mm, page_alloc: remove setup_pageset()

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.

Link: https://lkml.kernel.org/r/20201111092812.11329-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ced4366ee3d407524d6961aa90d0c71d65017b5a..b1e3483249c311dedf43e9379318befcb291dbc2 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5919,7 +5919,7 @@ 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);
 
@@ -5987,7 +5987,7 @@ 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();
@@ -6306,12 +6306,15 @@ 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;
 }
 
 /*