scx: Test CI

Let's add a CI action which verifies that we can build the kernel, and
run the tests in tools/testing/selftests/scx, on pushes and PRs.

Signed-off-by: David Vernet <[email protected]>

.github/workflows/build-run.yml

@@ -0,0 +1,48 @@
+name: build-run
+run-name: ${{ github.actor }} PR run
+on: [pull_request, push]
+jobs:
+  build-run-schedulers:
+    runs-on: ubuntu-22.04
+    steps:
+      ### OTHER REPOS ####
+
+      # Hard turn-off interactive mode
+      - run: echo 'debconf debconf/frontend select Noninteractive' | sudo debconf-set-selections
+
+      # Refresh packages list
+      - run: sudo apt update
+
+      ### DOWNLOAD AND INSTALL DEPENDENCIES ###
+
+      # Download dependencies packaged by Ubuntu
+      - run: sudo apt -y install coreutils cmake cargo elfutils libelf-dev libunwind-dev libzstd-dev linux-headers-generic linux-tools-common linux-tools-generic ninja-build python3-pip python3-requests qemu-kvm udev iproute2 busybox-static libvirt-clients kbd kmod file pahole rsync zstd
+
+      # clang 17
+      # Use a custom llvm.sh script which includes the -y flag for
+      # add-apt-repository. Otherwise, the CI job will hang. If and when
+      # https://github.com/opencollab/llvm-jenkins.debian.net/pull/26 is
+      # merged, we can go back to using https://apt.llvm.org/llvm.sh.
+      - run: wget https://raw.githubusercontent.com/Decave/llvm-jenkins.debian.net/fix_llvmsh/llvm.sh
+      - run: chmod +x llvm.sh
+      - run: sudo ./llvm.sh all
+      - run: sudo ln -sf /usr/bin/clang-17 /usr/bin/clang
+      - run: sudo ln -sf /usr/bin/llvm-strip-17 /usr/bin/llvm-strip
+
+      # bpftool
+      - run: git clone --recurse-submodules --branch v7.3.0 https://github.com/libbpf/bpftool.git
+      - run: make -j -C bpftool/src
+      - run: sudo make -j -C bpftool/src install
+
+      - uses: actions/checkout@v4
+
+      ### END DEPENDENCIES ###
+
+      # The actual build:
+      - run: make CC=clang LD=ld.lld olddefconfig
+      - run: cat tools/testing/selftests/scx/config | xargs ./scripts/config -e
+      - run: make CC=clang LD=ld.lld -j$(nproc)
+
+      # Test schedulers
+      - run: make CC=clang Ld=ld.lld -C tools/testing/selftests/scx -j$(nproc)
+      - run: ./tools/testing/selftests/scx/test_sched.sh ./vmlinux

tools/testing/selftests/scx/test_sched.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+#
+# Run a scheduler for TIMEOUT seconds inside virtme-ng and catch potential
+# errors, then unload the scheduler and return the exit status.
+
+# Maximum time for each scheduler run.
+TEST_TIMEOUT=30
+
+# Maximum timeout for the guest used for each scheduler run (this is used to
+# hard-shutdown the guest in case of system hangs).
+GUEST_TIMEOUT=60
+
+# List of schedulers to test
+#
+# TODO:
+#   - scx_layered: temporarily excluded because it
+#     cannot run with a default configuration
+#
+#SCHEDULERS="scx_simple scx_central scx_flatcg scx_nest scx_pair scx_qmap scx_userland scx_rusty scx_rustland"
+SCHEDULERS=""
+
+if [ ! -x `which vng` ]; then
+    echo "vng not found, please install virtme-ng to enable testing"
+    exit 1
+fi
+if [ $# -lt 1 ]; then
+    echo "Usage: $0 VMLINUZ"
+    exit 1
+fi
+kernel=$1
+
+rm -f /tmp/output
+timeout --preserve-status ${GUEST_TIMEOUT} \
+	vng --force-9p --disable-microvm -v -r ${kernel} -- \
+	"timeout --foreground --preserve-status ${TEST_TIMEOUT} ${sched_path}" \
+	2>&1 </dev/null | tee /tmp/output
+	sed -n  -e '/\bBUG:/q1' \
+		-e '/\bWARNING:/q1' \
+		-e '/\berror\b/Iq1' \
+		-e '/\bstall/Iq1' \
+		-e '/\btimeout\b/Iq1' /tmp/output
+res=$?
+if [ ${res} -ne 0 ]; then
+    echo "FAIL: ${sched}"
+    exit 1
+else
+    echo "OK: ${sched}"
+    exit 0
+fi