From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Nicholas Piggin <npiggin@gmail.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
"Paul E. McKenney" <paulmck@kernel.org>,
Will Deacon <will@kernel.org>,
Alan Stern <stern@rowland.harvard.edu>,
John Stultz <jstultz@google.com>,
Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>,
Frederic Weisbecker <frederic@kernel.org>,
Joel Fernandes <joel@joelfernandes.org>,
Josh Triplett <josh@joshtriplett.org>,
Uladzislau Rezki <urezki@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang1211@gmail.com>,
Ingo Molnar <mingo@redhat.com>, Waiman Long <longman@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Vlastimil Babka <vbabka@suse.cz>,
maged.michael@gmail.com, Mateusz Guzik <mjguzik@gmail.com>,
Jonas Oberhauser <jonas.oberhauser@huaweicloud.com>,
rcu@vger.kernel.org, linux-mm@kvack.org, lkmm@lists.linux.dev
Subject: Re: [RFC PATCH v3 3/4] hazptr: Implement Hazard Pointers
Date: Tue, 8 Oct 2024 13:05:29 -0400 [thread overview]
Message-ID: <a5cadedd-b462-4964-a1cf-f4623379b43e@efficios.com> (raw)
In-Reply-To: <20241008135034.1982519-4-mathieu.desnoyers@efficios.com>
On 2024-10-08 15:50, Mathieu Desnoyers wrote:
[...]
> +/* Retire the protected hazard pointer from @slot. */
> +static inline
> +void hazptr_retire(struct hazptr_slot *slot, void *addr)
> +{
> + WARN_ON_ONCE(slot->addr != addr);
> + smp_store_release(&slot->addr, NULL);
> +}
Actually, comparing this with the literature and past presentations
from Maged Michael, "retire" is not the appropriate name here.
With Hazard Pointers, AFAIU, the "retire" operation is similar to a
call_rcu() memory reclaim. It marks the object for eventual reclamation
when it is safe to do so.
The API here really just releases the recently protected hazard
pointer. So I will rename this to "hazptr_release()".
At this stage, this hazptr API does not implement any retire operation,
and only offers the hazptr_scan() for reader/updater synchronization,
leaving the actual reclaim to the caller.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
next prev parent reply other threads:[~2024-10-08 17:07 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-08 13:50 [RFC PATCH v3 0/4] sched+mm: Track lazy active mm existence with hazard pointers Mathieu Desnoyers
2024-10-08 13:50 ` [RFC PATCH v3 1/4] compiler.h: Introduce ptr_eq() to preserve address dependency Mathieu Desnoyers
2024-10-08 13:50 ` [RFC PATCH v3 2/4] Documentation: RCU: Refer to ptr_eq() Mathieu Desnoyers
2024-10-08 13:50 ` [RFC PATCH v3 3/4] hazptr: Implement Hazard Pointers Mathieu Desnoyers
2024-10-08 17:05 ` Mathieu Desnoyers [this message]
2024-10-08 13:50 ` [RFC PATCH v3 4/4] sched+mm: Use hazard pointers to track lazy active mm existence Mathieu Desnoyers
2024-10-08 19:51 ` Joel Fernandes
2024-10-14 8:27 ` kernel test robot
2024-10-15 13:33 ` Mathieu Desnoyers
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