Re: [PATCH] xfs: allocate sector sized IO buffer via page_frag_alloc

Matthew Wilcox
2019-02-26T03:29:28Z

On Tue, Feb 26, 2019 at 02:02:14PM +1100, Dave Chinner wrote:
> > Or what is the exact size of sub-page IO in xfs most of time? For
>
> Determined by mkfs parameters. Any power of 2 between 512 bytes and
> 64kB needs to be supported. e.g:
>
> # mkfs.xfs -s size=512 -b size=1k -i size=2k -n size=8k ....
>
> will have metadata that is sector sized (512 bytes), filesystem
> block sized (1k), directory block sized (8k) and inode cluster sized
> (32k), and will use all of them in large quantities.

If XFS is going to use each of these in large quantities, then it doesn't
seem unreasonable for XFS to create a slab for each type of metadata?