Releasing unused memory
per.liden at oracle.com
Thu Oct 18 10:19:14 UTC 2018
On 10/18/2018 12:02 PM, Aleksey Shipilev wrote:
> On 10/18/2018 11:56 AM, Per Liden wrote:
>> Of course, the hard part to answer here is "what's a reasonable GC frequency?". And, of course,
>> if it turns out that the workload all of a sudden needs all of that that headroom we were give,
>> than it's of course free to use it.
>> So, this essentially just means that the heuristics, for calculating when to do a GC, would use
>> a "target max capacity" instead of the real "max capacity" (Xmx) as input.
> Yes, this is where nasty feedback loops get introduced. We have been down this path, without much
> success. Happy to adopt the solution, if any :)
Yes, this has the problem that is puts the GC in a mode where it strives
to reach a back-to-back GC steady state, which probably isn't desirable.
So deciding what a reasonable GC frequency is will be hard without user
input. And one could argue that this user input _is_ Xmx, so don't
bother doing some conservative heap growth thing.
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