Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [High] Soft-limit reclaim bypasses the new private node filter, allowing eviction on private nodes. --
--- Patch [17]: [PATCH v5 17/36] mm/vmscan: disallow reclaim of private node memory --- commit 9fc4bff86adde3091fee2924952f9af9700e6308 Author: Gregory Price <[email protected]> mm/vmscan: disallow reclaim of private node memory This commit attempts to prevent reclaim on private nodes by adding a filter to shrink_node(). > diff --git a/mm/vmscan.c b/mm/vmscan.c > index e26c6931f5fde..86b2334c23b98 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -6141,6 +6141,13 @@ static void shrink_node(pg_data_t *pgdat, struct > scan_control *sc) > struct lruvec *target_lruvec; > bool reclaimable = false; > > + /* > + * Private nodes do not support reclaim by default, filtering here > + * captures all normal reclaim paths that may attempt eviction. > + */ > + if (node_is_private(pgdat->node_id)) > + return; > + [Severity: High] Does this filter successfully capture all normal reclaim paths? When the system uses memcg v1 and a cgroup exceeds its soft limit, global direct reclaim in shrink_zones() or kswapd in balance_pgdat() will invoke memcg1_soft_limit_reclaim(). This bypasses shrink_node() entirely: mm/vmscan.c:shrink_zones() { ... nr_soft_reclaimed = memcg1_soft_limit_reclaim(zone->zone_pgdat, sc->order, sc->gfp_mask, &nr_soft_scanned); ... } This leads to mem_cgroup_shrink_node() directly calling shrink_lruvec() without checking if the node is private: mm/vmscan.c:mem_cgroup_shrink_node() { ... shrink_lruvec(lruvec, &sc); ... } Will this allow unintended eviction on private nodes during soft limit reclaim? > if ((lru_gen_enabled() || lru_gen_switching()) && root_reclaim(sc)) { > memset(&sc->nr, 0, sizeof(sc->nr)); > lru_gen_shrink_node(pgdat, sc); -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=17
