From: Catalin Marinas <catalin.marinas@arm.com>
To: chenzhou <chenzhou10@huawei.com>
Cc: will@kernel.org, james.morse@arm.com, tglx@linutronix.de,
mingo@redhat.com, dyoung@redhat.com, bhe@redhat.com,
corbet@lwn.net, John.P.donnelly@oracle.com,
prabhakar.pkin@gmail.com, bhsharma@redhat.com,
horms@verge.net.au, robh+dt@kernel.org, arnd@arndb.de,
nsaenzjulienne@suse.de, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
linux-doc@vger.kernel.org, guohanjun@huawei.com,
xiexiuqi@huawei.com, huawei.libin@huawei.com,
wangkefeng.wang@huawei.com
Subject: Re: [PATCH v12 9/9] kdump: update Documentation about crashkernel
Date: Wed, 7 Oct 2020 17:24:53 +0100 [thread overview]
Message-ID: <20201007162453.GR3462@gaia> (raw)
In-Reply-To: <8644712d-1331-1efc-1cd2-6da8640145b7@huawei.com>
On Tue, Oct 06, 2020 at 10:10:54AM +0800, chenzhou wrote:
> On 2020/10/6 1:19, Catalin Marinas wrote:
> > On Mon, Sep 07, 2020 at 09:47:45PM +0800, Chen Zhou wrote:
> >> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
> >> index 2da65fef2a1c..549611abc581 100644
> >> --- a/Documentation/admin-guide/kdump/kdump.rst
> >> +++ b/Documentation/admin-guide/kdump/kdump.rst
> > [...]
> >> @@ -316,8 +325,18 @@ 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. And go for high allocation
> >> + directly if the required size is too large.
> >> + 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
> >> + in DMA zone.
> >> + For non-RPi4 platforms, change DMA zone memtioned above to DMA32 zone.
> > I don't think we should mention non-RPi4 explicitly here. I don't even
> > understand what the suggestion is since the only way is to disable
> > ZONE_DMA in the kernel config. I'd just stick to ZONE_DMA description
> > here.
> How about like this:
> If the kernel config ZONE_DMA is disabled, just try low allocation in DMA32 zone
> and high allocation above DMA32 zone.
Something like: "allocate 256M low memory in the DMA zone automatically
(or the DMA32 zone if CONFIG_ZONE_DMA is disabled)".
I'd keep it short.
--
Catalin
next prev parent reply other threads:[~2020-10-07 16:25 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 13:47 [PATCH v12 0/9] support reserving crashkernel above 4G on arm64 kdump Chen Zhou
2020-09-07 13:47 ` [PATCH v12 1/9] x86: kdump: move CRASH_ALIGN to 2M Chen Zhou
2020-09-08 1:21 ` Dave Young
2020-09-08 3:19 ` chenzhou
2020-09-07 13:47 ` [PATCH v12 2/9] x86: kdump: make the lower bound of crash kernel reservation consistent Chen Zhou
2020-09-07 13:47 ` [PATCH v12 3/9] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel[_low]() Chen Zhou
2020-09-18 3:01 ` Dave Young
2020-09-18 3:57 ` chenzhou
2020-09-18 5:26 ` Dave Young
2020-09-18 7:25 ` Baoquan He
2020-09-18 8:59 ` chenzhou
2020-09-18 9:06 ` chenzhou
2020-10-05 17:20 ` Catalin Marinas
2020-09-07 13:47 ` [PATCH v12 4/9] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c Chen Zhou
2020-09-07 13:47 ` [PATCH v12 5/9] arm64: kdump: introduce some macroes for crash kernel reservation Chen Zhou
2020-09-07 13:47 ` [PATCH v12 6/9] arm64: kdump: reimplement crashkernel=X Chen Zhou
2020-10-05 17:16 ` Catalin Marinas
2020-10-06 1:30 ` chenzhou
2020-09-07 13:47 ` [PATCH v12 7/9] kdump: add threshold for the required memory Chen Zhou
2020-10-05 17:12 ` Catalin Marinas
2020-10-06 1:34 ` chenzhou
2020-09-07 13:47 ` [PATCH v12 8/9] arm64: kdump: add memory for devices by DT property linux,usable-memory-range Chen Zhou
2020-09-07 13:47 ` [PATCH v12 9/9] kdump: update Documentation about crashkernel Chen Zhou
2020-10-05 17:19 ` Catalin Marinas
2020-10-06 2:10 ` chenzhou
2020-10-07 16:24 ` Catalin Marinas [this message]
2020-09-12 11:44 ` [PATCH v12 0/9] support reserving crashkernel above 4G on arm64 kdump John Donnelly
2020-10-05 17:09 ` Catalin Marinas
2020-10-05 17:42 ` Bhupesh Sharma
2020-10-06 1:48 ` chenzhou
2020-10-06 18:00 ` Catalin Marinas
2020-10-07 7:07 ` Bhupesh Sharma
2020-10-07 16:33 ` Catalin Marinas
2020-10-19 2:43 ` chenzhou
2020-09-15 7:16 ` chenzhou
2020-09-23 17:47 ` John Donnelly
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