[04/10] mm: fix LRU balancing effect of new transparent huge pages
diff mbox series

Message ID 20160606194836.3624-5-hannes@cmpxchg.org
State New, archived
Headers show
Series
  • mm: balance LRU lists based on relative thrashing
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Commit Message

Johannes Weiner June 6, 2016, 7:48 p.m. UTC
Currently, THP are counted as single pages until they are split right
before being swapped out. However, at that point the VM is already in
the middle of reclaim, and adjusting the LRU balance then is useless.

Always account THP by the number of basepages, and remove the fixup
from the splitting path.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
 mm/swap.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

Comments

Rik van Riel June 6, 2016, 9:36 p.m. UTC | #1
On Mon, 2016-06-06 at 15:48 -0400, Johannes Weiner wrote:
> Currently, THP are counted as single pages until they are split right
> before being swapped out. However, at that point the VM is already in
> the middle of reclaim, and adjusting the LRU balance then is useless.
> 
> Always account THP by the number of basepages, and remove the fixup
> from the splitting path.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> 

Reviewed-by: Rik van Riel <riel@redhat.com>
Michal Hocko June 7, 2016, 9:19 a.m. UTC | #2
On Mon 06-06-16 15:48:30, Johannes Weiner wrote:
> Currently, THP are counted as single pages until they are split right
> before being swapped out. However, at that point the VM is already in
> the middle of reclaim, and adjusting the LRU balance then is useless.
> 
> Always account THP by the number of basepages, and remove the fixup
> from the splitting path.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  mm/swap.c | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/mm/swap.c b/mm/swap.c
> index d2786a6308dd..c6936507abb5 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -249,13 +249,14 @@ void rotate_reclaimable_page(struct page *page)
>  }
>  
>  static void update_page_reclaim_stat(struct lruvec *lruvec,
> -				     int file, int rotated)
> +				     int file, int rotated,
> +				     unsigned int nr_pages)
>  {
>  	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
>  
> -	reclaim_stat->recent_scanned[file]++;
> +	reclaim_stat->recent_scanned[file] += nr_pages;
>  	if (rotated)
> -		reclaim_stat->recent_rotated[file]++;
> +		reclaim_stat->recent_rotated[file] += nr_pages;
>  }
>  
>  static void __activate_page(struct page *page, struct lruvec *lruvec,
> @@ -272,7 +273,7 @@ static void __activate_page(struct page *page, struct lruvec *lruvec,
>  		trace_mm_lru_activate(page);
>  
>  		__count_vm_event(PGACTIVATE);
> -		update_page_reclaim_stat(lruvec, file, 1);
> +		update_page_reclaim_stat(lruvec, file, 1, hpage_nr_pages(page));
>  	}
>  }
>  
> @@ -532,7 +533,7 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec,
>  
>  	if (active)
>  		__count_vm_event(PGDEACTIVATE);
> -	update_page_reclaim_stat(lruvec, file, 0);
> +	update_page_reclaim_stat(lruvec, file, 0, hpage_nr_pages(page));
>  }
>  
>  
> @@ -549,7 +550,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
>  		add_page_to_lru_list(page, lruvec, lru);
>  
>  		__count_vm_event(PGDEACTIVATE);
> -		update_page_reclaim_stat(lruvec, file, 0);
> +		update_page_reclaim_stat(lruvec, file, 0, hpage_nr_pages(page));
>  	}
>  }
>  
> @@ -809,9 +810,6 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
>  		list_head = page_tail->lru.prev;
>  		list_move_tail(&page_tail->lru, list_head);
>  	}
> -
> -	if (!PageUnevictable(page))
> -		update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
>  }
>  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>  
> @@ -826,7 +824,7 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
>  
>  	SetPageLRU(page);
>  	add_page_to_lru_list(page, lruvec, lru);
> -	update_page_reclaim_stat(lruvec, file, active);
> +	update_page_reclaim_stat(lruvec, file, active, hpage_nr_pages(page));
>  	trace_mm_lru_insertion(page, lru);
>  }
>  
> -- 
> 2.8.3
Minchan Kim June 8, 2016, 7:28 a.m. UTC | #3
On Mon, Jun 06, 2016 at 03:48:30PM -0400, Johannes Weiner wrote:
> Currently, THP are counted as single pages until they are split right
> before being swapped out. However, at that point the VM is already in
> the middle of reclaim, and adjusting the LRU balance then is useless.
> 
> Always account THP by the number of basepages, and remove the fixup
> from the splitting path.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Minchan Kim <minchan@kernel.org>

Patch
diff mbox series

diff --git a/mm/swap.c b/mm/swap.c
index d2786a6308dd..c6936507abb5 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -249,13 +249,14 @@  void rotate_reclaimable_page(struct page *page)
 }
 
 static void update_page_reclaim_stat(struct lruvec *lruvec,
-				     int file, int rotated)
+				     int file, int rotated,
+				     unsigned int nr_pages)
 {
 	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
 
-	reclaim_stat->recent_scanned[file]++;
+	reclaim_stat->recent_scanned[file] += nr_pages;
 	if (rotated)
-		reclaim_stat->recent_rotated[file]++;
+		reclaim_stat->recent_rotated[file] += nr_pages;
 }
 
 static void __activate_page(struct page *page, struct lruvec *lruvec,
@@ -272,7 +273,7 @@  static void __activate_page(struct page *page, struct lruvec *lruvec,
 		trace_mm_lru_activate(page);
 
 		__count_vm_event(PGACTIVATE);
-		update_page_reclaim_stat(lruvec, file, 1);
+		update_page_reclaim_stat(lruvec, file, 1, hpage_nr_pages(page));
 	}
 }
 
@@ -532,7 +533,7 @@  static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec,
 
 	if (active)
 		__count_vm_event(PGDEACTIVATE);
-	update_page_reclaim_stat(lruvec, file, 0);
+	update_page_reclaim_stat(lruvec, file, 0, hpage_nr_pages(page));
 }
 
 
@@ -549,7 +550,7 @@  static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
 		add_page_to_lru_list(page, lruvec, lru);
 
 		__count_vm_event(PGDEACTIVATE);
-		update_page_reclaim_stat(lruvec, file, 0);
+		update_page_reclaim_stat(lruvec, file, 0, hpage_nr_pages(page));
 	}
 }
 
@@ -809,9 +810,6 @@  void lru_add_page_tail(struct page *page, struct page *page_tail,
 		list_head = page_tail->lru.prev;
 		list_move_tail(&page_tail->lru, list_head);
 	}
-
-	if (!PageUnevictable(page))
-		update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
@@ -826,7 +824,7 @@  static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
 
 	SetPageLRU(page);
 	add_page_to_lru_list(page, lruvec, lru);
-	update_page_reclaim_stat(lruvec, file, active);
+	update_page_reclaim_stat(lruvec, file, active, hpage_nr_pages(page));
 	trace_mm_lru_insertion(page, lru);
 }