linux-kernel - Re: [PATCH v2] mm: page_alloc: Add debug log in free_reserved

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Date:   Wed, 13 Oct 2021 14:15:09 +0530
From:   Faiyaz Mohammed <faiyazm@...eaurora.org>
To:     David Hildenbrand <david@...hat.com>,
        Faiyaz Mohammed <quic_faiyazm@...eaurora.org>,
        akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     guptap@...eaurora.org
Subject: Re: [PATCH v2] mm: page_alloc: Add debug log in free_reserved_area
 for static memory



On 10/11/2021 2:04 PM, David Hildenbrand wrote:
> On 11.10.21 09:11, Faiyaz Mohammed wrote:
>> From: Faiyaz Mohammed <faiyazm@...eaurora.org>
>>
>> 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 pr_debug log in "free_reserved_area".
>> After adding log:
>> [    0.294837] 0x00000083600000-0x00000083603000
>> free_initrd_mem+0x20/0x28
>> [    0.294848] Freeing initrd memory: 12K.
>> [    0.695246] 0x00000081600000-0x00000081a00000 free_initmem+0x70/0xc8
>> [    0.696688] Freeing unused kernel memory: 4096K.
>>
>> Signed-off-by: Faiyaz Mohammed <faiyazm@...eaurora.org>
>> ---
>> changes in v2:
>>     - To avoid confusion, remove the memblock_dbg print and drop the
>>     memblock_free string, now using pr_debug to print the address ranges.
>>
>>   mm/page_alloc.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index 668edb1..395df3f 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -8153,6 +8153,11 @@ unsigned long free_reserved_area(void *start,
>> void *end, int poison, const char
>>       if (pages && s)
>>           pr_info("Freeing %s memory: %ldK\n", s, K(pages));
>>   +#ifdef CONFIG_HAVE_MEMBLOCK
>> +        pr_debug("%#016llx-%#016llx %pS\n",
>> +            __pa(start), __pa(end), (void *)_RET_IP_);
>> +#endif
>> +
> 
> Are we missing parentheses that the code indentation implies?
> Further, I think we want to use "%pa" instead of "%llx" and
> eventually drop the CONFIG_HAVE_MEMBLOCK dependency. Maybe
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index b37435c274cf..e7946e5ca094 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -8097,6 +8097,8 @@ EXPORT_SYMBOL(adjust_managed_page_count);
>  
>  unsigned long free_reserved_area(void *start, void *end, int poison,
> const char *s)
>  {
> +       const phys_addr_t pstart = __pa(start);
> +       const phys_addr_t pend = __pa(end);
>         void *pos;
>         unsigned long pages = 0;
>  
> @@ -8125,9 +8127,11 @@ unsigned long free_reserved_area(void *start,
> void *end, int poison, const char
>                 free_reserved_page(page);
>         }
>  
> -       if (pages && s)
> +       if (pages && s) {
>                 pr_info("Freeing %s memory: %ldK\n",
>                         s, pages << (PAGE_SHIFT - 10));
> +               pr_debug("[%pa-%pa] %pS\n", &pstart, &pend, (void
> *)_RET_IP_);
> +       }
>  
>         return pages;
>  }
> Sure, I will update it and push again.

Thanks and regards,
Mohammed Faiyaz