Re: [PATCH 1/5] vmscan: remove all_unreclaimable check from direct reclaim path completely

From: KOSAKI Motohiro
Date: Wed Mar 23 2011 - 22:48:28 EST


> On Thu, 24 Mar 2011 11:11:46 +0900 (JST) KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote:
>
> > Subject: [PATCH] vmscan: remove all_unreclaimable check from direct reclaim path completely
>
> zone.all_unreclaimable is there to prevent reclaim from wasting CPU
> cycles scanning a zone which has no reclaimable pages. When originally
> implemented it did this very well.
>
> That you guys keep breaking it, or don't feel like improving it is not a
> reason to remove it!
>
> If the code is unneeded and the kernel now reliably solves this problem
> by other means then this should have been fully explained in the
> changelog, but it was not even mentioned.

The changelog says, the logic was removed at 2008. three years ago.
even though it's unintentionally. and I and minchan tried to resurrect
the broken logic and resurrected a bug in the logic too. then, we
are discussed it should die or alive.

Which part is hard to understand for you?



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