lkml.org 
[lkml]   [2013]   [Nov]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: /proc/vmcore mmap() failure issue
Date
(2013/11/15 23:26), Vivek Goyal wrote:
> On Fri, Nov 15, 2013 at 06:41:52PM +0900, HATAYAMA Daisuke wrote:
>
> [..]
>>> Given the fact that hpa does not like fixing it in kernel. We are left
>>> with option of fixing it in following places.
>>>
>>> - Drop partial pages in kexec-tools
>>> - Drop partial pages in makeudmpfile.
>>> - Read partial pages using read() interface in makedumpfile
>>> - Modify /proc/vmcore to copy partial pages in second kernel's memory.
>>>
>>> It is not clear to me that partial pages are really useful. So I want
>>> to avoid modifying /proc/vmcore to deal with partial pages and increase
>>> complexity.
>>>
>>> So fixing makedumpfile (either option2 or option 3) seems least risky
>>> to me. In fact I would say let us keep it simple and truncate partial
>>> pages in makedumpfile to keep it simple. And look at option 3 once we
>>> have a strong use case for partial pages.
>>>
>>> What do you think?
>>>
>>
>> As you say, it's not clear that partial pages are really useful, but on
>> the other hand, it seems to me not clear that they are really useless.
>> I think we should get them as long as we have access to them.
>>
>> It seems best to me the option 3). Switching between read and mmap would
>> be not so complex and also it's by far flexible in makedumpfile than in
>> kernel.
>
> Ok, I am fine with option 3. It is more complicated option but safe
> option.

It sounds reasonable also to me.

> Is there any chance that you could look into fixing this. I have no
> experience writing code for makedumpfile.

I'll send a patch to fix this soon.


Thanks
Atsushi Kumagai


\
 
 \ /
  Last update: 2013-11-18 02:41    [W:2.679 / U:25.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site