lkml.org 
[lkml]   [2015]   [Sep]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCH] [v4] PM / hibernate: Fix hibernation panic caused by inconsistent e820 map
Date

Hi, Pavel,

> -----Original Message-----
> From: Pavel Machek [mailto:pavel@ucw.cz]
> Sent: Friday, September 18, 2015 1:47 PM
> To: Chen, Yu C
> Cc: rjw@rjwysocki.net; Brown, Len; linux-pm@vger.kernel.org; linux-
> kernel@vger.kernel.org; Zhang, Rui; jlee@suse.com;
> joeyli.kernel@gmail.com; yinghai@kernel.org; Ingo Molnar
> Subject: Re: [PATCH] [v4] PM / hibernate: Fix hibernation panic caused by
> inconsistent e820 map
>
> > > 3) I'm not sure I understand the changelog correctly. What happens
> > > when BIOS reports less memory on hibernation? Will you magically
> > > remove memory from kernel at runtime? Will /proc/meminfo be invalid
> after resume?
> > > Will all the memory management tuning need fixing?
> > >
> > Oh, I did not notice it before. So deleting the logic of '
> > info->num_physpages != get_num_physpages()' is not suitable.
> > The subset relationship should not be considered in this patch.
>
> Ok. So... if you really want, you can add some messages like "hey, this is bios
> bug, maybe updating bios is a good idea".. but please lets keep the original
> logic.
>
OK. I see, I'll not change its original code.
So can I add a function here that checks if current BIOS e820 map is
strictly the same as it was before S4? If it is not the same, we will print some warnnings
, and if we panic later, we will print that , the panic reason might be due to broken BIOS.
I think I can archive this by putting the e820_saved array into struct swsusp_info,
and pass it to second kernel:
struct swsusp_info will always occupy one page size, and has a lot of extra space left,
meanwhile the total size of e820 map will not exceed the PAGE_SIZE currently, it's safe
to put it in struct swsusp_info.

And this does not need much changing of current code. What do you think? Thanks.

Best Regards,
Yu





\
 
 \ /
  Last update: 2015-09-18 08:21    [W:0.756 / U:0.104 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site