On Dec 7, 2007 8:52 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Friday, 7 of December 2007, Huang, Ying wrote: > > This patch implements kexec based hibernate/resume. This is based on > > the facility provided by kexec_jump. The states save/restore code of > > ordinary kexec_jump is overridden by hibernate/resume specific > > code. > > Can you explain in more details how this works? Two blocking notifier chain named kjump_chain_pre and kjump_chain_post are defined, the basic procedure of kexec jump is as follow: call functions in kjump_chain_pre jump to peer kernel call functions in kjump_chain_post A command is the first parameter of functions in chain. If A command is processed in a function, the function will execute and stop the chain (return NOTIFY_STOP), otherwise it will do nothing (return NOTIFY_DONE). If no function has interest in the command, the default behavior will be executed (kexec_vcall_pre, kexec_vcall_post). So for each command the procedure is as follow: KJUMP_CMD_HIBERNATE_WRITE_IMAGE: [chain] kexec_snapshot jump to kexeced kernel [chain] kexec_prepare_write_image /* in kexeced kernel */ KJUMP_HIBERNATE_RESUME: [chain] kexec_prepare_resume /* in kexeced kernel */ jump to kexec kernel [chain] kexec_resume > > The ACPI methods are called at specified environment to conform > > the ACPI specification. A new reboot command is added to go to ACPI S4 > > state from user space. > > Well, I still don't like the amount of duplicated code introduced by this patch. Yes, there are too many duplicated code. They should be merged. But I want to delay the merging until the kexec based hibernation code goes more stable. > Also, IMO it should be using the mutual exclusion mechanisms used by the > existing hibernation code, ie. pm_mutex and the snapshot_device_available > atomic variable. Now the kexec_lock is used as a mutex between kexec related operations. It seems reasonable to use pm_mutex and maybe snapshot_device_available to eliminate potential conflict between kexec based hibernation and u/swsusp. Best Regards, Huang Ying _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
