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From: Li RongQing <roy.qing.li@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: Pravin Shelar <pshelar@nicira.com>, netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH][net-next] openvswitch: change the data type of error status to atomic_long_t
Date: Mon, 8 Sep 2014 19:23:11 +0800	[thread overview]
Message-ID: <CAJFZqHzeCCRJgrx5dTuLBMtfNf4QKkxU77PJXNXWuYcoBFuZWw@mail.gmail.com> (raw)
In-Reply-To: <20140907.161720.168413856991894569.davem@davemloft.net>

On Mon, Sep 8, 2014 at 7:17 AM, David Miller <davem@davemloft.net> wrote:
> From: Li RongQing <roy.qing.li@gmail.com>
> Date: Sun, 7 Sep 2014 17:24:11 +0800
>
>> 2.  I did not find that tx_dropped/tx_error/.. is protected by spin
>> lock under net dir,
>> sometime tx_dropped is atomic_long_t; sometime it is percpu variable;
>> sometime it is
>> u64,but does not need to protect.
>
> If it is only modified in ->ndo_start_xmit() then it is protected by
> the per-queue TX lock, as ->ndo_start_xmit() is always invoked with
> it held (except in LLTX drivers of course).


But reading tx_dropped is in process context, and maybe break by interrupt or
soft interrupt,  and no lock protect, or not the same lock protect.

-Roy

  reply	other threads:[~2014-09-08 11:23 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-06 11:06 [PATCH][net-next] openvswitch: change the data type of error status to atomic_long_t roy.qing.li
2014-09-07  3:44 ` Pravin Shelar
2014-09-07  9:24   ` Li RongQing
2014-09-07 23:17     ` David Miller
2014-09-08 11:23       ` Li RongQing [this message]
2014-09-08 22:21     ` Cong Wang
2014-09-08 22:26     ` Pravin Shelar
2014-09-09  0:29       ` Li RongQing
2014-09-09 18:47 ` David Miller

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