On Tue, Oct 22, 2019 at 10:48:02AM -0400, Johannes Weiner wrote:
> This function is getting long and unwieldy, split out the memcg bits.
>
> The updated 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 a new 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>
> ---
> mm/vmscan.c | 28 ++++++++++++++++++----------
> 1 file changed, 18 insertions(+), 10 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index db073b40c432..65baa89740dd 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -2722,18 +2722,10 @@ 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;
> - 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, NULL);
> do {
> @@ -2786,6 +2778,22 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
> sc->nr_reclaimed - reclaimed);
>
> } while ((memcg = mem_cgroup_iter(root, memcg, NULL)));
> +}
> +
> +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;
> @@ -2793,7 +2801,7 @@ 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,
Maybe target? Or target_memcg? The word root is associated with the root cgroup.
Other than root the patch looks good to me:
Reviewed-by: Roman Gushchin <guro@xxxxxx>
