Re: node-hotplug: is memset 0 safe in try_offline_node()?

From: Xishi Qiu
Date: Tue Mar 03 2015 - 21:53:15 EST


On 2015/3/4 10:22, Xishi Qiu wrote:

> On 2015/3/3 18:20, Gu Zheng wrote:
>
>> Hi Xishi,
>> On 03/03/2015 11:30 AM, Xishi Qiu wrote:
>>
>>> When hot-remove a numa node, we will clear pgdat,
>>> but is memset 0 safe in try_offline_node()?
>>
>> It is not safe here. In fact, this is a temporary solution here.
>> As you know, pgdat is accessed lock-less now, so protection
>> mechanism (RCUï) is needed to make it completely safe here,
>> but it seems a bit over-kill.
>>

Hi Gu,

Can we just remove "memset(pgdat, 0, sizeof(*pgdat));" ?
I find this will be fine in the stress test except the warning
when hot-add memory.

Thanks,
Xishi Qiu

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