Pingfan Liu <kernelf...@gmail.com> writes:
> Cc Kexec list. And keep the original content.
>
> On Thu, Sep 12, 2019 at 10:50 AM Pingfan Liu <kernelf...@gmail.com> wrote:
>>
>> 'mem=" option is an easy way to put high pressure on memory during some
>> test. Hence in stead of total mem, the effective usable memory size
^ ^
instead "actual" would be clearer
I think adding: "after applying the memory limit"
would help here.
>> should be considered when reserving mem for crashkernel. Otherwise
>> the boot up may experience oom issue.
^
OOM
>>
>> E.g passing
>> crashkernel="2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G", and
>> mem=5G on a 256G machine.
Spelling out the behaviour before and after would help here, eg:
.. "would reserve 4G prior to the change and 512M afterward."
>> Signed-off-by: Pingfan Liu <kernelf...@gmail.com>
>> Cc: Hari Bathini <hbath...@linux.ibm.com>
>> Cc: Michael Ellerman <m...@ellerman.id.au>
>> To: linuxppc-dev@lists.ozlabs.org
>> ---
>> v1 -> v2: fix the printk info about the total mem
>> arch/powerpc/kernel/machine_kexec.c | 7 ++++---
>> 1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/powerpc/kernel/machine_kexec.c
>> b/arch/powerpc/kernel/machine_kexec.c
>> index c4ed328..eec96dc 100644
>> --- a/arch/powerpc/kernel/machine_kexec.c
>> +++ b/arch/powerpc/kernel/machine_kexec.c
>> @@ -114,11 +114,12 @@ void machine_kexec(struct kimage *image)
>>
>> void __init reserve_crashkernel(void)
>> {
>> - unsigned long long crash_size, crash_base;
>> + unsigned long long crash_size, crash_base, total_mem_sz;
>> int ret;
>>
>> + total_mem_sz = memory_limit ? memory_limit :
>> memblock_phys_mem_size();
>> /* use common parsing */
>> - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
>> + ret = parse_crashkernel(boot_command_line, total_mem_sz,
>> &crash_size, &crash_base);
I think this change makes sense. But we have multiple arches that
implement similar logic, and I wonder if we should keep them all the
same.
eg:
arch/arm/kernel/setup.c: ret =
parse_crashkernel(boot_command_line, total_mem,
arch/arm64/mm/init.c: ret =
parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
arch/ia64/kernel/setup.c: ret =
parse_crashkernel(boot_command_line, total,
arch/mips/kernel/setup.c: ret =
parse_crashkernel(boot_command_line, total_mem,
arch/powerpc/kernel/fadump.c: ret =
parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
arch/powerpc/kernel/machine_kexec.c: ret =
parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
arch/s390/kernel/setup.c: rc =
parse_crashkernel(boot_command_line, memory_end, &crash_size,
arch/sh/kernel/machine_kexec.c: ret =
parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
arch/x86/kernel/setup.c: ret =
parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
>From a quick glance most of them don't seem to take the memory limit
into account.
So I guess the question is do we want all arches to implement the same
behaviour or do we think it doesn't matter if they differ in details
like this?
cheers
