Re: [PATCH 2/2] posix_fadvise.2: Document the behaviour of partial page discard requests

From: Michael Kerrisk (man-pages)
Date: Tue Dec 30 2014 - 15:49:03 EST


On 12/03/2014 01:42 AM, Mel Gorman wrote:
> It is not obvious from the interface that partial page discard requests
> are ignored. It should be spelled out.

Thanks, Mel. Applied.

Cheers,

Michael


> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
> ---
> man2/posix_fadvise.2 | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/man2/posix_fadvise.2 b/man2/posix_fadvise.2
> index 25d0c50..07313a9 100644
> --- a/man2/posix_fadvise.2
> +++ b/man2/posix_fadvise.2
> @@ -144,6 +144,11 @@ A program may periodically request the kernel to free cached data
> that has already been used, so that more useful cached pages are not
> discarded instead.
>
> +Requests to discard partial pages are ignored. It is preferable to preserve
> +needed data than discard unneeded data. If the application requires that
> +data be considered for discarding then \fIoffset\fP and \fIlen\fP must be
> +page-aligned.
> +
> Pages that have not yet been written out will be unaffected, so if the
> application wishes to guarantee that pages will be released, it should
> call
>


--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/