On Fri, Nov 20, 2015 at 05:31:59PM +0200, Octavian Purdila wrote: > On Fri, Nov 20, 2015 at 5:24 PM, Brian Foster <bfoster@xxxxxxxxxx> wrote: > > On Fri, Nov 20, 2015 at 04:26:28PM +0200, Octavian Purdila wrote: > >> On Fri, Nov 20, 2015 at 2:58 AM, Dave Chinner <david@xxxxxxxxxxxxx> wrote: > >> > On Fri, Nov 20, 2015 at 12:54:02AM +0100, Richard Weinberger wrote: > >> >> On Fri, Nov 20, 2015 at 12:24 AM, Dave Chinner <david@xxxxxxxxxxxxx> wrote: > >> >> > On Wed, Nov 18, 2015 at 12:46:21AM +0200, Octavian Purdila wrote: > >> >> >> Naive implementation for non-mmu architectures: allocate physically > >> >> >> contiguous xfs buffers with alloc_pages. Terribly inefficient with > >> >> >> memory and fragmentation on high I/O loads but it may be good enough > >> >> >> for basic usage (which most non-mmu architectures will need). > >> >> > > >> >> > Can you please explain why you want to use XFS on low end, basic > >> >> > non-MMU devices? XFS is a high performance, enterprise/HPC level > >> >> > filesystem - it's not a filesystem designed for small IoT level > >> >> > devices - so I'm struggling to see why we'd want to expend any > >> >> > effort to make XFS work on such devices.... > >> >> > >> >> The use case is the Linux Kernel Library: > >> >> https://lkml.org/lkml/2015/11/3/706 > >> >> > >> >> Using LKL and fuse you can mount any kernel filesystem using fuse > >> >> as non-root. > >> > > >> > IOWs, because we said no to unprivileged mounts, instead the > >> > proposal is to linking all the kernel code into userspace so you can > >> > do unprivielged mounts that way? > >> > > >> > >> LKL's goal is to make it easy for various applications to reuse Linux > >> kernel code instead of re-implementing it. Mounting filesystem images > >> is just one of the applications. > >> > >> > IOWs, you get to say "it secure because it's in userspace" and leave > >> > us filesystem people with all the shit that comes with allowing > >> > users to mount random untrusted filesystem images using code that > >> > was never designed to allow that to happen? > >> > > >> > >> It is already possible to mount arbitrary filesystem images in > >> userspace using VMs . LKL doesn't change that, it just reduces the > >> amount of dependencies you need to do so. > >> > > > > Perhaps a dumb question, but I'm not quite putting 2+2 together here. > > When I see nommu, I'm generally thinking hardware characteristics, but > > we're talking about a userspace kernel library here. So can you > > elaborate on how this relates to nommu? Does this library emulate kernel > > mechanisms in userspace via nommu mode or something of that nature? > > > > LKL is currently implemented as a virtual non-mmu architecture. That > makes it simpler and it will also allow us to support environments > where it is not possible to emulate paging (e.g. bootloaders). > Ok, so we aren't necessarily talking about running on typically limited, mmu-less hardware. Thanks! Brian > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx > http://oss.sgi.com/mailman/listinfo/xfs -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
