On Mon, Jun 3, 2019 at 3:00 PM Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
>
> This function is getting long and unwieldy. The new shrink_node()
> handles the generic (node) reclaim aspects:
> - global vmpressure notifications
> - writeback and congestion throttling
> - reclaim/compaction management
> - kswapd giving up on unreclaimable nodes
>
> It then calls shrink_node_memcgs() which handles cgroup specifics:
> - the cgroup tree traversal
> - memory.low considerations
> - per-cgroup slab shrinking callbacks
> - per-cgroup vmpressure notifications
>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
> ---
> mm/vmscan.c | 29 ++++++++++++++++++-----------
> 1 file changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index b85111474ee2..ee79b39d0538 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -2665,24 +2665,15 @@ static bool pgdat_memcg_congested(pg_data_t *pgdat, struct mem_cgroup *memcg)
> (memcg && memcg_congested(pgdat, memcg));
> }
>
> -static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
> +static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc)
> {
> - struct reclaim_state *reclaim_state = current->reclaim_state;
> struct mem_cgroup *root = sc->target_mem_cgroup;
> struct mem_cgroup_reclaim_cookie reclaim = {
> .pgdat = pgdat,
> .priority = sc->priority,
> };
> - unsigned long nr_reclaimed, nr_scanned;
> - bool reclaimable = false;
> struct mem_cgroup *memcg;
>
> -again:
> - memset(&sc->nr, 0, sizeof(sc->nr));
> -
> - nr_reclaimed = sc->nr_reclaimed;
> - nr_scanned = sc->nr_scanned;
> -
> memcg = mem_cgroup_iter(root, NULL, &reclaim);
> do {
> struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
> @@ -2750,6 +2741,22 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
> break;
> }
> } while ((memcg = mem_cgroup_iter(root, memcg, &reclaim)));
> +}
> +
> +static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
> +{
> + struct reclaim_state *reclaim_state = current->reclaim_state;
> + struct mem_cgroup *root = sc->target_mem_cgroup;
> + unsigned long nr_reclaimed, nr_scanned;
> + bool reclaimable = false;
> +
> +again:
> + memset(&sc->nr, 0, sizeof(sc->nr));
> +
> + nr_reclaimed = sc->nr_reclaimed;
> + nr_scanned = sc->nr_scanned;
> +
> + shrink_node_memcgs(pgdat, sc);
>
> if (reclaim_state) {
> sc->nr_reclaimed += reclaim_state->reclaimed_slab;
> @@ -2757,7 +2764,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
> }
>
> /* Record the subtree's reclaim efficiency */
> - vmpressure(sc->gfp_mask, sc->target_mem_cgroup, true,
> + vmpressure(sc->gfp_mask, root, true,
> sc->nr_scanned - nr_scanned,
> sc->nr_reclaimed - nr_reclaimed);
>
> --
> 2.21.0
>
