/** Release any free memory back to the system,
* but only if you are above a certain fraction of use of the
* total available PHYSICAL memory.
* Calling this could help the system avoid going into swap.
*
* NOTE: This only works if you linked against tcmalloc.
* NOTE 2: This takes at least 0.1 ms on a Ubuntu 10.10 system, because of
* the call to MemoryStats.update().
*
* @param threshold :: multiplier (0-1.0) of the amount of physical
* memory used that has to be in use before the call to
* release memory is actually called.
*/
void MemoryManagerImpl::releaseFreeMemoryIfAbove(double threshold)
{
UNUSED_ARG(threshold);
#ifdef USE_TCMALLOC
Kernel::MemoryStats mem;
mem.update();
double fraction_available = static_cast<double>(mem.availMem())
/ static_cast<double>(mem.totalMem());
if (fraction_available < (1.0 - threshold))
{
// Make TCMALLOC release memory to the system
MallocExtension::instance()->ReleaseFreeMemory();
}
#endif
}
