Re: [PATCH for-rc 2/9] RDMA/hns: Fix a long wait for cmdq event during reset

Leon Romanovsky
2024-07-08T08:27:59Z

On Mon, Jul 08, 2024 at 03:46:26PM +0800, Junxian Huang wrote:
>
>
> On 2024/7/8 15:33, Leon Romanovsky wrote:
> > On Mon, Jul 08, 2024 at 02:50:50PM +0800, Junxian Huang wrote:
> >>
> >>
> >> On 2024/7/8 13:38, Leon Romanovsky wrote:
> >>> On Mon, Jul 08, 2024 at 10:29:54AM +0800, Junxian Huang wrote:
> >>>>
> >>>>
> >>>> On 2024/7/7 16:30, Leon Romanovsky wrote:
> >>>>> On Fri, Jul 05, 2024 at 04:59:30PM +0800, Junxian Huang wrote:
> >>>>>> From: wenglianfa <wenglianfa@huawei.com>
> >>>>>>
> >>>>>> During reset, cmdq events won't be reported, leading to a long and
> >>>>>> unnecessary wait. Notify all the cmdqs to stop waiting at the beginning
> >>>>>> of reset.
> >>>>>>
> >>>>>> Fixes: 9a4435375cd1 ("IB/hns: Add driver files for hns RoCE driver")
> >>>>>> Signed-off-by: wenglianfa <wenglianfa@huawei.com>
> >>>>>> Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
> >>>>>> ---
> >>>>>> drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 18 ++++++++++++++++++
> >>>>>> 1 file changed, 18 insertions(+)
> >>>>>>
> >>>>>> diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> >>>>>> index a5d746a5cc68..ff135df1a761 100644
> >>>>>> --- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> >>>>>> +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
> >>>>>> @@ -6977,6 +6977,21 @@ static void hns_roce_hw_v2_uninit_instance(struct hnae3_handle *handle,
> >>>>>>
> >>>>>> handle->rinfo.instance_state = HNS_ROCE_STATE_NON_INIT;
> >>>>>> }
> >>>>>> +
> >>>>>> +static void hns_roce_v2_reset_notify_cmd(struct hns_roce_dev *hr_dev)
> >>>>>> +{
> >>>>>> + struct hns_roce_cmdq *hr_cmd = &hr_dev->cmd;
> >>>>>> + int i;
> >>>>>> +
> >>>>>> + if (!hr_dev->cmd_mod)
> >>>>>
> >>>>> What prevents cmd_mod from being changed?
> >>>>>
> >>>>
> >>>> It's set when the device is being initialized, and won't be changed after that.
> >>>
> >>> This is exactly the point, you are assuming that the device is already
> >>> ininitialized or not initialized at all. What prevents hns_roce_v2_reset_notify_cmd()
> >>> from being called in the middle of initialization?
> >>>
> >>> Thanks
> >>>
> >>
> >> This is ensured by hns3 NIC driver.
> >>
> >> Initialization and reset of hns RoCE are both called by hns3. It will check the state
> >> of RoCE device (see line 3798), and notify RoCE device to reset (hns_roce_v2_reset_notify_cmd()
> >> is called) only if the RoCE device has been already initialized:
> >
> > So why do you have "if (!hr_dev->cmd_mod)" check in the code?
> >
> > Thanks
> >
>
> cmd_mod indicates the mode of cmdq (0: poll mode, 1: event mode).
> This patch only affects event mode because HW won't report events during reset.

You set cmd_mod to 1 in hns_roce_hw_v2_init_instance() without any
condition, I don't see when hns v2 IB device is created and continue
to operate in polling mode.

Thanks

>
> Junxian
>
> >>
> >> 3791 static int hclge_notify_roce_client(struct hclge_dev *hdev,
> >> 3792 enum hnae3_reset_notify_type type)
> >> 3793 {
> >> 3794 struct hnae3_handle *handle = &hdev->vport[0].roce;
> >> 3795 struct hnae3_client *client = hdev->roce_client;
> >> 3796 int ret;
> >> 3797
> >> 3798 if (!test_bit(HCLGE_STATE_ROCE_REGISTERED, &hdev->state) || !client)
> >> 3799 return 0;
> >> 3800
> >> 3801 if (!client->ops->reset_notify)
> >> 3802 return -EOPNOTSUPP;
> >> 3803
> >> 3804 ret = client->ops->reset_notify(handle, type);
> >> 3805 if (ret)
> >> 3806 dev_err(&hdev->pdev->dev, "notify roce client failed %d(%d)",
> >> 3807 type, ret);
> >> 3808
> >> 3809 return ret;
> >> 3810 }
> >>
> >> And the bit is set (see line 11246) after the initialization has been done (line 11242):
> >>
> >> 11224 static int hclge_init_roce_client_instance(struct hnae3_ae_dev *ae_dev,
> >> 11225 struct hclge_vport *vport)
> >> 11226 {
> >> 11227 struct hclge_dev *hdev = ae_dev->priv;
> >> 11228 struct hnae3_client *client;
> >> 11229 int rst_cnt;
> >> 11230 int ret;
> >> 11231
> >> 11232 if (!hnae3_dev_roce_supported(hdev) || !hdev->roce_client ||
> >> 11233 !hdev->nic_client)
> >> 11234 return 0;
> >> 11235
> >> 11236 client = hdev->roce_client;
> >> 11237 ret = hclge_init_roce_base_info(vport);
> >> 11238 if (ret)
> >> 11239 return ret;
> >> 11240
> >> 11241 rst_cnt = hdev->rst_stats.reset_cnt;
> >> 11242 ret = client->ops->init_instance(&vport->roce);
> >> 11243 if (ret)
> >> 11244 return ret;
> >> 11245
> >> 11246 set_bit(HCLGE_STATE_ROCE_REGISTERED, &hdev->state);
> >> 11247 if (test_bit(HCLGE_STATE_RST_HANDLING, &hdev->state) ||
> >> 11248 rst_cnt != hdev->rst_stats.reset_cnt) {
> >> 11249 ret = -EBUSY;
> >> 11250 goto init_roce_err;
> >> 11251 }
> >>
> >> Junxian
> >>
> >>>>
> >>>> Junxian
> >>>>
> >>>>>> + return;
> >>>>>> +
> >>>>>> + for (i = 0; i < hr_cmd->max_cmds; i++) {
> >>>>>> + hr_cmd->context[i].result = -EBUSY;
> >>>>>> + complete(&hr_cmd->context[i].done);
> >>>>>> + }
> >>>>>> +}
> >>>>>> +
> >>>>>> static int hns_roce_hw_v2_reset_notify_down(struct hnae3_handle *handle)
> >>>>>> {
> >>>>>> struct hns_roce_dev *hr_dev;
> >>>>>> @@ -6997,6 +7012,9 @@ static int hns_roce_hw_v2_reset_notify_down(struct hnae3_handle *handle)
> >>>>>> hr_dev->dis_db = true;
> >>>>>> hr_dev->state = HNS_ROCE_DEVICE_STATE_RST_DOWN;
> >>>>>>
> >>>>>> + /* Complete the CMDQ event in advance during the reset. */
> >>>>>> + hns_roce_v2_reset_notify_cmd(hr_dev);
> >>>>>> +
> >>>>>> return 0;
> >>>>>> }
> >>>>>>
> >>>>>> --
> >>>>>> 2.33.0
> >>>>>>
> >>>>
> >>