Commit a9320aae authored Apr 28, 2022 by Wei Yang Committed by Andrew Morton Apr 28, 2022

mm/memcg: move generation assignment and comparison together

For each round-trip, we assign generation on first invocation and compare
it on subsequent invocations.

Let's move them together to make it more self-explaining. Also this
reduce a check on prev.

[hannes@cmpxchg.org: better comment to explain reclaim model]
Link: https://lkml.kernel.org/r/20220330234719.18340-4-richard.weiyang@gmail.com


Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 89d8330c

mm/memcontrol.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -1021,7 +1021,13 @@ struct mem_cgroup mem_cgroup_iter(struct mem_cgroup root,
		mz = root->nodeinfo[reclaim->pgdat->node_id];
		iter = &mz->iter;

		if (prev && reclaim->generation != iter->generation)
		/*
		* On start, join the current reclaim iteration cycle.
		* Exit when a concurrent walker completes it.
		*/
		if (!prev)
		reclaim->generation = iter->generation;
		else if (reclaim->generation != iter->generation)
		goto out_unlock;

		while (1) {
		@@ -1083,8 +1089,6 @@ struct mem_cgroup mem_cgroup_iter(struct mem_cgroup root,

		if (!memcg)
		iter->generation++;
		else if (!prev)
		reclaim->generation = iter->generation;
		}

		out_unlock: