Re: [PATCH v2 4/9] mm/vmscan: save a bit of stack space in shrink_lruvec

[Miaohe Lin]

On 2022/4/12 8:57, ying.huang@xxxxxxxxx wrote:
> On Sat, 2022-04-09 at 17:34 +0800, Miaohe Lin wrote:
>> LRU_UNEVICTABLE is not taken into account when shrink lruvec. So we can
>> save a bit of stack space by shrinking the array size of nr and targets
>> to NR_LRU_LISTS - 1. No functional change intended.
>>
>> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>> ---
>>  mm/vmscan.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index 59b96320f481..0e5818970998 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -2881,8 +2881,9 @@ static bool can_age_anon_pages(struct pglist_data *pgdat,
>>  
>>
>>  static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
>>  {
>> -	unsigned long nr[NR_LRU_LISTS];
>> -	unsigned long targets[NR_LRU_LISTS];
>> +	/* LRU_UNEVICTABLE is not taken into account. */
>> +	unsigned long nr[NR_LRU_LISTS - 1];
>> +	unsigned long targets[NR_LRU_LISTS - 1];
>>  	unsigned long nr_to_scan;
>>  	enum lru_list lru;
>>  	unsigned long nr_reclaimed = 0;
> 
> As Christoph pointed out, this is hacky without much benefit.  Please
> drop this patch.

Will drop this patch. Thanks.

> 
> Best Regards,
> Huang, Ying
> 
> .
>