From 89a1e7db39ed1015762d733379a4a5d443b1f4de Mon Sep 17 00:00:00 2001 From: Matthew Heon Date: Thu, 4 Jun 2020 14:28:01 -0400 Subject: Add parallel execution code for container operations This code will run container operations in parallel, up to a given maximum number of threads. Currently, it has only been enabled for local `podman rm` as a proof of concept. Signed-off-by: Matthew Heon --- cmd/podman/root.go | 11 +++++++- pkg/domain/infra/abi/containers.go | 21 ++++++++------ pkg/parallel/parallel.go | 44 +++++++++++++++++++++++++++++ pkg/parallel/parallel_linux.go | 57 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 124 insertions(+), 9 deletions(-) create mode 100644 pkg/parallel/parallel.go create mode 100644 pkg/parallel/parallel_linux.go diff --git a/cmd/podman/root.go b/cmd/podman/root.go index 59d536d0b..b62ee144a 100644 --- a/cmd/podman/root.go +++ b/cmd/podman/root.go @@ -4,12 +4,14 @@ import ( "fmt" "os" "path" + "runtime" "runtime/pprof" "strings" "github.com/containers/libpod/cmd/podman/registry" "github.com/containers/libpod/cmd/podman/validate" "github.com/containers/libpod/pkg/domain/entities" + "github.com/containers/libpod/pkg/parallel" "github.com/containers/libpod/pkg/rootless" "github.com/containers/libpod/pkg/tracing" "github.com/containers/libpod/version" @@ -137,6 +139,13 @@ func persistentPreRunE(cmd *cobra.Command, args []string) error { opentracing.StartSpanFromContext(cfg.SpanCtx, cmd.Name()) } + if cfg.MaxWorks <= 0 { + return errors.Errorf("maximum workers must be set to a positive number (got %d)", cfg.MaxWorks) + } + if err := parallel.SetMaxThreads(uint(cfg.MaxWorks)); err != nil { + return err + } + // Setup Rootless environment, IFF: // 1) in ABI mode // 2) running as non-root @@ -216,7 +225,7 @@ func rootFlags(opts *entities.PodmanConfig, flags *pflag.FlagSet) { flags.StringVar(&cfg.Containers.DefaultMountsFile, "default-mounts-file", cfg.Containers.DefaultMountsFile, "Path to default mounts file") flags.StringVar(&cfg.Engine.EventsLogger, "events-backend", cfg.Engine.EventsLogger, `Events backend to use ("file"|"journald"|"none")`) flags.StringSliceVar(&cfg.Engine.HooksDir, "hooks-dir", cfg.Engine.HooksDir, "Set the OCI hooks directory path (may be set multiple times)") - flags.IntVar(&opts.MaxWorks, "max-workers", 0, "The maximum number of workers for parallel operations") + flags.IntVar(&opts.MaxWorks, "max-workers", (runtime.NumCPU()*3)+1, "The maximum number of workers for parallel operations") flags.StringVar(&cfg.Engine.Namespace, "namespace", cfg.Engine.Namespace, "Set the libpod namespace, used to create separate views of the containers and pods on the system") flags.StringVar(&cfg.Engine.StaticDir, "root", "", "Path to the root directory in which data, including images, is stored") flags.StringVar(&opts.RegistriesConf, "registries-conf", "", "Path to a registries.conf to use for image processing") diff --git a/pkg/domain/infra/abi/containers.go b/pkg/domain/infra/abi/containers.go index 19232eff1..eb45d4630 100644 --- a/pkg/domain/infra/abi/containers.go +++ b/pkg/domain/infra/abi/containers.go @@ -23,6 +23,7 @@ import ( "github.com/containers/libpod/pkg/checkpoint" "github.com/containers/libpod/pkg/domain/entities" "github.com/containers/libpod/pkg/domain/infra/abi/terminal" + "github.com/containers/libpod/pkg/parallel" "github.com/containers/libpod/pkg/ps" "github.com/containers/libpod/pkg/rootless" "github.com/containers/libpod/pkg/signal" @@ -321,21 +322,25 @@ func (ic *ContainerEngine) ContainerRm(ctx context.Context, namesOrIds []string, return reports, nil } - for _, c := range ctrs { - report := entities.RmReport{Id: c.ID()} + errMap, err := parallel.ParallelContainerOp(ctx, ctrs, func(c *libpod.Container) error { err := ic.Libpod.RemoveContainer(ctx, c, options.Force, options.Volumes) if err != nil { if options.Ignore && errors.Cause(err) == define.ErrNoSuchCtr { logrus.Debugf("Ignoring error (--allow-missing): %v", err) - reports = append(reports, &report) - continue + return nil } logrus.Debugf("Failed to remove container %s: %s", c.ID(), err.Error()) - report.Err = err - reports = append(reports, &report) - continue } - reports = append(reports, &report) + return err + }) + if err != nil { + return nil, err + } + for ctr, err := range errMap { + report := new(entities.RmReport) + report.Id = ctr.ID() + report.Err = err + reports = append(reports, report) } return reports, nil } diff --git a/pkg/parallel/parallel.go b/pkg/parallel/parallel.go new file mode 100644 index 000000000..c9e4da50d --- /dev/null +++ b/pkg/parallel/parallel.go @@ -0,0 +1,44 @@ +package parallel + +import ( + "sync" + + "github.com/pkg/errors" + "github.com/sirupsen/logrus" + "golang.org/x/sync/semaphore" +) + +var ( + // Maximum number of jobs that will be used. + // Set a low, but non-zero, default. We'll be overriding it by default + // anyways. + numThreads uint = 8 + // Semaphore to control thread creation and ensure numThreads is + // respected. + jobControl *semaphore.Weighted + // Lock to control changing the semaphore - we don't want to do it + // while anyone is using it. + jobControlLock sync.RWMutex +) + +// SetMaxThreads sets the number of threads that will be used for parallel jobs. +func SetMaxThreads(threads uint) error { + if threads == 0 { + return errors.New("must give a non-zero number of threads to execute with") + } + + jobControlLock.Lock() + defer jobControlLock.Unlock() + + numThreads = threads + jobControl = semaphore.NewWeighted(int64(threads)) + logrus.Infof("Setting parallel job count to %d", threads) + + return nil +} + +// GetMaxThreads returns the current number of threads that will be used for +// parallel jobs. +func GetMaxThreads() uint { + return numThreads +} diff --git a/pkg/parallel/parallel_linux.go b/pkg/parallel/parallel_linux.go new file mode 100644 index 000000000..e3f086c0e --- /dev/null +++ b/pkg/parallel/parallel_linux.go @@ -0,0 +1,57 @@ +package parallel + +import ( + "context" + "sync" + + "github.com/containers/libpod/libpod" + "github.com/pkg/errors" + "github.com/sirupsen/logrus" +) + +// ParallelContainerOp performs the given function on the given set of +// containers, using a number of parallel threads. +// If no error is returned, each container specified in ctrs will have an entry +// in the resulting map; containers with no error will be set to nil. +func ParallelContainerOp(ctx context.Context, ctrs []*libpod.Container, applyFunc func(*libpod.Container) error) (map[*libpod.Container]error, error) { + jobControlLock.RLock() + defer jobControlLock.RUnlock() + + // We could use a sync.Map but given Go's lack of generic I'd rather + // just use a lock on a normal map... + // The expectation is that most of the time is spent in applyFunc + // anyways. + var ( + errMap map[*libpod.Container]error = make(map[*libpod.Container]error) + errLock sync.Mutex + allDone sync.WaitGroup + ) + + for _, ctr := range ctrs { + // Block until a thread is available + if err := jobControl.Acquire(ctx, 1); err != nil { + return nil, errors.Wrapf(err, "error acquiring job control semaphore") + } + + allDone.Add(1) + + c := ctr + go func() { + logrus.Debugf("Launching job on container %s", c.ID()) + + err := applyFunc(c) + errLock.Lock() + errMap[c] = err + errLock.Unlock() + + allDone.Done() + jobControl.Release(1) + }() + } + + allDone.Wait() + + return errMap, nil +} + +// TODO: Add an Enqueue() function that returns a promise -- cgit v1.2.3-54-g00ecf