Messages in this thread | | | Date | Thu, 26 Jun 2008 17:09:10 +0200 | From | Pavel Machek <> | Subject | Re: freeze vs freezer |
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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@nebensachen.de> 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
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