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From DE VITO Dominique <>
Subject question about commitlog segments and memlocking
Date Fri, 01 Aug 2014 09:53:58 GMT

The instruction < CLibrary.tryMlockall(); > is called at the very beginning of the setup()
Cassandra method.
So, the heap space is memlocked in memory (if OS rights are set).

"mlockall()" is called with "MCL_CURRENT" : "MCL_CURRENT  Lock all pages currently mapped
into the process's address space."

So, AFAIU(nderstand), the commitlog segments (or other off-heap structures) are NOT memlocked,
and may be swapped.

Is it also your understanding ?

If true, why not using "mlockall(MCL_FUTURE)" instead, or calling mlocka() after commitlog
segments allocation ?



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