From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leon Romanovsky Subject: Re: RDMA miniconf: Persistent device naming Date: Mon, 31 Jul 2017 19:54:53 +0300 Message-ID: <20170731165453.GD13672@mtr-leonro.local> References: <20170731113633.GU13672@mtr-leonro.local> <1501513246.2466.1.camel@wdc.com> <20170731164705.GB28204@obsidianresearch.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="avNtfD0ffNO6L/9g" Return-path: Content-Disposition: inline In-Reply-To: <20170731164705.GB28204-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Gunthorpe Cc: Bart Van Assche , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "liranl-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org" , "tzahio-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org" List-Id: linux-rdma@vger.kernel.org --avNtfD0ffNO6L/9g Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Jul 31, 2017 at 10:47:05AM -0600, Jason Gunthorpe wrote: > On Mon, Jul 31, 2017 at 03:00:47PM +0000, Bart Van Assche wrote: > > On Mon, 2017-07-31 at 14:36 +0300, Leon Romanovsky wrote: > > > I would like to propose the discussion about ability to add > > > persistent device naming to RDMA subsystem. > > > > > > Right now, the devices receive their names by simple addition of new free > > > index to the name (mlx5_0, mlx5_1 ...). Such naming scheme depends on the > > > PCI probing and in case of device reset can rename device. > > > > > > Such situation doesn't help to provide constant udev rules, reliable > > > ibverbs hotplug and advanced "set command" of RDMAtool which at some > > > point of time will require reinit of ib_device. > > > > > > In this discussion, I want to present netdev implementation of such > > > feature, talk about implications on libibverbs and suggest possible > > > device name convention. > > > > Hello Leon, > > > > Does this mean that there is user space software that depends on these names? > > Shouldn't all user space software be independent of the device names assigned > > by the kernel? For e.g. SCSI disks this was solved a long time ago by making > > /dev/disk/by-id/${name derived from persistent ID} soft links available. An > > example: > > > > $ ls -l /dev/disk/by-id/scsi-35001b44c698c2947 > > lrwxrwxrwx 1 root root 9 Jul 31 07:53 /dev/disk/by-id/scsi-35001b44c698c2947 -> ../../sda > > The problem with RDMA is it relies heavily on sysfs, and the sysfs > path name is what is being proposed to be changable. > > The best fix is going to be to consistently use the new stable index > to access all information, which means effectively obsoleting sysfs. > I want to take RDMA one step more, https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/ I called the topic name "persistent", but the right name is "predictable". Thanks > Jason > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html --avNtfD0ffNO6L/9g Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkhr/r4Op1/04yqaB5GN7iDZyWKcFAll/YN0ACgkQ5GN7iDZy WKdHLw/+KWuhFoQdQqpJQAFCS9Z5I3jJViJoPmXhNBTRSGyFyf88vw+2hWJesSUb IWrs8pBFh2XP00I2MguTBqdNU5eez46h4vhAWkc80MZR4RK9/fieHWa9BWqQkyQa OHjsRpEX/XmL6/i2mmtDSwPFQusLWBgDEPwDjbIs06Z5NCLSITzrqIJ5Bee42RDD U/nDXRz5SVqTof3G7Ir4rZs3tQJQBryB4FRw5YM5bVj4n6aD4tOGhphUz8t4PStF eW68HKZsckmmxLLyhPKocYrA9WBA20EWDi9V7Ze5/qpqgPfg9jl3aGsBDh7SmBOl iHN/nPxrj7w9DCdtazc74y8dWMZU6i+Dop/MvzQ0akEJOm0eneIqks4ELuPcNP9o GcHyn/pxKXNwiPdKLA1QqC0+Os+L2Dt7LqXVbkk3NGCgOO9IEmnC0eOsWTZkaHWX bKnsZO39C7zFEEQYaUBbIC6Kczk9dj7jT0ZvxI3/pFxZgyIxhAfQVr9b+fLjt5ct PWFJlmiJSFwSIYG21isi9x/zp+SJAk1DFbgN9s9gjRuI70OwM9YHHyhvmgQxjrRW 0bRbnXC6jTFHDirVJqY5gxhS6wiudQpPsi+3ajOUlj3j9VkKcRZ81MXtTjgCGa0H MN+2ygn6b6TZukjNzVNgs45lXrXa80PDUOw2iUuVC95TWDlKfEU= =il22 -----END PGP SIGNATURE----- --avNtfD0ffNO6L/9g-- -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html