On Fri, 9 Feb 2007 12:31:16 +0100 Nick Piggin <npiggin@xxxxxxx> wrote: > > > > > But that all becomes legacy path, so do we really care? Supposing fs > > > > > maintainers like perform_write, then after the main ones have implementations > > > > > we could switch over to the slow-but-correct prepare_write legacy path. > > > > > Or we could leave it, or we could use Linus's slightly-less-buggy scheme... > > > > > by that point I expect I'd be sick of arguing about it ;) > > > > > > > > It's worth "arguing" about. This is write(). What matters more?? > > > > > > That's the legacy path that uses prepare/commit (ie. supposing that all > > > major filesystems did get converted to perform_write). > > > > We'll never, ever, ever update and test all filesytems. What you're > > calling "legacy" code will be there for all time. > > I didn't say all; I still prefer correct than fast; For gawd's sake. You can make the kernel less buggy by removing SMP support. Guess what? Tradeoffs exist. > you are still free > to keep the fast-and-buggy code in the legacy path. You make it sound like this is a choice. It isn't. Nobody is going to go in and convert all those filesystems. > > > > I haven't had time to look at the perform_write stuff yet. > > > > > Of course I would still want my correct-but-slow version in that case, > > > but I just wouldn't care to argue if you still wanted to keep it fast. > > > > This is write(). We just cannot go and double-copy all the memory or take > > mmap_sem and do a full pagetable walk in there. It just means that we > > haven't found a suitable solution yet. > > You prefer speed over correctness even for little used filessytems, which > is fine because I'm sick of arguing about it. The main thing for me is that > important filesystems can be correct and fast. I wouldn't characterise it as "arguing". It's development. Going and sticking enormous slowdowns into write() to fix some bug which nobody is hitting is insane. We need to find a better fix, that's all. - 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
