with sata-connections).

if oom kills the processes, it seems, that every time there is more the 3GB free memory.

i attach the kernel-system-log from today.

i try to find out, which memory-area activate the oom killer, but without success.

goodby

Comment 1 Dieter Ferdinand 2013-02-13 14:28:53 UTC

Created attachment 93241 [details]
kernel log

Comment 2 Mohamad Abo-Ras 2018-12-26 17:29:37 UTC

Hello,


To get around this problem you will need to increase the default vmalloc size the kernel uses, which is done by passing the kernel the vmalloc= parameter at boot time. Do not go overboard and pick an arbitrarily massive number for this--you may not like the result. First look in /proc/meminfo at the VmallocTotal line to find out what the current value is and round that to the nearest 64Mb (122880kB is what shows here on a 32-bit machine with 1Gb of RAM, although strangely large numbers may appear for very small amounts of RAM--assume 128Mb if this happens... and buy more RAM). Now increase that number by 64Mb (128Mb + 64Mb is 192Mb) and test to see if all the devices/drivers initialize after a reboot. If they don't, add another 64Mb and try again until everything works.


Ref : 
https://www.mythtv.org/wiki/Common_Problem:_vmalloc_too_small 


May this will help to solve this issue 


Thanks,
Mohamad

Comment 3 Dieter Ferdinand 2018-12-26 20:33:18 UTC

hello,
if i remember right, i need the vmalloc-setting for the x-server and zfs, which i try to install.

after i don't get zfs running and can't using the system because the vmalloc parameter blocks so much ram that i can't use my programs, i don't make other test with zfs.

and after the x-server crash my server and later i have no more driver for the graficcard i don't run a hardware-x-server on my server, only tightvnc is used.

for my grafigcard i need e kernel driver and if i load this driver, my system hangs, so i have banned all drivers for grafic-hardware from my system.

i won't try in the future to use zfs or a hardware-x-server on this server so i remove the vmalloc-setting from the kernel-parameters.

at the moment i have too much to do and some software-problems which my server like usb-system hangs some time or i must reboot it, because some network-funktions hang and other such things.

i try kernel 3.16.62 last week and get only system freezing so i use 3.16.56 again.

my server runs fine with a kernel 3.2.37 and since i installed a newer kernel (i need it fur usb3) i have problems and kernels = 4.x are not usable to me (memory-problems (programs need much more memory), filesystemperformance slow down after 30-60 minutes to less then 1-2 MB/s and such things).
so i eliminate all things, if possible, which makes me problems und vmalloc is such a thing.

i can make some tests on my testsystem if i have time again.

goodby