On Mon, Aug 29, 2016 at 08:57:41AM -0400, Theodore Ts'o wrote: > It's been on my todo list. The only reason why I haven't done it yet > is because I knew you were working on a solution, and I didn't want to > do things one way for buffered I/O, and a different way for Direct > I/O, and disentangling the DIO code and the different assumptions of > how different file systems interact with the DIO code is a *mess*. It is. I have an almost working iomap direct I/O implementation, which simplifies a lot of this. Partially because it expects sane locking (a shared lock should be held over read, fortunately we now have i_rwsem for that) and allows less opt-in/out behavior, and partially just because we have so much better infrastructure now (iomap, bio chaining, iov_iters, ...). The iomap version is still work in progress, but I'm about to post a cut down version for block devices which reduces I/O latency by 20%. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>