Re: Possible deadloop in direct reclaim?

[KOSAKI Motohiro <kosaki.motohiro@gmail.com>]

(7/25/13 9:11 PM), Lisa Du wrote:
> Dear KOSAKI
>     In my test, I didn't set compaction. Maybe compaction is helpful to avoid this issue. I can have try later.
>     In my mind CONFIG_COMPACTION is an optional configuration right?

Right. But if you don't set it, application must NOT use >1 order allocations. It doesn't work and it is expected
result.
That's your application mistake.

>     If we don't use, and met such an issue, how should we deal with such infinite loop?
> 
>     I made a change in all_reclaimable() function, passed overnight tests, please help review, thanks in advance!
> @@ -2353,7 +2353,9 @@ static bool all_unreclaimable(struct zonelist *zonelist,
>                          continue;
>                  if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
>                          continue;
> -               if (!zone->all_unreclaimable)
> +               if (zone->all_unreclaimable)
> +                       continue;
> +               if (zone_reclaimable(zone))
>                          return false;

Please tell me why you chaned here.



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