OutOfMemory Exception

[Martin Pernollet]

Hi,

After switching PanamaGL from JDK17 to JDK19, I am facing an OutOfMemory exception.

The part where this occurs is in the loop that performs offscreen rendering and then copy the result to a BufferedImage later used for onscreen rendering.

This allocation

intnBytes=width*height*channels;

MemorySegmentpixelsRead= MemorySegment.allocateNative(nBytes,scope);

gl.glReadPixels(0,0,width,height,format,textureType,pixelsRead);

Fails as follow

java.lang.OutOfMemoryError: Cannot reserve 2169600 bytes of direct buffer memory (allocated: 4293080163, limit: 4294967296)

at java.base/java.nio.Bits.reserveMemory(Bits.java:178)

at java.base/java.nio.Buffer$1.reserveMemory(Buffer.java:860)

at java.base/jdk.internal.foreign.NativeMemorySegmentImpl.makeNativeSegment(NativeMemorySegmentImpl.java:122)

at java.base/java.lang.foreign.MemorySegment.allocateNative(MemorySegment.java:965)

at java.base/java.lang.foreign.MemorySegment.allocateNative(MemorySegment.java:942)

As shown on the VisualVM screenshot the heap grows at the beginning but is then freed. The exception happens when the heap reduces suddenly on the chart.

[Capture d’écran 2023-01-22 à 17.48.40.png]

The behavior is the same for all possible scopes provided by MemorySession (global, openConfined, openShared, openImplicit.

One thing : I can not unload() the MemorySegment when I am done using it (but this was also not possible in JDK17).

How could I track this memory leak? How could I ensure that useless memory get destroyed?

Thanks in advance,

Martin
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