On Mon, Apr 11, 2016 at 12:02 AM, James Simmons <jsimmons@xxxxxxxxxxxxx> wrote: > >> On Sun, Apr 10, 2016 at 03:37:42PM +0100, James Simmons wrote: >> > >> > > The lloop driver should be removed entirely - use the loop driver >> > > instead. >> > >> > I talked with Andreas last week at our annual Lustre users group meeting >> > about this. The reason I was told for existance is that some users were >> > using files on a Lustre file system with the loop back device. The >> > performance was really bad at the time so a lloop was developed to >> > overcome those limitations. Its been a long time so perhaps its time >> > to look at the default loop driver again to see if can perform now. If >> > it doesn't we will go the route of reworking the lloop driver in the >> > spirit of the cryptoloop device. >> >> The loop driver now supports using AIO/DIO on any file systems that >> implements ->read_iter and ->write_iter. If lustre doesn't support >> those or doesn't have proper performance using them it should be >> addressed in the file system. >> >> Note that the dio mode in the loop device is not the default and you >> need to manually enabled it, keep that in mind when testing. > > This is excellent news. The only sad thing is that most lustre users > are running distros that use kernels before the AIO/DIO enhancements > were landed :-( We will have to keep a copy around for those guys. But > first I need to test the performance of the loop back driver this > week before this can be dropped. Considered that this cleanup patch for lustre loop is quite simple and straightforward, I suggest to keep this cleanup patch as so and do the dropping in another patchset. Christoph, are you OK with that? Thanks, Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
