Hi Pavel, On Tue, Jul 16, 2019 at 10:26 PM Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> wrote: > > Added identity mapped page table, and keep MMU enabled while > kernel is being relocated from sparse pages to the final > destination during kexec. > > More description about the problem I am trying to solve here, can be > found here: > https://lore.kernel.org/lkml/20190709182014.16052-1-pasha.tatashin@xxxxxxxxxx/ > > This patch series works in terms, that I can kexec-reboot both in QEMU > and on a physical machine. However, I do not see performance improvement > during relocation. The performance is just as slow as before with disabled > caches. Thanks for the patchset, but if the changes still don't positively impact the kexec-reboot timings, I am not sure we if gain by adding these to the kernel. Like I mentioned in the previous threads, we have been carrying some relevant fixes for the same in Linux distros. I have been trying to find time to fix them and send them upstream, but I am caught up with some nasty kexec_file_load() issues on arm64 currently. So, I will find some time to work on them (may be next week) and will Cc you when I post them out after some checks on real physical hardware. Thanks, Bhupesh > Am I missing something? Perhaps, there is some flag that I should also > enable in page table? Please provide me with any suggestions. > > Pavel Tatashin (4): > arm64, mm: identity mapped page table > arm64, kexec: interface preparation for mmu enabled kexec > arm64, kexec: add kexec's own identity page table > arm64: Keep MMU on while kernel is being relocated > > arch/arm64/include/asm/ident_map.h | 26 ++++++ > arch/arm64/include/asm/kexec.h | 5 +- > arch/arm64/kernel/cpu-reset.S | 8 -- > arch/arm64/kernel/cpu-reset.h | 7 +- > arch/arm64/kernel/machine_kexec.c | 128 +++++++++++++++++++++------- > arch/arm64/kernel/relocate_kernel.S | 36 +++++--- > arch/arm64/mm/Makefile | 1 + > arch/arm64/mm/ident_map.c | 99 +++++++++++++++++++++ > 8 files changed, 255 insertions(+), 55 deletions(-) > create mode 100644 arch/arm64/include/asm/ident_map.h > create mode 100644 arch/arm64/mm/ident_map.c > > -- > 2.22.0 > > > _______________________________________________ > kexec mailing list > kexec@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/kexec
