Hi Bhupesh, On 2019/5/15 13:06, Bhupesh Sharma wrote: > +Cc kexec-list. > > Hi Chen, > > I think we are still in the quiet period of the merge cycle, but this is a change which will be useful for systems like HPE Apollo where we are looking at reserving crashkernel across a larger range. > > Some comments inline and in respective patch threads.. > > On 05/07/2019 09:20 AM, Chen Zhou wrote: >> This patch series enable reserving crashkernel on high memory in arm64. > > Please fix the patch subject, it should be v5. > Also please Cc the kexec-list (kexec@xxxxxxxxxxxxxxxxxxx) for future versions to allow wider review of the patchset. > >> We use crashkernel=X to reserve crashkernel below 4G, which will fail >> when there is no enough memory. Currently, crashkernel=Y@X can be used >> to reserve crashkernel above 4G, in this case, if swiotlb or DMA buffers >> are requierd, capture kernel will boot failure because of no low memory. > > ... ^^ required > > s/capture kernel will boot failure because of no low memory./capture kernel boot will fail because there is no low memory available for allocation. > >> When crashkernel is reserved above 4G in memory, kernel should reserve >> some amount of low memory for swiotlb and some DMA buffers. So there may >> be two crash kernel regions, one is below 4G, the other is above 4G. Then >> Crash dump kernel reads more than one crash kernel regions via a dtb >> property under node /chosen, >> linux,usable-memory-range = <BASE1 SIZE1 [BASE2 SIZE2]>. > > Please use consistent naming for the second kernel, better to use crash dump kernel. > > I have tested this on my HPE Apollo machine and with crashkernel=886M,high syntax, I can get the board to reserve a larger memory range for the crashkernel (i.e. 886M): > > # dmesg | grep -i crash > [ 0.000000] kexec_core: Reserving 256MB of low memory at 3560MB for crashkernel (System low RAM: 2029MB) > [ 0.000000] crashkernel reserved: 0x0000000bc5a00000 - 0x0000000bfd000000 (886 MB) > > kexec/kdump can also work also work fine on the board. > > So, with the changes suggested in this cover letter and individual patches, please feel free to add: > > Reviewed-and-Tested-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx> > > Thanks, > Bhupesh > Thanks for you review and test. I will fix these later. Thanks, Chen Zhou >> Besides, we need to modify kexec-tools: >> arm64: support more than one crash kernel regions(see [1]) >> >> I post this patch series about one month ago. The previous changes and >> discussions can be retrived from: >> >> Changes since [v4] >> - reimplement memblock_cap_memory_ranges for multiple ranges by Mike. >> >> Changes since [v3] >> - Add memblock_cap_memory_ranges back for multiple ranges. >> - Fix some compiling warnings. >> >> Changes since [v2] >> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as >> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate >> patch. >> >> Changes since [v1]: >> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c. >> - Remove memblock_cap_memory_ranges() i added in v1 and implement that >> in fdt_enforce_memory_region(). >> There are at most two crash kernel regions, for two crash kernel regions >> case, we cap the memory range [min(regs[*].start), max(regs[*].end)] >> and then remove the memory range in the middle. >> >> [1]: http://lists.infradead.org/pipermail/kexec/2019-April/022792.html >> [v1]: https://lkml.org/lkml/2019/4/2/1174 >> [v2]: https://lkml.org/lkml/2019/4/9/86 >> [v3]: https://lkml.org/lkml/2019/4/9/306 >> [v4]: https://lkml.org/lkml/2019/4/15/273 >> >> Chen Zhou (3): >> x86: kdump: move reserve_crashkernel_low() into kexec_core.c >> arm64: kdump: support reserving crashkernel above 4G >> kdump: update Documentation about crashkernel on arm64 >> >> Mike Rapoport (1): >> memblock: extend memblock_cap_memory_range to multiple ranges >> >> Documentation/admin-guide/kernel-parameters.txt | 6 +-- >> arch/arm64/include/asm/kexec.h | 3 ++ >> arch/arm64/kernel/setup.c | 3 ++ >> arch/arm64/mm/init.c | 72 +++++++++++++++++++------ >> arch/x86/include/asm/kexec.h | 3 ++ >> arch/x86/kernel/setup.c | 66 +++-------------------- >> include/linux/kexec.h | 5 ++ >> include/linux/memblock.h | 2 +- >> kernel/kexec_core.c | 56 +++++++++++++++++++ >> mm/memblock.c | 44 +++++++-------- >> 10 files changed, 157 insertions(+), 103 deletions(-) >> > > > . > _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
