On Fri, Sep 14, 2018 at 9:16 AM, Ray Strode <rstrode@xxxxxxxxxx> wrote: > Hi, > > On Fri, Sep 14, 2018 at 11:09 AM, Bastien Nocera <bnocera@xxxxxxxxxx> wrote: >>> The kernel shouldn't be exposing features it can't reliably provide. >>> Again, as I understand it, it's not even a hardware-supported situation, it >>> can >>> potentially fail on *any system* if the swap partition is filled up >>> the wrong way, >>> if i'm not mistaken. >> >> There's multiple levels of "support". The kernel doesn't know if it has enough >> swap, this is checked by user-space, systemd in this case. > But that's bonkers, there's no way systemd can know either. > The only way to make this reliable is if the kernel has a dedicated hibernate > partition the same size as ram that doesn't get used for anything but > hibernate, right? systemd knows what the kernel knows, cat /proc/meminfo - which includes what part of swap is used for swap, and what's needed for a hibernation image, and therefore if there's enough space on swap for both swap and hibernation to co-exist. I don't know if systemd uses any of the kernel test facilities in advance for things like whether all tasks are freezeable, whether any connected devices will prevent hibernation, and so on. The used to be some unused code in the installer, regarding partitioning for hibernation support, and I vaguely recall for most configurations it wanted double the amount of memory because it was conceivable the hibernation image would be the same size as RAM, and also it was desirable to fully utilize swap. Seems like that could be 1.25x RAM, expecting to swap out no more than 1/4, and possibly need a 1:1 RAM to hibernation image ratio. Anyway if you tell the kernel to hibernate, I think it tries to hibernate. Whereas systemd will advert to user space that hibernation isn't possible if it thinks it isn't possible, due to memory and swap space constraints. -- Chris Murphy _______________________________________________ desktop mailing list -- desktop@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to desktop-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/desktop@xxxxxxxxxxxxxxxxxxxxxxx
