Android 15 (AOSP experimental) and higher have support for building Android with a 16kB page size. This option uses additional memory but improves system performance.
16kB pages are only supported on arm64 targets with 16kB kernels. However,
there is also an option to simulate 16KB userspace on x86_64
for Cuttlefish.
To enable 16kB pages, set the following build options on a device:
PRODUCT_NO_BIONIC_PAGE_SIZE_MACRO := trueremoves thePAGE_SIZEdefine, and it makes components determine page size at runtime.PRODUCT_MAX_PAGE_SIZE_SUPPORTED := 16384which ensures platform ELF files are built with 16kB alignment. This larger-than-needed size is for future compatibility. With 16kB ELF alignment, the kernel can support 4kB/16kB page sizes.
Verify build flags
After selecting the lunch target, verify that the build flags are set up
correctly in the environment:
$ source build/envsetup.sh
$ lunch target
$ get_build_var TARGET_MAX_PAGE_SIZE_SUPPORTED
16384
$ get_build_var TARGET_NO_BIONIC_PAGE_SIZE_MACRO
true
If the previous two commands return 16384 and true respectively, your build
flags are set up correctly.
Build shared libraries with 16kB ELF alignment
To build shared libraries that are part of the android project, you only need to set these build flags in your target:
PRODUCT_NO_BIONIC_PAGE_SIZE_MACRO := truePRODUCT_MAX_PAGE_SIZE_SUPPORTED := 16384
To build shared libraries that aren't part of android project, you need to pass this linker flag:
-Wl,-z,max-page-size=16384