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Subject: Re: [RFC PATCH 3/5] numa: introduce per-cgroup preferred numa node
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
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From:   =?UTF-8?B?546L6LSH?= <yun.wang@linux.alibaba.com>
Message-ID: <e5e39d99-2b7a-db27-5aa0-ecc8d064257b@linux.alibaba.com>
Date:   Tue, 23 Apr 2019 17:41:09 +0800
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On 2019/4/23 下午4:55, Peter Zijlstra wrote:
> On Mon, Apr 22, 2019 at 10:13:36AM +0800, 王贇 wrote:
>> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
>> index af171ccb56a2..6513504373b4 100644
>> --- a/mm/mempolicy.c
>> +++ b/mm/mempolicy.c
>> @@ -2031,6 +2031,10 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
>>
>>  	pol = get_vma_policy(vma, addr);
>>
>> +	page = alloc_page_numa_preferred(gfp, order);
>> +	if (page)
>> +		goto out;
>> +
>>  	if (pol->mode == MPOL_INTERLEAVE) {
>>  		unsigned nid;
>>
> 
> This I think is wrong, it overrides app specific mbind() requests.

The original concern is that we scared the user apps insider cgroup deal
wrong with memory policy and do bad behavior, but now I agree that we
should not override the policy, the admin will take the responsibility.

Regards,
Michael Wang

>