From: Valentin Schneider <vschneid@redhat.com>
To: Frederic Weisbecker <frederic@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
"Paul E . McKenney" <paulmck@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
Neeraj Upadhyay <neeraj.upadhyay@amd.com>,
Uladzislau Rezki <urezki@gmail.com>,
Zqiang <qiang.zhang1211@gmail.com>, rcu <rcu@vger.kernel.org>
Subject: Re: [PATCH 0/6] rcu: Remove several redundant memory barriers
Date: Wed, 15 May 2024 19:32:30 +0200 [thread overview]
Message-ID: <xhsmhjzjvgevl.mognet@vschneid-thinkpadt14sgen2i.remote.csb> (raw)
In-Reply-To: <20240515125332.9306-1-frederic@kernel.org>
On 15/05/24 14:53, Frederic Weisbecker wrote:
> Reviewing Valentin's patchset made me stare at some memory barriers
> on the way.
Sorry not sorry? :-)
> Here is some removal proposal. Some may be beneficial on
> runtime (fqs snapshot with potentially as many smp_mb() as the number
> of online CPUs for each GP). Some happen on more rare path. In any
> case they clarify code reviews so we don't stumble upon mysterious
> barriers.
>
> Thanks.
>
> Frederic Weisbecker (6):
> rcu: Remove full ordering on second EQS snapshot
> rcu: Remove superfluous full memory barrier upon first EQS snapshot
> rcu/exp: Remove superfluous full memory barrier upon first EQS
> snapshot
> rcu: Remove full memory barrier on boot time eqs sanity check
> rcu: Remove full memory barrier on RCU stall printout
> rcu/exp: Remove redundant full memory barrier at the end of GP
>
> .../Tree-RCU-Memory-Ordering.rst | 6 +++---
> kernel/rcu/tree.c | 21 +++++++------------
> kernel/rcu/tree_exp.h | 16 +++++++++++---
> kernel/rcu/tree_stall.h | 4 ++--
> 4 files changed, 26 insertions(+), 21 deletions(-)
>
> --
> 2.44.0
next prev parent reply other threads:[~2024-05-15 17:32 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-15 12:53 [PATCH 0/6] rcu: Remove several redundant memory barriers Frederic Weisbecker
2024-05-15 12:53 ` [PATCH 1/6] rcu: Remove full ordering on second EQS snapshot Frederic Weisbecker
2024-05-15 17:32 ` Valentin Schneider
2024-05-15 12:53 ` [PATCH 2/6] rcu: Remove superfluous full memory barrier upon first " Frederic Weisbecker
2024-05-16 15:31 ` Valentin Schneider
2024-05-16 16:08 ` Frederic Weisbecker
2024-05-16 17:08 ` Valentin Schneider
2024-05-17 7:29 ` Andrea Parri
2024-05-17 11:40 ` Frederic Weisbecker
2024-05-17 16:27 ` Andrea Parri
2024-05-15 12:53 ` [PATCH 3/6] rcu/exp: " Frederic Weisbecker
2024-05-15 12:53 ` [PATCH 4/6] rcu: Remove full memory barrier on boot time eqs sanity check Frederic Weisbecker
2024-05-16 17:09 ` Valentin Schneider
2024-05-15 12:53 ` [PATCH 5/6] rcu: Remove full memory barrier on RCU stall printout Frederic Weisbecker
2024-05-16 17:09 ` Valentin Schneider
2024-05-15 12:53 ` [PATCH 6/6] rcu/exp: Remove redundant full memory barrier at the end of GP Frederic Weisbecker
2024-05-15 17:32 ` Valentin Schneider [this message]
2024-05-15 23:13 ` [PATCH 0/6] rcu: Remove several redundant memory barriers Frederic Weisbecker
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