diff options
| author | Ayush Ranjan <ayushranjan@google.com> | 2020-10-26 16:13:04 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2020-10-26 16:14:53 -0700 |
| commit | 652f11380e44b7c2083fa19d706f5cddf7fe0718 (patch) | |
| tree | 77e52a0b2078faf589b670e9e7117bf2bf6b6785 /pkg/sentry/fsimpl/gofer/gofer.go | |
| parent | 0bdcee38bdfa5c4585d28a0edd0c46e170cdc9b5 (diff) | |
[vfs] kernfs: Implement LRU cache for kernfs dentries.
Much like the VFS2 gofer client, kernfs too now caches dentries. The size of the
LRU cache is configurable via mount options.
Have adopted the same reference semantics from gofer client dentry.
Only sysfs and procfs use this LRU cache. The rest of the kernfs users (devpts,
fusefs, host, pipefs, sockfs) still use the no cache approach.
PiperOrigin-RevId: 339139835
Diffstat (limited to 'pkg/sentry/fsimpl/gofer/gofer.go')
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/gofer.go | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go index 604c6d7cd..80668ebc1 100644 --- a/pkg/sentry/fsimpl/gofer/gofer.go +++ b/pkg/sentry/fsimpl/gofer/gofer.go @@ -153,8 +153,7 @@ type filesystemOptions struct { msize uint32 version string - // maxCachedDentries is the maximum number of dentries with 0 references - // retained by the client. + // maxCachedDentries is the maximum size of filesystem.cachedDentries. maxCachedDentries uint64 // If forcePageCache is true, host FDs may not be used for application @@ -1312,6 +1311,10 @@ func (d *dentry) checkCachingLocked(ctx context.Context) { // resolution, which requires renameMu, so if d.refs is zero then it will // remain zero while we hold renameMu for writing.) refs := atomic.LoadInt64(&d.refs) + if refs == -1 { + // Dentry has already been destroyed. + return + } if refs > 0 { if d.cached { d.fs.cachedDentries.Remove(d) @@ -1320,10 +1323,6 @@ func (d *dentry) checkCachingLocked(ctx context.Context) { } return } - if refs == -1 { - // Dentry has already been destroyed. - return - } // Deleted and invalidated dentries with zero references are no longer // reachable by path resolution and should be dropped immediately. if d.vfsd.IsDead() { |