Re: [PATCH v9 0/2] mm/vmscan: fix demotion targets checks in reclaim/demotion

[Shakeel Butt <shakeel.butt@linux.dev>]

Hi Bing,

Please don't reply (i.e. use In-Reply-To) to older revision of your
series. Send each revision independently.

On Wed, Jan 14, 2026 at 08:53:01PM +0000, Bing Jiao wrote:
> This patch series addresses two issues in demote_folio_list(),
> can_demote(), and next_demotion_node() in reclaim/demotion.
> 
> 1. demote_folio_list() and can_demote() do not correctly check demotion
>    target against cpuset.mems_effective, which will cause (a) pages are
>    demoted

pages to be demoted

> to not-allowed nodes and (b) pages are failed to demote

page fail to demote

> even
>    if the system still have allowed demotion nodes.
> 
>    Patch 1 fixes this bug by update 

updating

> cpuset_node_allowed() and
>    mem_cgroup_node_allowed() to return effective_mems, allowing directly
>    logic-and operation against demotion targets.
> 
> 2. next_demotion_node() returns a preferred demotion target, but it does

does or does not?

>    check the node against allowed nodes.
> 
>    Patch 2 ensures that next_demotion_node() filters against the allowed
>    node mask and selects the closest demotion target to the source node.
>