Re: [RFC][PATCH 03/13] mm/vmscan: replace implicit RECLAIM_ZONE checks with explicit checks

[David Rientjes]

On Mon, 25 Jan 2021, Dave Hansen wrote:

> 
> From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> 
> RECLAIM_ZONE was assumed to be unused because it was never explicitly
> used in the kernel.  However, there were a number of places where it
> was checked implicitly by checking 'node_reclaim_mode' for a zero
> value.
> 
> These zero checks are not great because it is not obvious what a zero
> mode *means* in the code.  Replace them with a helper which makes it
> more obvious: node_reclaim_enabled().
> 
> This helper also provides a handy place to explicitly check the
> RECLAIM_ZONE bit itself.  Check it explicitly there to make it more
> obvious where the bit can affect behavior.
> 
> This should have no functional impact.
> 
> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> Reviewed-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
> Acked-by: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
> Cc: "Tobin C. Harding" <tobin@xxxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Huang Ying <ying.huang@xxxxxxxxx>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: Qian Cai <cai@xxxxxx>
> Cc: Daniel Wagner <dwagner@xxxxxxx>
> Cc: osalvador <osalvador@xxxxxxx>

Acked-by: David Rientjes <rientjes@xxxxxxxxxx>