incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From DE VITO Dominique <dominique.dev...@thalesgroup.com>
Subject question about commitlog segments and memlocking
Date Fri, 01 Aug 2014 09:53:58 GMT
Hi,

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 ?

Thanks.

Regards,
Dominique


Mime
View raw message