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

Junxian Huang
2024-07-08T08:45:37Z

On 2024/7/8 16:27, Leon Romanovsky wrote:
> 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
>

Event mode is the default. In hns_roce_cmd_use_events(), if kcalloc() fails
then it'll be set to polling mode instead.

Junxian

>>
>> 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
>>>>>>>>
>>>>>>
>>>>