On Tue, Feb 19, 2013 at 12:08 PM, Li Haifeng <omycle@xxxxxxxxx> wrote:
2013/2/19 Soham Chakraborty <sohamwonderpiku4u@xxxxxxxxx>:
> Hey dude,It's known that swap operation is done with memory reclaiming.There
>
> Apologies for this kind of approach but I was not sure whether I can
> directly mail the list with such a noobish question. I have been poking
> around in mm subsystem for around 2 years now and I have never got a fine,
> bullet proof answer to this question.
>
> Why would something swap even if there is free or cached memory available.
are three occasions for memory reclaiming: low on memory reclaiming,
Hibernation reclaiming, periodic reclaiming.
For periodic reclaiming, some page may be swapped out even if there is
free or cached memory available.
So, meaning even if there is free or cached memory available, periodic reclaiming might cause some pages to be swapped out. Is this the rationale. If so, which part of the source explains this behavior
Please correct me if my understanding is wrong.
Regards,
Haifeng Li
>
> I have read about all possible theories including lru algorithm,
> vm.swappiness, kernel heuristics, overcommit of memory and all. But I for
> the heck of me, can't understand what is the issue. And I can't make the end
> users satisfied too. I keep blabbering kernel heuristics too much.
>
> Do you have any answer to this question. If you think this is worthy of
> going to list, I will surely do so.
>
> Soham