linux-kernel - Re: [PATCH 2/2] mm/vmscan: make sure wakeup

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Date:   Tue, 29 Mar 2022 00:41:46 +0000
From:   Wei Yang <richard.weiyang@...il.com>
To:     "Huang, Ying" <ying.huang@...el.com>
Cc:     Wei Yang <richard.weiyang@...il.com>, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        mgorman@...hsingularity.net
Subject: Re: [PATCH 2/2] mm/vmscan: make sure wakeup_kswapd with managed zone

On Mon, Mar 28, 2022 at 09:08:34AM +0800, Huang, Ying wrote:
>Hi, Wei,
>
>Wei Yang <richard.weiyang@...il.com> writes:
>
>> wakeup_kswapd() only wake up kswapd when the zone is managed.
>>
>> For two callers of wakeup_kswapd(), they are node perspective.
>>
>>   * wake_all_kswapds
>>   * numamigrate_isolate_page
>>
>> If we picked up a !managed zone, this is not we expected.
>>
>> This patch makes sure we pick up a managed zone for wakeup_kswapd().
>>
>> Signed-off-by: Wei Yang <richard.weiyang@...il.com>
>> ---
>>  mm/migrate.c    | 2 +-
>>  mm/page_alloc.c | 2 ++
>>  2 files changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/migrate.c b/mm/migrate.c
>> index 3d60823afd2d..c4b654c0bdf0 100644
>> --- a/mm/migrate.c
>> +++ b/mm/migrate.c
>> @@ -2046,7 +2046,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
>>  		if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING))
>>  			return 0;
>>  		for (z = pgdat->nr_zones - 1; z >= 0; z--) {
>> -			if (populated_zone(pgdat->node_zones + z))
>> +			if (managed_zone(pgdat->node_zones + z))
>
>This looks good to me!  Thanks!  It seems that we can replace
>populated_zone() in migrate_balanced_pgdat() too.  Right?
>

Yes, you are right. I didn't spot this.

While this patch comes from the clue of wakeup_kswapd(), I am not sure it is
nice to put it in this patch together.

Which way you prefer to include this: merge the change into this one, or a
separate one?

-- 
Wei Yang
Help you, Help me