linux-kernel - Re: [PATCH 0/4] ucount: Simplify refcounting with rcuref

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Message-ID: <20250207204854.rc1gron_@linutronix.de>
Date: Fri, 7 Feb 2025 21:48:54 +0100
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: linux-kernel@...r.kernel.org, rcu@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>
Cc: MengEn Sun <mengensun@...cent.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	YueHong Wu <yuehongwu@...cent.com>,
	"Paul E. McKenney" <paulmck@...nel.org>,
	Joel Fernandes <joel@...lfernandes.org>,
	Josh Triplett <josh@...htriplett.org>,
	Boqun Feng <boqun.feng@...il.com>,
	Uladzislau Rezki <urezki@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	Lai Jiangshan <jiangshanlai@...il.com>,
	Zqiang <qiang.zhang1211@...il.com>
Subject: Re: [PATCH 0/4] ucount: Simplify refcounting with rcuref_t.

On 2025-02-03 16:05:21 [+0100], To linux-kernel@...r.kernel.org wrote:
> I noticed that the atomic_dec_and_lock_irqsave() in put_ucounts() loops
> sometimes even during boot. Something like 2-3 iterations but still.
> This series replaces the refcounting with rcuref_t and adds a RCU
> lookup.
> This allows a lockless lookup in alloc_ucounts() if the entry is
> available and a cmpxchg()less put of the item.

Andrew, could you please take this series?

Sebastian