[v2] LoongArch: mm: Set max_pfn with the PFN of the last page

[PATCH v2] LoongArch: mm: Set max_pfn with the PFN of the last page

Posted by Bibo Mao 11 months, 1 week ago

The current max_pfn equals to zero. In this case, it caused users cannot
get some page information through /proc such as kpagecount. The following
message is displayed by stress-ng test suite with the command
"stress-ng --verbose --physpage 1 -t 1".

 # stress-ng --verbose --physpage 1 -t 1
 stress-ng: error: [1691] physpage: cannot read page count for address 0x134ac000 in /proc/kpagecount, errno=22 (Invalid argument)
 stress-ng: error: [1691] physpage: cannot read page count for address 0x7ffff207c3a8 in /proc/kpagecount, errno=22 (Invalid argument)
 stress-ng: error: [1691] physpage: cannot read page count for address 0x134b0000 in /proc/kpagecount, errno=22 (Invalid argument)
 ...

After applying this patch, the kernel can pass the test.
 # stress-ng --verbose --physpage 1 -t 1
 stress-ng: debug: [1701] physpage: [1701] started (instance 0 on CPU 3)
 stress-ng: debug: [1701] physpage: [1701] exited (instance 0 on CPU 3)
 stress-ng: debug: [1700] physpage: [1701] terminated (success)

Cc: stable@vger.kernel.org
Fixes: ff6c3d81f2e8 ("NUMA: optimize detection of memory with no node id assigned by firmware")

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
 arch/loongarch/kernel/setup.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index edcfdfcad7d2..a9c1184ab893 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -390,6 +390,7 @@ static void __init arch_mem_init(char **cmdline_p)
 	if (usermem)
 		pr_info("User-defined physical RAM map overwrite\n");
 
+	max_low_pfn = max_pfn = PHYS_PFN(memblock_end_of_DRAM());
 	check_kernel_sections_mem();
 
 	/*

base-commit: 848e076317446f9c663771ddec142d7c2eb4cb43
-- 
2.39.3

Re: [PATCH v2] LoongArch: mm: Set max_pfn with the PFN of the last page

Posted by Huacai Chen 11 months, 1 week ago

Hi, Bibo,

On Thu, Mar 6, 2025 at 11:53 AM Bibo Mao <maobibo@loongson.cn> wrote:
>
> The current max_pfn equals to zero. In this case, it caused users cannot
> get some page information through /proc such as kpagecount. The following
> message is displayed by stress-ng test suite with the command
> "stress-ng --verbose --physpage 1 -t 1".
>
>  # stress-ng --verbose --physpage 1 -t 1
>  stress-ng: error: [1691] physpage: cannot read page count for address 0x134ac000 in /proc/kpagecount, errno=22 (Invalid argument)
>  stress-ng: error: [1691] physpage: cannot read page count for address 0x7ffff207c3a8 in /proc/kpagecount, errno=22 (Invalid argument)
>  stress-ng: error: [1691] physpage: cannot read page count for address 0x134b0000 in /proc/kpagecount, errno=22 (Invalid argument)
>  ...
>
> After applying this patch, the kernel can pass the test.
>  # stress-ng --verbose --physpage 1 -t 1
>  stress-ng: debug: [1701] physpage: [1701] started (instance 0 on CPU 3)
>  stress-ng: debug: [1701] physpage: [1701] exited (instance 0 on CPU 3)
>  stress-ng: debug: [1700] physpage: [1701] terminated (success)
>
> Cc: stable@vger.kernel.org
> Fixes: ff6c3d81f2e8 ("NUMA: optimize detection of memory with no node id assigned by firmware")
>
> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
> ---
>  arch/loongarch/kernel/setup.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
> index edcfdfcad7d2..a9c1184ab893 100644
> --- a/arch/loongarch/kernel/setup.c
> +++ b/arch/loongarch/kernel/setup.c
> @@ -390,6 +390,7 @@ static void __init arch_mem_init(char **cmdline_p)
>         if (usermem)
>                 pr_info("User-defined physical RAM map overwrite\n");
>
> +       max_low_pfn = max_pfn = PHYS_PFN(memblock_end_of_DRAM());
max_low_pfn is already calculated for all three cases, so here just
need "max_pfn = max_low_pfn".

Huacai

>         check_kernel_sections_mem();
>
>         /*
>
> base-commit: 848e076317446f9c663771ddec142d7c2eb4cb43
> --
> 2.39.3
>

Re: [PATCH v2] LoongArch: mm: Set max_pfn with the PFN of the last page

Posted by bibo mao 11 months, 1 week ago


On 2025/3/6 下午12:06, Huacai Chen wrote:
> Hi, Bibo,
> 
> On Thu, Mar 6, 2025 at 11:53 AM Bibo Mao <maobibo@loongson.cn> wrote:
>>
>> The current max_pfn equals to zero. In this case, it caused users cannot
>> get some page information through /proc such as kpagecount. The following
>> message is displayed by stress-ng test suite with the command
>> "stress-ng --verbose --physpage 1 -t 1".
>>
>>   # stress-ng --verbose --physpage 1 -t 1
>>   stress-ng: error: [1691] physpage: cannot read page count for address 0x134ac000 in /proc/kpagecount, errno=22 (Invalid argument)
>>   stress-ng: error: [1691] physpage: cannot read page count for address 0x7ffff207c3a8 in /proc/kpagecount, errno=22 (Invalid argument)
>>   stress-ng: error: [1691] physpage: cannot read page count for address 0x134b0000 in /proc/kpagecount, errno=22 (Invalid argument)
>>   ...
>>
>> After applying this patch, the kernel can pass the test.
>>   # stress-ng --verbose --physpage 1 -t 1
>>   stress-ng: debug: [1701] physpage: [1701] started (instance 0 on CPU 3)
>>   stress-ng: debug: [1701] physpage: [1701] exited (instance 0 on CPU 3)
>>   stress-ng: debug: [1700] physpage: [1701] terminated (success)
>>
>> Cc: stable@vger.kernel.org
>> Fixes: ff6c3d81f2e8 ("NUMA: optimize detection of memory with no node id assigned by firmware")
>>
>> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
>> ---
>>   arch/loongarch/kernel/setup.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
>> index edcfdfcad7d2..a9c1184ab893 100644
>> --- a/arch/loongarch/kernel/setup.c
>> +++ b/arch/loongarch/kernel/setup.c
>> @@ -390,6 +390,7 @@ static void __init arch_mem_init(char **cmdline_p)
>>          if (usermem)
>>                  pr_info("User-defined physical RAM map overwrite\n");
>>
>> +       max_low_pfn = max_pfn = PHYS_PFN(memblock_end_of_DRAM());
> max_low_pfn is already calculated for all three cases, so here just
> need "max_pfn = max_low_pfn".
In theory it should be.

However there are potential problems, it should be recalculated in 
function early_parse_mem() also if commandline "mem=" is added.

The other thing is that calculation init_numa_memory() is unnecessary 
since it is already calculated in memblock_init(). Memory block 
information comes from UEFI table or FDT table, and ACPI srat 
information only adds node information.

Regards
Bibo Mao
> 
> Huacai
> 
>>          check_kernel_sections_mem();
>>
>>          /*
>>
>> base-commit: 848e076317446f9c663771ddec142d7c2eb4cb43
>> --
>> 2.39.3
>>

Re: [PATCH v2] LoongArch: mm: Set max_pfn with the PFN of the last page

Posted by Huacai Chen 11 months, 1 week ago

On Thu, Mar 6, 2025 at 2:26 PM bibo mao <maobibo@loongson.cn> wrote:
>
>
>
> On 2025/3/6 下午12:06, Huacai Chen wrote:
> > Hi, Bibo,
> >
> > On Thu, Mar 6, 2025 at 11:53 AM Bibo Mao <maobibo@loongson.cn> wrote:
> >>
> >> The current max_pfn equals to zero. In this case, it caused users cannot
> >> get some page information through /proc such as kpagecount. The following
> >> message is displayed by stress-ng test suite with the command
> >> "stress-ng --verbose --physpage 1 -t 1".
> >>
> >>   # stress-ng --verbose --physpage 1 -t 1
> >>   stress-ng: error: [1691] physpage: cannot read page count for address 0x134ac000 in /proc/kpagecount, errno=22 (Invalid argument)
> >>   stress-ng: error: [1691] physpage: cannot read page count for address 0x7ffff207c3a8 in /proc/kpagecount, errno=22 (Invalid argument)
> >>   stress-ng: error: [1691] physpage: cannot read page count for address 0x134b0000 in /proc/kpagecount, errno=22 (Invalid argument)
> >>   ...
> >>
> >> After applying this patch, the kernel can pass the test.
> >>   # stress-ng --verbose --physpage 1 -t 1
> >>   stress-ng: debug: [1701] physpage: [1701] started (instance 0 on CPU 3)
> >>   stress-ng: debug: [1701] physpage: [1701] exited (instance 0 on CPU 3)
> >>   stress-ng: debug: [1700] physpage: [1701] terminated (success)
> >>
> >> Cc: stable@vger.kernel.org
> >> Fixes: ff6c3d81f2e8 ("NUMA: optimize detection of memory with no node id assigned by firmware")
> >>
> >> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
> >> ---
> >>   arch/loongarch/kernel/setup.c | 1 +
> >>   1 file changed, 1 insertion(+)
> >>
> >> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
> >> index edcfdfcad7d2..a9c1184ab893 100644
> >> --- a/arch/loongarch/kernel/setup.c
> >> +++ b/arch/loongarch/kernel/setup.c
> >> @@ -390,6 +390,7 @@ static void __init arch_mem_init(char **cmdline_p)
> >>          if (usermem)
> >>                  pr_info("User-defined physical RAM map overwrite\n");
> >>
> >> +       max_low_pfn = max_pfn = PHYS_PFN(memblock_end_of_DRAM());
> > max_low_pfn is already calculated for all three cases, so here just
> > need "max_pfn = max_low_pfn".
> In theory it should be.
>
> However there are potential problems, it should be recalculated in
> function early_parse_mem() also if commandline "mem=" is added.
>
Yes, you are right, thanks.

Huacai

> The other thing is that calculation init_numa_memory() is unnecessary
> since it is already calculated in memblock_init(). Memory block
> information comes from UEFI table or FDT table, and ACPI srat
> information only adds node information.
>
> Regards
> Bibo Mao
> >
> > Huacai
> >
> >>          check_kernel_sections_mem();
> >>
> >>          /*
> >>
> >> base-commit: 848e076317446f9c663771ddec142d7c2eb4cb43
> >> --
> >> 2.39.3
> >>
>
>