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From:   "Czerwacki, Eial" <eial.czerwacki@sap.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Arsh, Leonid" <leonid.arsh@sap.com>,
        "Twaig, Oren" <oren.twaig@sap.com>,
        SAP vSMP Linux Maintainer <linux.vsmp@sap.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Andra Paraschiv <andraprs@amazon.com>,
        Borislav Petkov <bp@suse.de>,
        Brijesh Singh <brijesh.singh@amd.com>,
        Eric Biggers <ebiggers@google.com>, Fei Li <fei1.li@intel.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Jens Axboe <axboe@kernel.dk>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Subject: Re: [PATCH v2] drivers/virt/vSMP: new driver
Thread-Topic: [PATCH v2] drivers/virt/vSMP: new driver
Thread-Index: AQHYuErwCwPojP5fak60UhGlJnJEo62/OPAAgAACsWWAAB5kAIAADNqvgAACQwCAAAE9j4AAFa6AgAAESN4=
Date:   Thu, 25 Aug 2022 12:02:12 +0000
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>On Thu, Aug 25, 2022 at 10:41:28AM +0000, Czerwacki, Eial wrote:=0A=
>> >On Thu, Aug 25, 2022 at 10:16:59AM +0000, Czerwacki, Eial wrote:=0A=
>> >> >> >And why is your version file a binary file?  It should just be a =
small=0A=
>> >> >> >text string, right?=0A=
>> >> >> not so small, it can reach up to 512kb.=0A=
>> >> >=0A=
>> >> >That was not obvious at all.  Please document this.=0A=
>> >> where should the document be?=0A=
>> >> in the code as a comment or in another file?=0A=
>> >=0A=
>> >In the Documentation/ABI/ file that describes this file.=0A=
>> ok, will place it there=0A=
>> =0A=
>> >=0A=
>> >> >And how in the world is a "version" that big?  What exactly does thi=
s=0A=
>> >> >contain?=0A=
>> >> it 's size depends on the number of resources it uses.=0A=
>> >> here is an example:=0A=
>> >> :~> cat /sys/hypervisor/vsmp/version  =0A=
>> >> SAP vSMP Foundation: 10.6.2862.0 (Aug 22 2022 15:21:02)=0A=
>> >> System configuration:=0A=
>> >>    Boards:      2=0A=
>> >>       1 x Proc. + I/O + Memory=0A=
>> >>       1 x NVM devices (Amazon.com Amazon EC2 NVMe Instance Storage)=
=0A=
>> >>    Processors:  1, Cores: 2, Threads: 4=0A=
>> >>        Intel(R) Xeon(R) Platinum 8124M CPU @ 3.00GHz Stepping 04=0A=
>> >>    Memory (MB): 30976 (of 103192), Cache: 7527, Private: 64689=0A=
>> >>       1 x  6400MB    [ 7825/ 321/ 1104]      =0A=
>> >>       1 x 24576MB    [95367/7206/63585]       00:1f.0#1=0A=
>> >>    Boot device: [HDD] NVMe: Amazon Elastic Block Store        =0A=
>> >> Supported until: Aug 22 2024=0A=
>> >=0A=
>> >That is crazy, and is not a version.  It's a "configuration".=0A=
>> it is called version for history reasons...=0A=
>=0A=
>There is no "history" here, you can create whatever sane interface you=0A=
>want right now, there is no backwards compatible issues involved at all.=
=0A=
you are correct, however, it depends on how much change the hypervisor code=
 requires=0A=
if any (latter is preferable)=0A=
=0A=
>=0A=
>> >See above, make it text only for the version.  If you want to export=0A=
>> >other things, be explicit and make them "one value per sysfs file" or=
=0A=
>> >use debugfs for debugging things that no one relies on.=0A=
>> so you suggest braking the summery into files, e.g. one for cpus, one fo=
r ram and etcetera?=0A=
>=0A=
>Again, who uses this information and what is it used for?=0A=
>=0A=
>thanks,=0A=
>=0A=
>greg k-h=0A=
=0A=
both user who uses the product and the development team.=0A=
it is used to provide a summery of the system. for example, which devices a=
re used=0A=
by the hypervisor.=0A=
=0A=
Thanks,=0A=
=0A=
Eial=