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McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Zqiang , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , rcu@vger.kernel.org, linux-mm@kvack.org, Alexander Viro , Christian Brauner Subject: Re: [RFC PATCH v2 0/8] kvfree_rcu() improvements Message-ID: References: <20260416091022.36823-1-harry@kernel.org> <214ca3ac-45b7-4131-86e5-ac134ab0bcbd@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <214ca3ac-45b7-4131-86e5-ac134ab0bcbd@kernel.org> X-Stat-Signature: i7b8ztapad54kxtzdfz7jhyrwwzrqucm X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 9BC6220014 X-Rspam-User: X-HE-Tag: 1776907880-813036 X-HE-Meta: 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 e6NTlsd7 TZyZFEwjNS3SYGPeSHOIwQY2en6J8YoTsKXO584rU4SCiT/FNtrlxfqjvCdgJ/uZPoyn5BTODyh3aqcUB86gwW/MTnBilVU9XX7zmrGcUkY9lHkF3sJeOnq+DIMeWdK4PvQ7YQ2K+mvfnLj0NA0ujryabaYetclxZzH7W6QA3mVT15HUdDhfixpbMXxL270Tiw4Wi5YbJCLbl4aI+wGj9iJiXKzvnMjVifo/hpfGIiw76/9KbHqa/K6qCbL5uGrmGw3muKTOFR8IDnVuZGRrP5+/R18Y186mRjAZ2Zl4ksZz/1K8= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Apr 22, 2026 at 04:30:07PM +0200, Vlastimil Babka (SUSE) wrote: > On 4/16/26 11:10, Harry Yoo (Oracle) wrote: > > # Part 1. Allow an 8-byte field to be used as an alternative to > > struct rcu_head for 2-argument kvfree_rcu() > > (patches 1-2) > > > > Technically, objects that are freed with k[v]free_rcu() need > > only one pointer to link objects, because we already know that > > the callback function is always kvfree(). For this purpose, > > struct rcu_head is unnecessarily large (16 bytes on 64-bit). > > > > Allow a smaller, 8-byte field (of struct rcu_ptr type) to be used > > with k[v]free_rcu(). Let's save one pointer per slab object. > > > > I have to admit that my naming skill isn't great; hopefully > > we'll come up with a better name than `struct rcu_ptr`. > > "rcu_ptr" sounds too generic to me. to me too ;) > Things like rcu_dereference() talk about > "RCU-protected pointer" and it could be misleading that "rcu_ptr" has > something to do with this. Agreed. > But maybe just "kvfree_rcu_head"? As IMHO It's an rcu_head specialized for > kvfree. I like the name better and will rename it, thanks! -- Cheers, Harry / Hyeonggon