Re: System freezes when RAM is full (64-bit)

[Michal Hocko <mhocko@suse.cz>]

On Thu 04-04-13 16:10:06, Ivan Danov wrote:
> Hi Michal,
> 
> Yes, I use swap partition (2GB), but I have applied some things for
> keeping the life of the SSD hard drive longer. All the things I have
> done are under point 3. at
> http://www.rileybrandt.com/2012/11/18/linux-ultrabook/.

OK, I guess I know what's going on here.
So you did set vm.swappiness=0 which (for some time) means that there is
almost no swapping going on (although you have plenty of swap as you are
mentioning above).
This shouldn't be a big deal normally but you are also backing your
/tmp on tmpfs which is in-memory filesystem. This means that if you
are writing to /tmp a lot then this content will fill up your memory
which is not swapped out until the memory reclaim is getting into real
troubles - most of the page cache is dropped by that time so your system
starts trashing.

I would encourage you to set swappiness to a more reasonable value (I
would use the default value which is 60). I understand that you are
concerned about your SSD lifetime but your user experience sounds like a
bigger priority ;)

> By system freezes, I mean that the desktop environment doesn't react
> on my input. Just sometimes the mouse is reacting very very choppy
> and slowly, but most of the times it is not reacting at all. In the
> attached file, I have the output of the script and the content of
> dmesg for all levels from warn to emerg, as well as my kernel config.

I haven't checked your attached data but you should get an overview from
Shmem line from /proc/meminfo which tells you how much shmem/tmpfs
memory you are using and grep "^Swap" /proc/meminfo will tell you more
about your swap usage.

> 
> Best,
> Ivan

HTH
-- 
Michal Hocko
SUSE Labs

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