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mm: vmscan: split shrink_node() into node part and memcgs part 

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

[hannes@cmpxchg.org: rename "root" to "target_memcg", per Roman]
  Link: http://lkml.kernel.org/r/20191025143640.GA386981@cmpxchg.org
Link: http://lkml.kernel.org/r/20191022144803.302233-8-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Weiner 2019-11-30 17:55:49 -08:00 committed by Linus Torvalds
parent afaf07a65d
commit 0f6a5cff43
1 changed files with 25 additions and 16 deletions
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41
mm/vmscan.c
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@ -2722,26 +2722,18 @@ 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 *target_memcg = sc->target_mem_cgroup;
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);
memcg = mem_cgroup_iter(target_memcg, NULL, NULL);
do {
struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
unsigned long reclaimed;
unsigned long scanned;
switch (mem_cgroup_protected(root, memcg)) {
switch (mem_cgroup_protected(target_memcg, memcg)) {
case MEMCG_PROT_MIN:
/*
* Hard protection.
@ -2785,7 +2777,23 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
sc->nr_scanned - scanned,
sc->nr_reclaimed - reclaimed);
} while ((memcg = mem_cgroup_iter(root, memcg, NULL)));
} while ((memcg = mem_cgroup_iter(target_memcg, 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 *target_memcg = 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, target_memcg, true,
sc->nr_scanned - nr_scanned,
sc->nr_reclaimed - nr_reclaimed);
@ -2849,7 +2857,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
*/
if (cgroup_reclaim(sc) && writeback_throttling_sane(sc) &&
sc->nr.dirty && sc->nr.dirty == sc->nr.congested)
set_memcg_congestion(pgdat, root, true);
set_memcg_congestion(pgdat, target_memcg, true);
/*
* Stall direct reclaim for IO completions if underlying BDIs
@ -2858,7 +2866,8 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc)
* the LRU too quickly.
*/
if (!sc->hibernation_mode && !current_is_kswapd() &&
current_may_throttle() && pgdat_memcg_congested(pgdat, root))
current_may_throttle() &&
pgdat_memcg_congested(pgdat, target_memcg))
wait_iff_congested(BLK_RW_ASYNC, HZ/10);
if (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed,