[PATCH v5] mm/page_alloc: fix min_free_kbytes calculation regarding ZONE_MOVABLE

[PATCH v5] mm/page_alloc: fix min_free_kbytes calculation regarding ZONE_MOVABLE

[liuq]

The current calculation of min_free_kbytes only uses ZONE_DMA and
ZONE_NORMAL pages,but the ZONE_MOVABLE zone->_watermark[WMARK_MIN]
will also divide part of min_free_kbytes.This will cause the min
watermark of ZONE_NORMAL to be too small in the presence of ZONE_MOVEABLE.

__GFP_HIGH and PF_MEMALLOC allocations usually don't need movable
zone pages, so just like ZONE_HIGHMEM, cap pages_min to a small
value in __setup_per_zone_wmarks().

On my testing machine with 16GB of memory (transparent hugepage is
turned off by default, and movablecore=12G is configured)
The following is a comparative test data of watermark_min

		no patch	add patch
ZONE_DMA	1		8
ZONE_DMA32	151		709
ZONE_NORMAL	233		1113
ZONE_MOVABLE	1434		128
min_free_kbytes	7288		7326

Signed-off-by: liuq <liuq131@chinatelecom.cn>
---
 mm/page_alloc.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 47421bedc12b..590ed8725e09 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6362,9 +6362,9 @@ static void __setup_per_zone_wmarks(void)
 	struct zone *zone;
 	unsigned long flags;
 
-	/* Calculate total number of !ZONE_HIGHMEM pages */
+	/* Calculate total number of !ZONE_HIGHMEM and !ZONE_MOVABLE pages */
 	for_each_zone(zone) {
-		if (!is_highmem(zone))
+		if (!is_highmem(zone) && zone_idx(zone) != ZONE_MOVABLE)
 			lowmem_pages += zone_managed_pages(zone);
 	}
 
@@ -6374,15 +6374,15 @@ static void __setup_per_zone_wmarks(void)
 		spin_lock_irqsave(&zone->lock, flags);
 		tmp = (u64)pages_min * zone_managed_pages(zone);
 		do_div(tmp, lowmem_pages);
-		if (is_highmem(zone)) {
+		if (is_highmem(zone) || zone_idx(zone) == ZONE_MOVABLE) {
 			/*
 			 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
-			 * need highmem pages, so cap pages_min to a small
-			 * value here.
+			 * need highmem and movable zones pages, so cap pages_min
+			 * to a small  value here.
 			 *
 			 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
 			 * deltas control async page reclaim, and so should
-			 * not be capped for highmem.
+			 * not be capped for highmem and movable zones.
 			 */
 			unsigned long min_pages;
 
-- 
2.27.0

Re: [PATCH v5] mm/page_alloc: fix min_free_kbytes calculation regarding ZONE_MOVABLE

[Huang, Ying]

liuq <liuq131@chinatelecom.cn> writes:

> The current calculation of min_free_kbytes only uses ZONE_DMA and
> ZONE_NORMAL pages,but the ZONE_MOVABLE zone->_watermark[WMARK_MIN]
> will also divide part of min_free_kbytes.This will cause the min
> watermark of ZONE_NORMAL to be too small in the presence of ZONE_MOVEABLE.
>
> __GFP_HIGH and PF_MEMALLOC allocations usually don't need movable
> zone pages, so just like ZONE_HIGHMEM, cap pages_min to a small
> value in __setup_per_zone_wmarks().
>
> On my testing machine with 16GB of memory (transparent hugepage is
> turned off by default, and movablecore=12G is configured)
> The following is a comparative test data of watermark_min
>
> 		no patch	add patch
> ZONE_DMA	1		8
> ZONE_DMA32	151		709
> ZONE_NORMAL	233		1113
> ZONE_MOVABLE	1434		128
> min_free_kbytes	7288		7326
>
> Signed-off-by: liuq <liuq131@chinatelecom.cn>

Thanks!

Reviewed-by: "Huang, Ying" <ying.huang@intel.com>

> ---
>  mm/page_alloc.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 47421bedc12b..590ed8725e09 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -6362,9 +6362,9 @@ static void __setup_per_zone_wmarks(void)
>  	struct zone *zone;
>  	unsigned long flags;
>  
> -	/* Calculate total number of !ZONE_HIGHMEM pages */
> +	/* Calculate total number of !ZONE_HIGHMEM and !ZONE_MOVABLE pages */
>  	for_each_zone(zone) {
> -		if (!is_highmem(zone))
> +		if (!is_highmem(zone) && zone_idx(zone) != ZONE_MOVABLE)
>  			lowmem_pages += zone_managed_pages(zone);
>  	}
>  
> @@ -6374,15 +6374,15 @@ static void __setup_per_zone_wmarks(void)
>  		spin_lock_irqsave(&zone->lock, flags);
>  		tmp = (u64)pages_min * zone_managed_pages(zone);
>  		do_div(tmp, lowmem_pages);
> -		if (is_highmem(zone)) {
> +		if (is_highmem(zone) || zone_idx(zone) == ZONE_MOVABLE) {
>  			/*
>  			 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
> -			 * need highmem pages, so cap pages_min to a small
> -			 * value here.
> +			 * need highmem and movable zones pages, so cap pages_min
> +			 * to a small  value here.
>  			 *
>  			 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
>  			 * deltas control async page reclaim, and so should
> -			 * not be capped for highmem.
> +			 * not be capped for highmem and movable zones.
>  			 */
>  			unsigned long min_pages;