On Fri, Feb 09, 2007 at 03:46:44AM -0800, Andrew Morton wrote: > On Fri, 9 Feb 2007 12:31:16 +0100 Nick Piggin <npiggin@xxxxxxx> wrote: > > > > > > > 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. I'm talking about known bugs. > Guess what? Tradeoffs exist. I agree that 60% is much too big of a hit for all filesystems. Which is why I propose this new aop. > > 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. IMO, once all the maintained filesystems are converted then it would be a good choice to make. You think otherwise and I won't argue. > > > > > > 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. Actually I'm doing this because I try to fix real data corruption problems which people are hitting. You told me I can't get those fixes in until I fix this problem. > We need to find a better fix, that's all. I actually found perform_write to be a speedup. And if perform_write is merged then I would be happy to not fix the prepare_write path, or wait for someone to come up with a better fix. - 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
