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

From: Vlastimil Babka
Date: Thu May 19 2016 - 08:13:50 EST


On 05/19/2016 02:11 PM, Vlastimil Babka wrote:
> 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")

Bah, not that one.

Fixes: accf62422b3a ("mm, kswapd: replace kswapd compaction with waking
up kcompactd")

> 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))
>>
>
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