Deallocating memory pages

Bernd Eckenfels bernd-2012 at
Tue Jan 29 21:43:03 UTC 2013

Am 29.01.2013, 21:23 Uhr, schrieb Hiroshi Yamauchi <yamauchi at>:
> The question is how likely they need the RAM and whether you'd be
> willing to pay the page deallocation cost to get this sort of memory
> management flexibility.

I wonder if there is any deallocation cost involved at all. The VM can
just mark the page as not-dirty and not-used. The only cost to use the
page again (at the same place) would be to zero it. (and even that could
be avoided if the VMM remembers the original owner and map it backl to the
process if that process touches it again and no other process had the need
for the page. Kind of same as buffer cache pages.

But I guess only some performance tests can answer that. (And add a test
for large/hugepages to avoid automatic page splits if they are partially


More information about the hotspot-gc-dev mailing list