lkml.org 
[lkml]   [2020]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC 2/5] mm, page_alloc: calculate pageset high and batch once per zone
Date
We currently call pageset_set_high_and_batch() for each possible cpu,
which repeats the same calculations of high and batch values.

Instead call it once per zone, and it applies the calculated values
to all per-cpu pagesets of the zone.

This also allows removing zone_pageset_init() and __zone_pcp_update() wrappers.

No functional change.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/page_alloc.c | 40 +++++++++++++++++-----------------------
1 file changed, 17 insertions(+), 23 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0b516208afda..f669a251f654 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6236,12 +6236,13 @@ static void setup_pageset(struct per_cpu_pageset *p)
pageset_update(&p->pcp, 0, 1);
}

-static void pageset_set_high_and_batch(struct zone *zone,
- struct per_cpu_pageset *p)
+static void zone_set_pageset_high_and_batch(struct zone *zone)
{
unsigned long new_high;
unsigned long new_batch;
int fraction = READ_ONCE(percpu_pagelist_fraction);
+ int cpu;
+ struct per_cpu_pageset *p;

if (fraction) {
new_high = zone_managed_pages(zone) / fraction;
@@ -6253,23 +6254,25 @@ static void pageset_set_high_and_batch(struct zone *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)
-{
- struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);

- pageset_init(pcp);
- pageset_set_high_and_batch(zone, pcp);
+ for_each_possible_cpu(cpu) {
+ p = per_cpu_ptr(zone->pageset, cpu);
+ pageset_update(&p->pcp, new_high, new_batch);
+ }
}

void __meminit setup_zone_pageset(struct zone *zone)
{
int cpu;
+ struct per_cpu_pageset *p;
+
zone->pageset = alloc_percpu(struct per_cpu_pageset);
- for_each_possible_cpu(cpu)
- zone_pageset_init(zone, cpu);
+ for_each_possible_cpu(cpu) {
+ p = per_cpu_ptr(zone->pageset, cpu);
+ pageset_init(p);
+ }
+
+ zone_set_pageset_high_and_batch(zone);
}

/*
@@ -8002,15 +8005,6 @@ int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
return 0;
}

-static void __zone_pcp_update(struct zone *zone)
-{
- unsigned int cpu;
-
- for_each_possible_cpu(cpu)
- pageset_set_high_and_batch(zone,
- per_cpu_ptr(zone->pageset, cpu));
-}
-
/*
* percpu_pagelist_fraction - changes the pcp->high for each zone on each
* cpu. It is the fraction of total pages in each zone that a hot per cpu
@@ -8043,7 +8037,7 @@ int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
goto out;

for_each_populated_zone(zone)
- __zone_pcp_update(zone);
+ zone_set_pageset_high_and_batch(zone);
out:
mutex_unlock(&pcp_batch_high_lock);
return ret;
@@ -8659,7 +8653,7 @@ EXPORT_SYMBOL(free_contig_range);
void __meminit zone_pcp_update(struct zone *zone)
{
mutex_lock(&pcp_batch_high_lock);
- __zone_pcp_update(zone);
+ zone_set_pageset_high_and_batch(zone);
mutex_unlock(&pcp_batch_high_lock);
}

--
2.28.0
\
 
 \ /
  Last update: 2020-09-07 18:43    [W:0.171 / U:3.592 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site