On Fri,  8 May 2015 15:33:43 -0400 Eric B Munson [off-list ref] wrote:

mlock() allows a user to control page out of program memory, but this
comes at the cost of faulting in the entire mapping when it is
allocated.  For large mappings where the entire area is not necessary
this is not ideal.

This series introduces new flags for mmap() and mlockall() that allow a
user to specify that the covered are should not be paged out, but only
after the memory has been used the first time.

Please tell us much much more about the value of these changes: the use
cases, the behavioural improvements and performance results which the
patchset brings to those use cases, etc.