Keep a file in memory an any cost

[JB]

Alain Spineux <aspineux <at> gmail.com> writes:

> 
> Joe: The index is modified very often and need to be flushed at
> regular interval, I don't want to handle read and write.
> JB: I already use mmap.
> JD: I already tried posix_fadvise with POSIX_FADV_WILLNEED, but this
> is not rock solid, if not used for a long time, data are not in the
> cache anymore.
> Bryn: mlock is what I was looking for. I'll make a try now.
> ...

I do not know if you are aware of:
$ man mmap
...
       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.
...

JB