Re: [RFC][PATCH][0/4] Memory controller (RSS Control)

[Balbir Singh <balbir@in.ibm.com>]

Paul Menage wrote:
> On 2/19/07, Andrew Morton <akpm@linux-foundation.org> wrote:
>>
>> Alas, I fear this might have quite bad worst-case behaviour.  One small
>> container which is under constant memory pressure will churn the
>> system-wide LRUs like mad, and will consume rather a lot of system time.
>> So it's a point at which container A can deleteriously affect things 
>> which
>> are running in other containers, which is exactly what we're supposed to
>> not do.
> 
> I think it's OK for a container to consume lots of system time during
> reclaim, as long as we can account that time to the container involved
> (i.e. if it's done during direct reclaim rather than by something like
> kswapd).
> 
> Churning the LRU could well be bad though, I agree.
> 

I completely agree with you on reclaim consuming time.

Churning the LRU can be avoided by the means I mentioned before

1. Add a container pointer (per page struct), it is also
    useful for the page cache controller
2. Check if the page belongs to a particular container before
    the list_del(&page->lru), so that those pages can be skipped.
3. Use a double LRU list by overloading the lru list_head of
    struct page.

> Paul
> 


-- 
	Warm Regards,
	Balbir Singh