Messages in this thread | | | Date | Tue, 28 Apr 2015 16:10:01 -0700 | From | Andrew Morton <> | Subject | Re: [RFC 1/3] mm: mmap make MAP_LOCKED really mlock semantic |
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On Tue, 28 Apr 2015 14:11:49 +0200 Michal Hocko <mhocko@suse.cz> wrote:
> The man page however says > " > MAP_LOCKED (since Linux 2.5.37) > Lock the pages of the mapped region into memory in the manner of > mlock(2). This flag is ignored in older kernels. > "
I'm trying to remember why we implemented MAP_LOCKED in the first place. Was it better than mmap+mlock in some fashion?
afaict we had a #define MAP_LOCKED in the header file but it wasn't implemented, so we went and wired it up. 13 years ago: https://lkml.org/lkml/2002/9/18/108
Anyway... the third way of doing this is to use plain old mmap() while mlockall(MCL_FUTURE) is in force. Has anyone looked at that, checked that the behaviour is sane and compared it with the mmap+mlock behaviour, the MAP_LOCKED behaviour and the manpages?
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