On Tue, Jun 12, 2018 at 04:24:20PM +0200, Jan Kara wrote: > On Tue 12-06-18 14:11:30, Amir Goldstein wrote: > > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > > --- > > > > Linus, > > > > I tried to find some space to cram i_generation in case > > I get rid of i_fsnotify_mask, but stumbled on a possible > > "lossless compression". > > > > Any caveats with this change? > > One concern I'd have is that i_blkbits is used relatively frequently (e.g. > for block device access) and 1-byte fetch can be slower than 4-byte fetch > on some architectures if I'm not mistaken. I'm not sure how big problem > that would be through. > > But if you're looking at reducing struct inode size, it appears we can save > one long by reorganizing struct address_space - there's currently 4-byte > hole after i_mmap_writeable and after wb_err. I already have something along those lines in the XArray series. http://git.infradead.org/users/willy/linux-dax.git/commitdiff/527c1696148fd3044866dd56991bbb51c24c0d7b
