From: Xiaozhou Liu <liuxiaozhou@bytedance.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH net] soreuseport: use RCU_INIT_POINTER() when NULLing
Date: Thu, 13 Dec 2018 11:35:32 +0800 [thread overview]
Message-ID: <20181213033526.athxdsztxsknebhs@bogon> (raw)
In-Reply-To: <116312bb-3891-b387-1fab-99ae7c61c0cb@gmail.com>
On Wed, Dec 12, 2018 at 05:08:45AM -0800, Eric Dumazet wrote:
>
> It is _not_ faster.
>
> Just different ways to do the exact same thing.
>
> For some reason you missed this two years old commit :
>
>
> commit 3a37f7275cda5ad25c1fe9be8f20c76c60d175fa
> Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Date: Sun May 1 18:46:54 2016 -0700
>
> rcu: No ordering for rcu_assign_pointer() of NULL
>
> This commit does a compile-time check for rcu_assign_pointer() of NULL,
> and uses WRITE_ONCE() rather than smp_store_release() in that case.
>
> Reported-by: Christoph Hellwig <hch@infradead.org>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Thanks for pointing this out. I guess the comments in include/linux/rcupdate.h
may need some updating.
Xiaozhou
prev parent reply other threads:[~2018-12-13 3:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-12 9:58 [PATCH net] soreuseport: use RCU_INIT_POINTER() when NULLing Xiaozhou Liu
2018-12-12 13:08 ` Eric Dumazet
2018-12-13 3:35 ` Xiaozhou Liu [this message]
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