diff mbox series

[v3,1/7] mm, page_alloc: clean up pageset high and batch update

Message ID 20201111092812.11329-2-vbabka@suse.cz (mailing list archive)
State New, archived
Headers show
Series disable pcplists during memory offline | expand

Commit Message

Vlastimil Babka Nov. 11, 2020, 9:28 a.m. UTC
The updates to pcplists' high and batch values are handled by multiple
functions that make the calculations hard to follow. Consolidate everything
to pageset_set_high_and_batch() and remove pageset_set_batch() and
pageset_set_high() wrappers.

The only special case using one of the removed wrappers was:
build_all_zonelists_init()
  setup_pageset()
    pageset_set_batch()
which was hardcoding batch as 0, so we can just open-code a call to
pageset_update() with constant parameters instead.

No functional change.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
---
 mm/page_alloc.c | 49 ++++++++++++++++++++-----------------------------
 1 file changed, 20 insertions(+), 29 deletions(-)

Comments

Pankaj Gupta Nov. 11, 2020, 9:55 a.m. UTC | #1
> The updates to pcplists' high and batch values are handled by multiple
> functions that make the calculations hard to follow. Consolidate everything
> to pageset_set_high_and_batch() and remove pageset_set_batch() and
> pageset_set_high() wrappers.
>
> The only special case using one of the removed wrappers was:
> build_all_zonelists_init()
>   setup_pageset()
>     pageset_set_batch()
> which was hardcoding batch as 0, so we can just open-code a call to
> pageset_update() with constant parameters instead.
>
> No functional change.
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Reviewed-by: Oscar Salvador <osalvador@suse.de>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> ---
>  mm/page_alloc.c | 49 ++++++++++++++++++++-----------------------------
>  1 file changed, 20 insertions(+), 29 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 7560240fcf7d..3f1c57344e73 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5911,7 +5911,7 @@ static void build_zonelists(pg_data_t *pgdat)
>   * not check if the processor is online before following the pageset pointer.
>   * Other parts of the kernel may not check if the zone is available.
>   */
> -static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
> +static void setup_pageset(struct per_cpu_pageset *p);
>  static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
>  static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
>
> @@ -5979,7 +5979,7 @@ build_all_zonelists_init(void)
>          * (a chicken-egg dilemma).
>          */
>         for_each_possible_cpu(cpu)
> -               setup_pageset(&per_cpu(boot_pageset, cpu), 0);
> +               setup_pageset(&per_cpu(boot_pageset, cpu));
>
>         mminit_verify_zonelist();
>         cpuset_init_current_mems_allowed();
> @@ -6288,12 +6288,6 @@ static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
>         pcp->batch = batch;
>  }
>
> -/* a companion to pageset_set_high() */
> -static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
> -{
> -       pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
> -}
> -
>  static void pageset_init(struct per_cpu_pageset *p)
>  {
>         struct per_cpu_pages *pcp;
> @@ -6306,35 +6300,32 @@ static void pageset_init(struct per_cpu_pageset *p)
>                 INIT_LIST_HEAD(&pcp->lists[migratetype]);
>  }
>
> -static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
> +static void setup_pageset(struct per_cpu_pageset *p)
>  {
>         pageset_init(p);
> -       pageset_set_batch(p, batch);
> +       pageset_update(&p->pcp, 0, 1);
>  }
>
>  /*
> - * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
> - * to the value high for the pageset p.
> + * Calculate and set new high and batch values for given per-cpu pageset of a
> + * zone, based on the zone's size and the percpu_pagelist_fraction sysctl.
>   */
> -static void pageset_set_high(struct per_cpu_pageset *p,
> -                               unsigned long high)
> -{
> -       unsigned long batch = max(1UL, high / 4);
> -       if ((high / 4) > (PAGE_SHIFT * 8))
> -               batch = PAGE_SHIFT * 8;
> -
> -       pageset_update(&p->pcp, high, batch);
> -}
> -
>  static void pageset_set_high_and_batch(struct zone *zone,
> -                                      struct per_cpu_pageset *pcp)
> +                                      struct per_cpu_pageset *p)
>  {
> -       if (percpu_pagelist_fraction)
> -               pageset_set_high(pcp,
> -                       (zone_managed_pages(zone) /
> -                               percpu_pagelist_fraction));
> -       else
> -               pageset_set_batch(pcp, zone_batchsize(zone));
> +       unsigned long new_high, new_batch;
> +
> +       if (percpu_pagelist_fraction) {
> +               new_high = zone_managed_pages(zone) / percpu_pagelist_fraction;
> +               new_batch = max(1UL, new_high / 4);
> +               if ((new_high / 4) > (PAGE_SHIFT * 8))
> +                       new_batch = PAGE_SHIFT * 8;
> +       } else {
> +               new_batch = zone_batchsize(zone);
> +               new_high = 6 * new_batch;
> +               new_batch = max(1UL, 1 * new_batch);
> +       }
> +       pageset_update(&p->pcp, new_high, new_batch);
>  }
>
>  static void __meminit zone_pageset_init(struct zone *zone, int cpu)

Looks good to me.
Acked-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
diff mbox series

Patch

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7560240fcf7d..3f1c57344e73 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5911,7 +5911,7 @@  static void build_zonelists(pg_data_t *pgdat)
  * not check if the processor is online before following the pageset pointer.
  * Other parts of the kernel may not check if the zone is available.
  */
-static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
+static void setup_pageset(struct per_cpu_pageset *p);
 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
 static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
 
@@ -5979,7 +5979,7 @@  build_all_zonelists_init(void)
 	 * (a chicken-egg dilemma).
 	 */
 	for_each_possible_cpu(cpu)
-		setup_pageset(&per_cpu(boot_pageset, cpu), 0);
+		setup_pageset(&per_cpu(boot_pageset, cpu));
 
 	mminit_verify_zonelist();
 	cpuset_init_current_mems_allowed();
@@ -6288,12 +6288,6 @@  static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
 	pcp->batch = batch;
 }
 
-/* a companion to pageset_set_high() */
-static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
-{
-	pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
-}
-
 static void pageset_init(struct per_cpu_pageset *p)
 {
 	struct per_cpu_pages *pcp;
@@ -6306,35 +6300,32 @@  static void pageset_init(struct per_cpu_pageset *p)
 		INIT_LIST_HEAD(&pcp->lists[migratetype]);
 }
 
-static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
+static void setup_pageset(struct per_cpu_pageset *p)
 {
 	pageset_init(p);
-	pageset_set_batch(p, batch);
+	pageset_update(&p->pcp, 0, 1);
 }
 
 /*
- * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
- * to the value high for the pageset p.
+ * Calculate and set new high and batch values for given per-cpu pageset of a
+ * zone, based on the zone's size and the percpu_pagelist_fraction sysctl.
  */
-static void pageset_set_high(struct per_cpu_pageset *p,
-				unsigned long high)
-{
-	unsigned long batch = max(1UL, high / 4);
-	if ((high / 4) > (PAGE_SHIFT * 8))
-		batch = PAGE_SHIFT * 8;
-
-	pageset_update(&p->pcp, high, batch);
-}
-
 static void pageset_set_high_and_batch(struct zone *zone,
-				       struct per_cpu_pageset *pcp)
+				       struct per_cpu_pageset *p)
 {
-	if (percpu_pagelist_fraction)
-		pageset_set_high(pcp,
-			(zone_managed_pages(zone) /
-				percpu_pagelist_fraction));
-	else
-		pageset_set_batch(pcp, zone_batchsize(zone));
+	unsigned long new_high, new_batch;
+
+	if (percpu_pagelist_fraction) {
+		new_high = zone_managed_pages(zone) / percpu_pagelist_fraction;
+		new_batch = max(1UL, new_high / 4);
+		if ((new_high / 4) > (PAGE_SHIFT * 8))
+			new_batch = PAGE_SHIFT * 8;
+	} else {
+		new_batch = zone_batchsize(zone);
+		new_high = 6 * new_batch;
+		new_batch = max(1UL, 1 * new_batch);
+	}
+	pageset_update(&p->pcp, new_high, new_batch);
 }
 
 static void __meminit zone_pageset_init(struct zone *zone, int cpu)