From: Zhen Lei <thunder.leizhen@huawei.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
<x86@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
<linux-kernel@vger.kernel.org>, Dave Young <dyoung@redhat.com>,
Baoquan He <bhe@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
<kexec@lists.infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
"Will Deacon" <will@kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
<devicetree@vger.kernel.org>, Jonathan Corbet <corbet@lwn.net>,
<linux-doc@vger.kernel.org>
Cc: Zhen Lei <thunder.leizhen@huawei.com>,
Randy Dunlap <rdunlap@infradead.org>,
Feng Zhou <zhoufeng.zf@bytedance.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Chen Zhou <dingguo.cz@antgroup.com>,
"John Donnelly" <John.p.donnelly@oracle.com>
Subject: [PATCH v19 13/13] kdump: update Documentation about crashkernel
Date: Tue, 28 Dec 2021 21:26:12 +0800 [thread overview]
Message-ID: <20211228132612.1860-14-thunder.leizhen@huawei.com> (raw)
In-Reply-To: <20211228132612.1860-1-thunder.leizhen@huawei.com>
From: Chen Zhou <chenzhou10@huawei.com>
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.
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
Documentation/admin-guide/kdump/kdump.rst | 11 +++++++++--
Documentation/admin-guide/kernel-parameters.txt | 11 +++++++++--
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
index cb30ca3df27c9b2..d4c287044be0c70 100644
--- a/Documentation/admin-guide/kdump/kdump.rst
+++ b/Documentation/admin-guide/kdump/kdump.rst
@@ -361,8 +361,15 @@ 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 fc34332c8d9a6df..5fafeea70f8f14d 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -783,6 +783,9 @@
[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]
@@ -799,6 +802,8 @@
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
@@ -807,13 +812,15 @@
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
--
2.25.1
prev parent reply other threads:[~2021-12-28 13:29 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-28 13:25 [PATCH v19 00/13] support reserving crashkernel above 4G on arm64 kdump Zhen Lei
2021-12-28 13:26 ` [PATCH v19 01/13] kdump: add helper parse_crashkernel_high_low() Zhen Lei
2021-12-30 10:14 ` Leizhen (ThunderTown)
2021-12-30 10:40 ` Borislav Petkov
2021-12-30 11:08 ` Leizhen (ThunderTown)
2021-12-31 9:22 ` Leizhen (ThunderTown)
2021-12-31 12:29 ` Leizhen (ThunderTown)
2022-01-11 15:03 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 02/13] x86/setup: Use parse_crashkernel_high_low() to simplify code Zhen Lei
2021-12-28 16:13 ` Borislav Petkov
2021-12-29 2:27 ` Leizhen (ThunderTown)
2021-12-29 7:27 ` Dave Young
2021-12-29 7:45 ` Dave Young
2021-12-29 10:11 ` Borislav Petkov
2021-12-29 10:38 ` Dave Young
2021-12-29 11:11 ` Borislav Petkov
2021-12-29 14:13 ` Leizhen (ThunderTown)
2021-12-29 10:03 ` Borislav Petkov
2021-12-29 10:46 ` Dave Young
2021-12-29 15:04 ` Leizhen (ThunderTown)
2021-12-29 16:51 ` Borislav Petkov
2021-12-30 2:39 ` Leizhen (ThunderTown)
2021-12-30 8:56 ` Leizhen (ThunderTown)
2021-12-29 12:19 ` Leizhen (ThunderTown)
2022-01-11 15:04 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 03/13] kdump: make parse_crashkernel_{high|low}() static Zhen Lei
2022-01-11 15:04 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 04/13] kdump: reduce unnecessary parameters of parse_crashkernel_{high|low}() Zhen Lei
2022-01-11 15:05 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 05/13] x86/setup: Add and use CRASH_BASE_ALIGN Zhen Lei
2022-01-11 15:06 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 06/13] kexec: move crashk[_low]_res to crash_core module Zhen Lei
2022-01-11 15:06 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 07/13] kdump: Add helper reserve_crashkernel_mem[_low]() Zhen Lei
2021-12-28 13:26 ` [PATCH v19 08/13] x86/setup: Move CRASH[_BASE]_ALIGN and CRASH_ADDR_{LOW|HIGH}_MAX to asm/kexec.h Zhen Lei
2021-12-28 13:26 ` [PATCH v19 09/13] x86/setup: Use generic reserve_crashkernel_mem[_low]() Zhen Lei
2021-12-28 13:26 ` [PATCH v19 10/13] arm64: kdump: introduce some macros for crash kernel reservation Zhen Lei
2021-12-28 13:26 ` [PATCH v19 11/13] arm64: kdump: reimplement crashkernel=X Zhen Lei
2022-01-12 14:45 ` Dave Kleikamp
2022-01-13 1:17 ` Leizhen (ThunderTown)
2021-12-28 13:26 ` [PATCH v19 12/13] of: fdt: Add memory for devices by DT property "linux,usable-memory-range" Zhen Lei
2021-12-28 13:26 ` Zhen Lei [this message]
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