Date:   Thu, 3 Dec 2020 21:56:01 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     "Kiyanovski, Arthur" <akiyano@...zon.com>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "davem@...emloft.net" <davem@...emloft.net>
Cc:     "Woodhouse, David" <dwmw@...zon.co.uk>,
        "Machulsky, Zorik" <zorik@...zon.com>,
        "Matushevsky, Alexander" <matua@...zon.com>,
        "Bshara, Saeed" <saeedb@...zon.com>,
        "Wilson, Matt" <msw@...zon.com>,
        "Liguori, Anthony" <aliguori@...zon.com>,
        "Bshara, Nafea" <nafea@...zon.com>,
        "Tzalik, Guy" <gtzalik@...zon.com>,
        "Belgazal, Netanel" <netanel@...zon.com>,
        "Saidi, Ali" <alisaidi@...zon.com>,
        "Herrenschmidt, Benjamin" <benh@...zon.com>,
        "Dagan, Noam" <ndagan@...zon.com>,
        "Agroskin, Shay" <shayagr@...zon.com>,
        "Jubran, Samih" <sameehj@...zon.com>
Subject: Re: [PATCH V3 net-next 1/9] net: ena: use constant value for
 net_device allocation

Am 03.12.2020 um 15:38 schrieb Kiyanovski, Arthur:
> 
> 
>> -----Original Message-----
>> From: Heiner Kallweit <hkallweit1@...il.com>
>> Sent: Wednesday, December 2, 2020 11:55 PM
>> To: Kiyanovski, Arthur <akiyano@...zon.com>; kuba@...nel.org;
>> netdev@...r.kernel.org
>> Cc: Woodhouse, David <dwmw@...zon.co.uk>; Machulsky, Zorik
>> <zorik@...zon.com>; Matushevsky, Alexander <matua@...zon.com>;
>> Bshara, Saeed <saeedb@...zon.com>; Wilson, Matt <msw@...zon.com>;
>> Liguori, Anthony <aliguori@...zon.com>; Bshara, Nafea
>> <nafea@...zon.com>; Tzalik, Guy <gtzalik@...zon.com>; Belgazal,
>> Netanel <netanel@...zon.com>; Saidi, Ali <alisaidi@...zon.com>;
>> Herrenschmidt, Benjamin <benh@...zon.com>; Dagan, Noam
>> <ndagan@...zon.com>; Agroskin, Shay <shayagr@...zon.com>; Jubran,
>> Samih <sameehj@...zon.com>
>> Subject: RE: [EXTERNAL] [PATCH V3 net-next 1/9] net: ena: use constant
>> value for net_device allocation
>>
>> CAUTION: This email originated from outside of the organization. Do not click
>> links or open attachments unless you can confirm the sender and know the
>> content is safe.
>>
>>
>>
>> Am 02.12.2020 um 21:03 schrieb akiyano@...zon.com:
>>> From: Arthur Kiyanovski <akiyano@...zon.com>
>>>
>>> The patch changes the maximum number of RX/TX queues it advertises to
>>> the kernel (via alloc_etherdev_mq()) from a value received from the
>>> device to a constant value which is the minimum between 128 and the
>>> number of CPUs in the system.
>>>
>>> By allocating the net_device struct with a constant number of queues,
>>> the driver is able to allocate it at a much earlier stage, before
>>> calling any ena_com functions. This would allow to make all log prints
>>> in ena_com to use netdev_* log functions instead or current pr_* ones.
>>>
>>
>> Did you test this? Usually using netdev_* before the net_device is registered
>> results in quite ugly messages. Therefore there's a number of patches doing
>> the opposite, replacing netdev_* with dev_* before register_netdev(). See
>> e.g.
>> 22148df0d0bd ("r8169: don't use netif_info et al before net_device has been
>> registered")
> 
> Thanks for your comment.
> Yes we did test it.
> Please see the discussion which led to this patch in a previous thread here:
> https://www.mail-archive.com/netdev@vger.kernel.org/msg353590.html
>  

Ah, I see. After reading the mail thread your motivation is clear.
You accept ugly messages when ena_com functions are called from probe()
for the sake of better messages when the same ena_com functions are
called later from other parts of the driver. Maybe an explanation of
this tradeoff would have been good in the commit message (or a link
to the mail thread).

>>> Signed-off-by: Shay Agroskin <shayagr@...zon.com>
>>> Signed-off-by: Arthur Kiyanovski <akiyano@...zon.com>
>>> ---
>>>  drivers/net/ethernet/amazon/ena/ena_netdev.c | 46
>>> ++++++++++----------
>>>  1 file changed, 23 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c
>>> b/drivers/net/ethernet/amazon/ena/ena_netdev.c
>>> index df1884d57d1a..985dea1870b5 100644
>>> --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
>>> +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
>>> @@ -29,6 +29,8 @@ MODULE_LICENSE("GPL");
>>>  /* Time in jiffies before concluding the transmitter is hung. */
>>> #define TX_TIMEOUT  (5 * HZ)
>>>
>>> +#define ENA_MAX_RINGS min_t(unsigned int,
>> ENA_MAX_NUM_IO_QUEUES,
>>> +num_possible_cpus())
>>> +
>>>  #define ENA_NAPI_BUDGET 64
>>>
>>>  #define DEFAULT_MSG_ENABLE (NETIF_MSG_DRV | NETIF_MSG_PROBE
>> |
>>> NETIF_MSG_IFUP | \ @@ -4176,18 +4178,34 @@ static int
>> ena_probe(struct
>>> pci_dev *pdev, const struct pci_device_id *ent)
>>>
>>>       ena_dev->dmadev = &pdev->dev;
>>>
>>> +     netdev = alloc_etherdev_mq(sizeof(struct ena_adapter),
>> ENA_MAX_RINGS);
>>> +     if (!netdev) {
>>> +             dev_err(&pdev->dev, "alloc_etherdev_mq failed\n");
>>> +             rc = -ENOMEM;
>>> +             goto err_free_region;
>>> +     }
>>> +
>>> +     SET_NETDEV_DEV(netdev, &pdev->dev);
>>> +     adapter = netdev_priv(netdev);
>>> +     adapter->ena_dev = ena_dev;
>>> +     adapter->netdev = netdev;
>>> +     adapter->pdev = pdev;
>>> +     adapter->msg_enable = netif_msg_init(debug,
>> DEFAULT_MSG_ENABLE);
>>> +
>>> +     pci_set_drvdata(pdev, adapter);
>>> +
>>>       rc = ena_device_init(ena_dev, pdev, &get_feat_ctx, &wd_state);
>>>       if (rc) {
>>>               dev_err(&pdev->dev, "ENA device init failed\n");
>>>               if (rc == -ETIME)
>>>                       rc = -EPROBE_DEFER;
>>> -             goto err_free_region;
>>> +             goto err_netdev_destroy;
>>>       }
>>>
>>>       rc = ena_map_llq_mem_bar(pdev, ena_dev, bars);
>>>       if (rc) {
>>>               dev_err(&pdev->dev, "ENA llq bar mapping failed\n");
>>> -             goto err_free_ena_dev;
>>> +             goto err_device_destroy;
>>>       }
>>>
>>>       calc_queue_ctx.ena_dev = ena_dev; @@ -4207,26 +4225,8 @@ static
>>> int ena_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>>>               goto err_device_destroy;
>>>       }
>>>
>>> -     /* dev zeroed in init_etherdev */
>>> -     netdev = alloc_etherdev_mq(sizeof(struct ena_adapter),
>> max_num_io_queues);
>>> -     if (!netdev) {
>>> -             dev_err(&pdev->dev, "alloc_etherdev_mq failed\n");
>>> -             rc = -ENOMEM;
>>> -             goto err_device_destroy;
>>> -     }
>>> -
>>> -     SET_NETDEV_DEV(netdev, &pdev->dev);
>>> -
>>> -     adapter = netdev_priv(netdev);
>>> -     pci_set_drvdata(pdev, adapter);
>>> -
>>> -     adapter->ena_dev = ena_dev;
>>> -     adapter->netdev = netdev;
>>> -     adapter->pdev = pdev;
>>> -
>>>       ena_set_conf_feat_params(adapter, &get_feat_ctx);
>>>
>>> -     adapter->msg_enable = netif_msg_init(debug,
>> DEFAULT_MSG_ENABLE);
>>>       adapter->reset_reason = ENA_REGS_RESET_NORMAL;
>>>
>>>       adapter->requested_tx_ring_size = calc_queue_ctx.tx_queue_size;
>>> @@ -4257,7 +4257,7 @@ static int ena_probe(struct pci_dev *pdev, const
>> struct pci_device_id *ent)
>>>       if (rc) {
>>>               dev_err(&pdev->dev,
>>>                       "Failed to query interrupt moderation feature\n");
>>> -             goto err_netdev_destroy;
>>> +             goto err_device_destroy;
>>>       }
>>>       ena_init_io_rings(adapter,
>>>                         0,
>>> @@ -4335,11 +4335,11 @@ static int ena_probe(struct pci_dev *pdev,
>> const struct pci_device_id *ent)
>>>       ena_disable_msix(adapter);
>>>  err_worker_destroy:
>>>       del_timer(&adapter->timer_service);
>>> -err_netdev_destroy:
>>> -     free_netdev(netdev);
>>>  err_device_destroy:
>>>       ena_com_delete_host_info(ena_dev);
>>>       ena_com_admin_destroy(ena_dev);
>>> +err_netdev_destroy:
>>> +     free_netdev(netdev);
>>>  err_free_region:
>>>       ena_release_bars(ena_dev, pdev);
>>>  err_free_ena_dev:
>>>
> 

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