Re: Swappiness vs. mmap() and interactive response

KOSAKI Motohiro
2009-04-29T07:50:37Z

>> Mapped page decrease rapidly: not happend (I guess, these page stay in
>>                                           active list on my system)
>> page fault large latency:     happend (latencytop display >200ms)
>
> hm.  The last two observations appear to be inconsistent.

it mean existing process don't slow down. but new process creation is very slow.

> Elladan, have you checked to see whether the Mapped: number in
> /proc/meminfo is decreasing?
>
>>
>> Then, I don't doubt vm replacement logic now.
>> but I need more investigate.
>> I plan to try following thing today and tommorow.
>>
>>  - XFS
>>  - LVM
>>  - another io scheduler (thanks Ted, good view point)
>>  - Rik's new patch
>
> It's not clear that we know what's happening yet, is it?  It's such a
> gross problem that you'd think that even our testing would have found
> it by now :(

Yes, unclear. but various testing can drill down the reason, I think.

> Elladan, do you know if earlier kernels (2.6.26 or thereabouts) had
> this severe a problem?
>
> (notes that we _still_ haven't unbusted prev_priority)