Messages in this thread | | | Date | Fri, 21 Sep 2007 18:13:40 +0300 | From | Mika Penttilä <> | Subject | Re: [linux-pm] [RFC][PATCH 0/2 -mm] kexec based hibernation -v3 |
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huang ying wrote: > On 9/21/07, Mika Penttilä <mika.penttila@kolumbus.fi> wrote: > >> huang ying wrote: >> >>> On 9/21/07, Mika Penttilä <mika.penttila@kolumbus.fi> wrote: >>> >>> >>>>> Usage: >>>>> >>>>> 1. Compile kernel with following options selected: >>>>> >>>>> CONFIG_X86_32=y >>>>> CONFIG_RELOCATABLE=y # not needed strictly, but it is more convenient with it >>>>> CONFIG_KEXEC=y >>>>> CONFIG_CRASH_DUMP=y # only needed by kexeced kernel to save/restore memory image >>>>> CONFIG_PM=y >>>>> CONFIG_KEXEC_JUMP=y >>>>> >>>>> 2. Download the kexec-tools-testing git tree, apply the kexec-tools >>>>> kjump patches (or download the source tar ball directly) and >>>>> compile. >>>>> >>>>> 3. Download and compile the krestore tool. >>>>> >>>>> 4. Prepare 2 root partition used by kernel A and kernel B/C, referred >>>>> as /dev/hda, /dev/hdb in following text. This is not strictly >>>>> necessary, I use this scheme for testing during development. >>>>> >>>>> 5. Boot kernel compiled for normal usage (kernal A). >>>>> >>>>> 6. Load kernel compiled for hibernating/restore usage (kernel B) with >>>>> kexec, the same kernel as that of 5 can be used if >>>>> CONFIG_RELOCATABLE=y and CONFIG_CRASH_DUMP=y are selected. >>>>> >>>>> The --elf64-core-headers should be specified in command line of >>>>> kexec, because only the 64bit ELF is supported by krestore tool. >>>>> >>>>> For example, the shell command line can be as follow: >>>>> >>>>> kexec -p -n /boot/bzImage --mem-min=0x100000 --mem-max=0xffffff >>>>> --elf64-core-headers --append="root=/dev/hdb single" >>>>> >>>>> 7. Jump to the hibernating kernel (kernel B) with following shell >>>>> command line: >>>>> >>>>> kexec -j >>>>> >>>>> 8. In the hibernating kernel (kernel B), the memory image of >>>>> hibernated kernel (kernel A) can be saved as follow: >>>>> >>>>> cp /proc/vmcore . >>>>> cp /sys/kernel/kexec_jump_back_entry . >>>>> >>>>> >>>>> >>>> Here we save also kernel B's pages. >>>> >>>> >>> No, the kernel B's pages will not be saved. Because when we build the >>> elfcore (/proc/vmcore) header, we exclude memory area used by kernel >>> B. The details can be found in kexec-tools patches. >>> >>> >>> >> Ok I see. But should the kernel B's e820 mem map be limited to 1m-16m in >> order not to allocate pages found also in A's space? Or does does the >> --mem-min and --mem-max do that also? >> > > That is what "memmap=exactmap memmap=640K@0K memmap=15M@1M" for. The > contents of e820 memmap will be overrided when these kernel parameters > are specified. > > Best Regards, > Huang Ying > Yes, you just didn't specify exactmap for kernel B in your instructions, but only for C. But it is also required for kernel B then?
Thanks, Mika
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