Re: [RFC] oom notifications via /dev/oom_notify

[Badari <pbadari@us.ibm.com>]

Rik van Riel wrote:
> On Tue, 30 Oct 2007 13:59:28 -0800
> Badari Pulavarty <pbadari@us.ibm.com> wrote:
>
>   
>> Interesting.. Our database folks wanted some kind of notification when
>> there is memory pressure and we are about to kill the biggest consumer
>> (in most cases, the most useful application :(). What actually they
>> want is a way to get notified, so that they can shrink their memory
>> footprint in response. Just notifying before OOM may not help, since
>> they don't have time to react. How does this notification help ? Are
>> they supposed to monitor swapping activity and decide ?
>>     
>
> Marcelo's code monitors swapping activity and will let userspace
> programs (that poll/select the device node) know when they should
> shrink their memory footprint.
>
> This is not "OOM" in the sense of "no more memory or swap", but
> in the sense of "we're low on memory - if you don't free something
> we'll slow you down by swapping stuff".
>
>   
I think having this kind of OOM notification is a decent start. But any 
applications that
wants to know notifications, would be more interested if kernel is 
swapping out any of
its data, than overall system swapping events. I guess, making it 
per-process or per-cgroup
may be logical extension. I am not sure if its really practical , though...

Thanks,
Badari

--
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>