From: David Woodhouse <dwmw2@infradead.org>
To: paulmck@kernel.org, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Puranjay Mohan <puranjay@kernel.org>,
linux-kernel@vger.kernel.org, Boqun Feng <boqun@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
Joel Fernandes <joelagnelf@nvidia.com>,
Uladzislau Rezki <urezki@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang@linux.dev>,
Linus Torvalds <torvalds@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Christian Brauner <brauner@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Liam R . Howlett" <liam@infradead.org>,
Lorenzo Stoakes <ljs@kernel.org>,
Alice Ryhl <aliceryhl@google.com>,
Andrew Ballance <andrewjballance@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@kernel.org>,
rcu@vger.kernel.org
Subject: Re: [RFC PATCH 00/12] RCU pseudo-transactions
Date: Tue, 10 Nov 2026 10:49:03 -0800 [thread overview]
Message-ID: <84fdca577207092bd16fc8f3949c9b7a776750ba.camel@infradead.org> (raw)
In-Reply-To: <3cb75140-1d10-4de3-86e6-c9d70edd2da5@paulmck-laptop>
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On Mon, 2026-11-09 at 17:34 -0800, Paul E. McKenney wrote:
> > Could the atomic flavor count its readers as srcu_read_lock_nmisafe()
> > does? Then a reader could also enter from NMI. The code I have for the
> > next version keeps one counter per NMI nesting level for this. With
> > SRCU, the sums of locks and unlocks handle the nesting already.
>
> The other user that I know of is David Woodhouse, now CCed.
>
> David, would you be OK with srcu_read_lock_atomic() using NMI-safe
> counters, similar to __srcu_read_lock_fast()?
I can't see any reason why I should object to that, as long as the
synchronize_srcu_atomic() stays in the 4-16µs bracket which was our
major criterion for this approach.
I'm still iterating on the KVM GPC use case¹, as sashiko-bot keeps
finding things that my own local sashiko runs don't.
¹ https://git.infradead.org/users/dwmw2/linux.git/shortlog/refs/heads/gpc-srcu-v3
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next prev parent reply other threads:[~2026-11-10 18:49 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-16 13:33 Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 01/12] rcu_txn: Add single-writer " Mathieu Desnoyers
2026-10-23 18:22 ` Puranjay Mohan
2026-11-10 15:11 ` Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 02/12] rcu_txn: Add KUnit tests Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 03/12] rcu_txn: Skip the record lookup with a Bloom filter Mathieu Desnoyers
2026-10-23 18:22 ` Puranjay Mohan
2026-11-10 15:12 ` Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 04/12] rcu_txn: Add CONFIG_DEBUG_RCU_TXN Mathieu Desnoyers
2026-10-23 18:22 ` Puranjay Mohan
2026-11-10 15:12 ` Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 05/12] rcu_txn: Add an hlist edited through transactions Mathieu Desnoyers
2026-10-23 18:22 ` Puranjay Mohan
2026-11-10 15:12 ` Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 06/12] rcu_txn: Add a doubly-linked list coherent in both directions Mathieu Desnoyers
2026-10-23 18:22 ` Puranjay Mohan
2026-11-10 15:13 ` Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 07/12] Documentation/RCU: Describe RCU pseudo-transactions Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 08/12] Documentation/litmus-tests: Add RCU pseudo-transaction tests Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 09/12] rcu_txn: Test a list writer against concurrent readers Mathieu Desnoyers
2026-10-23 18:22 ` Puranjay Mohan
2026-11-10 15:13 ` Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 10/12] rcu_txn: Test a commit from atomic context Mathieu Desnoyers
2026-10-23 18:22 ` Puranjay Mohan
2026-11-10 15:14 ` Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 11/12] samples: Add a cache on RCU pseudo-transactions under one mutex Mathieu Desnoyers
2026-10-16 13:33 ` [RFC PATCH 12/12] samples: Add a cache on RCU pseudo-transactions with a lock per node Mathieu Desnoyers
2026-10-23 18:22 ` Puranjay Mohan
2026-11-10 15:14 ` Mathieu Desnoyers
2026-10-19 0:55 ` [RFC PATCH 00/12] RCU pseudo-transactions Joel Fernandes
2026-10-23 13:37 ` Mathieu Desnoyers
2026-10-23 18:19 ` Puranjay Mohan
2026-10-27 19:57 ` Mathieu Desnoyers
2026-10-28 1:13 ` Mathieu Desnoyers
2026-11-10 0:25 ` Paul E. McKenney
2026-11-10 1:00 ` Mathieu Desnoyers
2026-11-10 1:34 ` Paul E. McKenney
2026-11-10 15:26 ` Mathieu Desnoyers
2026-11-10 18:54 ` Paul E. McKenney
2026-11-10 18:49 ` David Woodhouse [this message]
2026-11-10 19:03 ` Paul E. McKenney
2026-11-10 15:11 ` Mathieu Desnoyers
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