libukallocbbuddy can't allocate 1G memory even if 4G memory provided

[ChaoyiHuang]

Describe the bug

provide 4G to unikraft application to test memory, and malloc 1G memory will fail.

		pMem = malloc(1024*1024*1024);
        if (pMem == NULL) {
                printf("no enough memory\n");
                return 0;
        }

libukallocbbuddy reported out of memory.

	[    1.842053] Info: {r:0x126aaf,f:0x11f50} [libukboot] <boot.c @  514> Calling main(1, ['/home/joehuang_sweden/catalog/native/testmem/.unikraft/build/memspeed_qemu-x86_64'])
	[    1.911369] Warn: {r:0x1256f9,f:0x11eb0} [libukallocbbuddy] <bbuddy.c @  351> 12000: Cannot handle palloc request of order 19: Out of memory
	no enough memory

Steps to reproduce

in the native helloworld.c, try to malloc 1G memory, even if 4G is provided to the unikraft application, still oom

Expected behavior

malloc succeeds

Which architectures were you using or does this bug affect?

x86_64

Which platforms were you using or does this bug affect?

kvm

Relevant log output

[    1.842053] Info: {r:0x126aaf,f:0x11f50} [libukboot] <boot.c @  514> Calling main(1, ['/home/joehuang_sweden/catalog/native/testmem/.unikraft/build/memspeed_qemu-x86_64'])
	[    1.911369] Warn: {r:0x1256f9,f:0x11eb0} [libukallocbbuddy] <bbuddy.c @  351> 12000: Cannot handle palloc request of order 19: Out of memory
	no enough memory