Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] io_uring: wakeup threads waiting for EPOLLOUT events
To:     Stefano Garzarella <sgarzare@redhat.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>, io-uring@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
References: <20200116134946.184711-1-sgarzare@redhat.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <2d2dda92-3c50-ee62-5ffe-0589d4c8fc0d@kernel.dk>
Date:   Thu, 16 Jan 2020 08:29:07 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.2.2
MIME-Version: 1.0
In-Reply-To: <20200116134946.184711-1-sgarzare@redhat.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 1/16/20 6:49 AM, Stefano Garzarella wrote:
> io_uring_poll() sets EPOLLOUT flag if there is space in the
> SQ ring, then we should wakeup threads waiting for EPOLLOUT
> events when we expose the new SQ head to the userspace.
> 
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
> 
> Do you think is better to change the name of 'cq_wait' and 'cq_fasync'?

I honestly think it'd be better to have separate waits for in/out poll,
the below patch will introduce some unfortunate cacheline traffic
between the submitter and completer side.

-- 
Jens Axboe