On Mon, Sep 22, 2014 at 11:48 AM, Jeff Moyer <jmoyer@xxxxxxxxxx> wrote: > Christoph Hellwig <hch@xxxxxxxxxxxxx> writes: > >> Without the atomic WRITE SCATTERED use case adding the syscalls seems >> rather pointless, and I'd really avoid blocking nice software only >> features like the per-I/O nonblock flag (and the similarly trivial >> per-I/O sync option I have a prototype for) on it. > > Andreas and Zach pointed out that the scatter/gather system calls also > help network file systems. I'm not yet sure how much work it would be, > but it certainly seems worth considering readx/writex (or whatever we > want to call them) to avoid needlessly adding a ton of system calls. > > Cheers, > Jeff I spent some time thinking about multi-position scatter/gather in context of this over the weekend. The non-blocking case seams easy, the implementation I purposed needs an extra loop. Where this gets hairy is making the non-trivial blocking case work well (as in have concurrent requests for each of the ranges) in the filesystem code. If that's the road we're going to go down I have a gut feeling we're going to get stuck in the same spot(s) as the other non-blocking buffered r/w attempts from the past. Best, - Milosz -- Milosz Tanski CTO 16 East 34th Street, 15th floor New York, NY 10016 p: 646-253-9055 e: milosz@xxxxxxxxx -- 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
