From: Sedat Dilek <sedat.dilek@gmail.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
"Paul E . McKenney" <paulmck@kernel.org>,
linux-fsdevel@vger.kernel.org, Akira Yokosawa <akiyks@gmail.com>,
Alan Stern <stern@rowland.harvard.edu>,
Andrea Parri <parri.andrea@gmail.com>,
Boqun Feng <boqun.feng@gmail.com>,
Daniel Lustig <dlustig@nvidia.com>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
Dave Chinner <david@fromorbit.com>,
David Howells <dhowells@redhat.com>,
Jade Alglave <j.alglave@ucl.ac.uk>,
Luc Maranget <luc.maranget@inria.fr>,
Nicholas Piggin <npiggin@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH] tools/memory-model: document the "one-time init" pattern
Date: Fri, 17 Jul 2020 07:49:02 +0200 [thread overview]
Message-ID: <CA+icZUVztkBRBhs_NQpTOg7rc34VkBQ1GCr5iXgw+P9XORwd9A@mail.gmail.com> (raw)
In-Reply-To: <20200717044427.68747-1-ebiggers@kernel.org>
On Fri, Jul 17, 2020 at 6:48 AM Eric Biggers <ebiggers@kernel.org> wrote:
>
> From: Eric Biggers <ebiggers@google.com>
...
> This is motivated by the discussion at
> https://lkml.kernel.org/linux-fsdevel/20200713033330.205104-1-ebiggers@kernel.org/T/#u
...
> +In where cases where taking the mutex in the "already initialized" case
"In cases where..." (drop first "where")
> +presents scalability concerns, the implementation can be optimized to
> +check the 'inited' flag outside the mutex. Unfortunately, this
> +optimization is often implemented incorrectly by using a plain load.
> +That violates the memory model and may result in unpredictable behavior.
- Sedat -
next prev parent reply other threads:[~2020-07-17 5:49 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-17 4:44 [PATCH] tools/memory-model: document the "one-time init" pattern Eric Biggers
2020-07-17 5:49 ` Sedat Dilek [this message]
2020-07-17 12:35 ` Matthew Wilcox
2020-07-17 14:26 ` Alan Stern
2020-07-17 17:47 ` Matthew Wilcox
2020-07-17 17:51 ` Alan Stern
2020-07-18 1:02 ` Eric Biggers
2020-07-27 12:51 ` Matthew Wilcox
2020-07-17 21:05 ` Darrick J. Wong
2020-07-18 0:44 ` Darrick J. Wong
2020-07-18 1:38 ` Eric Biggers
2020-07-18 2:13 ` Matthew Wilcox
2020-07-18 5:28 ` Eric Biggers
2020-07-18 14:35 ` Alan Stern
2020-07-20 2:07 ` Dave Chinner
2020-07-20 9:00 ` Peter Zijlstra
2020-07-27 15:17 ` Alan Stern
2020-07-27 15:28 ` Matthew Wilcox
2020-07-27 16:01 ` Paul E. McKenney
2020-07-27 16:31 ` Alan Stern
2020-07-27 16:59 ` Matthew Wilcox
2020-07-27 19:13 ` Alan Stern
2020-07-17 20:53 ` Darrick J. Wong
2020-07-18 0:58 ` Eric Biggers
2020-07-18 1:25 ` Alan Stern
2020-07-18 1:40 ` Matthew Wilcox
2020-07-18 2:00 ` Dave Chinner
2020-07-18 14:21 ` Alan Stern
2020-07-18 2:00 ` Eric Biggers
2020-07-18 1:42 ` Dave Chinner
2020-07-18 14:08 ` Alan Stern
2020-07-20 1:33 ` Dave Chinner
2020-07-20 14:52 ` Alan Stern
2020-07-20 15:37 ` Darrick J. Wong
2020-07-20 15:39 ` Matthew Wilcox
2020-07-20 16:04 ` Paul E. McKenney
2020-07-20 16:48 ` peterz
2020-07-20 22:06 ` Paul E. McKenney
2020-07-20 16:12 ` Alan Stern
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