Messages in this thread | | | Date | Fri, 27 Mar 2015 01:35:16 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v7 0/5] vfs: Non-blockling buffered fs read (page cache only) |
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On Fri, 27 Mar 2015 01:18:22 -0700 Christoph Hellwig <hch@infradead.org> wrote:
> On Thu, Mar 26, 2015 at 08:28:24PM -0700, Andrew Morton wrote: > > I still don't understand why pwritev() exists. We discussed this last > > time but it seems nothing has changed. I'm not seeing here an adequate > > description of why it exists nor a justification for its addition. > > pwritev2? I have patches to support per-I/O O_DSYNC with it, lots of > folks including Samba and SCSI targets want this because their protocols > support it. The patches were posted with earlier versions of Miklos > series. > > It's cleaner to add the two system calls in go when we plan using them > anyway and have symmetric infrastructure, and I did not hear any > disagreement with that on LSF. Did you skip this session?
Put it in the changelogs. All of it. A conference discussion is no use to people who weren't there.
> > And (again) we've discussed this before, but the patchset gets resent > > as if nothing had happened. > > We had long discussiosn about it both here and at LSF. We had everyone > agree and nod there, and only your repeated argument here, so maybe it's > not Miklos who is disonnected but you?
I don't find conferences to be a good place to conduct code and design review.
> Also that whole fincore argument is rather hypothetic - it's only been > pushed in to ugly to live multiplexers that also expose things like > pfns, while with preadv2 we have a trivial and easy to use API read to > merge, and various consumerms just waiting for it.
fincore() doesn't have to be ugly. Please address the design issues I raised. How is pread2() useful to the class of applications which cannot proceed until all data is available?
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