On 21/06/2024 00:34, Chris Li wrote: >> + * thp_swap_allocator_test >> + * >> + * The purpose of this test program is helping check if THP swpout >> + * can correctly get swap slots to swap out as a whole instead of >> + * being split. It randomly releases swap entries through madvise >> + * DONTNEED and do swapout on two memory areas: a memory area for >> + * 64KB THP and the other area for small folios. The second memory >> + * can be enabled by "-s". >> + * Before running the program, we need to setup a zRAM or similar >> + * swap device by: >> + * echo lzo > /sys/block/zram0/comp_algorithm >> + * echo 64M > /sys/block/zram0/disksize >> + * echo never > /sys/kernel/mm/transparent_hugepage/hugepages-2048kB/enabled >> + * echo always > /sys/kernel/mm/transparent_hugepage/hugepages-64kB/enabled >> + * mkswap /dev/zram0 >> + * swapon /dev/zram0 > > This setup needs to go into run_vmtest.sh as well. > > Also tear it down after the test. Additionally, if keeping this as a selftest, you'll want to add CONFIG_ZRAM=y to tools/testing/selftests/mm/config so that automated systems ensure zram is available in the kernel under test. And you will need to ensure that the zram device has a higher priority than any other already configured swap devices. Otherwise there will not even be an attempt to use it for mTHP. The easy way is to do "swapoff -a" as the first step but that makes cleanup tricky.
