Re: [PATCH 1/4] Add kswapd descriptor.

[Ying Han <yinghan@google.com>]

On Tue, Dec 7, 2010 at 5:28 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@jp.fujitsu.com> wrote:
> On Tue, 7 Dec 2010 17:24:12 -0800
> Ying Han <yinghan@google.com> wrote:
>
>> On Tue, Dec 7, 2010 at 4:39 PM, KAMEZAWA Hiroyuki
>> <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>> > On Tue, 7 Dec 2010 09:28:01 -0800
>> > Ying Han <yinghan@google.com> wrote:
>> >
>> >> On Tue, Dec 7, 2010 at 4:33 AM, Mel Gorman <mel@csn.ul.ie> wrote:
>> >
>> >> Potentially there will
>> >> > also be a very large number of new IO sources. I confess I haven't read the
>> >> > thread yet so maybe this has already been thought of but it might make sense
>> >> > to have a 1:N relationship between kswapd and memcgroups and cycle between
>> >> > containers. The difficulty will be a latency between when kswapd wakes up
>> >> > and when a particular container is scanned. The closer the ratio is to 1:1,
>> >> > the less the latency will be but the higher the contenion on the LRU lock
>> >> > and IO will be.
>> >>
>> >> No, we weren't talked about the mapping anywhere in the thread. Having
>> >> many kswapd threads
>> >> at the same time isn't a problem as long as no locking contention (
>> >> ext, 1k kswapd threads on
>> >> 1k fake numa node system). So breaking the zone->lru_lock should work