[v1] mm/mglru: improve reclaim loop and dirty folio handling

[PATCH 5/8] mm/mglru: use a smaller batch for reclaim

Posted by Kairui Song via B4 Relay 2 weeks, 6 days ago

From: Kairui Song <kasong@tencent.com>

With a fixed number to reclaim calculated at the beginning, making each
following step smaller should reduce the lock contention and avoid
over-aggressive reclaim of folios, as it will abort earlier when the
number of folios to be reclaimed is reached.

Signed-off-by: Kairui Song <kasong@tencent.com>
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4f4548ff3a17..2ff1609ff4de 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -5007,7 +5007,7 @@ static bool try_to_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
 			break;
 		}
 
-		nr_batch = min(nr_to_scan, MAX_LRU_BATCH);
+		nr_batch = min(nr_to_scan, MIN_LRU_BATCH);
 		delta = evict_folios(nr_batch, lruvec, sc, swappiness);
 		if (!delta)
 			break;

-- 
2.53.0

Re: [PATCH 5/8] mm/mglru: use a smaller batch for reclaim

Posted by Chen Ridong 1 week, 6 days ago


On 2026/3/18 3:09, Kairui Song via B4 Relay wrote:
> From: Kairui Song <kasong@tencent.com>
> 
> With a fixed number to reclaim calculated at the beginning, making each
> following step smaller should reduce the lock contention and avoid
> over-aggressive reclaim of folios, as it will abort earlier when the
> number of folios to be reclaimed is reached.
> 
> Signed-off-by: Kairui Song <kasong@tencent.com>
> ---
>  mm/vmscan.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 4f4548ff3a17..2ff1609ff4de 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -5007,7 +5007,7 @@ static bool try_to_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
>  			break;
>  		}
>  
> -		nr_batch = min(nr_to_scan, MAX_LRU_BATCH);
> +		nr_batch = min(nr_to_scan, MIN_LRU_BATCH);
>  		delta = evict_folios(nr_batch, lruvec, sc, swappiness);
>  		if (!delta)
>  			break;
> 

LGTM.

Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>

-- 
Best regards,
Ridong

Re: [PATCH 5/8] mm/mglru: use a smaller batch for reclaim

Posted by Axel Rasmussen 2 weeks, 3 days ago

On Tue, Mar 17, 2026 at 12:11 PM Kairui Song via B4 Relay
<devnull+kasong.tencent.com@kernel.org> wrote:
>
> From: Kairui Song <kasong@tencent.com>
>
> With a fixed number to reclaim calculated at the beginning, making each
> following step smaller should reduce the lock contention and avoid
> over-aggressive reclaim of folios, as it will abort earlier when the
> number of folios to be reclaimed is reached.
>
> Signed-off-by: Kairui Song <kasong@tencent.com>

Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>

> ---
>  mm/vmscan.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 4f4548ff3a17..2ff1609ff4de 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -5007,7 +5007,7 @@ static bool try_to_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
>                         break;
>                 }
>
> -               nr_batch = min(nr_to_scan, MAX_LRU_BATCH);
> +               nr_batch = min(nr_to_scan, MIN_LRU_BATCH);
>                 delta = evict_folios(nr_batch, lruvec, sc, swappiness);
>                 if (!delta)
>                         break;
>
> --
> 2.53.0
>
>