Hi!
> >> Patch would be welcome, actually. It turns out blocking new
> >> IO-requests is not completely trivial.
>
> Quite. But I'm not sure I see what this is all about yet. From the IDE
> and SCSI subsystems I remember that they block all I/O from higher levels
> once the suspend callbacks have been executed. I haven't made an effort
> to understand the freezer (or indeed anything related to hibernation)
> yet since I don't even use hibernation myself (only s2ram). Do you have
s2ram also uses freezer these days. Difference is s2ram does not
really need it.
> any suggestion where to start reading up on things so I can get an idea
> what the issues are and what you would like IDE / SCSI / ... to do?
I'd like block layer to block any process that tries to do I/O.
> > Is this the same thing the per-device IO-queue-freeze patches for
> >HDAPS also
> > need to do? If so, you may want to talk to Elias Oltmanns
> > <eo@xxxxxxxxxxxxxx> about it. Added to CC.
>
> Thanks for the heads up Henrique. Even though these issues seem to be
> related up to a certain degree, there probably are some important
> differences. When suspending a system, the emphasis is on leaving the
> system in a consistent state (think of journalled file systems), whereas
> disk shock protection is mainly concerned with stopping I/O as soon as
> possible. As yet, I cannot possibly say to what extend these two
> concepts can be reconciled in the sense of sharing some common code.
Actually, I believe requirements are same.
'don't do i/o in dangerous period'.
swsusp will just do sync() before entering dangerous period. That
provides consistent-enough state...
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
|