linux-kernel - Re: [PATCH v3] mm: page_alloc: Add debug log in free_reserved

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Message-ID: <64195d6f-09e3-9ab6-bcb2-d68a79665fcf@redhat.com>
Date:   Thu, 14 Oct 2021 09:22:50 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Faiyaz Mohammed <faiyazm@...eaurora.org>,
        akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     guptap@...eaurora.org
Subject: Re: [PATCH v3] mm: page_alloc: Add debug log in free_reserved_area
 for static memory

On 14.10.21 09:12, 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 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 v3:
> 	- Update the format specifier.
> 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 | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index b37435c..13adda5 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 +8127,12 @@ 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;
>  }
> 

Acked-by: David Hildenbrand <david@...hat.com>

Thanks!

-- 
Thanks,

David / dhildenb