Re: [RFC][PATCH] the proposal of improve page reclaim by throttle

From: Balbir Singh
Date: Thu Feb 21 2008 - 06:07:29 EST


KOSAKI Motohiro wrote:
> Hi balbir-san
>
>> It's good to keep the main reclaim code and the memory controller reclaim in
>> sync, so this is a nice effort.
>
> thank you.
> I will repost next version (fixed nick's opinion) while a few days.
>
>> > @@ -1456,7 +1501,7 @@ unsigned long try_to_free_mem_cgroup_pag
>> > int target_zone = gfp_zone(GFP_HIGHUSER_MOVABLE);
>> >
>> > zones = NODE_DATA(numa_node_id())->node_zonelists[target_zone].zones;
>> > - if (do_try_to_free_pages(zones, sc.gfp_mask, &sc))
>> > + if (try_to_free_pages_throttled(zones, 0, sc.gfp_mask, &sc))
>> > return 1;
>> > return 0;
>> > }
>>
>> try_to_free_pages_throttled checks for zone_watermark_ok(), that will not work
>> in the case that we are reclaiming from a cgroup which over it's limit. We need
>> a different check, to see if the mem_cgroup is still over it's limit or not.
>
> That makes sense.
>
> unfortunately, I don't know mem-cgroup so much.
> What do i use function, instead?

One option could be that once the memory controller has this feature, we'll need
no changes in try_to_free_mem_cgroup_pages.

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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