RFR (M/L): 8137099: G1 needs to "upgrade" GC within the safepoint if it can't allocate during that safepoint to avoid OoME
thomas.schatzl at oracle.com
Tue Jan 9 10:11:06 UTC 2018
On Tue, 2018-01-09 at 10:54 +0100, Thomas Schatzl wrote:
> Hi again,
> On Tue, 2018-01-09 at 10:52 +0100, Thomas Schatzl wrote:
> > Hi all,
> > Erik Duveblad had some offline comments:
> > New webrevs:
> > http://cr.openjdk.java.net/~tschatzl/8137099/webrev.2_to_3/ (diff)
> > http://cr.openjdk.java.net/~tschatzl/8137099/webrev.3/ (full)
> > - inverting some conditions in the clauses to read better
> > - extract out the condition to do the maximally compacting full gc
> > added in this change into a separate method.
> > Erik Duveblad also noted that this change contains some slight
> > behavioral change in when a collection is started. I.e. previously
> > TLAB allocation by itself could not cause a GC. Since this change
> > is already quite big, he suggested to fix this in a follow-up, and
> > push them together.
Some detail got lost here: previously TLAB allocation could not result
in a Full GC, it can now (that maximally compacting GC).
Its side effects need to be investigated a bit more.
> additionally we agreed to retarget both changes to 11 to let it
> bake a bit.
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