netdev - Re: [PATCH 2/2] virtio-net: reduce the CPU consumption of dim worker

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Date: Fri, 22 Mar 2024 10:03:21 +0800
From: kernel test robot <lkp@...el.com>
To: Heng Qi <hengqi@...ux.alibaba.com>, netdev@...r.kernel.org,
	virtualization@...ts.linux.dev, Jason Wang <jasowang@...hat.com>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Eric Dumazet <edumazet@...gle.com>,
	"David S. Miller" <davem@...emloft.net>,
	Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
Cc: oe-kbuild-all@...ts.linux.dev
Subject: Re: [PATCH 2/2] virtio-net: reduce the CPU consumption of dim worker

Hi Heng,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on next-20240321]
[cannot apply to v6.8]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Heng-Qi/virtio-net-fix-possible-dim-status-unrecoverable/20240321-194759
base:   linus/master
patch link:    https://lore.kernel.org/r/1711021557-58116-3-git-send-email-hengqi%40linux.alibaba.com
patch subject: [PATCH 2/2] virtio-net: reduce the CPU consumption of dim worker
config: x86_64-defconfig (https://download.01.org/0day-ci/archive/20240322/202403220916.cSUxehuW-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240322/202403220916.cSUxehuW-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202403220916.cSUxehuW-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/net/virtio_net.c:2564: warning: Function parameter or struct member 'vi' not described in 'virtnet_cvq_response'


vim +2564 drivers/net/virtio_net.c

  2552	
  2553	/**
  2554	 * virtnet_cvq_response - get the response for filled ctrlq requests
  2555	 * @poll: keep polling ctrlq when a NULL buffer is obtained.
  2556	 * @dim_oneshot: process a dim cmd then exit, excluding user commands.
  2557	 *
  2558	 * Note that user commands must be processed synchronously
  2559	 *  (poll = true, dim_oneshot = false).
  2560	 */
  2561	static void virtnet_cvq_response(struct virtnet_info *vi,
  2562					 bool poll,
  2563					 bool dim_oneshot)
> 2564	{
  2565		unsigned tmp;
  2566		void *res;
  2567	
  2568		while (true) {
  2569			res = virtqueue_get_buf(vi->cvq, &tmp);
  2570			if (virtqueue_is_broken(vi->cvq)) {
  2571				dev_warn(&vi->dev->dev, "Control vq is broken.\n");
  2572				return;
  2573			}
  2574	
  2575			if (!res) {
  2576				if (!poll)
  2577					return;
  2578	
  2579				cond_resched();
  2580				cpu_relax();
  2581				continue;
  2582			}
  2583	
  2584			/* this does not occur inside the process of waiting dim */
  2585			if (res == ((void *)vi))
  2586				return;
  2587	
  2588			virtnet_process_dim_cmd(vi, res);
  2589			/* When it is a user command, we must wait until the
  2590			 * processing result is processed synchronously.
  2591			 */
  2592			if (dim_oneshot)
  2593				return;
  2594		}
  2595	}
  2596	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki