Re: [PATCH 08/27] mm, vmscan: Simplify the logic deciding whether kswapd sleeps

[Vlastimil Babka]

On 06/21/2016 04:15 PM, Mel Gorman wrote:
> kswapd goes through some complex steps trying to figure out if it
> should stay awake based on the classzone_idx and the requested order.
> It is unnecessarily complex and passes in an invalid classzone_idx to
> balance_pgdat().  What matters most of all is whether a larger order has
> been requsted and whether kswapd successfully reclaimed at the previous
> order. This patch irons out the logic to check just that and the end result
> is less headache inducing.
>
> Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

I'm just not entirely convinced that the direct full sleep bypass is worth the 
added complexity. I can even imagine it being counter productive in some 
situations. But it's not a big issue.