diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 48 |
1 files changed, 47 insertions, 1 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 967bc7ea239d..b19ebb3a666b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2231,9 +2231,21 @@ static inline bool should_continue_reclaim(struct zone *zone, } } -static void shrink_zone(struct zone *zone, struct scan_control *sc) +/** + * __shrink_zone - shrinks a given zone + * + * @zone: zone to shrink + * @sc: scan control with additional reclaim parameters + * @honor_memcg_guarantee: do not reclaim memcgs which are within their memory + * guarantee + * + * Returns the number of reclaimed memcgs. + */ +static unsigned __shrink_zone(struct zone *zone, struct scan_control *sc, + bool honor_memcg_guarantee) { unsigned long nr_reclaimed, nr_scanned; + unsigned nr_scanned_groups = 0; do { struct mem_cgroup *root = sc->target_mem_cgroup; @@ -2250,7 +2262,20 @@ static void shrink_zone(struct zone *zone, struct scan_control *sc) do { struct lruvec *lruvec; + /* Memcg might be protected from the reclaim */ + if (honor_memcg_guarantee && + mem_cgroup_within_guarantee(memcg, root)) { + /* + * It would be more optimal to skip the memcg + * subtree now but we do not have a memcg iter + * helper for that. Anyone? + */ + memcg = mem_cgroup_iter(root, memcg, &reclaim); + continue; + } + lruvec = mem_cgroup_zone_lruvec(zone, memcg); + nr_scanned_groups++; sc->swappiness = mem_cgroup_swappiness(memcg); shrink_lruvec(lruvec, sc); @@ -2279,6 +2304,27 @@ static void shrink_zone(struct zone *zone, struct scan_control *sc) } while (should_continue_reclaim(zone, sc->nr_reclaimed - nr_reclaimed, sc->nr_scanned - nr_scanned, sc)); + + return nr_scanned_groups; +} + +static void shrink_zone(struct zone *zone, struct scan_control *sc) +{ + bool honor_guarantee = true; + + while (!__shrink_zone(zone, sc, honor_guarantee)) { + /* + * The previous round of reclaim didn't find anything to scan + * because + * a) the whole reclaimed hierarchy is within guarantee so + * we fallback to ignore the guarantee because other option + * would be the OOM + * b) multiple reclaimers are racing and so the first round + * should be retried + */ + if (mem_cgroup_all_within_guarantee(sc->target_mem_cgroup)) + honor_guarantee = false; + } } /* Returns true if compaction should go ahead for a high-order request */ |