From: Saeed Mahameed <saeedm@dev.mellanox.co.il>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
Saeed Mahameed <saeedm@mellanox.com>,
Tariq Toukan <tariqt@mellanox.com>
Subject: Re: [Patch net-next v2] mlx5: use RCU lock in mlx5_eq_cq_get()
Date: Wed, 6 Feb 2019 16:56:25 -0800 [thread overview]
Message-ID: <CALzJLG8miALNwMxf1vFZKEj2WoFdMyZZWMBXdtHYMkvvmgkAzQ@mail.gmail.com> (raw)
In-Reply-To: <CAM_iQpVF-71uQtybZLqLDWZQS=JxjD_23fAjxyfy7oLBzw-BoA@mail.gmail.com>
On Wed, Feb 6, 2019 at 4:53 PM Cong Wang <xiyou.wangcong@gmail.com> wrote:
>
> On Wed, Feb 6, 2019 at 4:28 PM Eric Dumazet <eric.dumazet@gmail.com> wrote:
> >
> >
> >
> > On 02/06/2019 04:04 PM, Cong Wang wrote:
> >
> > > synchronize_irq() is called before mlx5_cq_put(), so I don't
> > > see why readers could get 0 refcnt.
> >
> > Then the more reasons to get rid of the refcount increment/decrement completely ...
> >
> > Technically, even the rcu_read_lock() and rcu_read_unlock() are not needed,
> > since synchronize_irq() is enough.
>
> Excellent point.
>
> For the refcnt, I am afraid we still have to hold refcnt for the tasklet,
> mlx5_cq_tasklet_cb. But yeah, should be safe to remove from IRQ
> path.
the tasklet path is for rdma CQs only, netdev cqs handling will be refcnt free.
next prev parent reply other threads:[~2019-02-07 0:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-06 23:00 [Patch net-next v2] mlx5: use RCU lock in mlx5_eq_cq_get() Cong Wang
2019-02-06 23:36 ` Eric Dumazet
2019-02-06 23:55 ` Eric Dumazet
2019-02-07 0:04 ` Cong Wang
2019-02-07 0:28 ` Eric Dumazet
2019-02-07 0:51 ` Saeed Mahameed
2019-02-07 0:53 ` Cong Wang
2019-02-07 0:56 ` Saeed Mahameed [this message]
2019-02-11 22:41 ` Saeed Mahameed
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