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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 -

  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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