Commit 0a8b4f1d authored by Vlastimil Babka's avatar Vlastimil Babka Committed by Linus Torvalds
Browse files

mm, page_alloc: calculate pageset high and batch once per zone 

We currently call pageset_set_high_and_batch() for each possible cpu,
which repeats the same calculations of high and batch values.

Instead call the function just once per zone, and make it apply the
calculated values to all per-cpu pagesets of the zone.

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

No functional change.

Link: https://lkml.kernel.org/r/20201111092812.11329-3-vbabka@suse.cz


Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
Reviewed-by: default avatarOscar Salvador <osalvador@suse.de>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarPankaj Gupta <pankaj.gupta@cloud.ionos.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7115ac6e

mm/page_alloc.c

+18 −24
Original line number Diff line number Diff line
@@ -6315,13 +6315,14 @@ static void setup_pageset(struct per_cpu_pageset *p) 
}



/*

 * Calculate and set new high and batch values for given per-cpu pageset of a

 * Calculate and set new high and batch values for all per-cpu pagesets of a

 * zone, based on the zone's size and the percpu_pagelist_fraction sysctl.

 */

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, new_batch;

	struct per_cpu_pageset *p;

	int cpu;



	if (percpu_pagelist_fraction) {

		new_high = zone_managed_pages(zone) / percpu_pagelist_fraction;
@@ -6333,23 +6334,25 @@ static void pageset_set_high_and_batch(struct zone *zone, 
		new_high = 6 * new_batch;

		new_batch = max(1UL, 1 * new_batch);

	}



	for_each_possible_cpu(cpu) {

		p = per_cpu_ptr(zone->pageset, cpu);

		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);

}



void __meminit setup_zone_pageset(struct zone *zone)

{

	struct per_cpu_pageset *p;

	int cpu;



	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);

}



/*
@@ -8083,15 +8086,6 @@ 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
@@ -8124,7 +8118,7 @@ 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;
@@ -8731,7 +8725,7 @@ 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);

}

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