Re: [patch 04/15] mm/mempolicy: add nodes_empty check in SYSC_migrate_pages

[Yisheng Xie <xieyisheng1@huawei.com>]

Hi Vlastimil,

On 2017/12/1 23:20, Vlastimil Babka wrote:
> On 11/30/2017 11:15 PM, akpm@linux-foundation.org wrote:
>> From: Yisheng Xie <xieyisheng1@huawei.com>
>> Subject: mm/mempolicy: add nodes_empty check in SYSC_migrate_pages
>>
>> As in manpage of migrate_pages, the errno should be set to EINVAL when
>> none of the node IDs specified by new_nodes are on-line and allowed by the
>> process's current cpuset context, or none of the specified nodes contain
>> memory.  However, when test by following case:
>>
>> 	new_nodes = 0;
>> 	old_nodes = 0xf;
>> 	ret = migrate_pages(pid, old_nodes, new_nodes, MAX);
>>
>> The ret will be 0 and no errno is set.  As the new_nodes is empty, we
>> should expect EINVAL as documented.
>>
>> To fix the case like above, this patch check whether target nodes AND
>> current task_nodes is empty, and then check whether AND
>> node_states[N_MEMORY] is empty.
>>
>> Link: http://lkml.kernel.org/r/1510882624-44342-4-git-send-email-xieyisheng1@huawei.com
>> Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
>> Cc: Andi Kleen <ak@linux.intel.com>
>> Cc: Chris Salls <salls@cs.ucsb.edu>
>> Cc: Christopher Lameter <cl@linux.com>
>> Cc: David Rientjes <rientjes@google.com>
>> Cc: Ingo Molnar <mingo@kernel.org>
>> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
>> Cc: Tan Xiaojun <tanxiaojun@huawei.com>
>> Cc: Vlastimil Babka <vbabka@suse.cz>
>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> 
> My previous concerns here were a mistake as I explained in my reply to
> v4. So you can add
> 
> Acked-by: Vlastimil Babka <vbabka@suse.cz>

Thanks
Yisheng Xie

> 
> and proceed with the series. Thanks.
> 
>> ---
>>

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