Re: [PATCH V2] dmabuf: ensure unique directory name for dmabuf stats

From: Charan Teja Kalla
Date: Thu May 12 2022 - 10:50:29 EST


Thanks Christian for the comments!!

On 5/11/2022 12:33 PM, Christian König wrote:
>
>> The single number approach, generated by atomic, wouldn't break the
>> uapi, but that number won't give any meaningful information especially
>> when this is targeted just for debug purpose. And just 'inode' is not
>> usable for already stated reasons.
>
> Well, why do you want to use the ino in the first place? This is an
> anonymous inode not associated with any filesystem, so that number is
> meaningless anyway.
>

It is just for ease of debugging. Nothing more. I can quickly traverse
the /sys/kernel/dmabuf/buffers/* and get complete information about the
dmabuf buffers while relating to which process this buffer is allocated
by, using this inode as the 'unique' reference.

https://cs.android.com/android/platform/superproject/+/master:system/memory/libmeminfo/libdmabufinfo/tools/dmabuf_dump.cpp

>> How about using the atomic number generated it self used as inode
>> number? I see tmpfs also maintains its own inode numbers for the same
>> overflow reasons[2].
>
> Yeah, that could potentially work as well.
>

Thanks. Will work on the next version of this patch.

> Regards,
> Christian.