Re: High system load and 3TB of memory.

[Vlastimil Babka <vbabka@suse.cz>]

On 03/14/2015 06:33 PM, Andrey Korolyov wrote:
> On Sat, Mar 14, 2015 at 8:25 PM,  <jesper@krogh.cc> wrote:
>>> On Sat, Mar 14, 2015 at 8:05 PM,  <jesper@krogh.cc> wrote:
>>>> Hi
>>>> I have a 3.13 (ubuntu LTS) server with 3TB of memory and under certain
>>>> load
>>>> conditions it can spiral off to 80+% system load. Per recommendation on
>>>> IRC
>>>> yesterday I have captured 2 perf reports (I'm new to perf, so I'm not
>>>> sure they tell precisely whats needed.
>>>>
>>>> Bad situation (high sysload 80%+)
>>
>>
>>> Hi Jesper, please take a look on
>>> http://marc.info/?l=linux-mm&m=141605213522925&w=2, there is a long
>>> and unfinished discussion as it seems very problematic to make a
>>> deterministic reproduction of the bug in our environments. If you can
>>> observe same lockups with more ease, it`ll help a lot in the issue
>>> pinning and fixing.
>>
>>
>> Hi Andrey.
>>
>> Yes it looks indeed familiar. I can do a fair amount of testing and our
>> normal production load triggers the problem 6-10 times per day and I'm
>> willing to garther data to help move forward. What do you suggest is next?
>>
>> Jesper
>>
>>
>
> There is a couple of patches suggested by Vlastimil and others through
> discussion, not me neither Christian was able to test them properly
> due to kind of environment where bug primarily live (production envs
> for both of us). The bare test-env reproducer is a big step forward
> indeed. Since then bug was reported a couple of times and workarounded
> (by setting ridiculously large amount of memory for vm.min_free), the
> larger memory room is (given intensive disk i/o which is able to fill
> all memory with certain ratio of active/inactive pages I suppose), the
> easier it is to catch the issue.

Right, it would be great if you could try it with 3.18+ kernel and 
possibly Joonsoo's patch from
http://marc.info/?l=linux-mm&m=141774145601066


--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>