[External] Re: [PATCH 2/2] net/mlx5: improve log file path

[Yang Ming]

On 2025/3/10 22:59, Stephen Hemminger wrote:
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>
> On Tue, 4 Mar 2025 06:23:06 +0000
> Bing Zhao <bingz at nvidia.com> wrote:
>
>> Hi Ming,
>>
>>> -----Original Message-----
>>> From: Yang Ming <ming.1.yang at nokia-sbell.com>
>>> Sent: Friday, December 13, 2024 5:25 PM
>>> To: Dariusz Sosnowski <dsosnowski at nvidia.com>; Slava Ovsiienko
>>> <viacheslavo at nvidia.com>; Bing Zhao <bingz at nvidia.com>; Ori Kam
>>> <orika at nvidia.com>; Suanming Mou <suanmingm at nvidia.com>; Matan Azrad
>>> <matan at nvidia.com>
>>> Cc: dev at dpdk.org; Yang Ming <ming.1.yang at nokia-sbell.com>
>>> Subject: [PATCH 2/2] net/mlx5: improve log file path
>>>
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> 1. /var/log is hard code which is not a good coding style.
>>> 2. /var/log may be not allowed to be written via container's read-only
>>> mode.
>>>
>>> Signed-off-by: Yang Ming <ming.1.yang at nokia-sbell.com>
>>> ---
>>>   drivers/net/mlx5/mlx5_rxtx.c | 3 ++-
>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
>>> index eadadcdffb..a0da73c9c3 100644
>>> --- a/drivers/net/mlx5/mlx5_rxtx.c
>>> +++ b/drivers/net/mlx5/mlx5_rxtx.c
>>> @@ -12,6 +12,7 @@
>>>   #include <rte_prefetch.h>
>>>   #include <rte_common.h>
>>>   #include <rte_branch_prediction.h>
>>> +#include <rte_eal.h>
>>>   #include <rte_ether.h>
>>>   #include <rte_cycles.h>
>>>   #include <rte_flow.h>
>>> @@ -311,7 +312,7 @@ mlx5_set_swp_types_table(void)
>>>          }
>>>   }
>>>
>>> -#define MLX5_SYSTEM_LOG_DIR "/var/log"
>>> +#define MLX5_SYSTEM_LOG_DIR rte_eal_get_runtime_dir()
>> I agree that using the fixed PATH is not a good practice. Can you ensure that the runtime DIR is with RW+ permissions?
> Drivers doing any kind of custom logging is bad practice.
> This should be handled by EAL logging, not private fprintf's
>
>
>
Hi Stephen,

Yes, I completely agree with you. The DPDK driver should utilize EAL 
logging instead of fprintf. We have recently addressed an issue where 
DPDK was applied in a container with a read-only file system mode. In 
this mode, the /var/log directory is read-only. However, when DPDK is 
running, the directory specified by rte_eal_get_runtime_dir() must be 
configured with read-write permissions. Therefore, we have made this 
minor improvement.

Please note that we are not the developers of the Mellanox CX4/CX5 NIC, 
nor are we affiliated with the manufacturer of these NICs. As such, we 
are unable to make the improvements you described.

Brs,
Yang Ming