From: Bhupesh Sharma <bhsharma@redhat.com>
To: Chen Zhou <chenzhou10@huawei.com>,
catalin.marinas@arm.com, will.deacon@arm.com,
akpm@linux-foundation.org, ard.biesheuvel@linaro.org,
rppt@linux.ibm.com, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, ebiederm@xmission.com
Cc: wangkefeng.wang@huawei.com, takahiro.akashi@linaro.org,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
horms@verge.net.au, Bhupesh SHARMA <bhupesh.linux@gmail.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 0/4] support reserving crashkernel above 4G on arm64 kdump
Date: Wed, 15 May 2019 10:36:24 +0530 [thread overview]
Message-ID: <a9d017d0-82d3-3e5f-4af2-4c611393106d@redhat.com> (raw)
In-Reply-To: <20190507035058.63992-1-chenzhou10@huawei.com>
+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@lists.infradead.org) 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@redhat.com>
Thanks,
Bhupesh
> 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(-)
>
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next prev parent reply other threads:[~2019-05-15 5:06 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-07 3:50 [PATCH 0/4] support reserving crashkernel above 4G on arm64 kdump Chen Zhou
2019-05-07 3:50 ` [PATCH 1/4] x86: kdump: move reserve_crashkernel_low() into kexec_core.c Chen Zhou
2019-06-05 16:29 ` James Morse
2019-06-13 11:26 ` Chen Zhou
2019-06-12 8:45 ` Dave Young
2019-06-13 11:27 ` Chen Zhou
2019-05-07 3:50 ` [PATCH 2/4] arm64: kdump: support reserving crashkernel above 4G Chen Zhou
2019-06-05 16:29 ` James Morse
2019-06-13 11:27 ` Chen Zhou
2019-06-13 12:44 ` James Morse
2019-05-07 3:50 ` [PATCH 3/4] memblock: extend memblock_cap_memory_range to multiple ranges Chen Zhou
2019-05-07 3:50 ` [PATCH 4/4] kdump: update Documentation about crashkernel on arm64 Chen Zhou
2019-05-15 5:16 ` Bhupesh Sharma
2019-05-16 3:23 ` Chen Zhou
2019-05-15 5:06 ` Bhupesh Sharma [this message]
2019-05-16 3:19 ` [PATCH 0/4] support reserving crashkernel above 4G on arm64 kdump Chen Zhou
2019-06-03 2:24 ` Chen Zhou
2019-06-05 16:32 ` James Morse
2019-06-13 11:27 ` Chen Zhou
2019-06-13 12:43 ` James Morse
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