Messages in this thread | | | Date | Sat, 11 Jan 2014 22:15:21 +0100 | From | Pavel Machek <> | Subject | Re: No freezing of kernel threads (was: Re: [GIT PULL] libata fixes for v3.13-rc5) |
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Hi!
> > Well, it looks like we don't really know why things are done the way they > > are done at least in some cases, so in my personal view it would be good to > > go through all of the kernel freezer users just for this reason alone. We > > can't really say which of them are legitimate without that and how difficult > > it would be for them to switch over to using something more fine grained than > > the freezer. > > I'm a bit worried about things which may not be explicit. > ie. something which is broken but sorta working because things like > writeback and jbd are frozen. I think I worry about that because I > remember one argument for kernel freezer from way way back, that it's > too hard to implement proper suspend/resume for all drivers and by > freezing most kthreads things should mostly work, which sounded pretty > crazy to me even back then. Hopefully, we don't have much left > depending on such magic.
Careful there. Hibernation depends on data on disk not changing after freeze.
So you definitely do _not_ want writeback/jbd running while uswsusp does its image writing.
(I wonder what happens if uswsusp needs to trigger writeback to free memory. But I'm too scared to check :-). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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