From 7a704474b3022dabbb68f72bf18a3d89ec1c0a24 Mon Sep 17 00:00:00 2001 From: Yosry Ahmed Date: Wed, 21 Jun 2023 02:30:53 +0000 Subject: mm: memcg: rename and document global_reclaim() Evidently, global_reclaim() can be a confusing name. Especially that it used to exist before with a subtly different definition (removed by commit b5ead35e7e1d ("mm: vmscan: naming fixes: global_reclaim() and sane_reclaim()"). It can be interpreted as non-cgroup reclaim, even though it returns true for cgroup reclaim on the root memcg (through memory.reclaim). Rename it to root_reclaim() in an attempt to make it less ambiguous, and add documentation to it as well as cgroup_reclaim. Link: https://lkml.kernel.org/r/20230621023053.432374-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed Reported-by: Johannes Weiner Closes: https://lore.kernel.org/lkml/20230405200150.GA35884@cmpxchg.org/ Acked-by: Yu Zhao Cc: Michal Hocko Cc: Muchun Song Cc: Roman Gushchin Cc: Shakeel Butt Signed-off-by: Andrew Morton --- mm/vmscan.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'mm/vmscan.c') diff --git a/mm/vmscan.c b/mm/vmscan.c index 049342b6317c..b7068be8a034 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -429,12 +429,17 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) up_read(&shrinker_rwsem); } +/* Returns true for reclaim through cgroup limits or cgroup interfaces. */ static bool cgroup_reclaim(struct scan_control *sc) { return sc->target_mem_cgroup; } -static bool global_reclaim(struct scan_control *sc) +/* + * Returns true for reclaim on the root cgroup. This is true for direct + * allocator reclaim and reclaim through cgroup interfaces on the root cgroup. + */ +static bool root_reclaim(struct scan_control *sc) { return !sc->target_mem_cgroup || mem_cgroup_is_root(sc->target_mem_cgroup); } @@ -489,7 +494,7 @@ static bool cgroup_reclaim(struct scan_control *sc) return false; } -static bool global_reclaim(struct scan_control *sc) +static bool root_reclaim(struct scan_control *sc) { return true; } @@ -546,7 +551,7 @@ static void flush_reclaim_state(struct scan_control *sc) * memcg reclaim, to make reporting more accurate and reduce * underestimation, but it's probably not worth the complexity for now. */ - if (current->reclaim_state && global_reclaim(sc)) { + if (current->reclaim_state && root_reclaim(sc)) { sc->nr_reclaimed += current->reclaim_state->reclaimed; current->reclaim_state->reclaimed = 0; } @@ -5325,7 +5330,7 @@ static long get_nr_to_scan(struct lruvec *lruvec, struct scan_control *sc, bool static unsigned long get_nr_to_reclaim(struct scan_control *sc) { /* don't abort memcg reclaim to ensure fairness */ - if (!global_reclaim(sc)) + if (!root_reclaim(sc)) return -1; return max(sc->nr_to_reclaim, compact_gap(sc->order)); @@ -5477,7 +5482,7 @@ static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc { struct blk_plug plug; - VM_WARN_ON_ONCE(global_reclaim(sc)); + VM_WARN_ON_ONCE(root_reclaim(sc)); VM_WARN_ON_ONCE(!sc->may_writepage || !sc->may_unmap); lru_add_drain(); @@ -5538,7 +5543,7 @@ static void lru_gen_shrink_node(struct pglist_data *pgdat, struct scan_control * struct blk_plug plug; unsigned long reclaimed = sc->nr_reclaimed; - VM_WARN_ON_ONCE(!global_reclaim(sc)); + VM_WARN_ON_ONCE(!root_reclaim(sc)); /* * Unmapped clean folios are already prioritized. Scanning for more of @@ -6260,7 +6265,7 @@ static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) bool proportional_reclaim; struct blk_plug plug; - if (lru_gen_enabled() && !global_reclaim(sc)) { + if (lru_gen_enabled() && !root_reclaim(sc)) { lru_gen_shrink_lruvec(lruvec, sc); return; } @@ -6501,7 +6506,7 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc) struct lruvec *target_lruvec; bool reclaimable = false; - if (lru_gen_enabled() && global_reclaim(sc)) { + if (lru_gen_enabled() && root_reclaim(sc)) { lru_gen_shrink_node(pgdat, sc); return; } -- cgit