On Sat, Mar 04, 2023 at 04:39:02PM +0000, Matthew Wilcox wrote: > I'm getting more and more > comfortable with the idea that "Linux doesn't support block sizes > > PAGE_SIZE on 32-bit machines" is an acceptable answer. First of all filesystems would need to add support for a larger block sizes > PAGE_SIZE, and that takes effort. It is also a support question too. I think garnering consensus from filesystem developers we don't want to support block sizes > PAGE_SIZE on 32-bit systems would be a good thing to review at LSFMM or even on this list. I hightly doubt anyone is interested in that support. > XFS already works with arbitrary-order folios. But block sizes > PAGE_SIZE is work which is still not merged. It *can* be with time. That would allow one to muck with larger block sizes than 4k on x86-64 for instance. Without this, you can't play ball. > The only needed piece is > specifying to the VFS that there's a minimum order for this particular > inode, and having the VFS honour that everywhere. Other than the above too, don't we still also need to figure out what fs APIs would incur larger order folios? And then what about corner cases with the page cache? I was hoping some of these nooks and crannies could be explored with tmpfs. Luis
