linux-kernel - Re: [PATCH] mm: memcontrol: Set the correct memcg swappiness restriction

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Message-ID: <6e6570d2-44a2-1da1-6c2a-38766786c40c@suse.cz>
Date:   Tue, 3 Aug 2021 17:20:40 +0200
From:   Vlastimil Babka <vbabka@...e.cz>
To:     Michal Hocko <mhocko@...e.com>,
        Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc:     akpm@...ux-foundation.org, hannes@...xchg.org,
        vdavydov.dev@...il.com, cgroups@...r.kernel.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: memcontrol: Set the correct memcg swappiness
 restriction

On 7/30/21 8:39 AM, Michal Hocko wrote:
> On Fri 30-07-21 14:26:35, Baolin Wang wrote:
>> Since commit c843966c556d ("mm: allow swappiness that prefers reclaiming
>> anon over the file workingset") has expended the swappiness value to
>> make swap to be preferred in some systems. We should also change the
>> memcg swappiness restriction to allow memcg swap-preferred.
>> 
>> Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
> 
> Yes, this looks like an omission. It doesn't really make sense to have
> two different constrains on the value.
> 
> Acked-by: Michal Hocko <mhocko@...e.com>

So, also Fixes: c843966c556d ("mm: allow swappiness that prefers reclaiming anon
over the file workingset")
?

> Thanks!
> 
>> ---
>>  mm/memcontrol.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index 6580c23..988fc94 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -4046,7 +4046,7 @@ static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
>>  {
>>  	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
>>  
>> -	if (val > 100)
>> +	if (val > 200)
>>  		return -EINVAL;
>>  
>>  	if (!mem_cgroup_is_root(memcg))
>> -- 
>> 1.8.3.1
>