Restrict syscall caching to paths backed by the build's main `FileSystem`.
Avoids wasteful caching of in-memory and transient `FileSystem` types.
PiperOrigin-RevId: 492560997
Change-Id: I19865c33f91566fb101c98508fe8897f9ad115f5
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/WorkspaceBuilder.java b/src/main/java/com/google/devtools/build/lib/runtime/WorkspaceBuilder.java
index e1a6244..f4fcabc 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/WorkspaceBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/WorkspaceBuilder.java
@@ -30,6 +30,7 @@
import com.google.devtools.build.lib.skyframe.SkyframeExecutorFactory;
import com.google.devtools.build.lib.skyframe.SkyframeExecutorRepositoryHelpersHolder;
import com.google.devtools.build.lib.util.AbruptExitException;
+import com.google.devtools.build.lib.vfs.SingleFileSystemSyscallCache;
import com.google.devtools.build.lib.vfs.SyscallCache;
import com.google.devtools.build.skyframe.SkyFunction;
import com.google.devtools.build.skyframe.SkyFunctionName;
@@ -96,7 +97,8 @@
BlazeWorkspace build(
BlazeRuntime runtime,
PackageFactory packageFactory,
- SubscriberExceptionHandler eventBusExceptionHandler) throws AbruptExitException {
+ SubscriberExceptionHandler eventBusExceptionHandler)
+ throws AbruptExitException {
// Set default values if none are set.
if (skyframeExecutorFactory == null) {
skyframeExecutorFactory = new SequencedSkyframeExecutorFactory();
@@ -105,6 +107,9 @@
perCommandSyscallCache = createPerBuildSyscallCache();
}
+ SingleFileSystemSyscallCache singleFsSyscallCache =
+ new SingleFileSystemSyscallCache(perCommandSyscallCache, runtime.getFileSystem());
+
SkyframeExecutor skyframeExecutor =
skyframeExecutorFactory.create(
packageFactory,
@@ -114,7 +119,7 @@
workspaceStatusActionFactory,
diffAwarenessFactories.build(),
skyFunctions.buildOrThrow(),
- perCommandSyscallCache,
+ singleFsSyscallCache,
skyframeExecutorRepositoryHelpersHolder,
skyKeyStateReceiver == null
? SkyframeExecutor.SkyKeyStateReceiver.NULL_INSTANCE
@@ -128,7 +133,7 @@
workspaceStatusActionFactory,
binTools,
allocationTracker,
- perCommandSyscallCache);
+ singleFsSyscallCache);
}
/**
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/SingleFileSystemSyscallCache.java b/src/main/java/com/google/devtools/build/lib/vfs/SingleFileSystemSyscallCache.java
new file mode 100644
index 0000000..9befa7f
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/vfs/SingleFileSystemSyscallCache.java
@@ -0,0 +1,101 @@
+// Copyright 2022 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.vfs;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.io.IOException;
+import java.util.Collection;
+import javax.annotation.Nullable;
+
+/**
+ * A {@link SyscallCache} that delegates to a caching implementation only for paths with a
+ * particular {@link FileSystem}.
+ *
+ * <p>Any calls that pass a {@link Path} backed by a different {@link FileSystem} are routed to
+ * {@link SyscallCache#NO_CACHE}. This can be used to ensure that only calls for the build's main
+ * {@link FileSystem} are cached. Common alternative filesystems for which caching is wasteful
+ * include:
+ *
+ * <ul>
+ * <li>{@link
+ * com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider.BundledFileSystem}, an
+ * in-memory filesystem (no real filesystem ops to save).
+ * <li>An {@linkplain com.google.devtools.build.lib.vfs.OutputService.ActionFileSystemType
+ * action-scoped filesystem} where there is no potential for reuse outside a single action's
+ * execution, and caching prolongs the lifetime of the instance.
+ */
+public final class SingleFileSystemSyscallCache implements SyscallCache {
+
+ private final SyscallCache delegate;
+ private final FileSystem fs;
+
+ public SingleFileSystemSyscallCache(SyscallCache delegate, FileSystem fs) {
+ this.delegate = checkNotNull(delegate);
+ this.fs = checkNotNull(fs);
+ }
+
+ @Override
+ public Collection<Dirent> readdir(Path path) throws IOException {
+ return delegateFor(path).readdir(path);
+ }
+
+ @Nullable
+ @Override
+ public FileStatus statIfFound(Path path, Symlinks symlinks) throws IOException {
+ return delegateFor(path).statIfFound(path, symlinks);
+ }
+
+ @Nullable
+ @Override
+ public DirentTypeWithSkip getType(Path path, Symlinks symlinks) throws IOException {
+ return delegateFor(path).getType(path, symlinks);
+ }
+
+ @Override
+ public byte[] getFastDigest(Path path) throws IOException {
+ return delegateFor(path).getFastDigest(path);
+ }
+
+ @Override
+ public byte[] getxattr(Path path, String xattrName) throws IOException {
+ return delegateFor(path).getxattr(path, xattrName);
+ }
+
+ @Override
+ public byte[] getxattr(Path path, String xattrName, Symlinks followSymlinks) throws IOException {
+ return delegateFor(path).getxattr(path, xattrName, followSymlinks);
+ }
+
+ @Override
+ public void noteAnalysisPhaseEnded() {
+ delegate.noteAnalysisPhaseEnded();
+ }
+
+ @Override
+ public void clear() {
+ delegate.clear();
+ }
+
+ /** Returns the underlying {@link SyscallCache} used for eligible paths. */
+ // TODO(b/245929310): This shouldn't be exposed.
+ public SyscallCache getUnderlyingCache() {
+ return delegate;
+ }
+
+ private SyscallCache delegateFor(Path path) {
+ return path.getFileSystem().equals(fs) ? delegate : SyscallCache.NO_CACHE;
+ }
+}
