[PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[Faiyaz Mohammed]

For INITRD and initmem memory is reserved through "memblock_reserve"
during boot up but it is free via "free_reserved_area" instead
of "memblock_free".
For example:
[    0.294848] Freeing initrd memory: 12K.
[    0.696688] Freeing unused kernel memory: 4096K.

To get the start and end address of the above freed memory and to account
proper memblock added memblock_dbg log in "free_reserved_area".
After adding log:
[    0.294837] memblock_free: [0x00000083600000-0x00000083603000] free_initrd_mem+0x20/0x28
[    0.294848] Freeing initrd memory: 12K.
[    0.695246] memblock_free: [0x00000081600000-0x00000081a00000] free_initmem+0x70/0xc8
[    0.696688] Freeing unused kernel memory: 4096K.

Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
---
 mm/page_alloc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b37435c..f85c3b2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start, void *end, int poison, const char
 		pr_info("Freeing %s memory: %ldK\n",
 			s, pages << (PAGE_SHIFT - 10));
 
+#ifdef CONFIG_HAVE_MEMBLOCK
+		memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
+			__pa(start), __pa(end), (void *)_RET_IP_);
+#endif
+
 	return pages;
 }
 
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[David Hildenbrand]

On 28.09.21 11:04, Faiyaz Mohammed wrote:
> For INITRD and initmem memory is reserved through "memblock_reserve"
> during boot up but it is free via "free_reserved_area" instead
> of "memblock_free".
> For example:
> [    0.294848] Freeing initrd memory: 12K.
> [    0.696688] Freeing unused kernel memory: 4096K.
> 
> To get the start and end address of the above freed memory and to account
> proper memblock added memblock_dbg log in "free_reserved_area".
> After adding log:
> [    0.294837] memblock_free: [0x00000083600000-0x00000083603000] free_initrd_mem+0x20/0x28
> [    0.294848] Freeing initrd memory: 12K.
> [    0.695246] memblock_free: [0x00000081600000-0x00000081a00000] free_initmem+0x70/0xc8
> [    0.696688] Freeing unused kernel memory: 4096K.
> 
> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
> ---
>   mm/page_alloc.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index b37435c..f85c3b2 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start, void *end, int poison, const char
>   		pr_info("Freeing %s memory: %ldK\n",
>   			s, pages << (PAGE_SHIFT - 10));
>   
> +#ifdef CONFIG_HAVE_MEMBLOCK
> +		memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
> +			__pa(start), __pa(end), (void *)_RET_IP_);
> +#endif

IMHO, the "memblock_free" part is misleading. Something was allocated 
early via memblock, then we transitioned to the buddy, now we're freeing 
that early allocation via the buddy.

I would not expect memblock_dbg once memblock might not actually be 
alive anymore.

-- 
Thanks,

David / dhildenb

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[Faiyaz Mohammed]

On 9/28/2021 4:09 PM, David Hildenbrand wrote:
> On 28.09.21 11:04, Faiyaz Mohammed wrote:
>> For INITRD and initmem memory is reserved through "memblock_reserve"
>> during boot up but it is free via "free_reserved_area" instead
>> of "memblock_free".
>> For example:
>> [    0.294848] Freeing initrd memory: 12K.
>> [    0.696688] Freeing unused kernel memory: 4096K.
>>
>> To get the start and end address of the above freed memory and to account
>> proper memblock added memblock_dbg log in "free_reserved_area".
>> After adding log:
>> [    0.294837] memblock_free: [0x00000083600000-0x00000083603000]
>> free_initrd_mem+0x20/0x28
>> [    0.294848] Freeing initrd memory: 12K.
>> [    0.695246] memblock_free: [0x00000081600000-0x00000081a00000]
>> free_initmem+0x70/0xc8
>> [    0.696688] Freeing unused kernel memory: 4096K.
>>
>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
>> ---
>>   mm/page_alloc.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index b37435c..f85c3b2 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start,
>> void *end, int poison, const char
>>           pr_info("Freeing %s memory: %ldK\n",
>>               s, pages << (PAGE_SHIFT - 10));
>>   +#ifdef CONFIG_HAVE_MEMBLOCK
>> +        memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
>> +            __pa(start), __pa(end), (void *)_RET_IP_);
>> +#endif
> 
> IMHO, the "memblock_free" part is misleading. Something was allocated
> early via memblock, then we transitioned to the buddy, now we're freeing
> that early allocation via the buddy.
> Yes, we're freeing the early allocation via buddy, but for proper
memblock accounting we need this debug print.

> I would not expect memblock_dbg once memblock might not actually be
> alive anymore.
> 
Here we can add pr_info as well, but the intention is to get callsite
and address info when the memblock=debug is pass through command line
and it is for debugging purpose.

Thanks and regards,
Mohammed Faiyaz

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[David Hildenbrand]

On 28.09.21 12:53, Faiyaz Mohammed wrote:
> 
> 
> On 9/28/2021 4:09 PM, David Hildenbrand wrote:
>> On 28.09.21 11:04, Faiyaz Mohammed wrote:
>>> For INITRD and initmem memory is reserved through "memblock_reserve"
>>> during boot up but it is free via "free_reserved_area" instead
>>> of "memblock_free".
>>> For example:
>>> [    0.294848] Freeing initrd memory: 12K.
>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>
>>> To get the start and end address of the above freed memory and to account
>>> proper memblock added memblock_dbg log in "free_reserved_area".
>>> After adding log:
>>> [    0.294837] memblock_free: [0x00000083600000-0x00000083603000]
>>> free_initrd_mem+0x20/0x28
>>> [    0.294848] Freeing initrd memory: 12K.
>>> [    0.695246] memblock_free: [0x00000081600000-0x00000081a00000]
>>> free_initmem+0x70/0xc8
>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>
>>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
>>> ---
>>>    mm/page_alloc.c | 5 +++++
>>>    1 file changed, 5 insertions(+)
>>>
>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>> index b37435c..f85c3b2 100644
>>> --- a/mm/page_alloc.c
>>> +++ b/mm/page_alloc.c
>>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start,
>>> void *end, int poison, const char
>>>            pr_info("Freeing %s memory: %ldK\n",
>>>                s, pages << (PAGE_SHIFT - 10));
>>>    +#ifdef CONFIG_HAVE_MEMBLOCK
>>> +        memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
>>> +            __pa(start), __pa(end), (void *)_RET_IP_);
>>> +#endif
>>
>> IMHO, the "memblock_free" part is misleading. Something was allocated
>> early via memblock, then we transitioned to the buddy, now we're freeing
>> that early allocation via the buddy.
>> Yes, we're freeing the early allocation via buddy, but for proper
> memblock accounting we need this debug print.
> 

What do you mean with "accounting" ? These are debug statements.


-- 
Thanks,

David / dhildenb

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[Faiyaz Mohammed]

On 9/28/2021 4:46 PM, David Hildenbrand wrote:
> On 28.09.21 12:53, Faiyaz Mohammed wrote:
>>
>>
>> On 9/28/2021 4:09 PM, David Hildenbrand wrote:
>>> On 28.09.21 11:04, Faiyaz Mohammed wrote:
>>>> For INITRD and initmem memory is reserved through "memblock_reserve"
>>>> during boot up but it is free via "free_reserved_area" instead
>>>> of "memblock_free".
>>>> For example:
>>>> [    0.294848] Freeing initrd memory: 12K.
>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>
>>>> To get the start and end address of the above freed memory and to
>>>> account
>>>> proper memblock added memblock_dbg log in "free_reserved_area".
>>>> After adding log:
>>>> [    0.294837] memblock_free: [0x00000083600000-0x00000083603000]
>>>> free_initrd_mem+0x20/0x28
>>>> [    0.294848] Freeing initrd memory: 12K.
>>>> [    0.695246] memblock_free: [0x00000081600000-0x00000081a00000]
>>>> free_initmem+0x70/0xc8
>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>
>>>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
>>>> ---
>>>>    mm/page_alloc.c | 5 +++++
>>>>    1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>>> index b37435c..f85c3b2 100644
>>>> --- a/mm/page_alloc.c
>>>> +++ b/mm/page_alloc.c
>>>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start,
>>>> void *end, int poison, const char
>>>>            pr_info("Freeing %s memory: %ldK\n",
>>>>                s, pages << (PAGE_SHIFT - 10));
>>>>    +#ifdef CONFIG_HAVE_MEMBLOCK
>>>> +        memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
>>>> +            __pa(start), __pa(end), (void *)_RET_IP_);
>>>> +#endif
>>>
>>> IMHO, the "memblock_free" part is misleading. Something was allocated
>>> early via memblock, then we transitioned to the buddy, now we're freeing
>>> that early allocation via the buddy.
>>> Yes, we're freeing the early allocation via buddy, but for proper
>> memblock accounting we need this debug print.
>>
> 
> What do you mean with "accounting" ? These are debug statements.
> 
> 
Yes, these are debug statements, which help to know the a-b address
belongs to x callsite. This info is required when memblock=debug is
passed through command line and CONFIG_HAVE_MEMBLOCK is enabled.

Thanks,
Mohammed Faiyaz

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[David Hildenbrand]

On 29.09.21 10:58, Faiyaz Mohammed wrote:
> 
> 
> On 9/28/2021 4:46 PM, David Hildenbrand wrote:
>> On 28.09.21 12:53, Faiyaz Mohammed wrote:
>>>
>>>
>>> On 9/28/2021 4:09 PM, David Hildenbrand wrote:
>>>> On 28.09.21 11:04, Faiyaz Mohammed wrote:
>>>>> For INITRD and initmem memory is reserved through "memblock_reserve"
>>>>> during boot up but it is free via "free_reserved_area" instead
>>>>> of "memblock_free".
>>>>> For example:
>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>
>>>>> To get the start and end address of the above freed memory and to
>>>>> account
>>>>> proper memblock added memblock_dbg log in "free_reserved_area".
>>>>> After adding log:
>>>>> [    0.294837] memblock_free: [0x00000083600000-0x00000083603000]
>>>>> free_initrd_mem+0x20/0x28
>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>> [    0.695246] memblock_free: [0x00000081600000-0x00000081a00000]
>>>>> free_initmem+0x70/0xc8
>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>
>>>>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
>>>>> ---
>>>>>     mm/page_alloc.c | 5 +++++
>>>>>     1 file changed, 5 insertions(+)
>>>>>
>>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>>>> index b37435c..f85c3b2 100644
>>>>> --- a/mm/page_alloc.c
>>>>> +++ b/mm/page_alloc.c
>>>>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start,
>>>>> void *end, int poison, const char
>>>>>             pr_info("Freeing %s memory: %ldK\n",
>>>>>                 s, pages << (PAGE_SHIFT - 10));
>>>>>     +#ifdef CONFIG_HAVE_MEMBLOCK
>>>>> +        memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
>>>>> +            __pa(start), __pa(end), (void *)_RET_IP_);
>>>>> +#endif
>>>>
>>>> IMHO, the "memblock_free" part is misleading. Something was allocated
>>>> early via memblock, then we transitioned to the buddy, now we're freeing
>>>> that early allocation via the buddy.
>>>> Yes, we're freeing the early allocation via buddy, but for proper
>>> memblock accounting we need this debug print.
>>>
>>
>> What do you mean with "accounting" ? These are debug statements.
>>
>>
> Yes, these are debug statements, which help to know the a-b address
> belongs to x callsite. This info is required when memblock=debug is
> passed through command line and CONFIG_HAVE_MEMBLOCK is enabled.

The issue I'm having is talking in the name of memblock "memblock_dbg, 
memblock_free", when memblock might no longer be around. We have other 
places where we free early memblock allocations back to the buddy.

-- 
Thanks,

David / dhildenb

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[Faiyaz Mohammed]

Hi,

Sorry for delayed response.

On 9/29/2021 10:33 PM, David Hildenbrand wrote:
> On 29.09.21 10:58, Faiyaz Mohammed wrote:
>>
>>
>> On 9/28/2021 4:46 PM, David Hildenbrand wrote:
>>> On 28.09.21 12:53, Faiyaz Mohammed wrote:
>>>>
>>>>
>>>> On 9/28/2021 4:09 PM, David Hildenbrand wrote:
>>>>> On 28.09.21 11:04, Faiyaz Mohammed wrote:
>>>>>> For INITRD and initmem memory is reserved through "memblock_reserve"
>>>>>> during boot up but it is free via "free_reserved_area" instead
>>>>>> of "memblock_free".
>>>>>> For example:
>>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>>
>>>>>> To get the start and end address of the above freed memory and to
>>>>>> account
>>>>>> proper memblock added memblock_dbg log in "free_reserved_area".
>>>>>> After adding log:
>>>>>> [    0.294837] memblock_free: [0x00000083600000-0x00000083603000]
>>>>>> free_initrd_mem+0x20/0x28
>>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>>> [    0.695246] memblock_free: [0x00000081600000-0x00000081a00000]
>>>>>> free_initmem+0x70/0xc8
>>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>>
>>>>>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
>>>>>> ---
>>>>>>     mm/page_alloc.c | 5 +++++
>>>>>>     1 file changed, 5 insertions(+)
>>>>>>
>>>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>>>>> index b37435c..f85c3b2 100644
>>>>>> --- a/mm/page_alloc.c
>>>>>> +++ b/mm/page_alloc.c
>>>>>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start,
>>>>>> void *end, int poison, const char
>>>>>>             pr_info("Freeing %s memory: %ldK\n",
>>>>>>                 s, pages << (PAGE_SHIFT - 10));
>>>>>>     +#ifdef CONFIG_HAVE_MEMBLOCK
>>>>>> +        memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
>>>>>> +            __pa(start), __pa(end), (void *)_RET_IP_);
>>>>>> +#endif
>>>>>
>>>>> IMHO, the "memblock_free" part is misleading. Something was allocated
>>>>> early via memblock, then we transitioned to the buddy, now we're
>>>>> freeing
>>>>> that early allocation via the buddy.
>>>>> Yes, we're freeing the early allocation via buddy, but for proper
>>>> memblock accounting we need this debug print.
>>>>
>>>
>>> What do you mean with "accounting" ? These are debug statements.
>>>
>>>
>> Yes, these are debug statements, which help to know the a-b address
>> belongs to x callsite. This info is required when memblock=debug is
>> passed through command line and CONFIG_HAVE_MEMBLOCK is enabled.
> 
> The issue I'm having is talking in the name of memblock "memblock_dbg,
> memblock_free", when memblock might no longer be around. We have other
> places where we free early memblock allocations back to the buddy.
I didn't find place where we free early memblock allocation back to the
buddy.

Why "memblock_dbg" print with "memblock_free" string?.
- After buddy took over, buddy will free memblock reserved memory
through free_reserved_area and it will print the freed memory size, but
the freed memory through buddy still be part of memblock.reserved.regions.
- To know the address ranges, added the "memblock_dbg" print along with
"membloc_free" string.
- If it is misleading or confusing, we can remove the "memblock_free"
string from the "memblock_dgb" print and we can just print the address
range when "memlock=debug" pass through command line.

Thanks and regards,
Mohammed Faiyaz

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[David Hildenbrand]

On 06.10.21 14:13, Faiyaz Mohammed wrote:
> Hi,
> 
> Sorry for delayed response.
> 
> On 9/29/2021 10:33 PM, David Hildenbrand wrote:
>> On 29.09.21 10:58, Faiyaz Mohammed wrote:
>>>
>>>
>>> On 9/28/2021 4:46 PM, David Hildenbrand wrote:
>>>> On 28.09.21 12:53, Faiyaz Mohammed wrote:
>>>>>
>>>>>
>>>>> On 9/28/2021 4:09 PM, David Hildenbrand wrote:
>>>>>> On 28.09.21 11:04, Faiyaz Mohammed wrote:
>>>>>>> For INITRD and initmem memory is reserved through "memblock_reserve"
>>>>>>> during boot up but it is free via "free_reserved_area" instead
>>>>>>> of "memblock_free".
>>>>>>> For example:
>>>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>>>
>>>>>>> To get the start and end address of the above freed memory and to
>>>>>>> account
>>>>>>> proper memblock added memblock_dbg log in "free_reserved_area".
>>>>>>> After adding log:
>>>>>>> [    0.294837] memblock_free: [0x00000083600000-0x00000083603000]
>>>>>>> free_initrd_mem+0x20/0x28
>>>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>>>> [    0.695246] memblock_free: [0x00000081600000-0x00000081a00000]
>>>>>>> free_initmem+0x70/0xc8
>>>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>>>
>>>>>>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
>>>>>>> ---
>>>>>>>      mm/page_alloc.c | 5 +++++
>>>>>>>      1 file changed, 5 insertions(+)
>>>>>>>
>>>>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>>>>>> index b37435c..f85c3b2 100644
>>>>>>> --- a/mm/page_alloc.c
>>>>>>> +++ b/mm/page_alloc.c
>>>>>>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start,
>>>>>>> void *end, int poison, const char
>>>>>>>              pr_info("Freeing %s memory: %ldK\n",
>>>>>>>                  s, pages << (PAGE_SHIFT - 10));
>>>>>>>      +#ifdef CONFIG_HAVE_MEMBLOCK
>>>>>>> +        memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
>>>>>>> +            __pa(start), __pa(end), (void *)_RET_IP_);
>>>>>>> +#endif
>>>>>>
>>>>>> IMHO, the "memblock_free" part is misleading. Something was allocated
>>>>>> early via memblock, then we transitioned to the buddy, now we're
>>>>>> freeing
>>>>>> that early allocation via the buddy.
>>>>>> Yes, we're freeing the early allocation via buddy, but for proper
>>>>> memblock accounting we need this debug print.
>>>>>
>>>>
>>>> What do you mean with "accounting" ? These are debug statements.
>>>>
>>>>
>>> Yes, these are debug statements, which help to know the a-b address
>>> belongs to x callsite. This info is required when memblock=debug is
>>> passed through command line and CONFIG_HAVE_MEMBLOCK is enabled.
>>
>> The issue I'm having is talking in the name of memblock "memblock_dbg,
>> memblock_free", when memblock might no longer be around. We have other
>> places where we free early memblock allocations back to the buddy.
> I didn't find place where we free early memblock allocation back to the
> buddy.

One example I know is

section_deactivate()->free_map_bootmem()->vmemmap_free()-> ... 
free_pagetable()->free_reserved_page().

when we free the vmemmap allocated via memblock back to the buddy.

> 
> Why "memblock_dbg" print with "memblock_free" string?.
> - After buddy took over, buddy will free memblock reserved memory
> through free_reserved_area and it will print the freed memory size, but
> the freed memory through buddy still be part of memblock.reserved.regions.
> - To know the address ranges, added the "memblock_dbg" print along with
> "membloc_free" string.
> - If it is misleading or confusing, we can remove the "memblock_free"
> string from the "memblock_dgb" print and we can just print the address
> range when "memlock=debug" pass through command line.

That would be better, but do we really have to depend on 
"memlock=debug"? Can't we do pr_debug() ?

-- 
Thanks,

David / dhildenb

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[Faiyaz Mohammed]

On 10/6/2021 5:48 PM, David Hildenbrand wrote:
> On 06.10.21 14:13, Faiyaz Mohammed wrote:
>> Hi,
>>
>> Sorry for delayed response.
>>
>> On 9/29/2021 10:33 PM, David Hildenbrand wrote:
>>> On 29.09.21 10:58, Faiyaz Mohammed wrote:
>>>>
>>>>
>>>> On 9/28/2021 4:46 PM, David Hildenbrand wrote:
>>>>> On 28.09.21 12:53, Faiyaz Mohammed wrote:
>>>>>>
>>>>>>
>>>>>> On 9/28/2021 4:09 PM, David Hildenbrand wrote:
>>>>>>> On 28.09.21 11:04, Faiyaz Mohammed wrote:
>>>>>>>> For INITRD and initmem memory is reserved through
>>>>>>>> "memblock_reserve"
>>>>>>>> during boot up but it is free via "free_reserved_area" instead
>>>>>>>> of "memblock_free".
>>>>>>>> For example:
>>>>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>>>>
>>>>>>>> To get the start and end address of the above freed memory and to
>>>>>>>> account
>>>>>>>> proper memblock added memblock_dbg log in "free_reserved_area".
>>>>>>>> After adding log:
>>>>>>>> [    0.294837] memblock_free: [0x00000083600000-0x00000083603000]
>>>>>>>> free_initrd_mem+0x20/0x28
>>>>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>>>>> [    0.695246] memblock_free: [0x00000081600000-0x00000081a00000]
>>>>>>>> free_initmem+0x70/0xc8
>>>>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>>>>
>>>>>>>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
>>>>>>>> ---
>>>>>>>>      mm/page_alloc.c | 5 +++++
>>>>>>>>      1 file changed, 5 insertions(+)
>>>>>>>>
>>>>>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>>>>>>> index b37435c..f85c3b2 100644
>>>>>>>> --- a/mm/page_alloc.c
>>>>>>>> +++ b/mm/page_alloc.c
>>>>>>>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void
>>>>>>>> *start,
>>>>>>>> void *end, int poison, const char
>>>>>>>>              pr_info("Freeing %s memory: %ldK\n",
>>>>>>>>                  s, pages << (PAGE_SHIFT - 10));
>>>>>>>>      +#ifdef CONFIG_HAVE_MEMBLOCK
>>>>>>>> +        memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
>>>>>>>> +            __pa(start), __pa(end), (void *)_RET_IP_);
>>>>>>>> +#endif
>>>>>>>
>>>>>>> IMHO, the "memblock_free" part is misleading. Something was
>>>>>>> allocated
>>>>>>> early via memblock, then we transitioned to the buddy, now we're
>>>>>>> freeing
>>>>>>> that early allocation via the buddy.
>>>>>>> Yes, we're freeing the early allocation via buddy, but for proper
>>>>>> memblock accounting we need this debug print.
>>>>>>
>>>>>
>>>>> What do you mean with "accounting" ? These are debug statements.
>>>>>
>>>>>
>>>> Yes, these are debug statements, which help to know the a-b address
>>>> belongs to x callsite. This info is required when memblock=debug is
>>>> passed through command line and CONFIG_HAVE_MEMBLOCK is enabled.
>>>
>>> The issue I'm having is talking in the name of memblock "memblock_dbg,
>>> memblock_free", when memblock might no longer be around. We have other
>>> places where we free early memblock allocations back to the buddy.
>> I didn't find place where we free early memblock allocation back to the
>> buddy.
> 
> One example I know is
> 
> section_deactivate()->free_map_bootmem()->vmemmap_free()-> ...
> free_pagetable()->free_reserved_page().
> 
> when we free the vmemmap allocated via memblock back to the buddy.
> 
>>
>> Why "memblock_dbg" print with "memblock_free" string?.
>> - After buddy took over, buddy will free memblock reserved memory
>> through free_reserved_area and it will print the freed memory size, but
>> the freed memory through buddy still be part of
>> memblock.reserved.regions.
>> - To know the address ranges, added the "memblock_dbg" print along with
>> "membloc_free" string.
>> - If it is misleading or confusing, we can remove the "memblock_free"
>> string from the "memblock_dgb" print and we can just print the address
>> range when "memlock=debug" pass through command line.
> 
> That would be better, but do we really have to depend on
> "memlock=debug"?
Yes, because we need that print when memblock=debug is pass through
command line, like other memblock debug messages.


Thanks and regards,
Mohammed Faiyaz

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

[Faiyaz Mohammed]

On 10/6/2021 5:48 PM, David Hildenbrand wrote:
> On 06.10.21 14:13, Faiyaz Mohammed wrote:
>> Hi,
>>
>> Sorry for delayed response.
>>
>> On 9/29/2021 10:33 PM, David Hildenbrand wrote:
>>> On 29.09.21 10:58, Faiyaz Mohammed wrote:
>>>>
>>>>
>>>> On 9/28/2021 4:46 PM, David Hildenbrand wrote:
>>>>> On 28.09.21 12:53, Faiyaz Mohammed wrote:
>>>>>>
>>>>>>
>>>>>> On 9/28/2021 4:09 PM, David Hildenbrand wrote:
>>>>>>> On 28.09.21 11:04, Faiyaz Mohammed wrote:
>>>>>>>> For INITRD and initmem memory is reserved through
>>>>>>>> "memblock_reserve"
>>>>>>>> during boot up but it is free via "free_reserved_area" instead
>>>>>>>> of "memblock_free".
>>>>>>>> For example:
>>>>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>>>>
>>>>>>>> To get the start and end address of the above freed memory and to
>>>>>>>> account
>>>>>>>> proper memblock added memblock_dbg log in "free_reserved_area".
>>>>>>>> After adding log:
>>>>>>>> [    0.294837] memblock_free: [0x00000083600000-0x00000083603000]
>>>>>>>> free_initrd_mem+0x20/0x28
>>>>>>>> [    0.294848] Freeing initrd memory: 12K.
>>>>>>>> [    0.695246] memblock_free: [0x00000081600000-0x00000081a00000]
>>>>>>>> free_initmem+0x70/0xc8
>>>>>>>> [    0.696688] Freeing unused kernel memory: 4096K.
>>>>>>>>
>>>>>>>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
>>>>>>>> ---
>>>>>>>>      mm/page_alloc.c | 5 +++++
>>>>>>>>      1 file changed, 5 insertions(+)
>>>>>>>>
>>>>>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>>>>>>> index b37435c..f85c3b2 100644
>>>>>>>> --- a/mm/page_alloc.c
>>>>>>>> +++ b/mm/page_alloc.c
>>>>>>>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void
>>>>>>>> *start,
>>>>>>>> void *end, int poison, const char
>>>>>>>>              pr_info("Freeing %s memory: %ldK\n",
>>>>>>>>                  s, pages << (PAGE_SHIFT - 10));
>>>>>>>>      +#ifdef CONFIG_HAVE_MEMBLOCK
>>>>>>>> +        memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
>>>>>>>> +            __pa(start), __pa(end), (void *)_RET_IP_);
>>>>>>>> +#endif
>>>>>>>
>>>>>>> IMHO, the "memblock_free" part is misleading. Something was
>>>>>>> allocated
>>>>>>> early via memblock, then we transitioned to the buddy, now we're
>>>>>>> freeing
>>>>>>> that early allocation via the buddy.
>>>>>>> Yes, we're freeing the early allocation via buddy, but for proper
>>>>>> memblock accounting we need this debug print.
>>>>>>
>>>>>
>>>>> What do you mean with "accounting" ? These are debug statements.
>>>>>
>>>>>
>>>> Yes, these are debug statements, which help to know the a-b address
>>>> belongs to x callsite. This info is required when memblock=debug is
>>>> passed through command line and CONFIG_HAVE_MEMBLOCK is enabled.
>>>
>>> The issue I'm having is talking in the name of memblock "memblock_dbg,
>>> memblock_free", when memblock might no longer be around. We have other
>>> places where we free early memblock allocations back to the buddy.
>> I didn't find place where we free early memblock allocation back to the
>> buddy.
> 
> One example I know is
> 
> section_deactivate()->free_map_bootmem()->vmemmap_free()-> ...
> free_pagetable()->free_reserved_page().
> 
> when we free the vmemmap allocated via memblock back to the buddy.
> 
>>
>> Why "memblock_dbg" print with "memblock_free" string?.
>> - After buddy took over, buddy will free memblock reserved memory
>> through free_reserved_area and it will print the freed memory size, but
>> the freed memory through buddy still be part of
>> memblock.reserved.regions.
>> - To know the address ranges, added the "memblock_dbg" print along with
>> "membloc_free" string.
>> - If it is misleading or confusing, we can remove the "memblock_free"
>> string from the "memblock_dgb" print and we can just print the address
>> range when "memlock=debug" pass through command line.
> 
> That would be better, but do we really have to depend on
> "memlock=debug"? Can't we do pr_debug() ?
> 
Yes, I think we can do pr_debug. I will update the patch and push again.

Thanks and regards,
Mohammed Faiyaz