Re: [PATCH] mm: compact: fix zoneindex in compact

[Vlastimil Babka]

On 05/19/2016 01:58 PM, Chen Feng wrote:
> While testing the kcompactd in my platform 3G MEM only DMA ZONE.
> I found the kcompactd never wakeup. It seems the zoneindex
> has already minus 1 before. So the traverse here should be <=.

Ouch, thanks!

> Signed-off-by: Chen Feng <puck.chen@xxxxxxxxxxxxx>

Fixes: 0f87baf4f7fb ("mm: wake kcompactd before kswapd's short sleep")
Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
>  mm/compaction.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 8fa2540..e5122d9 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -1742,7 +1742,7 @@ static bool kcompactd_node_suitable(pg_data_t *pgdat)
>  	struct zone *zone;
>  	enum zone_type classzone_idx = pgdat->kcompactd_classzone_idx;
>  
> -	for (zoneid = 0; zoneid < classzone_idx; zoneid++) {
> +	for (zoneid = 0; zoneid <= classzone_idx; zoneid++) {
>  		zone = &pgdat->node_zones[zoneid];
>  
>  		if (!populated_zone(zone))
>