Re: [PATCH v12 3/9] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel[_low]()

chenzhou
2020-09-18T09:07:11Z

Hi Catalin,

On 2020/9/18 16:59, chenzhou wrote:
> Hi Baoquan,
>
> On 2020/9/18 15:25, Baoquan He wrote:
>> Hi,
>>
>> On 09/07/20 at 09:47pm, Chen Zhou wrote:
>>> To make the functions reserve_crashkernel[_low]() as generic,
>>> replace some hard-coded numbers with macro CRASH_ADDR_LOW_MAX.
>>>
>>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>>> ---
>>> arch/x86/kernel/setup.c | 11 ++++++-----
>>> 1 file changed, 6 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>>> index d7fd90c52dae..71a6a6e7ca5b 100644
>>> --- a/arch/x86/kernel/setup.c
>>> +++ b/arch/x86/kernel/setup.c
>>> @@ -430,7 +430,7 @@ static int __init reserve_crashkernel_low(void)
>>> unsigned long total_low_mem;
>>> int ret;
>>>
>>> - total_low_mem = memblock_mem_size(1UL << (32 - PAGE_SHIFT));
>>> + total_low_mem = memblock_mem_size(CRASH_ADDR_LOW_MAX >> PAGE_SHIFT);
>> Just note that the replacement has been done in another patch from Mike
>> Rapoport, partially. He seems to have done reserve_crashkernel_low()
>> part, there's one left in reserve_crashkernel(), you might want to check
>> that.
>>
>> Mike's patch which is from a patchset has been merged into Andrew's next
>> tree.
>>
>> commit 6e50f7672ffa362e9bd4bc0c0d2524ed872828c5
>> Author: Mike Rapoport <rppt@linux.ibm.com>
>> Date: Wed Aug 26 15:22:32 2020 +1000
>>
>> x86/setup: simplify reserve_crashkernel()
As Baoquan said, some functions have been changed in the next tree,
if i need to rebase on top of the next tree.

Thanks,
Chen Zhou
> Yeah, the function reserve_crashkernel() has been changed in the next tree.
> Thanks for your review and reminder.
>
> Thanks,
> Chen Zhou
>>>
>>> /* crashkernel=Y,low */
>>> ret = parse_crashkernel_low(boot_command_line, total_low_mem, &low_size, &base);
>>> @@ -451,7 +451,7 @@ static int __init reserve_crashkernel_low(void)
>>> return 0;
>>> }
>>>
>>> - low_base = memblock_find_in_range(CRASH_ALIGN, 1ULL << 32, low_size, CRASH_ALIGN);
>>> + low_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX, low_size, CRASH_ALIGN);
>>> if (!low_base) {
>>> pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
>>> (unsigned long)(low_size >> 20));
>>> @@ -504,8 +504,9 @@ static void __init reserve_crashkernel(void)
>>> if (!crash_base) {
>>> /*
>>> * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
>>> - * crashkernel=x,high reserves memory over 4G, also allocates
>>> - * 256M extra low memory for DMA buffers and swiotlb.
>>> + * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
>>> + * also allocates 256M extra low memory for DMA buffers
>>> + * and swiotlb.
>>> * But the extra memory is not required for all machines.
>>> * So try low memory first and fall back to high memory
>>> * unless "crashkernel=size[KMG],high" is specified.
>>> @@ -539,7 +540,7 @@ static void __init reserve_crashkernel(void)
>>> return;
>>> }
>>>
>>> - if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
>>> + if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
>>> memblock_free(crash_base, crash_size);
>>> return;
>>> }
>>> --
>>> 2.20.1
>>>
>> .
>>