On 03/01/2022 10:31 PM, Mike Rapoport wrote:
On Tue, Mar 01, 2022 at 07:51:23PM +0800, Tiezhu Yang wrote:
On 03/01/2022 05:55 PM, Mike Rapoport wrote:
Hi,
On Tue, Mar 01, 2022 at 12:28:57PM +0800, Tiezhu Yang wrote:
In the current code, the kernel command-line parameter mem= and memmap=
can not work well on MIPS, this patchset refactors the related code to
fix them.
For kdump on MIPS, if the users want to limit the memory region for the
capture kernel to avoid corrupting the memory image of the panic kernel,
use the parameter memmap=limit@base is the proper way, I will submit a
patch to use memmap=limit@base for kexec-tools after this patchset is
applied.
Sorry, apparently I misread the prevoius version.
What's wrong with the current implementation of mem=limit@base for the
kdump case?
In the current code, without this patchset, kernel boot hangs when add
mem=3G, mem=3G@64M or memmap=3G@64M to the command-line, it means that
the parameter mem= and memmap= have bug on mips.
I can see how mem=3G may be wrong when the memory does not start at 0, but
it seems to do the right thing of mem=3G@64M.
Do you see system hangs with mem=3G@64M?
Yes.
Do you have the logs before the hang?
Here are the logs:
[ 0.000000] Linux version 5.17.0-rc3+ (loongson@linux) (gcc (GCC)
7.3.1 20180303 (Red Hat 7.3.1-6), GNU ld version
2.28-13.fc21.loongson.6) #1 SMP PREEMPT Wed Mar 2 09:07:39 CST 2022
[ 0.000000] CpuClock = 1800000000
[ 0.000000] The bridge chip is LS7A
[ 0.000000] CP0_Config3: CP0 16.3 (0xdc8030a0)
[ 0.000000] CP0_PageGrain: CP0 5.1 (0x28000000)
[ 0.000000] NUMA: Discovered 4 cpus on 1 nodes
[ 0.000000] Node0: mem_type:1, mem_start:0x200000, mem_size:0xee MB
[ 0.000000] start_pfn:0x80, end_pfn:0x3c00, num_physpages:0x3b80
[ 0.000000] Node0: mem_type:2, mem_start:0x90200000, mem_size:0x6fe MB
[ 0.000000] start_pfn:0x24080, end_pfn:0x40000,
num_physpages:0x1fb00
[ 0.000000] Node0: mem_type:2, mem_start:0x120000000, mem_size:0x1600 MB
[ 0.000000] start_pfn:0x48000, end_pfn:0xa0000,
num_physpages:0x77b00
[ 0.000000] Node0's addrspace_offset is 0x0
[ 0.000000] Node0: start_pfn=0x80, end_pfn=0xa0000
[ 0.000000] NUMA: set cpumask cpu 0 on node 0
[ 0.000000] NUMA: set cpumask cpu 1 on node 0
[ 0.000000] NUMA: set cpumask cpu 2 on node 0
[ 0.000000] NUMA: set cpumask cpu 3 on node 0
[ 0.000000] printk: bootconsole [early0] enabled
[ 0.000000] CPU0 revision is: 0014c001 (ICT Loongson-3)
[ 0.000000] FPU revision is: 00f70501
[ 0.000000] MSA revision is: 00060140
[ 0.000000] OF: fdt: No chosen node found, continuing without
[ 0.000000] MIPS: machine is loongson,loongson64g-4core-ls7a
[ 0.000000] User-defined physical RAM map overwrite
[ 0.000000] Kernel sections are not in the memory maps
[ 0.000000] Initrd not found or empty - disabling initrd
As for memmap= option, it does not specify the memory map but rather alters
the memory map passed by the firmware. Particularity in MIPS implementation
it allows to add a single range of available or reserved memory.
AFAIU, for the kdump use-case mem=X@Y should suffice.
We can modify some code to make mem=X@Y work well,
but according to Documentation/admin-guide/kernel-parameters.txt,
the common way is mem=X and memmap=X@Y, so mem=X@Y for mips seems
odd, the intention of this patchset is to make mem= and memmap=
work well and consistent with the other archs.
Thanks,
Tiezhu
Thanks,
Tiezhu
v4: Fix some build warnings reported by kernel test robot
v3: Modify patch #3 to maintain compatibility for memmap=limit{$,#,!}base,
commented by Mike Rapoport, thank you
v2: Add some new patches to support memmap=limit@base
Tiezhu Yang (4):
MIPS: Refactor early_parse_mem() to fix mem= parameter
memblock: Introduce memblock_mem_range_remove_map()
MIPS: Refactor early_parse_memmap() to fix memmap= parameter
MIPS: Remove not used variable usermem
arch/mips/kernel/setup.c | 69 ++++++++++++++++++++++--------------------------
include/linux/memblock.h | 1 +
mm/memblock.c | 9 +++++--
3 files changed, 40 insertions(+), 39 deletions(-)
--
2.1.0
