On Sun, Jul 21, 2013 at 12:53:10PM -0700, Linus Torvalds wrote: > So it's been another week, and -rc2 is out there. > > The patch looks a bit odd, because by bulk 95% of the patch is just > the removal of the CSR staging driver that wasn't getting any > traction, so the diffstat (and the dirstat in particular) is not very > interesting or readable, since that driver removal basically > overshadows everything else. But I do admit to love seeing code > removal patches. > > And of the rest of the patch, a noticeable part is all those > one-liners all over that just remove the __cpuinit markers that people > agreed were just more pain than gain to maintain. We had already made > the markers be no-ops earlier, so they didn't matter for code > generation, and here in rc2 they get actually removed. > > End result: we have two separate events that generate a lot of noise > in the patch, but aren't really interesting per se. They do make the > patch harder to read, though. > > Ignoring those noisy parts of the patch, there's a couple of things > worth noting about rc2. I think most of the patches here are nice > fixes, but I wanted to give two heads-ups: > > (a) the O_TMPFILE flag that is new to 3.11 has been going through a > few ABI/API cleanups (and a few fixes to the implementation too), but > I think we're done now. So if you're interested in the concept of > unnamed temporary files, go ahead and test it out. The lack of name > not only gets rid of races/complications with filename generation, it > can make the whole thing more efficient since you don't have the > directory operations that can cause serializing IO etc.
I'll just point out that it can make the whole thing worse, too. For example, for ext3/4, the tmpfile being created has to be added to the orphan inode list which is protected by a filesystem global mutex. Hence scalability of O_TMPFILE is massively limited on ext3/ext4 due to architectural issues within ext3/4. Other filesystems will be more efficient, but because they have more scalable/complex orphan inode handling it's going to take longer to implement O_TMPFILE support for them.... Cheers, Dave. -- Dave Chinner da...@fromorbit.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
