Re: [PATCH v2] mm: page_alloc: Add debug log in free_reserved_area for static memory

[David Hildenbrand]

On 11.10.21 09:11, Faiyaz Mohammed wrote:
> From: Faiyaz Mohammed <faiyazm@xxxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxxx>
> ---
> 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;
 }



--
Thanks,

David / dhildenb