[v2] introduce kmemdump

[RFC][PATCH v2 16/29] mm/show_mem: Annotate static information into Kmemdump

Posted by Eugen Hristev 2 months, 1 week ago

Annotate vital static information into kmemdump:
 - _totalram_pages

Information on these variables is stored into dedicated kmemdump section.

Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
---
 mm/show_mem.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/show_mem.c b/mm/show_mem.c
index 41999e94a56d..93a5dc041ae1 100644
--- a/mm/show_mem.c
+++ b/mm/show_mem.c
@@ -14,12 +14,14 @@
 #include <linux/mmzone.h>
 #include <linux/swap.h>
 #include <linux/vmstat.h>
+#include <linux/kmemdump.h>
 
 #include "internal.h"
 #include "swap.h"
 
 atomic_long_t _totalram_pages __read_mostly;
 EXPORT_SYMBOL(_totalram_pages);
+KMEMDUMP_VAR_CORE(_totalram_pages, sizeof(_totalram_pages));
 unsigned long totalreserve_pages __read_mostly;
 unsigned long totalcma_pages __read_mostly;
 
-- 
2.43.0

Re: [RFC][PATCH v2 16/29] mm/show_mem: Annotate static information into Kmemdump

Posted by David Hildenbrand 2 months, 1 week ago

On 24.07.25 15:54, Eugen Hristev wrote:
> Annotate vital static information into kmemdump:
>   - _totalram_pages
> 
> Information on these variables is stored into dedicated kmemdump section.
> 
> Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
> ---
>   mm/show_mem.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/mm/show_mem.c b/mm/show_mem.c
> index 41999e94a56d..93a5dc041ae1 100644
> --- a/mm/show_mem.c
> +++ b/mm/show_mem.c
> @@ -14,12 +14,14 @@
>   #include <linux/mmzone.h>
>   #include <linux/swap.h>
>   #include <linux/vmstat.h>
> +#include <linux/kmemdump.h>
>   
>   #include "internal.h"
>   #include "swap.h"
>   
>   atomic_long_t _totalram_pages __read_mostly;
>   EXPORT_SYMBOL(_totalram_pages);
> +KMEMDUMP_VAR_CORE(_totalram_pages, sizeof(_totalram_pages));

Tagging these variables that way is really rather ... controversial.

As these are exported globals, isn't there a way to have a list of what 
to include and what not somewhere else?

Not sure if any of that would win a beauty price, though.

-- 
Cheers,

David / dhildenb

Re: [RFC][PATCH v2 16/29] mm/show_mem: Annotate static information into Kmemdump

Posted by Eugen Hristev 2 months, 1 week ago


On 7/30/25 16:55, David Hildenbrand wrote:
> On 24.07.25 15:54, Eugen Hristev wrote:
>> Annotate vital static information into kmemdump:
>>   - _totalram_pages
>>
>> Information on these variables is stored into dedicated kmemdump section.
>>
>> Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
>> ---
>>   mm/show_mem.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/mm/show_mem.c b/mm/show_mem.c
>> index 41999e94a56d..93a5dc041ae1 100644
>> --- a/mm/show_mem.c
>> +++ b/mm/show_mem.c
>> @@ -14,12 +14,14 @@
>>   #include <linux/mmzone.h>
>>   #include <linux/swap.h>
>>   #include <linux/vmstat.h>
>> +#include <linux/kmemdump.h>
>>   
>>   #include "internal.h"
>>   #include "swap.h"
>>   
>>   atomic_long_t _totalram_pages __read_mostly;
>>   EXPORT_SYMBOL(_totalram_pages);
>> +KMEMDUMP_VAR_CORE(_totalram_pages, sizeof(_totalram_pages));
> 
> Tagging these variables that way is really rather ... controversial.
> 
> As these are exported globals, isn't there a way to have a list of what 
> to include and what not somewhere else?
> 
> Not sure if any of that would win a beauty price, though.
> 

Annotating the variable was suggested here :

https://lore.kernel.org/lkml/87h61wn2qq.ffs@tglx/

It does not win a beauty prize but it's simple and efficient at least.
Do you think it would be better to gather all the annotations for the
globals in a single place ?

Eugen

Re: [RFC][PATCH v2 16/29] mm/show_mem: Annotate static information into Kmemdump

Posted by David Hildenbrand 2 months, 1 week ago

On 30.07.25 16:04, Eugen Hristev wrote:
> 
> 
> On 7/30/25 16:55, David Hildenbrand wrote:
>> On 24.07.25 15:54, Eugen Hristev wrote:
>>> Annotate vital static information into kmemdump:
>>>    - _totalram_pages
>>>
>>> Information on these variables is stored into dedicated kmemdump section.
>>>
>>> Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
>>> ---
>>>    mm/show_mem.c | 2 ++
>>>    1 file changed, 2 insertions(+)
>>>
>>> diff --git a/mm/show_mem.c b/mm/show_mem.c
>>> index 41999e94a56d..93a5dc041ae1 100644
>>> --- a/mm/show_mem.c
>>> +++ b/mm/show_mem.c
>>> @@ -14,12 +14,14 @@
>>>    #include <linux/mmzone.h>
>>>    #include <linux/swap.h>
>>>    #include <linux/vmstat.h>
>>> +#include <linux/kmemdump.h>
>>>    
>>>    #include "internal.h"
>>>    #include "swap.h"
>>>    
>>>    atomic_long_t _totalram_pages __read_mostly;
>>>    EXPORT_SYMBOL(_totalram_pages);
>>> +KMEMDUMP_VAR_CORE(_totalram_pages, sizeof(_totalram_pages));
>>
>> Tagging these variables that way is really rather ... controversial.
>>
>> As these are exported globals, isn't there a way to have a list of what
>> to include and what not somewhere else?
>>
>> Not sure if any of that would win a beauty price, though.
>>
> 
> Annotating the variable was suggested here :
> 
> https://lore.kernel.org/lkml/87h61wn2qq.ffs@tglx/
> 
> It does not win a beauty prize but it's simple and efficient at least.
> Do you think it would be better to gather all the annotations for the
> globals in a single place ?

See my other mail regarding VMCOREINFO.

-- 
Cheers,

David / dhildenb