[bug report] NVMe/IB: reset_controller need more than 1min

[Max Gurtovoy]

On 2/14/2022 1:32 PM, Sagi Grimberg wrote:
>
>> Hi Sagi/Max
>> Here are more findings with the bisect:
>>
>> The time for reset operation changed from 3s[1] to 12s[2] after
>> commit[3], and after commit[4], the reset operation timeout at the
>> second reset[5], let me know if you need any testing for it, thanks.
>
> Does this at least eliminate the timeout?
> -- 
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index a162f6c6da6e..60e415078893 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -25,7 +25,7 @@ extern unsigned int nvme_io_timeout;
>  extern unsigned int admin_timeout;
>  #define NVME_ADMIN_TIMEOUT     (admin_timeout * HZ)
>
> -#define NVME_DEFAULT_KATO      5
> +#define NVME_DEFAULT_KATO      10
>
>  #ifdef CONFIG_ARCH_NO_SG_CHAIN
>  #define  NVME_INLINE_SG_CNT  0
> -- 
>
or for the initial test you can use --keep-alive-tmo=<10 or 15> flag in 
the connect command

>>
>> [1]
>> # time nvme reset /dev/nvme0
>>
>> real 0m3.049s
>> user 0m0.000s
>> sys 0m0.006s
>> [2]
>> # time nvme reset /dev/nvme0
>>
>> real 0m12.498s
>> user 0m0.000s
>> sys 0m0.006s
>> [3]
>> commit 5ec5d3bddc6b912b7de9e3eb6c1f2397faeca2bc (HEAD)
>> Author: Max Gurtovoy <maxg at mellanox.com>
>> Date:   Tue May 19 17:05:56 2020 +0300
>>
>>      nvme-rdma: add metadata/T10-PI support
>>
>> [4]
>> commit a70b81bd4d9d2d6c05cfe6ef2a10bccc2e04357a (HEAD)
>> Author: Hannes Reinecke <hare at suse.de>
>> Date:   Fri Apr 16 13:46:20 2021 +0200
>>
>>      nvme: sanitize KATO setting-
>
> This change effectively changed the keep-alive timeout
> from 15 to 5 and modified the host to send keepalives every
> 2.5 seconds instead of 5.
>
> I guess that in combination that now it takes longer to
> create and delete rdma resources (either qps or mrs)
> it starts to timeout in setups where there are a lot of
> queues.