ci: Address tight disk space on GHA runners (#4974)

- Mount the host's root under /host/root so it's visible in the
containers.
- Remove stuff we don't need to free lots of disk space.
- While we're at it, arrange for the commands (copied from OSL) that
allow the containers to see a CPU, when available.

This is freeing 20+ GB!

---------

Signed-off-by: Larry Gritz <lg@larrygritz.com>

Author: lgritz

.github/workflows/build-steps.yml

@@ -18,6 +18,9 @@ on:
         type: string
       container:
         type: string
+      container_volumes:
+        type: string
+        default: '[]'
       cc_compiler:
         type: string
       cxx_compiler:
@@ -84,7 +87,11 @@ jobs:
     runs-on: ${{ inputs.runner }}
     container:
       image: ${{ inputs.container }}
-
+      volumes: ${{ fromJson( inputs.container_volumes ) }}
+      options: -v /:/host/root ${{ (contains(inputs.runner, 'gpu') && '-e NVIDIA_DRIVER_CAPABILITIES=compute,graphics,utility --gpus all') || '-e A=x' }}
+      # Extra options:
+      # - Ensure the GPU runners have OptiX is visible in the container.
+      # - Mount the native filesystem under /host/root
     env:
       CXX: ${{inputs.cxx_compiler}}
       CC: ${{inputs.cc_compiler}}

.github/workflows/ci.yml

@@ -252,6 +252,7 @@ jobs:
       nametag: ${{ matrix.nametag || 'unnamed!' }}
       runner: ${{ matrix.runner || 'ubuntu-latest' }}
       container: ${{ matrix.container }}
+      container_volumes: ${{ matrix.container_volumes || '[]' }}
       cc_compiler: ${{ matrix.cc_compiler }}
       cxx_compiler: ${{ matrix.cxx_compiler }}
       cxx_std: ${{ matrix.cxx_std || '17' }}

src/build-scripts/gh-installdeps.bash

@@ -7,7 +7,14 @@
 
 
 set -ex
-df -h
+
+# Make extra space on the runners
+df -h .
+time rm -rf /usr/local/lib/android /host/root/usr/local/lib/android &
+sleep 3
+# rather than block, delete in background, but give it a few secs to start
+# clearing things out before moving on.
+# Other candidates, if we need it: /usr/share/dotnet /usr/local/.ghcup
 
 
 #
@@ -231,7 +238,8 @@ if [[ "$USE_ICC" != "" ]] ; then
     export CC=icc
 fi
 
-df -h
+df -h .
+df -h /host/root || true
 
 # Save the env for use by other stages
 src/build-scripts/save-env.bash