Messages in this thread | | | Date | Mon, 22 Sep 2014 12:32:02 -0400 | Subject | Re: [RFC PATCH 0/7] Non-blockling buffered fs read (page cache only) | From | Milosz Tanski <> |
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On Mon, Sep 22, 2014 at 11:48 AM, Jeff Moyer <jmoyer@redhat.com> wrote: > Christoph Hellwig <hch@infradead.org> 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@adfin.com
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