On 02/03/10 14:42, Robert Haas wrote:
On Wed, Feb 3, 2010 at 6:53 AM, Greg Stark<gsst...@mit.edu> wrote:
On Tue, Feb 2, 2010 at 7:45 PM, Robert Haas<robertmh...@gmail.com> wrote:
I think you're probably right, but it's not clear what the new name
should be until we have a comment explaining what the function is
responsible for.
So I wrote some comments but wasn't going to repost the patch with the
unchanged name without explanation... But I think you're right though
I was looking at it the other way around. I want to have an API for a
two-stage sync and of course if I do that I'll comment it to explain
that clearly.
The gist of the comments was that the function is preparing to fsync
to initiate the i/o early and allow the later fsync to fast -- but
also at the same time have the beneficial side-effect of avoiding
cache poisoning. It's not clear that the two are necessarily linked
though. Perhaps we need two separate apis, though it'll be hard to
keep them separate on all platforms.
Well, maybe we should start with a discussion of what kernel calls
you're aware of on different platforms and then we could try to put an
API around it.
In linux there is sync_file_range. On newer Posixish systems one can
emulate that with mmap() and msync() (in batches obviously).
No idea about windows.
Andres
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