Messages in this thread | | | Subject | Re: [PATCH 4/4] kdump: update Documentation about crashkernel on arm64 | From | Bhupesh Sharma <> | Date | Wed, 15 May 2019 10:46:05 +0530 |
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On 05/07/2019 09:20 AM, Chen Zhou wrote: > Now we support crashkernel=X,[high,low] on arm64, update the > Documentation. > > Signed-off-by: Chen Zhou <chenzhou10@huawei.com> > --- > Documentation/admin-guide/kernel-parameters.txt | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 268b10a..03a08aa 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -705,7 +705,7 @@ > memory region [offset, offset + size] for that kernel > image. If '@offset' is omitted, then a suitable offset > is selected automatically. > - [KNL, x86_64] select a region under 4G first, and > + [KNL, x86_64, arm64] select a region under 4G first, and > fall back to reserve region above 4G when '@offset' > hasn't been specified. > See Documentation/kdump/kdump.txt for further details. > @@ -718,14 +718,14 @@ > Documentation/kdump/kdump.txt for an example. > > crashkernel=size[KMG],high > - [KNL, x86_64] range could be above 4G. Allow kernel > + [KNL, x86_64, arm64] range could be above 4G. Allow kernel > to allocate physical memory region from top, so could > be above 4G if system have more than 4G ram installed. > Otherwise memory region will be allocated below 4G, if > available. > It will be ignored if crashkernel=X is specified. > crashkernel=size[KMG],low > - [KNL, x86_64] range under 4G. When crashkernel=X,high > + [KNL, x86_64, arm64] range under 4G. When crashkernel=X,high > is passed, kernel could allocate physical memory region > above 4G, that cause second kernel crash on system > that require some amount of low memory, e.g. swiotlb >
IMO, it is a good time to update 'Documentation/kdump/kdump.txt' with this patchset itself for both x86_64 and arm64, where we still specify only the old format for 'crashkernel' boot-argument:
Section: Boot into System Kernel =======================
On arm64, use "crashkernel=Y[@X]". Note that the start address of the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000). ...
We can update this to add the new crashkernel=size[KMG],low or crashkernel=size[KMG],high format as well.
Thanks, Bhupesh
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