Hi Pavel, On Tue, Jul 9, 2019 at 2:46 AM Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> wrote: > > Currently, it is only allowed to reserve memory for crash kernel, because > it is a requirement in order to be able to boot into crash kernel without > touching memory of crashed kernel is to have memory reserved. > > The second benefit for having memory reserved for kexec kernel is > that it does not require a relocation after segments are loaded into > memory. > > If kexec functionality is used for a fast system update, with a minimal > downtime, the relocation of kernel + initramfs might take a significant > portion of reboot. > > In fact, on the machine that we are using, that has ARM64 processor > it takes 0.35s to relocate during kexec, thus taking 52% of kernel reboot > time: > > kernel shutdown 0.03s > relocation 0.35s > kernel startup 0.29s > > Image: 13M and initramfs is 24M. If initramfs increases, the relocation > time increases proportionally. > > While, it is possible to add 'kexeckernel=' parameters support to other > architectures by modifying reserve_crashkernel(), in this series this is > done for arm64 only. > > Pavel Tatashin (5): > kexec: quiet down kexec reboot > kexec: add resource for normal kexec region > kexec: export common crashkernel/kexeckernel parser > kexec: use reserved memory for normal kexec reboot > arm64, kexec: reserve kexeckernel region > > .../admin-guide/kernel-parameters.txt | 7 ++ > arch/arm64/kernel/setup.c | 5 ++ > arch/arm64/mm/init.c | 83 ++++++++++++------- > include/linux/crash_core.h | 6 ++ > include/linux/ioport.h | 1 + > include/linux/kexec.h | 6 +- > kernel/crash_core.c | 27 +++--- > kernel/kexec_core.c | 50 +++++++---- > 8 files changed, 127 insertions(+), 58 deletions(-) > > -- > 2.22.0 This seems like an issue with time spent while doing sha256 verification while in purgatory. Can you please try the following two patches which enable D-cache in purgatory before SHA verification and disable it before switching to kernel: http://lists.infradead.org/pipermail/kexec/2017-May/018839.html http://lists.infradead.org/pipermail/kexec/2017-May/018840.html Note that these were not accepted upstream but are included in several distros in some form or the other :) Thanks, Bhupesh
