From: Xishi Qiu <qiuxishi@huawei.com>
To: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
Andrew Morton <akpm@linux-foundation.org>,
Tang Chen <tangchen@cn.fujitsu.com>,
Yinghai Lu <yinghai@kernel.org>, Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Toshi Kani <toshi.kani@hp.com>, Mel Gorman <mgorman@suse.de>,
Tejun Heo <tj@kernel.org>, Xiexiuqi <xiexiuqi@huawei.com>,
Hanjun Guo <guohanjun@huawei.com>, Li Zefan <lizefan@huawei.com>
Subject: Re: node-hotplug: is memset 0 safe in try_offline_node()?
Date: Wed, 4 Mar 2015 10:52:38 +0800 [thread overview]
Message-ID: <54F67376.8050001@huawei.com> (raw)
In-Reply-To: <54F66C52.4070600@huawei.com>
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 (RCUi 1/4 ?) 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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next prev parent reply other threads:[~2015-03-04 2:53 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-03 3:30 node-hotplug: is memset 0 safe in try_offline_node()? Xishi Qiu
2015-03-03 10:20 ` Gu Zheng
2015-03-04 2:22 ` Xishi Qiu
2015-03-04 2:52 ` Xishi Qiu [this message]
2015-03-04 3:56 ` Gu Zheng
2015-03-04 8:03 ` Xishi Qiu
2015-03-04 8:53 ` Kamezawa Hiroyuki
2015-03-04 9:53 ` Gu Zheng
2015-03-04 3:53 ` Gu Zheng
2015-03-04 7:01 ` Xishi Qiu
2015-03-04 8:31 ` Xie XiuQi
2015-03-05 8:26 ` Gu Zheng
2015-03-05 9:39 ` Xishi Qiu
2015-03-05 9:45 ` Gu Zheng
2015-03-11 1:12 ` Gu Zheng
2015-03-11 2:51 ` Xie XiuQi
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