private int computeOffHeapLocalMaxMemory() {

    long availableOffHeapMemoryInMB = 0;
    if (testAvailableOffHeapMemory != null) {
      availableOffHeapMemoryInMB =
          OffHeapStorage.parseOffHeapMemorySize(testAvailableOffHeapMemory) / (1024 * 1024);
    } else if (InternalDistributedSystem.getAnyInstance() == null) {
      localMaxMemoryExists = false;
      // fix 52033: return non-negative, non-zero temporary placeholder for offHeapLocalMaxMemory
      return OFF_HEAP_LOCAL_MAX_MEMORY_PLACEHOLDER;
    } else {
      String offHeapSizeConfigValue =
          InternalDistributedSystem.getAnyInstance().getOriginalConfig().getOffHeapMemorySize();
      availableOffHeapMemoryInMB =
          OffHeapStorage.parseOffHeapMemorySize(offHeapSizeConfigValue) / (1024 * 1024);
    }

    if (availableOffHeapMemoryInMB > Integer.MAX_VALUE) {
      logger.warn(
          "Reduced local max memory for partition attribute when setting from available off-heap memory size");
      return Integer.MAX_VALUE;
    }

    localMaxMemoryExists = true;
    return (int) availableOffHeapMemoryInMB;
  }
By default the partition can use up to 100% of the allocated off-heap memory.
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionAttributesImpl.java