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    SubjectRe: [PATCH 3/9] mm, page_alloc: remove setup_pageset()
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    On 22.09.20 16:37, Vlastimil Babka wrote:
    > 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;
    > }
    >
    > /*
    >

    Reviewed-by: David Hildenbrand <david@redhat.com>

    --
    Thanks,

    David / dhildenb

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