[PATCH 3/9] mm, page_alloc: remove setup_pageset()

Vlastimil Babka
2020-09-22T14:37:23Z

We initialize boot-time pagesets with setup_pageset(), which sets high and
batch values that effectively disable pcplists.

We can remove this wrapper if we just set these values for all pagesets in
pageset_init(). Non-boot pagesets then subsequently update them to the proper
values.

No functional change.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/page_alloc.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 26069c8d1b19..76c2b4578723 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5823,7 +5823,7 @@ 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);
+static void pageset_init(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);

@@ -5891,7 +5891,7 @@ build_all_zonelists_init(void)
* (a chicken-egg dilemma).
*/
for_each_possible_cpu(cpu)
- setup_pageset(&per_cpu(boot_pageset, cpu));
+ pageset_init(&per_cpu(boot_pageset, cpu));

mminit_verify_zonelist();
cpuset_init_current_mems_allowed();
@@ -6210,12 +6210,15 @@ static void pageset_init(struct per_cpu_pageset *p)
pcp = &p->pcp;
for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
INIT_LIST_HEAD(&pcp->lists[migratetype]);
-}

-static void setup_pageset(struct per_cpu_pageset *p)
-{
- pageset_init(p);
- pageset_update(&p->pcp, 0, 1);
+ /*
+ * Set batch and high values safe for a boot pageset. A true percpu
+ * pageset's initialization will update them subsequently. Here we don't
+ * need to be as careful as pageset_update() as nobody can access the
+ * pageset yet.
+ */
+ pcp->high = 0;
+ pcp->batch = 1;
}

/*
--
2.28.0