From c8cee7108f1a1b37e89961c6dd69ccab97952c86 Mon Sep 17 00:00:00 2001 From: Fabricio Voznika Date: Wed, 17 Apr 2019 12:56:23 -0700 Subject: Use FD limit and file size limit from host FD limit and file size limit is read from the host, instead of using hard-coded defaults, given that they effect the sandbox process. Also limit the direct cache to use no more than half if the available FDs. PiperOrigin-RevId: 244050323 Change-Id: I787ad0fdf07c49d589e51aebfeae477324fe26e6 --- runsc/boot/fs.go | 19 ++++++++++++- runsc/boot/limits.go | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++-- runsc/boot/loader.go | 4 +++ 3 files changed, 97 insertions(+), 3 deletions(-) (limited to 'runsc') diff --git a/runsc/boot/fs.go b/runsc/boot/fs.go index 8dfb6dce6..761142d98 100644 --- a/runsc/boot/fs.go +++ b/runsc/boot/fs.go @@ -20,10 +20,10 @@ import ( "path/filepath" "strconv" "strings" + "syscall" // Include filesystem types that OCI spec might mount. _ "gvisor.googlesource.com/gvisor/pkg/sentry/fs/dev" - _ "gvisor.googlesource.com/gvisor/pkg/sentry/fs/gofer" _ "gvisor.googlesource.com/gvisor/pkg/sentry/fs/host" _ "gvisor.googlesource.com/gvisor/pkg/sentry/fs/proc" _ "gvisor.googlesource.com/gvisor/pkg/sentry/fs/sys" @@ -38,6 +38,7 @@ import ( "gvisor.googlesource.com/gvisor/pkg/log" "gvisor.googlesource.com/gvisor/pkg/sentry/context" "gvisor.googlesource.com/gvisor/pkg/sentry/fs" + "gvisor.googlesource.com/gvisor/pkg/sentry/fs/gofer" "gvisor.googlesource.com/gvisor/pkg/sentry/fs/ramfs" "gvisor.googlesource.com/gvisor/pkg/syserror" "gvisor.googlesource.com/gvisor/runsc/specutils" @@ -81,6 +82,22 @@ func (f *fdDispenser) empty() bool { return len(f.fds) == 0 } +func adjustDirentCache(k *kernel.Kernel) error { + var hl syscall.Rlimit + if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &hl); err != nil { + return fmt.Errorf("getting RLIMIT_NOFILE: %v", err) + } + if int64(hl.Cur) != syscall.RLIM_INFINITY { + newSize := hl.Cur / 2 + if newSize < gofer.DefaultDirentCacheSize { + log.Infof("Setting gofer dirent cache size to %d", newSize) + gofer.DefaultDirentCacheSize = newSize + k.DirentCacheLimiter = fs.NewDirentCacheLimiter(newSize) + } + } + return nil +} + // setupRootContainerFS creates a mount namespace containing the root filesystem // and all mounts. 'rootCtx' is used to walk directories to find mount points. // 'setMountNS' is called after namespace is created. It must set the mount NS diff --git a/runsc/boot/limits.go b/runsc/boot/limits.go index e3e716bf9..32e62cdf7 100644 --- a/runsc/boot/limits.go +++ b/runsc/boot/limits.go @@ -16,8 +16,11 @@ package boot import ( "fmt" + "sync" + "syscall" specs "github.com/opencontainers/runtime-spec/specs-go" + "gvisor.googlesource.com/gvisor/pkg/log" "gvisor.googlesource.com/gvisor/pkg/sentry/limits" ) @@ -41,10 +44,43 @@ var fromLinuxResource = map[string]limits.LimitType{ "RLIMIT_STACK": limits.Stack, } -func createLimitSet(spec *specs.Spec) (*limits.LimitSet, error) { +func findName(lt limits.LimitType) string { + for k, v := range fromLinuxResource { + if v == lt { + return k + } + } + return "unknown" +} + +var defaults defs + +type defs struct { + mu sync.Mutex + set *limits.LimitSet + err error +} + +func (d *defs) get() (*limits.LimitSet, error) { + d.mu.Lock() + defer d.mu.Unlock() + + if d.err != nil { + return nil, d.err + } + if d.set == nil { + if err := d.initDefaults(); err != nil { + d.err = err + return nil, err + } + } + return d.set, nil +} + +func (d *defs) initDefaults() error { ls, err := limits.NewLinuxLimitSet() if err != nil { - return nil, err + return err } // Set default limits based on what containers get by default, ex: @@ -66,6 +102,43 @@ func createLimitSet(spec *specs.Spec) (*limits.LimitSet, error) { ls.SetUnchecked(limits.SignalsPending, limits.Limit{Cur: 0, Max: 0}) ls.SetUnchecked(limits.Stack, limits.Limit{Cur: 8388608, Max: limits.Infinity}) + // Read host limits that directly affect the sandbox and adjust the defaults + // based on them. + for _, res := range []int{syscall.RLIMIT_FSIZE, syscall.RLIMIT_NOFILE} { + var hl syscall.Rlimit + if err := syscall.Getrlimit(res, &hl); err != nil { + return err + } + + lt, ok := limits.FromLinuxResource[res] + if !ok { + return fmt.Errorf("unknown rlimit type %v", res) + } + hostLimit := limits.Limit{ + Cur: limits.FromLinux(hl.Cur), + Max: limits.FromLinux(hl.Max), + } + + defaultLimit := ls.Get(lt) + if hostLimit.Cur != limits.Infinity && hostLimit.Cur < defaultLimit.Cur { + log.Warningf("Host limit is lower than recommended, resource: %q, host: %d, recommended: %d", findName(lt), hostLimit.Cur, defaultLimit.Cur) + } + if hostLimit.Cur != defaultLimit.Cur || hostLimit.Max != defaultLimit.Max { + log.Infof("Setting limit from host, resource: %q {soft: %d, hard: %d}", findName(lt), hostLimit.Cur, hostLimit.Max) + ls.SetUnchecked(lt, hostLimit) + } + } + + d.set = ls + return nil +} + +func createLimitSet(spec *specs.Spec) (*limits.LimitSet, error) { + ls, err := defaults.get() + if err != nil { + return nil, err + } + // Then apply overwrites on top of defaults. for _, rl := range spec.Process.Rlimits { lt, ok := fromLinuxResource[rl.Type] diff --git a/runsc/boot/loader.go b/runsc/boot/loader.go index 56cb137f0..88a834aa5 100644 --- a/runsc/boot/loader.go +++ b/runsc/boot/loader.go @@ -274,6 +274,10 @@ func New(args Args) (*Loader, error) { return nil, fmt.Errorf("initializing kernel: %v", err) } + if err := adjustDirentCache(k); err != nil { + return nil, err + } + // Turn on packet logging if enabled. if args.Conf.LogPackets { log.Infof("Packet logging enabled") -- cgit v1.2.3