Re: Hibernation considerations

[jimmy bahuleyan]

Al Boldi wrote:
> 
> This should be the responsibility of the kexec'd hibernating kernel.  Note 
> though in (6), the normal kernel takes care of preparing devices, then the 
> hibernating kernel dumps the image and either calls S4 or S3.  On resume 
> from S3 it can immediately switch over to the normal kernel, and from S4 the 
> known bootup would occur.
> 
>> (8) Hibernation and restore should not be too slow
>>
>>     In my opinion, if more than one minute is needed to hibernate the
>> system with the help of certain hibernation framework, then this framework
>> is not very useful in practice.  It might be useful to perform some
>> special tasks (eg. moving a server to another place without taking it
>> down), but it is not very useful, for example, to notebook users.
> 
> The latest hibernating kexec patches boot a kexec'd modular kernel with 
> initramfs into crashkernel=16M@16M in less than one second.  Switch-back is 
> almost instant.  Add to this the time required to either store or restore 
> the image, and it may be obvious that this approach isn't slower, but maybe 
> even faster than the current swsusp.
> 

What about (9)? Would it be that a user choosing to build a kernel with
hibernate support gets a additional modular kernel built (which he
should then use for resumption) or he should configure & build the
modular kernel independent of main kernel?

Or will the Linux boot procedure change so that it always goes thru a
modular part followed by kexec (just to be uniform)?

Although the kexec approach seems interesting, the final user-scenario
seems a bit complex (or confusing).

-jb
-- 
Tact is the art of making a point without making an enemy.
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