[PATCH v2] mm/mm_init.c: print mem_init info after defer_init is done

[PATCH v2] mm/mm_init.c: print mem_init info after defer_init is done

[Wei Yang]

Current call flow looks like this:

start_kernel
  mm_core_init
    mem_init
    mem_init_print_info
  rest_init
    kernel_init
      kernel_init_freeable
        page_alloc_init_late
          deferred_init_memmap

If CONFIG_DEFERRED_STRUCT_PAGE_INIT, the time mem_init_print_info()
calls, pages are not totally initialized and freed to buddy.

This has one issue

  * nr_free_pages() just contains partial free pages in the system,
    which is not we expect.

Let's print the mem info after defer_init is done.

Also this would help changing totalram_pages accounting, since we plan
to move the accounting into __free_pages_core().

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: David Hildenbrand <david@redhat.com>

---
v2:
  * mention this would help changing totalram_pages accounting
  * instead of moving the function ahead, add function declaration ahead
  * add a comment before calling mem_init_print_info
---
 mm/mm_init.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index f72b852bd5b8..769d5ba6bf38 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2322,6 +2322,7 @@ void set_zone_contiguous(struct zone *zone)
 	zone->contiguous = true;
 }
 
+static void __init mem_init_print_info(void);
 void __init page_alloc_init_late(void)
 {
 	struct zone *zone;
@@ -2348,6 +2349,8 @@ void __init page_alloc_init_late(void)
 	files_maxfiles_init();
 #endif
 
+	/* Accounting of total+free memory is stable at this point. */
+	mem_init_print_info();
 	buffer_init();
 
 	/* Discard memblock private memory */
@@ -2737,7 +2740,6 @@ void __init mm_core_init(void)
 	kmsan_init_shadow();
 	stack_depot_early_init();
 	mem_init();
-	mem_init_print_info();
 	kmem_cache_init();
 	/*
 	 * page_owner must be initialized after buddy is ready, and also after
-- 
2.34.1

Re: [PATCH v2] mm/mm_init.c: print mem_init info after defer_init is done

[David Hildenbrand]

On 11.06.24 16:52, Wei Yang wrote:
> Current call flow looks like this:
> 
> start_kernel
>    mm_core_init
>      mem_init
>      mem_init_print_info
>    rest_init
>      kernel_init
>        kernel_init_freeable
>          page_alloc_init_late
>            deferred_init_memmap
> 
> If CONFIG_DEFERRED_STRUCT_PAGE_INIT, the time mem_init_print_info()
> calls, pages are not totally initialized and freed to buddy.
> 
> This has one issue
> 
>    * nr_free_pages() just contains partial free pages in the system,
>      which is not we expect.
> 
> Let's print the mem info after defer_init is done.
> 
> Also this would help changing totalram_pages accounting, since we plan
> to move the accounting into __free_pages_core().
> 
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> CC: David Hildenbrand <david@redhat.com>

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

Hoping this won't reveal other surprises.

-- 
Cheers,

David / dhildenb

Re: [PATCH v2] mm/mm_init.c: print mem_init info after defer_init is done

[Wei Yang]

On Tue, Jun 11, 2024 at 05:12:13PM +0200, David Hildenbrand wrote:
>On 11.06.24 16:52, Wei Yang wrote:
>> Current call flow looks like this:
>> 
>> start_kernel
>>    mm_core_init
>>      mem_init
>>      mem_init_print_info
>>    rest_init
>>      kernel_init
>>        kernel_init_freeable
>>          page_alloc_init_late
>>            deferred_init_memmap
>> 
>> If CONFIG_DEFERRED_STRUCT_PAGE_INIT, the time mem_init_print_info()
>> calls, pages are not totally initialized and freed to buddy.
>> 
>> This has one issue
>> 
>>    * nr_free_pages() just contains partial free pages in the system,
>>      which is not we expect.
>> 
>> Let's print the mem info after defer_init is done.
>> 
>> Also this would help changing totalram_pages accounting, since we plan
>> to move the accounting into __free_pages_core().
>> 
>> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
>> CC: David Hildenbrand <david@redhat.com>
>
>Acked-by: David Hildenbrand <david@redhat.com>
>
>Hoping this won't reveal other surprises.
>

:-)

>-- 
>Cheers,
>
>David / dhildenb

-- 
Wei Yang
Help you, Help me