linux-kernel - Re: [PATCH] mm: Restore per-memcg proactive reclaim with !CONFIG

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Message-ID: <nqhi5o3viu4dv7wgjklmh6ssvpimjuecnmsf4hhjxvr3u23epg@iaau6lairrkb>
Date: Sat, 17 Jan 2026 11:07:20 -0800
From: Shakeel Butt <shakeel.butt@...ux.dev>
To: Yosry Ahmed <yosry.ahmed@...ux.dev>
Cc: Andrew Morton <akpm@...ux-foundation.org>, 
	David Hildenbrand <david@...nel.org>, Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, 
	"Liam R. Howlett" <Liam.Howlett@...cle.com>, Vlastimil Babka <vbabka@...e.cz>, 
	Mike Rapoport <rppt@...nel.org>, Suren Baghdasaryan <surenb@...gle.com>, 
	Michal Hocko <mhocko@...e.com>, Johannes Weiner <hannes@...xchg.org>, 
	Qi Zheng <zhengqi.arch@...edance.com>, Davidlohr Bueso <dave@...olabs.net>, linux-mm@...ck.org, 
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] mm: Restore per-memcg proactive reclaim with !CONFIG_NUMA

On Fri, Jan 16, 2026 at 08:52:47PM +0000, Yosry Ahmed wrote:
> Commit 2b7226af730c ("mm/memcg: make memory.reclaim interface generic")
> moved proactive reclaim logic from memory.reclaim handler to a generic
> user_proactive_reclaim() helper to be used for per-node proactive
> reclaim.
> 
> However, user_proactive_reclaim() was only defined under CONFIG_NUMA,
> with a stub always returning 0 otherwise. This broke memory.reclaim on
> !CONFIG_NUMA configs, causing it to report success without actually
> attempting reclaim.
> 
> Move the definition of user_proactive_reclaim() outside CONFIG_NUMA, and
> instead define a stub for __node_reclaim() in the !CONFIG_NUMA case.
> __node_reclaim() is only called from user_proactive_reclaim() when a
> write is made to sys/devices/system/node/nodeX/reclaim, which is only
> defined with CONFIG_NUMA.
> 
> Fixes: 2b7226af730c ("mm/memcg: make memory.reclaim interface generic")
> Cc: stable@...r.kernel.org
> Signed-off-by: Yosry Ahmed <yosry.ahmed@...ux.dev>

Acked-by: Shakeel Butt <shakeel.butt@...ux.dev>