From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: wency@cn.fujitsu.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, rientjes@google.com,
liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org,
paulus@samba.org, minchan.kim@gmail.com,
akpm@linux-foundation.org
Subject: Re: [PATCH 2/4] memory-hotplug: add node_device_release
Date: Mon, 1 Oct 2012 14:12:13 -0400 [thread overview]
Message-ID: <CAHGf_=qZVe_KfThZa5yEm+4w3MMREs1xqya5HmKWsWjyTcjkzA@mail.gmail.com> (raw)
In-Reply-To: <50693E30.3010006@jp.fujitsu.com>
On Mon, Oct 1, 2012 at 2:54 AM, Yasuaki Ishimatsu
<isimatu.yasuaki@jp.fujitsu.com> wrote:
> Hi Kosaki-san,
>
>
> 2012/09/29 7:19, KOSAKI Motohiro wrote:
>>>>>
>>>>> I don't understand it. How can we get rid of the warning?
>>>>
>>>>
>>>> See cpu_device_release() for example.
>>>
>>>
>>> If we implement a function like cpu_device_release(), the warning
>>> disappears. But the comment says in the function "Never copy this
>>> way...".
>>> So I think it is illegal way.
>>
>>
>> What does "illegal" mean?
>
>
> The "illegal" means the code should not be mimicked.
>
>
>> You still haven't explain any benefit of your code. If there is zero
>> benefit, just kill it.
>> I believe everybody think so.
>>
>> Again, Which benefit do you have?
>
>
> The patch has a benefit to delets a warning message.
>
>
>>
>>>>>> Why do we need this node_device_release() implementation?
>>>>>
>>>>>
>>>>> I think that this is a manner of releasing object related kobject.
>>>>
>>>>
>>>> No. Usually we never call memset() from release callback.
>>>
>>>
>>> What we want to release is a part of array, not a pointer.
>>> Therefore, there is only this way instead of kfree().
>>
>>
>> Why? Before your patch, we don't have memset() and did work it.
>
>
> If we does not apply the patch, a warning message is shown.
> So I think it did not work well.
>
>
>> I can't understand what mean "only way".
>
>
> For deleting a warning message, I created a node_device_release().
> In the manner of releasing kobject, the function frees a object related
> to the kobject. So most functions calls kfree() for releasing it.
> In node_device_release(), we need to free a node struct. If the node
> struct is pointer, I can free it by kfree. But the node struct is a part
> of node_devices[] array. I cannot free it. So I filled the node struct
> with 0.
>
> But you think it is not good. Do you have a good solution?
Do nothing. just add empty release function and kill a warning.
Obviously do nothing can't make any performance drop nor any
side effect.
meaningless memset() is just silly from point of cache pollution view.
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next prev parent reply other threads:[~2012-10-01 18:12 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-27 5:45 [PATCH 0/4] bugfix for memory hotplug wency
2012-09-27 5:45 ` [PATCH 1/4] memory-hotplug: add memory_block_release wency
2012-09-27 10:20 ` Ni zhan Chen
2012-09-28 0:24 ` Yasuaki Ishimatsu
2012-09-28 1:35 ` KOSAKI Motohiro
2012-09-28 3:45 ` Yasuaki Ishimatsu
2012-09-28 6:04 ` Ni zhan Chen
2012-09-28 6:11 ` Yasuaki Ishimatsu
2012-09-28 6:14 ` Ni zhan Chen
2012-09-28 22:30 ` KOSAKI Motohiro
2012-09-27 20:11 ` KOSAKI Motohiro
2012-09-27 5:45 ` [PATCH 2/4] memory-hotplug: add node_device_release wency
2012-09-27 10:38 ` Ni zhan Chen
2012-09-27 20:13 ` KOSAKI Motohiro
2012-09-28 0:07 ` Yasuaki Ishimatsu
2012-09-28 1:13 ` KOSAKI Motohiro
2012-09-28 1:30 ` Yasuaki Ishimatsu
2012-09-28 1:37 ` KOSAKI Motohiro
2012-09-28 9:55 ` Yasuaki Ishimatsu
2012-09-28 22:19 ` KOSAKI Motohiro
2012-10-01 6:54 ` Yasuaki Ishimatsu
2012-10-01 18:12 ` KOSAKI Motohiro [this message]
2012-10-05 1:00 ` Yasuaki Ishimatsu
2012-10-05 18:39 ` KOSAKI Motohiro
2012-09-27 5:45 ` [PATCH 3/4] memory-hotplug: clear hwpoisoned flag when onlining pages wency
2012-09-27 12:27 ` Ni zhan Chen
2012-09-27 20:17 ` KOSAKI Motohiro
2012-09-28 1:53 ` Wen Congyang
2012-09-27 5:45 ` [PATCH 4/4] memory-hotplug: auto offline page_cgroup when onlining memory block failed wency
2012-09-27 12:44 ` Ni zhan Chen
2012-09-27 20:19 ` KOSAKI Motohiro
2012-09-27 21:18 ` [PATCH 0/4] bugfix for memory hotplug Andrew Morton
2012-09-29 2:31 ` Ni zhan Chen
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