Messages in this thread | | | Date | Fri, 7 Apr 2023 14:03:23 +0200 | From | Simon Horman <> | Subject | Re: [PATCH -next v3 1/2] riscv: kdump: Implement crashkernel=X,[high,low] |
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On Fri, Apr 07, 2023 at 06:02:05AM +0800, Chen Jiahao wrote: > On riscv, the current crash kernel allocation logic is trying to > allocate within 32bit addressible memory region by default, if > failed, try to allocate without 4G restriction. > > In need of saving DMA zone memory while allocating a relatively large > crash kernel region, allocating the reserved memory top down in > high memory, without overlapping the DMA zone, is a mature solution. > Here introduce the parameter option crashkernel=X,[high,low]. > > One can reserve the crash kernel from high memory above DMA zone range > by explicitly passing "crashkernel=X,high"; or reserve a memory range > below 4G with "crashkernel=X,low". > > Signed-off-by: Chen Jiahao <chenjiahao16@huawei.com>
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> @@ -1180,14 +1206,37 @@ static void __init reserve_crashkernel(void) > return; > } > > - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), > + ret = parse_crashkernel(cmdline, memblock_phys_mem_size(), > &crash_size, &crash_base); > - if (ret || !crash_size) > + if (ret == -ENOENT) { > + /* > + * crashkernel=X,[high,low] can be specified or not, but > + * invalid value is not allowed.
nit: Perhaps something like this would be easier to correlate with the code that follows:
/* Fallback to crashkernel=X,[high,low] */
> + */ > + ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base); > + if (ret || !crash_size) > + return; > + > + /* > + * crashkernel=Y,low is valid only when crashkernel=X,high > + * is passed and high memory is reserved successful.
nit: s/successful/successfully/
> + */ > + ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base); > + if (ret == -ENOENT) > + crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; > + else if (ret) > + return; > + > + search_start = search_low_max; > + } else if (ret || !crash_size) { > + /* Invalid argument value specified */ > return; > + }
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