From: Baoquan He <bhe@redhat.com>
To: Chen Zhou <chenzhou10@huawei.com>
Cc: mingo@redhat.com, tglx@linutronix.de, rppt@kernel.org,
dyoung@redhat.com, catalin.marinas@arm.com, will@kernel.org,
nsaenzjulienne@suse.de, corbet@lwn.net,
John.P.donnelly@oracle.com, prabhakar.pkin@gmail.com,
horms@verge.net.au, robh+dt@kernel.org, arnd@arndb.de,
james.morse@arm.com, xiexiuqi@huawei.com, guohanjun@huawei.com,
huawei.libin@huawei.com, wangkefeng.wang@huawei.com,
linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kexec@lists.infradead.org
Subject: Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
Date: Thu, 18 Feb 2021 16:40:06 +0800 [thread overview]
Message-ID: <20210218083822.GL2871@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20210130071025.65258-12-chenzhou10@huawei.com>
On 01/30/21 at 03:10pm, Chen Zhou wrote:
> For arm64, the behavior of crashkernel=X has been changed, which
> tries low allocation in DMA zone and fall back to high allocation
> if it fails.
>
> We can also use "crashkernel=X,high" to select a high region above
> DMA zone, which also tries to allocate at least 256M low memory in
> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
> specified size low memory.
>
> So update the Documentation.
Nice document adding which also takes care of x86 code implementation,
thanks. By the way, maybe you can remove John's 'Tested-by' since it
doesn't make much sense to test a document patch.
Acked-by: Baoquan He <bhe@redhat.com>
>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
> Documentation/admin-guide/kdump/kdump.rst | 22 ++++++++++++++++---
> .../admin-guide/kernel-parameters.txt | 11 ++++++++--
> 2 files changed, 28 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
> index 75a9dd98e76e..0877c76f8015 100644
> --- a/Documentation/admin-guide/kdump/kdump.rst
> +++ b/Documentation/admin-guide/kdump/kdump.rst
> @@ -299,7 +299,16 @@ Boot into System Kernel
> "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
> starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>
> - On x86 and x86_64, use "crashkernel=64M@16M".
> + On x86 use "crashkernel=64M@16M".
> +
> + On x86_64, use "crashkernel=X" to select a region under 4G first, and
> + fall back to reserve region above 4G. And go for high allocation
> + directly if the required size is too large.
> + We can also use "crashkernel=X,high" to select a region above 4G, which
> + also tries to allocate at least 256M below 4G automatically and
> + "crashkernel=Y,low" can be used to allocate specified size low memory.
> + Use "crashkernel=Y@X" if you really have to reserve memory from specified
> + start address X.
>
> On ppc64, use "crashkernel=128M@32M".
>
> @@ -316,8 +325,15 @@ Boot into System Kernel
> kernel will automatically locate the crash kernel image within the
> first 512MB of RAM if X is not given.
>
> - On arm64, use "crashkernel=Y[@X]". Note that the start address of
> - the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
> + On arm64, use "crashkernel=X" to try low allocation in DMA zone and
> + fall back to high allocation if it fails.
> + We can also use "crashkernel=X,high" to select a high region above
> + DMA zone, which also tries to allocate at least 256M low memory in
> + DMA zone automatically.
> + "crashkernel=Y,low" can be used to allocate specified size low memory.
> + Use "crashkernel=Y@X" if you really have to reserve memory from
> + specified start address X. Note that the start address of the kernel,
> + X if explicitly specified, must be aligned to 2MiB (0x200000).
>
> Load the Dump-capture Kernel
> ============================
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a10b545c2070..908e5c8b61ba 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -738,6 +738,9 @@
> [KNL, X86-64] Select a region under 4G first, and
> fall back to reserve region above 4G when '@offset'
> hasn't been specified.
> + [KNL, arm64] Try low allocation in DMA zone and fall back
> + to high allocation if it fails when '@offset' hasn't been
> + specified.
> See Documentation/admin-guide/kdump/kdump.rst for further details.
>
> crashkernel=range1:size1[,range2:size2,...][@offset]
> @@ -754,6 +757,8 @@
> Otherwise memory region will be allocated below 4G, if
> available.
> It will be ignored if crashkernel=X is specified.
> + [KNL, arm64] range in high memory.
> + Allow kernel to allocate physical memory region from top.
> crashkernel=size[KMG],low
> [KNL, X86-64] range under 4G. When crashkernel=X,high
> is passed, kernel could allocate physical memory region
> @@ -762,13 +767,15 @@
> requires at least 64M+32K low memory, also enough extra
> low memory is needed to make sure DMA buffers for 32-bit
> devices won't run out. Kernel would try to allocate at
> - at least 256M below 4G automatically.
> + least 256M below 4G automatically.
> This one let user to specify own low range under 4G
> for second kernel instead.
> 0: to disable low allocation.
> It will be ignored when crashkernel=X,high is not used
> or memory reserved is below 4G.
> -
> + [KNL, arm64] range in low memory.
> + This one let user to specify a low range in DMA zone for
> + crash dump kernel.
> cryptomgr.notests
> [KNL] Disable crypto self-tests
>
> --
> 2.20.1
>
next prev parent reply other threads:[~2021-02-18 10:22 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-30 7:10 [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump Chen Zhou
2021-01-30 7:10 ` [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN Chen Zhou
2021-02-18 3:29 ` Baoquan He
2021-02-24 14:19 ` Catalin Marinas
2021-02-25 7:25 ` Baoquan He
2021-02-26 6:45 ` chenzhou
2021-02-26 15:38 ` Eric W. Biederman
2021-03-02 7:43 ` Baoquan He
2021-03-29 2:34 ` chenzhou
2021-01-30 7:10 ` [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent Chen Zhou
2021-02-18 3:33 ` Baoquan He
2021-02-24 14:35 ` Catalin Marinas
2021-02-25 7:08 ` Baoquan He
2021-02-25 14:42 ` Catalin Marinas
2021-02-25 15:44 ` Baoquan He
2021-02-26 7:32 ` chenzhou
2021-01-30 7:10 ` [PATCH v14 03/11] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel() Chen Zhou
2021-02-18 8:23 ` Baoquan He
2021-01-30 7:10 ` [PATCH v14 04/11] x86: kdump: move xen_pv_domain() check and insert_resource() to setup_arch() Chen Zhou
2021-02-18 4:14 ` Baoquan He
2021-01-30 7:10 ` [PATCH v14 05/11] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c Chen Zhou
2021-01-30 7:10 ` [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h Chen Zhou
2021-02-18 6:31 ` Baoquan He
2021-02-18 7:05 ` chenzhou
2021-01-30 7:10 ` [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation Chen Zhou
2021-02-04 16:20 ` Nicolas Saenz Julienne
2021-02-04 16:27 ` Nicolas Saenz Julienne
2021-01-30 7:10 ` [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X Chen Zhou
2021-02-24 16:04 ` Catalin Marinas
2021-02-26 10:31 ` chenzhou
2021-02-26 10:43 ` chenzhou
2021-01-30 7:10 ` [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config Chen Zhou
2021-02-18 7:31 ` Baoquan He
2021-02-18 7:40 ` Baoquan He
2021-02-18 8:35 ` Baoquan He
2021-02-20 3:22 ` chenzhou
2021-01-30 7:10 ` [PATCH v14 10/11] arm64: kdump: add memory for devices by DT property linux,usable-memory-range Chen Zhou
2021-01-30 7:10 ` [PATCH v14 11/11] kdump: update Documentation about crashkernel Chen Zhou
2021-01-30 17:53 ` Randy Dunlap
2021-02-04 1:53 ` chenzhou
2021-02-18 8:40 ` Baoquan He [this message]
2021-02-20 3:25 ` chenzhou
2021-02-08 6:46 ` [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump chenzhou
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