Regarding Humongous Allocation - G1GC

[Kim Barrett]

On 8/27/24 5:04 AM, Ravi wrote:

> Dear Experts,
>
> We have an application running on jre 1.8u261 with the below jvm 
> arguments:
>  -Xms8g -Xmx8g -XX:MetaspaceSize=2g -XX:MaxMetaspaceSize=2g 
> -XX:+UseG1GC -XX:ParallelGCThreads=2 -XX:ConcGCThreads=1 
> -XX:+PrintFlagsFinal
>
> From the jfrs, we could see Humongous allocation failures are 
> happening in the G1New and aswell G1Old spaces:

I think humongous allocation failure will first attempt a young collection.
This may free regions, potentially resulting in a sequence of free regions
sufficient to satisfy the humongous allocation request. Only if that 
fails is
a full collection performed.  That seems to be what your trace shows, e.g. a
fill (G1Old) collection occurring shortly after the young (G1New) collection
in each case.
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