On Sunday, February 10, 2013 07:55:05 PM Pavel Machek wrote: > Hi! > > > > > > The whole memory shrinking we do for hibernation is now done by > > > > > allocating > > > > > memory, so the freezer is not necessary for *that* and there's *zero* > > > > > difference between suspend and hibernation with respect to why the > > > > > freezer is > > > > > used. > > > > > > > > Funny. Freezer was put there so that hibernation image was safe to > > > > write out. You need disk subsystems in workable state for hibernation. > > > > > > I'm not really sure what you're talking about. Why do you think the > > > freezer is > > > necessary for that? > > Well, from freezer you need: > > 1) user process frozen. > > 2) essential locks _not_ held so that block devices are still functional. > > > > > mmap... what is problem with mmap? For suspend, memory is powered, so > > > > you can permit people changing it. > > > > > > Suppose mmap is used to make the registers of some device available to > > > user > > > space. Yes, that can happen. > > "Don't do it, then". Yes, can happen, but hopefully is not too common > these days. [And... freezer doing 1) but not 2) would be enough to > handle that. Freezer doing 1) but not 2) would also be simpler...]
Again, I'm not sure what you mean. Are you trying to say that it would be OK to freeze user space tasks in the D state? Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
