diff mbox series

[5.4,1/5] memblock: free_unused_memmap: use pageblock units instead of MAX_ORDER

Message ID 20211213085710.28962-2-mark-pk.tsai@mediatek.com (mailing list archive)
State New
Headers show
Series memblock, arm: fixes for freeing of the memory map | expand

Commit Message

Mark-PK Tsai (蔡沛剛) Dec. 13, 2021, 8:57 a.m. UTC
From: Mike Rapoport <rppt@linux.ibm.com>

commit e2a86800d58639b3acde7eaeb9eb393dca066e08 upstream.

The code that frees unused memory map uses rounds start and end of the
holes that are freed to MAX_ORDER_NR_PAGES to preserve continuity of the
memory map for MAX_ORDER regions.

Lots of core memory management functionality relies on homogeneity of the
memory map within each pageblock which size may differ from MAX_ORDER in
certain configurations.

Although currently, for the architectures that use free_unused_memmap(),
pageblock_order and MAX_ORDER are equivalent, it is cleaner to have common
notation thought mm code.

Replace MAX_ORDER_NR_PAGES with pageblock_nr_pages and update the comments
to make it more clear why the alignment to pageblock boundaries is
required.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/lkml/20210630071211.21011-1-rppt@kernel.org/
[backport upstream modification in mm/memblock.c to arch/arm/mm/init.c]
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
---
 arch/arm/mm/init.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Comments

Mike Rapoport Dec. 13, 2021, 10:31 a.m. UTC | #1
On Mon, Dec 13, 2021 at 04:57:06PM +0800, Mark-PK Tsai wrote:

> Subject: [PATCH 5.4 1/5] memblock: free_unused_memmap: use pageblock units instead of MAX_ORDER

I'd replace memblock: with arm: in the subject. I believe it's clearer this
way.

The same applies for the second patch in the series and for 5.10 posting.

> From: Mike Rapoport <rppt@linux.ibm.com>
> 
> commit e2a86800d58639b3acde7eaeb9eb393dca066e08 upstream.
> 
> The code that frees unused memory map uses rounds start and end of the
> holes that are freed to MAX_ORDER_NR_PAGES to preserve continuity of the
> memory map for MAX_ORDER regions.
> 
> Lots of core memory management functionality relies on homogeneity of the
> memory map within each pageblock which size may differ from MAX_ORDER in
> certain configurations.
> 
> Although currently, for the architectures that use free_unused_memmap(),
> pageblock_order and MAX_ORDER are equivalent, it is cleaner to have common
> notation thought mm code.
> 
> Replace MAX_ORDER_NR_PAGES with pageblock_nr_pages and update the comments
> to make it more clear why the alignment to pageblock boundaries is
> required.
> 
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> Tested-by: Tony Lindgren <tony@atomide.com>
> Link: https://lore.kernel.org/lkml/20210630071211.21011-1-rppt@kernel.org/
> [backport upstream modification in mm/memblock.c to arch/arm/mm/init.c]
> Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
> ---
>  arch/arm/mm/init.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
> index 7ea4d3b43444..6905dd8bc03f 100644
> --- a/arch/arm/mm/init.c
> +++ b/arch/arm/mm/init.c
> @@ -381,11 +381,11 @@ static void __init free_unused_memmap(void)
>  				 ALIGN(prev_end, PAGES_PER_SECTION));
>  #else
>  		/*
> -		 * Align down here since the VM subsystem insists that the
> -		 * memmap entries are valid from the bank start aligned to
> -		 * MAX_ORDER_NR_PAGES.
> +		 * Align down here since many operations in VM subsystem
> +		 * presume that there are no holes in the memory map inside
> +		 * a pageblock
>  		 */
> -		start = round_down(start, MAX_ORDER_NR_PAGES);
> +		start = round_down(start, pageblock_nr_pages);
>  #endif
>  		/*
>  		 * If we had a previous bank, and there is a space
> @@ -395,12 +395,12 @@ static void __init free_unused_memmap(void)
>  			free_memmap(prev_end, start);
>  
>  		/*
> -		 * Align up here since the VM subsystem insists that the
> -		 * memmap entries are valid from the bank end aligned to
> -		 * MAX_ORDER_NR_PAGES.
> +		 * Align up here since many operations in VM subsystem
> +		 * presume that there are no holes in the memory map inside
> +		 * a pageblock
>  		 */
>  		prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
> -				 MAX_ORDER_NR_PAGES);
> +				 pageblock_nr_pages);
>  	}
>  
>  #ifdef CONFIG_SPARSEMEM
> -- 
> 2.18.0
>
diff mbox series

Patch

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 7ea4d3b43444..6905dd8bc03f 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -381,11 +381,11 @@  static void __init free_unused_memmap(void)
 				 ALIGN(prev_end, PAGES_PER_SECTION));
 #else
 		/*
-		 * Align down here since the VM subsystem insists that the
-		 * memmap entries are valid from the bank start aligned to
-		 * MAX_ORDER_NR_PAGES.
+		 * Align down here since many operations in VM subsystem
+		 * presume that there are no holes in the memory map inside
+		 * a pageblock
 		 */
-		start = round_down(start, MAX_ORDER_NR_PAGES);
+		start = round_down(start, pageblock_nr_pages);
 #endif
 		/*
 		 * If we had a previous bank, and there is a space
@@ -395,12 +395,12 @@  static void __init free_unused_memmap(void)
 			free_memmap(prev_end, start);
 
 		/*
-		 * Align up here since the VM subsystem insists that the
-		 * memmap entries are valid from the bank end aligned to
-		 * MAX_ORDER_NR_PAGES.
+		 * Align up here since many operations in VM subsystem
+		 * presume that there are no holes in the memory map inside
+		 * a pageblock
 		 */
 		prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
-				 MAX_ORDER_NR_PAGES);
+				 pageblock_nr_pages);
 	}
 
 #ifdef CONFIG_SPARSEMEM