Re: [PATCH] mremap.2: Add note about mremap with locked areas

From: Michael Kerrisk (man-pages)
Date: Fri Sep 11 2015 - 07:47:51 EST


On 08/28/2015 08:42 PM, Eric B Munson wrote:
> When mremap() is used to move or expand a mapping that is locked with
> mlock() or equivalent it will attempt to populate the new area.
> However, like mmap(MAP_LOCKED), mremap() will not fail if the area
> cannot be populated. Also like mmap(MAP_LOCKED) this might come as a
> surprise to users and should be noted.

Thanks, Eric!

Applied, with Michael's Acked-by added.

Cheers,

Michael


> Signed-off-by: Eric B Munson <emunson@xxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>
> Cc: linux-man@xxxxxxxxxxxxxxx
> Cc: linux-mm@xxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> ---
> man2/mremap.2 | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/man2/mremap.2 b/man2/mremap.2
> index 071adb5..cf884e6 100644
> --- a/man2/mremap.2
> +++ b/man2/mremap.2
> @@ -196,6 +196,17 @@ and the prototype for
> did not allow for the
> .I new_address
> argument.
> +
> +If
> +.BR mremap ()
> +is used to move or expand an area locked with
> +.BR mlock (2)
> +or equivalent, the
> +.BR mremap ()
> +call will make a best effort to populate the new area but will not fail
> +with
> +.B ENOMEM
> +if the area cannot be populated.
> .SH SEE ALSO
> .BR brk (2),
> .BR getpagesize (2),
>


--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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