Huang, Ying wrote: > > Hibernating process: > > 1. Normal kernel running > 2. Hibernating is triggered, sys_kexec_load is used to load > hibernating kernel and initramfs into memory. Then > sys_reboot(LINUX_REBOOT_CMD_KSPAWN) is invoked. > 3. In sys_reboot, kexec_jump is called to save device/CPU state, > then relocate_kernel is called. kexec_jump and relocate_kernel > reside in individual page in 16M~512M. > 4. In relocate_kernel, 0~16M is backupped firstly, then the > hibernating kernel and initramfs is copied to 0~16M, after that, > the hibernating kernel is booted. > 5. In hibernating kernel, the memory of normal kernel (it is in > 16M~512M) is saved into a hibernation image through /dev/mem > and ELF header. > > > Resume process: > > 1. Resuming kernel is booted as a normal kernel, but the memory is > restricted to 0~16M. > 2. Checking whether there is a effective hibernation image. If > there isn't, the memory of 16M~512M is hot added, and the normal > boot up process continues; If there is, a resuming process is > triggered. > 3. sys_kexec_load is used to restore the memory state of hibernated > kernel. The sys_kexec_load works in crashdump way, that is, the > hibernation image is copied to destination location in 16M~512M > in sys_kexec_load instead of relocate_kernel. There is no half > of memory size restriction. > 4. sys_reboot is called to trigger jumping back, which will jump back > to kexec_jump of hibernated kernel. > 5. In kexec_jump of hibernated kernel, the memory of 0~16M is copied > back from the backup area in 16M~512M. The memory state of > hibernated kernel is restored totally. The CPU and device state > can be restored after that. > > > If there is too much difficulty to hot add memory in step 2. A more > conservative method can be used as step 1 and step 2. > > 1. A normal kernel is booted. > 2. Checking whether there is a effective hibernation image. If there > isn't, continue the normal boot process; otherwise, a resuming > kernel is kexeced in memory 0~16M. The resuming process will > continue in kexeced resuming kernel.
During Resume no kexec'ing is necessary; the normal kernel should be able to read the hibernation image via the /dev/snapshot interface. Thanks! -- Al - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
