tokio-epoll-uring: make io engine configurable (#6118)

- intoduce concept of IoEngineKind to VirtualFile
- introduce a global OnceCell that contains the IoEngineKind
- introduce OpenOptions that enum-dispatches to the respective
  IoEngineKind's `OpenOptions` type.
- dispatch the currently supported VirtualFile operations
  (open, read) through the IoEngineKind
- add a pageserver config file variable, defaulting to the current StdFs
  => tokio-epoll-uring is off by default
- cover both ioengines in CI `cargo test` runs
- run all the regression tests with both engine kinds (doubling the
amount of regression tests per run in the interest of maximizing
tokio-epoll-uring usage before it hits production)

---------

Co-authored-by: Alexander Bayandin <alexander@neon.tech>

.github/workflows/build_and_test.yml

@@ -199,6 +199,10 @@ jobs:
           #
           git config --global --add safe.directory ${{ github.workspace }}
           git config --global --add safe.directory ${GITHUB_WORKSPACE}
+          for r in 14 15 16; do
+            git config --global --add safe.directory "${{ github.workspace }}/vendor/postgres-v$r"
+            git config --global --add safe.directory "${GITHUB_WORKSPACE}/vendor/postgres-v$r"
+          done
 
       - name: Checkout
         uses: actions/checkout@v3
@@ -330,7 +334,9 @@ jobs:
 
       - name: Run cargo test
         run: |
-          ${cov_prefix} cargo test $CARGO_FLAGS $CARGO_FEATURES
+          for io_engine in std-fs tokio-epoll-uring ; do
+            NEON_PAGESERVER_UNIT_TEST_VIRTUAL_FILE_IOENGINE=$io_engine ${cov_prefix} cargo test $CARGO_FLAGS $CARGO_FEATURES
+          done
 
           # Run separate tests for real S3
           export ENABLE_REAL_S3_REMOTE_STORAGE=nonempty
@@ -415,6 +421,7 @@ jobs:
       matrix:
         build_type: [ debug, release ]
         pg_version: [ v14, v15, v16 ]
+        pageserver_virtual_file_io_engine: [ std-fs, tokio-epoll-uring ]
     steps:
       - name: Checkout
         uses: actions/checkout@v3
@@ -437,6 +444,7 @@ jobs:
           TEST_RESULT_CONNSTR: ${{ secrets.REGRESS_TEST_RESULT_CONNSTR_NEW }}
           CHECK_ONDISK_DATA_COMPATIBILITY: nonempty
           BUILD_TAG: ${{ needs.tag.outputs.build-tag }}
+          PAGESERVER_VIRTUAL_FILE_IO_ENGINE: ${{ matrix.pageserver_virtual_file_io_engine }}
 
       - name: Merge and upload coverage data
         if: matrix.build_type == 'debug' && matrix.pg_version == 'v14'
@@ -455,6 +463,7 @@ jobs:
       matrix:
         pytest_split_group: [ 1, 2, 3, 4 ]
         build_type: [ release ]
+        pageserver_virtual_file_io_engine: [ std-fs, tokio-epoll-uring ]
     steps:
       - name: Checkout
         uses: actions/checkout@v3
@@ -471,6 +480,7 @@ jobs:
           VIP_VAP_ACCESS_TOKEN: "${{ secrets.VIP_VAP_ACCESS_TOKEN }}"
           PERF_TEST_RESULT_CONNSTR: "${{ secrets.PERF_TEST_RESULT_CONNSTR }}"
           TEST_RESULT_CONNSTR: "${{ secrets.REGRESS_TEST_RESULT_CONNSTR_NEW }}"
+          PAGESERVER_VIRTUAL_FILE_IO_ENGINE: "${{ matrix.pageserver_virtual_file_io_engine }}"
       # XXX: no coverage data handling here, since benchmarks are run on release builds,
       # while coverage is currently collected for the debug ones
 
@@ -1097,6 +1107,10 @@ jobs:
           #
           git config --global --add safe.directory ${{ github.workspace }}
           git config --global --add safe.directory ${GITHUB_WORKSPACE}
+          for r in 14 15 16; do
+            git config --global --add safe.directory "${{ github.workspace }}/vendor/postgres-v$r"
+            git config --global --add safe.directory "${GITHUB_WORKSPACE}/vendor/postgres-v$r"
+          done
 
       - name: Checkout
         uses: actions/checkout@v3

.github/workflows/neon_extra_builds.yml

@@ -142,6 +142,10 @@ jobs:
           #
           git config --global --add safe.directory ${{ github.workspace }}
           git config --global --add safe.directory ${GITHUB_WORKSPACE}
+          for r in 14 15 16; do
+            git config --global --add safe.directory "${{ github.workspace }}/vendor/postgres-v$r"
+            git config --global --add safe.directory "${GITHUB_WORKSPACE}/vendor/postgres-v$r"
+          done
 
       - name: Checkout
         uses: actions/checkout@v4
@@ -238,6 +242,20 @@ jobs:
       options: --init
 
     steps:
+      - name: Fix git ownership
+        run: |
+          # Workaround for `fatal: detected dubious ownership in repository at ...`
+          #
+          # Use both ${{ github.workspace }} and ${GITHUB_WORKSPACE} because they're different on host and in containers
+          #   Ref https://github.com/actions/checkout/issues/785
+          #
+          git config --global --add safe.directory ${{ github.workspace }}
+          git config --global --add safe.directory ${GITHUB_WORKSPACE}
+          for r in 14 15 16; do
+            git config --global --add safe.directory "${{ github.workspace }}/vendor/postgres-v$r"
+            git config --global --add safe.directory "${GITHUB_WORKSPACE}/vendor/postgres-v$r"
+          done
+
       - name: Checkout
         uses: actions/checkout@v4
         with: