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

[PATCH] 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.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: David Hildenbrand <david@redhat.com>
---
 mm/mm_init.c | 104 +++++++++++++++++++++++++--------------------------
 1 file changed, 52 insertions(+), 52 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index f72b852bd5b8..34a6de20ef77 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2322,6 +2322,57 @@ void set_zone_contiguous(struct zone *zone)
 	zone->contiguous = true;
 }
 
+static void __init mem_init_print_info(void)
+{
+	unsigned long physpages, codesize, datasize, rosize, bss_size;
+	unsigned long init_code_size, init_data_size;
+
+	physpages = get_num_physpages();
+	codesize = _etext - _stext;
+	datasize = _edata - _sdata;
+	rosize = __end_rodata - __start_rodata;
+	bss_size = __bss_stop - __bss_start;
+	init_data_size = __init_end - __init_begin;
+	init_code_size = _einittext - _sinittext;
+
+	/*
+	 * Detect special cases and adjust section sizes accordingly:
+	 * 1) .init.* may be embedded into .data sections
+	 * 2) .init.text.* may be out of [__init_begin, __init_end],
+	 *    please refer to arch/tile/kernel/vmlinux.lds.S.
+	 * 3) .rodata.* may be embedded into .text or .data sections.
+	 */
+#define adj_init_size(start, end, size, pos, adj) \
+	do { \
+		if (&start[0] <= &pos[0] && &pos[0] < &end[0] && size > adj) \
+			size -= adj; \
+	} while (0)
+
+	adj_init_size(__init_begin, __init_end, init_data_size,
+		     _sinittext, init_code_size);
+	adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
+	adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
+	adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
+	adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
+
+#undef	adj_init_size
+
+	pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
+#ifdef	CONFIG_HIGHMEM
+		", %luK highmem"
+#endif
+		")\n",
+		K(nr_free_pages()), K(physpages),
+		codesize / SZ_1K, datasize / SZ_1K, rosize / SZ_1K,
+		(init_data_size + init_code_size) / SZ_1K, bss_size / SZ_1K,
+		K(physpages - totalram_pages() - totalcma_pages),
+		K(totalcma_pages)
+#ifdef	CONFIG_HIGHMEM
+		, K(totalhigh_pages())
+#endif
+		);
+}
+
 void __init page_alloc_init_late(void)
 {
 	struct zone *zone;
@@ -2348,6 +2399,7 @@ void __init page_alloc_init_late(void)
 	files_maxfiles_init();
 #endif
 
+	mem_init_print_info();
 	buffer_init();
 
 	/* Discard memblock private memory */
@@ -2666,57 +2718,6 @@ static void __init report_meminit(void)
 		pr_info("mem auto-init: clearing system memory may take some time...\n");
 }
 
-static void __init mem_init_print_info(void)
-{
-	unsigned long physpages, codesize, datasize, rosize, bss_size;
-	unsigned long init_code_size, init_data_size;
-
-	physpages = get_num_physpages();
-	codesize = _etext - _stext;
-	datasize = _edata - _sdata;
-	rosize = __end_rodata - __start_rodata;
-	bss_size = __bss_stop - __bss_start;
-	init_data_size = __init_end - __init_begin;
-	init_code_size = _einittext - _sinittext;
-
-	/*
-	 * Detect special cases and adjust section sizes accordingly:
-	 * 1) .init.* may be embedded into .data sections
-	 * 2) .init.text.* may be out of [__init_begin, __init_end],
-	 *    please refer to arch/tile/kernel/vmlinux.lds.S.
-	 * 3) .rodata.* may be embedded into .text or .data sections.
-	 */
-#define adj_init_size(start, end, size, pos, adj) \
-	do { \
-		if (&start[0] <= &pos[0] && &pos[0] < &end[0] && size > adj) \
-			size -= adj; \
-	} while (0)
-
-	adj_init_size(__init_begin, __init_end, init_data_size,
-		     _sinittext, init_code_size);
-	adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
-	adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
-	adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
-	adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
-
-#undef	adj_init_size
-
-	pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
-#ifdef	CONFIG_HIGHMEM
-		", %luK highmem"
-#endif
-		")\n",
-		K(nr_free_pages()), K(physpages),
-		codesize / SZ_1K, datasize / SZ_1K, rosize / SZ_1K,
-		(init_data_size + init_code_size) / SZ_1K, bss_size / SZ_1K,
-		K(physpages - totalram_pages() - totalcma_pages),
-		K(totalcma_pages)
-#ifdef	CONFIG_HIGHMEM
-		, K(totalhigh_pages())
-#endif
-		);
-}
-
 /*
  * Set up kernel memory allocators
  */
@@ -2737,7 +2738,6 @@ 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] mm/mm_init.c: print mem_init info after defer_init is done

[David Hildenbrand]

On 11.06.24 05:08, 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.
> 

Maybe mention that this will also help changing totalpage accounting.

> Let's print the mem info after defer_init is done.
> 
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> CC: David Hildenbrand <david@redhat.com>
> ---
>   mm/mm_init.c | 104 +++++++++++++++++++++++++--------------------------
>   1 file changed, 52 insertions(+), 52 deletions(-)
> 
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index f72b852bd5b8..34a6de20ef77 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -2322,6 +2322,57 @@ void set_zone_contiguous(struct zone *zone)
>   	zone->contiguous = true;
>   }
>   
> +static void __init mem_init_print_info(void)

Can you avoid all that churn simply by doing a

static void __init mem_init_print_info(void);

somewhere at the beginning of this file?

> +{
> +	unsigned long physpages, codesize, datasize, rosize, bss_size;
> +	unsigned long init_code_size, init_data_size;
> +
> +	physpages = get_num_physpages();
> +	codesize = _etext - _stext;
> +	datasize = _edata - _sdata;
> +	rosize = __end_rodata - __start_rodata;
> +	bss_size = __bss_stop - __bss_start;
> +	init_data_size = __init_end - __init_begin;
> +	init_code_size = _einittext - _sinittext;
> +
> +	/*
> +	 * Detect special cases and adjust section sizes accordingly:
> +	 * 1) .init.* may be embedded into .data sections
> +	 * 2) .init.text.* may be out of [__init_begin, __init_end],
> +	 *    please refer to arch/tile/kernel/vmlinux.lds.S.
> +	 * 3) .rodata.* may be embedded into .text or .data sections.
> +	 */
> +#define adj_init_size(start, end, size, pos, adj) \
> +	do { \
> +		if (&start[0] <= &pos[0] && &pos[0] < &end[0] && size > adj) \
> +			size -= adj; \
> +	} while (0)
> +
> +	adj_init_size(__init_begin, __init_end, init_data_size,
> +		     _sinittext, init_code_size);
> +	adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
> +	adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
> +	adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
> +	adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
> +
> +#undef	adj_init_size
> +
> +	pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
> +#ifdef	CONFIG_HIGHMEM
> +		", %luK highmem"
> +#endif
> +		")\n",
> +		K(nr_free_pages()), K(physpages),
> +		codesize / SZ_1K, datasize / SZ_1K, rosize / SZ_1K,
> +		(init_data_size + init_code_size) / SZ_1K, bss_size / SZ_1K,
> +		K(physpages - totalram_pages() - totalcma_pages),
> +		K(totalcma_pages)
> +#ifdef	CONFIG_HIGHMEM
> +		, K(totalhigh_pages())
> +#endif
> +		);
> +}
> +
>   void __init page_alloc_init_late(void)
>   {
>   	struct zone *zone;
> @@ -2348,6 +2399,7 @@ void __init page_alloc_init_late(void)
>   	files_maxfiles_init();
>   #endif
>   

Maybe add a comment like

/* Accounting of total+free memory is stable at this point. */

> +	mem_init_print_info();


-- 
Cheers,

David / dhildenb

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

[Wei Yang]

On Tue, Jun 11, 2024 at 04:26:56PM +0200, David Hildenbrand wrote:
>On 11.06.24 05:08, 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.
>> 
>
>Maybe mention that this will also help changing totalpage accounting.
>

Sure.

>> Let's print the mem info after defer_init is done.
>> 
>> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
>> CC: David Hildenbrand <david@redhat.com>
>> ---
>>   mm/mm_init.c | 104 +++++++++++++++++++++++++--------------------------
>>   1 file changed, 52 insertions(+), 52 deletions(-)
>> 
>> diff --git a/mm/mm_init.c b/mm/mm_init.c
>> index f72b852bd5b8..34a6de20ef77 100644
>> --- a/mm/mm_init.c
>> +++ b/mm/mm_init.c
>> @@ -2322,6 +2322,57 @@ void set_zone_contiguous(struct zone *zone)
>>   	zone->contiguous = true;
>>   }
>> +static void __init mem_init_print_info(void)
>
>Can you avoid all that churn simply by doing a
>
>static void __init mem_init_print_info(void);
>
>somewhere at the beginning of this file?

Ok, if this is preferred.

>
>> +{
>> +	unsigned long physpages, codesize, datasize, rosize, bss_size;
>> +	unsigned long init_code_size, init_data_size;
>> +
>> +	physpages = get_num_physpages();
>> +	codesize = _etext - _stext;
>> +	datasize = _edata - _sdata;
>> +	rosize = __end_rodata - __start_rodata;
>> +	bss_size = __bss_stop - __bss_start;
>> +	init_data_size = __init_end - __init_begin;
>> +	init_code_size = _einittext - _sinittext;
>> +
>> +	/*
>> +	 * Detect special cases and adjust section sizes accordingly:
>> +	 * 1) .init.* may be embedded into .data sections
>> +	 * 2) .init.text.* may be out of [__init_begin, __init_end],
>> +	 *    please refer to arch/tile/kernel/vmlinux.lds.S.
>> +	 * 3) .rodata.* may be embedded into .text or .data sections.
>> +	 */
>> +#define adj_init_size(start, end, size, pos, adj) \
>> +	do { \
>> +		if (&start[0] <= &pos[0] && &pos[0] < &end[0] && size > adj) \
>> +			size -= adj; \
>> +	} while (0)
>> +
>> +	adj_init_size(__init_begin, __init_end, init_data_size,
>> +		     _sinittext, init_code_size);
>> +	adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
>> +	adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
>> +	adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
>> +	adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
>> +
>> +#undef	adj_init_size
>> +
>> +	pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
>> +#ifdef	CONFIG_HIGHMEM
>> +		", %luK highmem"
>> +#endif
>> +		")\n",
>> +		K(nr_free_pages()), K(physpages),
>> +		codesize / SZ_1K, datasize / SZ_1K, rosize / SZ_1K,
>> +		(init_data_size + init_code_size) / SZ_1K, bss_size / SZ_1K,
>> +		K(physpages - totalram_pages() - totalcma_pages),
>> +		K(totalcma_pages)
>> +#ifdef	CONFIG_HIGHMEM
>> +		, K(totalhigh_pages())
>> +#endif
>> +		);
>> +}
>> +
>>   void __init page_alloc_init_late(void)
>>   {
>>   	struct zone *zone;
>> @@ -2348,6 +2399,7 @@ void __init page_alloc_init_late(void)
>>   	files_maxfiles_init();
>>   #endif
>
>Maybe add a comment like
>
>/* Accounting of total+free memory is stable at this point. */
>
>> +	mem_init_print_info();
>
>
>-- 
>Cheers,
>
>David / dhildenb

-- 
Wei Yang
Help you, Help me