On 2020/9/3 1:13, Catalin Marinas wrote: > On Sat, Aug 01, 2020 at 09:08:56PM +0800, Chen Zhou wrote: >> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst >> index 2da65fef2a1c..4b58f97351d5 100644 >> --- a/Documentation/admin-guide/kdump/kdump.rst >> +++ b/Documentation/admin-guide/kdump/kdump.rst >> @@ -299,7 +299,15 @@ 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. >> + 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 +324,15 @@ 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 ZONE_DMA, and >> + fall back to high allocation if it fails. And go for high allocation >> + directly if the required size is too large. If crash_base is outside > I wouldn't mention crash_base in the admin guide. That's an > implementation detail really and admins are not supposed to read the > source code to make sense of the documentation. ZONE_DMA is also a > kernel internal, so you'd need to define what it is for arm64. At least > the DMA and DMA32 zones are printed during kernel boot. Ok, i will fix this in next version. > >> + ZONE_DMA, try to allocate at least 256M in ZONE_DMA automatically. >> + "crashkernel=Y,low" can be used to allocate specified size low memory. >> + For non-RPi4 platforms, change ZONE_DMA memtioned above to ZONE_DMA32. >> + 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). _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
