Re: [PATCH v3 0/2] memcg: reduce cacheline contention from lruvec stat

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 27 Oct 2026 15:57:43 -0700 Joanne Koong <joannelkoong@gmail.com> wrote:

> Here's an updated version of the "Fix this by moving the memcg_pn_cold
> group..." paragraph in patch 1 that mentions this:
> 
> Fix this by moving the memcg_pn_cold group, which is only touched when
> the memcg is reparented or freed, right after memcg_pn_read_mostly.
> SLAB_HWCACHE_ALIGN only aligns objects to a cacheline, and the struct
> is 576 bytes, so depending on where an object lands, its read-mostly
> cacheline is now paired either with its cold cacheline or with the last
> cacheline of the preceding object, which holds the end of
> lru_zone_size[] and the reclaim iterator. Both are rarely written
> outside of reclaim, so either way the read-mostly cacheline is no
> longer paired with the LRU list heads.
> 
> Would you be able to swap it in or would you prefer that I send a v4?

Thanks.  I'll take care of this when I process the patchset.  Which
will be quite soon now we're all merged up.