From: Shakeel Butt <shakeel.butt@linux.dev>
To: Ridong Chen <ridong.chen@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
David Hildenbrand <david@kernel.org>,
Michal Hocko <mhocko@kernel.org>, Qi Zheng <qi.zheng@linux.dev>,
Lorenzo Stoakes <ljs@kernel.org>,
Kairui Song <kasong@tencent.com>, Barry Song <baohua@kernel.org>,
Axel Rasmussen <axelrasmussen@google.com>,
Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Roman Gushchin <roman.gushchin@linux.dev>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Ridong Chen <chenridong@xiaomi.com>
Subject: Re: [PATCH] mm/vmscan: drop the combined limit gate in __node_reclaim()
Date: Wed, 26 Aug 2026 11:30:36 -0700 [thread overview]
Message-ID: <ao8wt1YA6ahtQb7W@linux.dev> (raw)
In-Reply-To: <20260826124409.35569-1-ridong.chen@linux.dev>
On Wed, Aug 26, 2026 at 08:44:09PM +0800, Ridong Chen wrote:
> From: Ridong Chen <chenridong@xiaomi.com>
>
> __node_reclaim() is called from two paths: node_reclaim() and
> user_proactive_reclaim().
>
> node_reclaim() already bails out early unless node_pagecache_reclaimable()
> is over pgdat->min_unmapped_pages or the reclaimable slab is over
> pgdat->min_slab_pages. The identical check inside __node_reclaim() that
> guards the shrink_node() loop is therefore redundant for this path.
>
> user_proactive_reclaim() is proactive reclaim driven by userspace and
> should not be gated by the per-node min_unmapped_pages / min_slab_pages
> limits at all [1]. With the gate in place, a proactive request is silently
> turned into a no-op whenever the node happens to sit below both
> thresholds.
>
> Drop the gate in __node_reclaim() and always run the shrink_node() loop.
> The node_reclaim() path is unchanged, since its caller has already applied
> the same test; the proactive path is no longer wrongly gated.
>
> [1] https://sashiko.dev/#/patchset/20260723045718.2052070-1-ridong.chen@linux.dev
> Fixes: b980077899ea ("mm: introduce per-node proactive reclaim interface")
> Assisted-by: Claude:claude-opus-4-8
> Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
next prev parent reply other threads:[~2026-08-26 18:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-26 12:44 [PATCH] mm/vmscan: drop the combined limit gate in __node_reclaim() Ridong Chen
2026-08-26 13:51 ` Michal Hocko
2026-08-26 18:30 ` Shakeel Butt [this message]
2026-08-27 13:56 ` Davidlohr Bueso
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