arch/arm64/kdump.rst

9 reserved memory is needed to pre-load the kdump kernel and boot such
21 large chunk of memomy can be found. The low memory reservation needs to
24 - crashkernel=size@offset
25 - crashkernel=size
26 - crashkernel=size,high crashkernel=size,low
28 Low memory and high memory
31 For kdump reservations, low memory is the memory area under a specific
32 limit, usually decided by the accessible address bits of the DMA-capable
34 vmcore dumping can be ignored. On arm64, the low memory upper bound is
37 whole system RAM is low memory. Outside of the low memory described
44 --------------------------
46 The crashkernel memory must be reserved at the user-specified region or
51 -------------------
56 Firstly, the kernel searches the low memory area for an available region
59 If searching for low memory fails, the kernel falls back to searching
62 the low memory will be done. Currently the default size is 128M,
63 sufficient for the low memory needs of the kdump kernel.
69 3) crashkernel=size,high crashkernel=size,low
70 ---------------------------------------------
72 crashkernel=size,(high|low) are an important supplement to
74 to be allocated from the high memory and low memory respectively. On
75 many systems the low memory is precious and crashkernel reservations
80 low memory reservation will be done subsequently.
83 searching the low memory with the specified size in crashkernel=,high.
84 If it succeeds, no further reservation for low memory is needed.
88 - If crashkernel=,low is not specified, the default low memory
91 - if crashkernel=0,low is specified, it means that the low memory