Date: Tue, 25 Jan 2005 19:07:21 -0200 From: =?ISO-8859-1?Q?Jo=E3o_Carlos_Mendes_Lu=EDs?= <jonny@jonny.eng.br> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Dominic Marks <dom@helenmarks.co.uk> Subject: Re: Resuming from a crashdump Message-ID: <41F6B509.2080101@jonny.eng.br> In-Reply-To: <200501251948.j0PJmpYG048845@apollo.backplane.com> References: <86pszu639o.fsf@borg.borderworlds.dk> <86brbe6052.fsf@borg.borderworlds.dk> <Pine.BSI.4.58L.0501241423530.27294@vp4.netgate.net> <200501242240.j0OMeIXP043763@apollo.backplane.com> <41F59242.7090900@jonny.eng.br> <200501251948.j0PJmpYG048845@apollo.backplane.com>
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Matthew Dillon wrote:
> Well, I don't want do disuade you from trying, but I think you are
> seriously underestimating the effort required to restore device state.
>
> You basically would either have to make all device drivers support a new
> hibernation/restore API (because it is not really possible to restore
Shouldn't it be very similar to the suspend API?
> a device driver based on a dump), or you would need to implement some
> higher level utility code (e.g. scripts and such) to try to record and
> restore the state at a higher level, such as for network interfaces,
> and not allow any restored processes to run until that's done. Either
> way it would get messy very quickly.
>
> Also, if the machine has a lot of memory it could take longer to save
> and restore then to reboot from scratch. A typical laptop HD is
Indeed true, but when I use windows hibernate I don't intend to
simply bypass boot procedures, I want to keep the workspace active. If
the workspace is not important, I simply shutdown, as it is also a
profilatic memory cleaning. ;-)
> I think it would probably be more realistic to persue a process
> save/restore rather then a kernel save/restore. The overhead is going
> to be the disk I/O anyway and that seems to be about the same either
> way (maybe less for a process restore), plus you can at least demand-load
> the process restore.
Let's suppose I want to keep my X desktop intact. Should I
save/restore processes in which order? X server or X clients? They
need to interact with each other, and if one try to interact while the
other has already "died", it will simply close and die too. That's why
I think a kernel save/restore is better for a full hibernation
situation. Of course single process hibernation is also useful! I am a
very old user, from the times where LaTeX had to core dump after
initializing variables to startup faster later. ;-)
Jonny
--
João Carlos Mendes Luís - Networking Engineer - jonny@jonny.eng.br
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