Re: msync() behaviour broken for MS_ASYNC, revert patch?

[Nick Piggin <nickpiggin@yahoo.com.au>]

Andrew Morton wrote:
> Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>
> > Instead of
> > LINUX_FADV_ASYNC_WRITE
> > LINUX_FADV_WRITE_WAIT
> >
> > can we have something more consistent? Perhaps
> > FADV_WRITE_ASYNC
> > FADV_WRITE_SYNC
>
>
> Nope, I had a bit of a think about this and decided that the two operations
> which we need are:

Do you need to introduce a completely new concept 'wait upon writeout'
though? Not to say they can't solve the problem but I don't think they
are any more expressive and they definitely depart from the norm which
has always been sync / async AFAIK.

It may be a very useful operation in kernel, but I think userspace either
wants to definitely know the data is on disk (WRITE_SYNC), or give a hint
to start writing (WRITE_ASYNC).

From a kernel implementation point of view, WRITE_SYNC may be doing
several things (start writeout, wait writeout), but from userspace it is
just a single logical operation.

--
SUSE Labs, Novell Inc.
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