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Date: Fri, 31 Jan 2025 08:29:47 +0100
From: Christoph Hellwig <hch@lst.de>
To: Daniel Wagner <dwagner@suse.de>
Cc: Christoph Hellwig <hch@lst.de>, Daniel Wagner <wagi@kernel.org>,
	Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@kernel.dk>,
	Sagi Grimberg <sagi@grimberg.me>, Ming Lei <ming.lei@redhat.com>,
	James Smart <james.smart@broadcom.com>,
	Hannes Reinecke <hare@suse.de>, linux-nvme@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-block@vger.kernel.org
Subject: Re: [PATCH 1/3] nvme-tcp: rate limit error message in send path
Message-ID: <20250131072947.GB16012@lst.de>
References: <20250128-nvme-misc-fixes-v1-0-40c586581171@kernel.org> <20250128-nvme-misc-fixes-v1-1-40c586581171@kernel.org> <20250129060534.GA29266@lst.de> <216ab5ef-1c8b-4f3e-8a1a-f11e28994620@flourine.local>
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On Thu, Jan 30, 2025 at 04:25:35PM +0100, Daniel Wagner wrote:
> On Wed, Jan 29, 2025 at 07:05:34AM +0100, Christoph Hellwig wrote:
> > On Tue, Jan 28, 2025 at 05:34:46PM +0100, Daniel Wagner wrote:
> > > If a lot of request are in the queue, this message is spamming the logs,
> > > thus rate limit it.
> > 
> > Are in the queue when what happens?  Not that I'm against this,
> > but if we have a known condition where this error is printed a lot
> > we should probably skip it entirely for that?
> 
> The condition is that all the elements in the queue->send_list could fail as a
> batch. I had a bug in my patches which re-queued all the failed command
> immediately and semd them out again, thus spamming the log.
> 
> This behavior doesn't exist in upstream. I just thought it might make
> sense to rate limit as precaution. I don't know if it is worth the code
> churn.

I'm fine with the rate limiting.  I was just wondering if there is
a case where we'd easily hit it and could do even better.