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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: =?utf-8?B?QW5kcsOp?= Almeida <andrealmeid@igalia.com>
Cc: Juri Lelli <juri.lelli@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Darren Hart <dvhart@infradead.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-rt-users <linux-rt-users@vger.kernel.org>,
	Valentin Schneider <vschneid@redhat.com>,
	Waiman Long <longman@redhat.com>
Subject: Re: Futex hash_bucket lock can break isolation and cause priority
 inversion on RT
Message-ID: <20241008180911.JiqZxSLg@linutronix.de>
References: <ZwVOMgBMxrw7BU9A@jlelli-thinkpadt14gen4.remote.csb>
 <98b3dcb0-8b64-45a5-9531-16aeb010c052@igalia.com>
 <20241008155129.z7ZZVzW3@linutronix.de>
 <46c259c2-5503-4a63-94ae-96660e5ce0eb@igalia.com>
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In-Reply-To: <46c259c2-5503-4a63-94ae-96660e5ce0eb@igalia.com>

On 2024-10-08 12:59:24 [-0300], Andr=C3=A9 Almeida wrote:
>=20
> So if every process has it owns hb-lock, every process has their own buck=
et?
> It would act just like a linked list then?

If you have one hb-lock, yes. But you could have 4 or 8 slots. A slot
has 64 bytes due to alignment. As-is the 8 slots would occupy 512 bytes
of memory.

Sebastian