On Sun, 6 May 2007, Rafael J. Wysocki wrote: > > > I think we may need yet another callback, executed before pre_snapshot() > > > and before we shrink memory during the hibernation, to be used by drivers > > > that need a lot of additional memory in pre_snapshot(). > > > > pre_snapshot_early() > > OK I changed my mind -- pre_hibernate() seems like a better name. There could be a matching post_hibernate(), if anyone finds it necessary. I considered pre_freeze(), but that's not such a good choice since the freezer can be used for other things in addition to hibernation. > So, I think the hibernation code ordering should be like this (let's forget > about ACPI for now): > > 1) tasks are frozen > 2) pre_snapshot_early() Or rather: 2) pre_hibernate() > 3) memory is freed for the snapshot image > 4) pre_snapshod() > 5) nonboot CPUs are offlined > 6) IRQs are disabled > 7) pre_snapshot_late() > 8) sysdev_pre_snapshot() > 9) snapshot image is created > 10) sysdev_post_snapshot() > 11) post_snapshot_early() > 12) IRQs are enabled > 13) nonboot CPUs are enabled > 14) post_snapshot() > 15) snapshot image is saved > 16) device_shutdown() > 17) system is powered off > > Apart from this, we may need notifiers for subsystems that should do something > before the freezing and after the thawing of tasks (like FUSE etc.). Quite so. > Also, if there's an error, we have to be able to thaw tasks after > post_snapshot() and continue running. > > The restore code, IMO, should be like this (again, let's ignore ACPI for now): > > 1) boot kernel is started, initrd is loaded etc. > 2) tasks are frozen > 3) snapshot image is loaded > 4) pre_restore() > 5) nonboot CPUs are offlined > 6) IRQs are disabled > 7) pre_restore_late() > 8) sysdev_pre_restore() > 9) boot kernel is replaced with the 'hibernated' kernel > 10) sysdev_post_restore() > 11) post_restore_early() > 12) IRQs are enabled > 13) nonboot CPUs are enabled > 14) post_restore() > 15) tasks are thawed > 16) system is running > > and we may need a notifier for subsystems that should do something after > tasks have been thawed. It sounds good to me. Now if only it were possible to get rid of those pesky sysdevs... Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
