Commit d2af3397 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm: vmscan: replace shrink_node() loop with a retry jump 

Most of the function body is inside a loop, which imposes an additional
indentation and scoping level that makes the code a bit hard to follow and
modify.

The looping only happens in case of reclaim-compaction, which isn't the
common case.  So rather than adding yet another function level to the
reclaim path and have every reclaim invocation go through a level that
only exists for one specific cornercase, use a retry goto.

Link: http://lkml.kernel.org/r/20191022144803.302233-6-hannes@cmpxchg.org


Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: default avatarRoman Gushchin <guro@fb.com>
Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b5ead35e

mm/vmscan.c

+115 −116
Original line number Diff line number Diff line
@@ -2729,13 +2729,11 @@ static bool pgdat_memcg_congested(pg_data_t *pgdat, struct mem_cgroup *memcg) 
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;



	do {

		struct mem_cgroup *root = sc->target_mem_cgroup;

	struct mem_cgroup *memcg;



again:

	memset(&sc->nr, 0, sizeof(sc->nr));



	nr_reclaimed = sc->nr_reclaimed;
@@ -2865,8 +2863,9 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc) 
	    current_may_throttle() && pgdat_memcg_congested(pgdat, root))

		wait_iff_congested(BLK_RW_ASYNC, HZ/10);



	} while (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed,

					 sc));

	if (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed,

				    sc))

		goto again;



	/*

	 * Kswapd gives up on balancing particular nodes after too