fix atomic limits check

alan.adamson at oracle.com alan.adamson at oracle.com
Wed Jun 18 09:07:42 PDT 2025


On 6/17/25 10:32 PM, Christoph Hellwig wrote:
> On Tue, Jun 17, 2025 at 10:40:35AM -0700, alan.adamson at oracle.com wrote:
>> I changed the config a bit:
>>
>> CTRL 0 - AWUN=31 AWUPF=15
>> CTRL 1 - AWUN=31 AWUPF=31
>> CTRL 2 - AWUN=15 AWUPF=7
>> CTRL 3 - AWUN=15 AWUPF=15
>>      NS - NAWUN=31 NAWUPF=15
>>      NS - NAWUN=127 NAWUPF=63
> I'm a bit confused what this config means.  The NS lines here are
> multiple namespaces?

CTRL 0 - 2 - each has 1 namespace, none of which define namespace atomic 
parameters.

CTRL 3 - has 2 namespaces both define namespace atomic parameters.

>
>> [root at localhost ~]# sh testxx.sh nvme0n3
> But this is all about the controller 0 above, which now has multiple
> namespaces?
>
>> + cat /sys/block/nvme0n3/queue/atomic_write_max_bytes
>> 8192
>> [root at localhost ~]# dmesg | grep -i awupf
>> [root at localhost ~]#
>>
>> AWUPF of 7 isn't consistent with an atomic_write_max_bytes of 8192.
> It is consistent with an (N)AWUPF=15, and it is namespace number 3.  Are
> you testing controller 3 above or is the namespace shared between
> controller 0 and controller 3?

CTRL 2 (nvme0n3) has AWUPF=7 which means it supports a max atomic write 
size of 4096b, but /sys/block/nvme0n3/queue/atomic_write_max_bytes is 8192b.

Alan




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