https://bugzilla.kernel.org/show_bug.cgi?id=34102
--- Comment #10 from Martin Steigerwald Martin@Lichtvoll.de 2011-05-09 15:15:49 --- This wasn't a hang I think, see there.
I tried to hibernate two running KDE 4 sessions with reserved_size upto 64 MiB:
shambhala:/sys/power> cat reserved_size 67108864
Which failed with:
May 9 16:41:47 localhost kernel: PM: freeze of devices complete after 524.427 msecs May 9 16:41:47 localhost kernel: PM: late freeze of devices complete after 0.509 msecs May 9 16:41:47 localhost kernel: ACPI: Preparing to enter system sleep state S4 May 9 16:41:47 localhost kernel: PM: Saving platform NVS memory May 9 16:41:47 localhost kernel: Extended CMOS year: 2000 May 9 16:41:47 localhost kernel: PM: Creating hibernation image: May 9 16:41:47 localhost kernel: PM: Need to copy 218459 pages May 9 16:41:47 localhost kernel: PM: Normal pages needed: 113686 + 1024, available pages: 113492 May 9 16:41:47 localhost kernel: PM: Not enough free memory May 9 16:41:47 localhost kernel: PM: Error -12 creating hibernation image May 9 16:41:47 localhost kernel: Extended CMOS year: 2000 May 9 16:41:47 localhost kernel: ACPI: Waking up from system sleep state S4 May 9 16:41:47 localhost kernel: PM: early recover of devices complete after 0.366 msecs
Does it make sense to go to even higher values? I am a bit puzzled, since for one KDE 4 session a value of 2 MiB has turned out to be enough for about 5-10 attempts - it didn't fail once.
Maybe here there is simply not enough memory available no matter what I reserve for driver allocation? If so, then so be it. That might be just a limit for a 2 GB RAM machine.
Is there a way to tell for sure whether reserved size is too low or there are general memory constraints? TuxOnIce logged how much of the reserved extra pages it used. Can in-kernel-hibernation do this too?