The patch titled Subject: mm/memcg: move generation assignment and comparison together has been added to the -mm tree. Its filename is mm-memcg-move-generation-assignment-and-comparison-together.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-move-generation-assignment-and-comparison-together.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-move-generation-assignment-and-comparison-together.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Wei Yang <richard.weiyang@xxxxxxxxx> 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@xxxxxxxxxxx: better comment to explain reclaim model] Link: https://lkml.kernel.org/r/20220330234719.18340-4-richard.weiyang@xxxxxxxxx Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Reviewed-by: Roman Gushchin <roman.gushchin@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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: _ Patches currently in -mm which might be from richard.weiyang@xxxxxxxxx are mm-memcg-mz-already-removed-from-rb_tree-if-not-null.patch mm-memcg-set-memcg-after-css-verified-and-got-reference.patch mm-memcg-set-pos-explicitly-for-reclaim-and-reclaim.patch mm-memcg-move-generation-assignment-and-comparison-together.patch mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order.patch mm-vmscan-reclaim-only-affects-managed_zones.patch mm-vmscan-make-sure-wakeup_kswapd-with-managed-zone.patch mm-vmscan-sc-reclaim_idx-must-be-a-valid-zone-index.patch