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Howlett" , "Gary Guo" , "Miguel Ojeda" , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , "Benno Lossin" , "Andreas Hindborg" , "Trevor Gross" , "Danilo Krummrich" , "Frederic Weisbecker" , "Neeraj Upadhyay" , "Joel Fernandes" , "Josh Triplett" , "Uladzislau Rezki" , "Steven Rostedt" , "Mathieu Desnoyers" , "Lai Jiangshan" , "Zqiang" , "Andrew Ballance" , , , , , Subject: Re: [PATCH RFC 0/2] rcu box container for Rust + maple tree load_rcu X-Mailer: aerc 0.21.0 References: <20260116-rcu-box-v1-0-38ebfbcd53f0@google.com> In-Reply-To: X-ClientProxiedBy: LO4P123CA0108.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:191::23) To LOVP265MB8871.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:488::16) Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LOVP265MB8871:EE_|LO4P265MB6350:EE_ X-MS-Office365-Filtering-Correlation-Id: 2ab56a88-1da6-497a-1656-08de55e7ed47 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|366016|10070799003|1800799024; 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Dropping my RcuBox<_> must use kfree_rcu() or >> > synchronize_rcu() or it is unsound. So it can't just be a Box. >> >=20 >>=20 >> RcuOld will call synchronize_rcu() before dropping >> `P`. And I think we can have an asynchronous drop pointer type like >> `RcuOld` that requires `P` is a type like `Box`, > > One blocker on that is Drop impls cannot be specialized. We probably > need a different pointer type like RcuOldAsync... I won't be too worried on this apsect, you could just branch on a const in = the drop function. Alternatively, we can have a method like this impl RcuOld> { fn drop_async(self) { // do call_rcu } } Best, Gary