diff options
Diffstat (limited to 'pkg/sentry')
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/filesystem.go | 20 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/gofer.go | 9 |
2 files changed, 25 insertions, 4 deletions
diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go index 77b1fc881..40c9243f0 100644 --- a/pkg/sentry/fsimpl/gofer/filesystem.go +++ b/pkg/sentry/fsimpl/gofer/filesystem.go @@ -259,8 +259,10 @@ func (fs *filesystem) getChildLocked(ctx context.Context, parent *dentry, name s } parent.cacheNewChildLocked(child, name) // For now, child has 0 references, so our caller should call - // child.checkCachingLocked(). + // child.checkCachingLocked(). parent gained a ref so we should also call + // parent.checkCachingLocked() so it can be removed from the cache if needed. *ds = appendDentry(*ds, child) + *ds = appendDentry(*ds, parent) return child, nil } @@ -621,6 +623,8 @@ func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, op } } d.IncRef() + // Call d.checkCachingLocked() so it can be removed from the cache if needed. + ds = appendDentry(ds, d) return &d.vfsd, nil } @@ -635,6 +639,8 @@ func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPa return nil, err } d.IncRef() + // Call d.checkCachingLocked() so it can be removed from the cache if needed. + ds = appendDentry(ds, d) return &d.vfsd, nil } @@ -673,7 +679,7 @@ func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs. // MkdirAt implements vfs.FilesystemImpl.MkdirAt. func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MkdirOptions) error { creds := rp.Credentials() - return fs.doCreateAt(ctx, rp, true /* dir */, func(parent *dentry, name string, _ **[]*dentry) error { + return fs.doCreateAt(ctx, rp, true /* dir */, func(parent *dentry, name string, ds **[]*dentry) error { // If the parent is a setgid directory, use the parent's GID // rather than the caller's and enable setgid. kgid := creds.EffectiveKGID @@ -693,6 +699,7 @@ func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts v kuid: creds.EffectiveKUID, kgid: creds.EffectiveKGID, }) + *ds = appendDentry(*ds, parent) } if fs.opts.interop != InteropModeShared { parent.incLinks() @@ -746,6 +753,7 @@ func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts v kgid: creds.EffectiveKGID, endpoint: opts.Endpoint, }) + *ds = appendDentry(*ds, parent) return nil case linux.S_IFIFO: parent.createSyntheticChildLocked(&createSyntheticOpts{ @@ -755,6 +763,7 @@ func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts v kgid: creds.EffectiveKGID, pipe: pipe.NewVFSPipe(true /* isNamed */, pipe.DefaultPipeSize), }) + *ds = appendDentry(*ds, parent) return nil } // Retain error from gofer if synthetic file cannot be created internally. @@ -803,6 +812,8 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf start.IncRef() defer start.DecRef(ctx) unlock() + // start is intentionally not added to ds (which would remove it from the + // cache) because doing so regresses performance in practice. return start.open(ctx, rp, &opts) } @@ -859,6 +870,8 @@ afterTrailingSymlink: child.IncRef() defer child.DecRef(ctx) unlock() + // child is intentionally not added to ds (which would remove it from the + // cache) because doing so regresses performance in practice. return child.open(ctx, rp, &opts) } @@ -1106,6 +1119,7 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving } // Insert the dentry into the tree. d.cacheNewChildLocked(child, name) + *ds = appendDentry(*ds, d) if d.cachedMetadataAuthoritative() { d.touchCMtime() d.dirents = nil @@ -1302,6 +1316,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa oldParent.decRefNoCaching() ds = appendDentry(ds, oldParent) newParent.IncRef() + ds = appendDentry(ds, newParent) if renamed.isSynthetic() { oldParent.syntheticChildren-- newParent.syntheticChildren++ @@ -1445,6 +1460,7 @@ func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath if d.isSocket() { if !d.isSynthetic() { d.IncRef() + ds = appendDentry(ds, d) return &endpoint{ dentry: d, path: opts.Addr, diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go index f491aa641..21692d2ac 100644 --- a/pkg/sentry/fsimpl/gofer/gofer.go +++ b/pkg/sentry/fsimpl/gofer/gofer.go @@ -1412,8 +1412,13 @@ func (d *dentry) OnZeroWatches(ctx context.Context) { d.checkCachingLocked(ctx, false /* renameMuWriteLocked */) } -// checkCachingLocked should be called after d's reference count becomes 0 or it -// becomes disowned. +// checkCachingLocked should be called after d's reference count becomes 0 or +// it becomes disowned. +// +// For performance, checkCachingLocked can also be called after d's reference +// count becomes non-zero, so that d can be removed from the LRU cache. This +// may help in reducing the size of the cache and hence reduce evictions. Note +// that this is not necessary for correctness. // // It may be called on a destroyed dentry. For example, // renameMu[R]UnlockAndCheckCaching may call checkCachingLocked multiple times |