Avoid compaction stalls during checkpoint restore

.github/workflows/build.yml

@@ -2,6 +2,11 @@ name: CI
 
 "on":
   workflow_dispatch:
+    inputs:
+      checkpoint_version:
+        description: 'Compatible checkpoint commit (12 hex digits; empty uses source revision)'
+        required: false
+        type: string
   push:
     branches:
       - "*"
@@ -25,9 +30,12 @@ jobs:
       uses: actions/checkout@v5
 
     - name: build
+      env:
+        CHECKPOINT_VERSION: ${{ inputs.checkpoint_version }}
       run: |
           mkdir -p bin
-          make copy TARGETS=runsc DESTINATION=bin/
+          [[ -z "$CHECKPOINT_VERSION" || "$CHECKPOINT_VERSION" =~ ^[0-9a-f]{12}$ ]]
+          make copy TARGETS=runsc DESTINATION=bin/ BAZEL_OPTIONS="--workspace_status_command='tools/workspace_status.sh $CHECKPOINT_VERSION'"
 
     - name: Upload runsc
       uses: actions/upload-artifact@v4

pkg/sentry/pgalloc/pgalloc.go

@@ -1479,6 +1479,9 @@ func (f *MemoryFile) AdviseHugepageRanges(ranges []memmap.FileRange) error {
 }
 
 func (f *MemoryFile) adviseHugepageRanges(ranges []memmap.FileRange) {
+	if !f.opts.ExpectHugepages {
+		return
+	}
 	warned := false
 	for _, fr := range ranges {
 		f.forEachMappingSlice(fr, func(bs []byte) {

pkg/sentry/state/stateio/pagesfile.go

@@ -21,6 +21,9 @@ import (
 const (
 	pagesFileFDDefaultMaxIOBytes  = 256 << 10
 	pagesFileFDDefaultMaxParallel = 128
+	// Keep 32 MiB in flight with fewer threads faulting restored shmem pages.
+	pagesFileFDDefaultMaxReadBytes    = 4 << 20
+	pagesFileFDDefaultMaxReadParallel = 8
 )
 
 // NewPagesFileFDReader returns a FDReader that reads a pages file from the
@@ -39,7 +42,7 @@ func NewPagesFileFDReader(fd int32, maxReadBytes uint64, maxParallel int) *FDRea
 // the given host file descriptor, using defaults for MaxReadBytes and
 // MaxParallel. It takes ownership of the file descriptor.
 func NewPagesFileFDReaderDefault(fd int32) *FDReader {
-	return NewPagesFileFDReader(fd, pagesFileFDDefaultMaxIOBytes, pagesFileFDDefaultMaxParallel)
+	return NewPagesFileFDReader(fd, pagesFileFDDefaultMaxReadBytes, pagesFileFDDefaultMaxReadParallel)
 }
 
 // NewPagesFileFDWriter returns a FDWriter that writes a pages file to the

tools/workspace_status.sh

@@ -15,4 +15,4 @@
 # limitations under the License.
 
 # The STABLE_ prefix will trigger a re-link if it changes.
-echo STABLE_VERSION "$(git describe --always --tags --abbrev=12 --dirty 2>/dev/null || echo 0.0.0)"
+echo STABLE_VERSION "${1:-$(git describe --always --tags --abbrev=12 --dirty 2>/dev/null || echo 0.0.0)}"