diff options
| -rw-r--r-- | pkg/sentry/kernel/kernel.go | 5 | ||||
| -rw-r--r-- | pkg/sentry/pgalloc/pgalloc.go | 21 | ||||
| -rw-r--r-- | pkg/sentry/pgalloc/save_restore.go | 11 |
3 files changed, 24 insertions, 13 deletions
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go index 91889b573..85d73ace2 100644 --- a/pkg/sentry/kernel/kernel.go +++ b/pkg/sentry/kernel/kernel.go @@ -304,10 +304,11 @@ func (k *Kernel) SaveTo(w io.Writer) error { defer k.resumeTimeLocked() // Evict all evictable MemoryFile allocations. - k.mf.FlushEvictions() + k.mf.StartEvictions() + k.mf.WaitForEvictions() // Flush write operations on open files so data reaches backing storage. - // This must come after k.mf.FlushEvictions() since eviction may cause file + // This must come after MemoryFile eviction since eviction may cause file // writes. if err := k.tasks.flushWritesToFiles(ctx); err != nil { return err diff --git a/pkg/sentry/pgalloc/pgalloc.go b/pkg/sentry/pgalloc/pgalloc.go index 9c1313f6f..2b9924ad7 100644 --- a/pkg/sentry/pgalloc/pgalloc.go +++ b/pkg/sentry/pgalloc/pgalloc.go @@ -190,6 +190,11 @@ const ( // reclaimer goroutine is out of work (pages to reclaim), then evicts all // pending evictable allocations immediately. DelayedEvictionEnabled + + // DelayedEvictionManual requires that evictable allocations are only + // evicted when MemoryFile.StartEvictions() is called. This is extremely + // dangerous outside of tests. + DelayedEvictionManual ) // usageInfo tracks usage information. @@ -264,7 +269,7 @@ func NewMemoryFile(file *os.File, opts MemoryFileOpts) (*MemoryFile, error) { switch opts.DelayedEviction { case DelayedEvictionDefault: opts.DelayedEviction = DelayedEvictionEnabled - case DelayedEvictionDisabled, DelayedEvictionEnabled: + case DelayedEvictionDisabled, DelayedEvictionEnabled, DelayedEvictionManual: default: return nil, fmt.Errorf("invalid MemoryFileOpts.DelayedEviction: %v", opts.DelayedEviction) } @@ -1075,6 +1080,14 @@ func (f *MemoryFile) markReclaimed(fr platform.FileRange) { } } +// StartEvictions requests that f evict all evictable allocations. It does not +// wait for eviction to complete; for this, see MemoryFile.WaitForEvictions. +func (f *MemoryFile) StartEvictions() { + f.mu.Lock() + defer f.mu.Unlock() + f.startEvictionsLocked() +} + // Preconditions: f.mu must be locked. func (f *MemoryFile) startEvictionsLocked() { for user, info := range f.evictable { @@ -1122,6 +1135,12 @@ func (f *MemoryFile) startEvictionGoroutineLocked(user EvictableMemoryUser, info }() } +// WaitForEvictions blocks until f is no longer evicting any evictable +// allocations. +func (f *MemoryFile) WaitForEvictions() { + f.evictionWG.Wait() +} + type usageSetFunctions struct{} func (usageSetFunctions) MinKey() uint64 { diff --git a/pkg/sentry/pgalloc/save_restore.go b/pkg/sentry/pgalloc/save_restore.go index 9534d1aed..d4ba384b1 100644 --- a/pkg/sentry/pgalloc/save_restore.go +++ b/pkg/sentry/pgalloc/save_restore.go @@ -28,15 +28,6 @@ import ( "gvisor.googlesource.com/gvisor/pkg/state" ) -// FlushEvictions blocks until f has finished evicting all evictable -// allocations. -func (f *MemoryFile) FlushEvictions() { - f.mu.Lock() - f.startEvictionsLocked() - f.mu.Unlock() - f.evictionWG.Wait() -} - // SaveTo writes f's state to the given stream. func (f *MemoryFile) SaveTo(w io.Writer) error { // Wait for reclaim. @@ -51,7 +42,7 @@ func (f *MemoryFile) SaveTo(w io.Writer) error { // Ensure that there are no pending evictions. if len(f.evictable) != 0 { - panic(fmt.Sprintf("evictions still pending for %d users; call FlushEvictions before SaveTo", len(f.evictable))) + panic(fmt.Sprintf("evictions still pending for %d users; call StartEvictions and WaitForEvictions before SaveTo", len(f.evictable))) } // Ensure that all pages that contain data have knownCommitted set, since |