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Subject: Re: [PATCH RFC v2 4/4] mm/mempolicy: add nodes_empty check in
 SYSC_migrate_pages
To: Christopher Lameter <cl@linux.com>, Vlastimil Babka <vbabka@suse.cz>
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From: Yisheng Xie <xieyisheng1@huawei.com>
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Date: Tue, 7 Nov 2017 19:23:52 +0800
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hi Christopher and Vlastimil,

Thanks for your comment!
On 2017/11/6 23:29, Christopher Lameter wrote:
> On Mon, 6 Nov 2017, Vlastimil Babka wrote:
> 
>> I'm not sure what exactly is the EPERM intention. Should really the
>> capability of THIS process override the cpuset restriction of the TARGET
>> process? Maybe yes. Then, does "insufficient privilege (CAP_SYS_NICE) to
> 
> CAP_SYS_NICE never overrides cpuset restrictions. The cap can be used to
> migrate pages that are *also* mapped by other processes (and thus move
> pages of another process which may have different cpu set restrictions!).

So you means the specified nodes should be a subset of target cpu set, right?

Thanks
Yisheng Xie
> The cap should not allow migrating pages to nodes that are not allowed by
> the cpuset of the current process.
> 
> 
> 
> .
>