Re: [PATCH -mmotm-2009-12-10-17-19] Fix wrong rss count of smaps

From: Minchan Kim
Date: Mon Dec 28 2009 - 04:59:36 EST


On Mon, Dec 28, 2009 at 2:43 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> On Mon, 28 Dec 2009 14:31:54 +0900
> Minchan Kim <minchan.kim@xxxxxxxxx> wrote:
>>
>> > BTW, how about counting ZERO page in smaps? Ignoring them completely sounds
>> > not very good.
>>
>> I am not use it is useful.
>>
>> zero page snapshot of ongoing process is useful?
>> Doesn't Admin need to know about zero page?
>> Let's admins use it well. If we remove zero page again?
>> How many are applications use smaps?
>> Did we have a problem without it?
>>
> My concern is that hiding indormation which was exported before.
> No more than that and no strong demand.
>
>
>> When I think of it, there are too many qeustions.
>> Most important thing to add new statistics is just need of customer.
>>
>> Frankly speaking, I don't have good scenario of using zero page.
>> Do you have any scenario it is valueable?
>>
> read before write ? maybe sometimes happens.
>
> For example. current glibc's calloc() avoids memset() if the pages are
> dropped by MADVISE (without unmap).
>
> Before starting zero-page works, I checked "questions" in lkml and
> found some reports that some applications start to go OOM after zero-page
> removal.
>
> For me, I know one of my customer's application depends on behavior of
> zero page (on RHEL5). So, I tried to add again it before RHEL6 because
> I think removal of zero-page corrupts compatibility.
>

Okay. I will repost the patch.

> Thanks,
> -Kame
>
>



--
Kind regards,
Minchan Kim
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