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From: Jakub Kicinski <kuba@kernel.org>
To: "Subash Abhinov Kasiviswanathan (KS)" <quic_subashab@quicinc.com>
Cc: <davem@davemloft.net>, <edumazet@google.com>, <pabeni@redhat.com>,
	<netdev@vger.kernel.org>, <vadim.fedorenko@linux.dev>,
	<lkp@intel.com>, <horms@kernel.org>,
	Sean Tranchetti <quic_stranche@quicinc.com>
Subject: Re: [PATCH net-next v4] net: qualcomm: rmnet: Add side band flow control support
Date: Tue, 10 Oct 2023 11:21:59 -0700	[thread overview]
Message-ID: <20231010112159.2e2e1b86@kernel.org> (raw)
In-Reply-To: <b1efa230-b30b-0ace-5e99-fe8593eeb12e@quicinc.com>

On Tue, 10 Oct 2023 09:23:12 -0600 Subash Abhinov Kasiviswanathan (KS)
wrote:
> > I'm not sure what you mean. Qdiscs can form hierarchies.
> > You put mq first and then whatever child qdisc you want for individual
> > queues.  
> 
> There is no userspace interface exposed today currently to invoke 
> netif_tx_stop_queue(dev, queue) / netif_tx_wake_queue(dev, queue). The 
> API itself can only be invoked within kernel.
> 
> I was wondering if it would be acceptable to add a user accessible 
> interface in core networking to stop_queue / wake_queue instead of the 
> driver.

Maybe not driver queue control but if there's no qdisc which allows
users to pause from user space, I think that would be a much easier
sale.

That said the flow of the whole thing seems a bit complex.
Can't the driver somehow be notified by the device directly?
User space will suffer from all sort of wake up / scheduling
latencies, it'd be better if the whole sleep / wake thing was 
handled in the kernel.

  reply	other threads:[~2023-10-10 18:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-06  0:16 [PATCH net-next v4] net: qualcomm: rmnet: Add side band flow control support Subash Abhinov Kasiviswanathan
2023-10-10  2:42 ` Jakub Kicinski
2023-10-10  4:00   ` Subash Abhinov Kasiviswanathan (KS)
2023-10-10 14:56     ` Jakub Kicinski
2023-10-10 15:23       ` Subash Abhinov Kasiviswanathan (KS)
2023-10-10 18:21         ` Jakub Kicinski [this message]
2023-10-10 21:32           ` Subash Abhinov Kasiviswanathan (KS)
2023-10-11  0:35             ` Subash Abhinov Kasiviswanathan (KS)

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