For description/justification of this kernel patch, please read epollondemand.txt.

A user-level threading library 'libfibre' has adopted an option to use this patch. Here is the link: libfibre

Step 0: The required softwares are unzip qemu git fakeroot build-essential ncurses-dev xz-utils libssl-dev bc flex libelf-dev bison. apt install them if not installed.

Step 1: ./setup.sh -i to download and prepare the env and source code for 'kernel', 'buildroot', and 'libfibre'.

Step 2 (optional): Initialize an empty repo at linux-5.4/ to track the the source code of the kernel.

Step 3: ./setup.sh -k to build the source code under linux-5.4/.

Step 4: ./setup.sh -b to build the source code under buildroot/ (toolchain and rootfs) and apps/.

Step 5: ./setup.sh -r to run the qemu with the unmodified kernel and unmodified libfibre.

Step 6: ./usepatch.sh lx to apply the patch to the kernel.

Step 7: ./setup.sh -kbr to rebuild the kernel and libfibre, then run the qemu for the modified kernel and libfibre

Step 8: ./usepatch.sh lx -R to undo the patch to the kernel.

Sometimes the script pauses, press Enter to continue or Ctrl-C to abort.

Inside qemu, press Ctrl-C to kill the process inside qemu, and press Ctrl-] to kill qemu itself.