From: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
To: Bo Zhang <zhangbo0325@gmail.com>,
akpm@linux-foundation.org, david@kernel.org
Cc: surenb@google.com, mhocko@suse.com, brendan.jackman@linux.dev,
hannes@cmpxchg.org, ziy@nvidia.com, ljs@kernel.org,
liam@infradead.org, rppt@kernel.org, qi.zheng@linux.dev,
shakeel.butt@linux.dev, kasong@tencent.com, baohua@kernel.org,
axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com,
zhaonanzhe@xiaomi.com, lipengfei28@xiaomi.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Bo Zhang <zhangbo56@xiaomi.com>
Subject: Re: [RFC PATCH v2 0/4] mm: compaction: mTHP-friendly memory compaction
Date: Tue, 20 Oct 2026 16:52:19 +0200 [thread overview]
Message-ID: <11264869-00ad-44ea-b39c-a78347af0ee1@kernel.org> (raw)
In-Reply-To: <20261001001412.3837085-1-zhangbo56@xiaomi.com>
On 10/1/26 02:14, Bo Zhang wrote:
> Open questions:
>
> 1. In skip_isolation_on_order() and elsewhere, the target order is read
> from huge_anon_orders_always directly, since during proactive
> compaction cc->order is -1 (via compact_memory) and there is no clean
> way to plumb the mTHP order down.
Isn't using struct compact_control clean enough? There's already many
fields like
bool direct_compaction; /* False from kcompactd or /proc/... */
bool proactive_compaction; /* kcompactd proactive compaction */
Who says is_via_compact_memory() cannot be refactored into something using
these kinds of fields and not 'order' being -1, which could be then used as
the target order.
> This variable can change under
> userspace at any time, making the semantics fragile. Ideas on how to
> pass the target order through the proactive path cleanly are welcome.
>
prev parent reply other threads:[~2026-10-20 14:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-01 0:14 Bo Zhang
2026-10-01 0:14 ` [RFC PATCH v2 1/4] mm: compaction: parameterize fragmentation score by order Bo Zhang
2026-10-01 0:14 ` [RFC PATCH v2 2/4] mm: compaction: target mTHP order for proactive compaction Bo Zhang
2026-10-19 8:12 ` Dev Jain
2026-10-19 14:50 ` Xueyuan Chen
2026-10-19 15:03 ` Bo Zhang
2026-10-20 6:48 ` Dev Jain
2026-10-19 15:47 ` Bo Zhang
2026-10-01 0:14 ` [RFC PATCH v2 3/4] mm: compaction: skip isolating large folios that already satisfy mTHP Bo Zhang
2026-10-01 0:14 ` [RFC PATCH v2 4/4] mm: compaction: skip unmovable blocks for non-costly proactive mTHP compaction Bo Zhang
2026-10-19 9:43 ` Dev Jain
2026-10-19 15:50 ` [RFC PATCH v2 0/4] mm: compaction: mTHP-friendly memory compaction Xueyuan Chen
2026-10-20 14:52 ` Vlastimil Babka (SUSE) [this message]
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