From: Bhupesh Sharma <bhsharma@redhat.com>
To: Chen Zhou <chenzhou10@huawei.com>,
catalin.marinas@arm.com, will.deacon@arm.com,
akpm@linux-foundation.org, rppt@linux.ibm.com,
ard.biesheuvel@linaro.org, takahiro.akashi@linaro.org
Cc: linux-mm@kvack.org, wangkefeng.wang@huawei.com,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 0/3] support reserving crashkernel above 4G on arm64 kdump
Date: Tue, 9 Apr 2019 13:20:16 +0800 [thread overview]
Message-ID: <49012d55-2020-e2ac-1102-59a5f3911a29@redhat.com> (raw)
In-Reply-To: <20190403030546.23718-1-chenzhou10@huawei.com>
Hi Chen,
Thanks for the patchset.
Before I review the patches in detail, I have a couple of generic
queries. Please see them in-line:
On 04/03/2019 11:05 AM, Chen Zhou wrote:
> 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.
>
> 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]>.
>
> Besides, we need to modify kexec-tools:
> arm64: support more than one crash kernel regions
>
> Chen Zhou (3):
> arm64: kdump: support reserving crashkernel above 4G
> arm64: kdump: support more than one crash kernel regions
> kdump: update Documentation about crashkernel on arm64
>
> Documentation/admin-guide/kernel-parameters.txt | 4 +-
> arch/arm64/kernel/setup.c | 3 +
> arch/arm64/mm/init.c | 108 ++++++++++++++++++++----
> include/linux/memblock.h | 1 +
> mm/memblock.c | 40 +++++++++
> 5 files changed, 139 insertions(+), 17 deletions(-)
I am wondering about the use-case for the same. I remember normally
fedora-based arm64 systems can do well with a maximum crashkernel size
of <=512MB reserved below the 4G boundary.
So, do you mean that for your use-case (may be a huawei board based
setup?), you need:
- more than 512MB of crashkernel size, or
- you want to split the crashkernel reservation across the 4GB boundary
irrespective of the crashkernel size value.
Thanks,
Bhupesh
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next prev parent reply other threads:[~2019-04-09 5:20 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-03 3:05 [PATCH 0/3] support reserving crashkernel above 4G on arm64 kdump Chen Zhou
2019-04-03 3:05 ` [PATCH 1/3] arm64: kdump: support reserving crashkernel above 4G Chen Zhou
2019-04-04 14:46 ` Mike Rapoport
2019-04-05 3:03 ` Chen Zhou
2019-04-03 3:05 ` [PATCH 2/3] arm64: kdump: support more than one crash kernel regions Chen Zhou
2019-04-03 11:29 ` Mike Rapoport
2019-04-03 13:51 ` Chen Zhou
2019-04-04 14:44 ` Mike Rapoport
2019-04-05 2:17 ` Chen Zhou
2019-04-05 3:47 ` Chen Zhou
2019-04-08 6:57 ` Mike Rapoport
2019-04-08 8:39 ` Chen Zhou
2019-04-08 15:38 ` Chen Zhou
2019-04-03 3:05 ` [PATCH 3/3] kdump: update Documentation about crashkernel on arm64 Chen Zhou
2019-04-09 5:20 ` Bhupesh Sharma [this message]
2019-04-09 9:07 ` [PATCH 0/3] support reserving crashkernel above 4G on arm64 kdump Chen Zhou
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