On Tue 22-10-19 10:48:01, Johannes Weiner wrote:
> A lruvec holds LRU pages owned by a certain NUMA node and cgroup.
> Instead of awkwardly passing around a combination of a pgdat and a
> memcg pointer, pass down the lruvec as soon as we can look it up.
>
> Nested callers that need to access node or cgroup properties can look
> them them up if necessary, but there are only a few cases.
>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> ---
> mm/vmscan.c | 21 ++++++++++-----------
> 1 file changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 235d1fc72311..db073b40c432 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -2280,9 +2280,10 @@ enum scan_balance {
> * nr[0] = anon inactive pages to scan; nr[1] = anon active pages to scan
> * nr[2] = file inactive pages to scan; nr[3] = file active pages to scan
> */
> -static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
> - struct scan_control *sc, unsigned long *nr)
> +static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
> + unsigned long *nr)
> {
> + struct mem_cgroup *memcg = lruvec_memcg(lruvec);
> int swappiness = mem_cgroup_swappiness(memcg);
> struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
> u64 fraction[2];
> @@ -2530,13 +2531,8 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
> }
> }
>
> -/*
> - * This is a basic per-node page freer. Used by both kswapd and direct reclaim.
> - */
> -static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memcg,
> - struct scan_control *sc)
> +static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
> {
> - struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
> unsigned long nr[NR_LRU_LISTS];
> unsigned long targets[NR_LRU_LISTS];
> unsigned long nr_to_scan;
> @@ -2546,7 +2542,7 @@ static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memc
> struct blk_plug plug;
> bool scan_adjusted;
>
> - get_scan_count(lruvec, memcg, sc, nr);
> + get_scan_count(lruvec, sc, nr);
>
> /* Record the original scan target for proportional adjustments later */
> memcpy(targets, nr, sizeof(nr));
> @@ -2741,6 +2737,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
>
> memcg = mem_cgroup_iter(root, NULL, NULL);
> do {
> + struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
> unsigned long reclaimed;
> unsigned long scanned;
>
> @@ -2777,7 +2774,8 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
>
> reclaimed = sc->nr_reclaimed;
> scanned = sc->nr_scanned;
> - shrink_node_memcg(pgdat, memcg, sc);
> +
> + shrink_lruvec(lruvec, sc);
>
> shrink_slab(sc->gfp_mask, pgdat->node_id, memcg,
> sc->priority);
> @@ -3281,6 +3279,7 @@ unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
> pg_data_t *pgdat,
> unsigned long *nr_scanned)
> {
> + struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
> struct scan_control sc = {
> .nr_to_reclaim = SWAP_CLUSTER_MAX,
> .target_mem_cgroup = memcg,
> @@ -3307,7 +3306,7 @@ unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
> * will pick up pages from other mem cgroup's as well. We hack
> * the priority and make it zero.
> */
> - shrink_node_memcg(pgdat, memcg, &sc);
> + shrink_lruvec(lruvec, &sc);
>
> trace_mm_vmscan_memcg_softlimit_reclaim_end(
> cgroup_ino(memcg->css.cgroup),
> --
> 2.23.0
--
Michal Hocko
SUSE Labs
