Re: [PATCH v2 1/2] mm: memcg: refactor page state unit helpers

From: Michal Koutný
Date: Wed Oct 04 2023 - 05:02:18 EST


On Tue, Oct 03, 2023 at 12:47:25PM -0700, Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote:
> Those constants are shared with code outside of memcg, namely enum
> node_stat_item and enum vm_event_item, and IIUC they are used
> differently outside of memcg. Did I miss something?

The difference is not big, e.g.
mod_lruvec_state(lruvec, WORKINGSET_ACTIVATE_BASE + type, delta);
could be
__count_memcg_events(
container_of(lruvec, struct mem_cgroup_per_node, lruvec)->memcg,
WORKINGSET_ACTIVATE_BASE + type, delta
);

Yes, it would mean transferring WORKINGSET_* items from enum
node_stat_item to enum vm_event_item.
IOW, I don't know what is the effective difference between
mod_memcg_lruvec_state() and count_memcg_events().
Is it per-memcg vs per-memcg-per-node resolution?
(Is _that_ read by workingset mechanism?)

Thanks,
Michal

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