| Re: [RFC][PATCH][0/4] Memory controller (RSS Control) [message #10431 is a reply to message #10418] |
Mon, 19 February 2007 10:39   |
Balbir Singh
Messages: 491
Registered: August 2006
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Senior Member |
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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
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