Generate vmlinux.h headers in parallel

Generate vmlinux.h headers for all supported architectures in parallel,
by using dedicated jobs. Doing so speeds up the workflow from ~27min to
~6min.

Signed-off-by: Daniel Müller <deso@posteo.net>

Author: d-e-s-o

.github/workflows/vmlinux.h.yml

@@ -9,8 +9,18 @@ on:
 
 jobs:
   gen-headers:
-    name: Generate vmlinux.h
+    name: Generate vmlinux.h (${{ matrix.arch }})
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        arch:
+          - x86_64
+          - aarch64
+          - arm
+          - loongarch64
+          - ppc64le
+          - riscv64
+          - s390x
 
     steps:
 
@@ -48,35 +58,40 @@ jobs:
           ./scripts/install-dependencies.sh
           ./scripts/install-bpftool.sh
 
-      - name: x86_64/vmlinux.h
+      - name: Generate ${{ matrix.arch }}/vmlinux.h
         shell: bash
-        run: ./scripts/gen-vmlinux-header.sh x86_64
+        run: ./scripts/gen-vmlinux-header.sh ${{ matrix.arch }}
 
-      - name: aarch64/vmlinux.h
-        shell: bash
-        run: ./scripts/gen-vmlinux-header.sh aarch64
-
-      - name: arm/vmlinux.h
-        shell: bash
-        run: ./scripts/gen-vmlinux-header.sh arm
-
-      - name: loongarch64/vmlinux.h
-        shell: bash
-        run: ./scripts/gen-vmlinux-header.sh loongarch64
+      - name: Upload headers
+        uses: actions/upload-artifact@v4
+        with:
+          name: vmlinux.h-${{ matrix.arch }}
+          if-no-files-found: error
+          path: ./vmlinux.h/${{ matrix.arch }}
 
-      - name: ppc64le/vmlinux.h
-        shell: bash
-        run: ./scripts/gen-vmlinux-header.sh ppc64le
+  combine-headers:
+    name: Combine all vmlinux.h headers
+    runs-on: ubuntu-latest
+    needs: gen-headers
 
-      - name: riscv64/vmlinux.h
-        shell: bash
-        run: ./scripts/gen-vmlinux-header.sh riscv64
+    steps:
+      - name: Download all artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: vmlinux.h-*
 
-      - name: s390x/vmlinux.h
+      - name: Reorganize headers
         shell: bash
-        run: ./scripts/gen-vmlinux-header.sh s390x
-
-      - name: Upload headers
+        run: |
+          mkdir -p vmlinux.h
+          for dir in vmlinux.h-*/; do
+            arch="${dir#vmlinux.h-}"
+            arch="${arch%/}"
+            mkdir -p "vmlinux.h/$arch"
+            mv "$dir"* "vmlinux.h/$arch/"
+          done
+
+      - name: Upload combined headers
         uses: actions/upload-artifact@v4
         with:
           name: vmlinux.h