| From: Wei Yang <richard.weiyang@gmail.com> |
| Subject: 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> |
| --- |
| |
| mm/memcontrol.c | 10 +++++++--- |
| 1 file changed, 7 insertions(+), 3 deletions(-) |
| |
| --- a/mm/memcontrol.c~mm-memcg-move-generation-assignment-and-comparison-together |
| +++ a/mm/memcontrol.c |
| @@ -1021,7 +1021,13 @@ struct mem_cgroup *mem_cgroup_iter(struc |
| 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(struc |
| |
| if (!memcg) |
| iter->generation++; |
| - else if (!prev) |
| - reclaim->generation = iter->generation; |
| } |
| |
| out_unlock: |
| _ |
