FADV_DONTNEED support

[Ben Gamari]

Ben Gamari <bgamari.foss at gmail.com> writes:

> While going through an old todo list I found that these patches had fallen by
> the way-side. About a year ago I initiated a discussion[1] with the Linux
> kernel folks regarding the lack of any useable fadvise support on the kernel
> side. As a result, I was observing extremely poor performance on my server
> after backup as executable pages were being swapped out in favor of data
> waiting to be flushed to disk. This is an extremely poor trade-off in the case
> of a backup but the user-mode had no way to communicate this to the
> kernel as few POSIX implementations had working implementations of
> fadvise.
>
Any opinion on merging this? I'd be happy to port it forward if there
are conflicts.

Cheers,

- Ben