[Carry 3962] Support `process.scheduler` #4025

lifubang · 2023-09-25T10:52:57Z

(this is a carry of #3962)

Spec: opencontainers/runtime-spec#1188
Close: #3895 #3962

libcontainer/specconv/spec_linux.go

kolyshkin · 2023-09-27T00:30:07Z

libcontainer/process_linux.go

@@ -81,6 +81,7 @@ func (p *setnsProcess) signal(sig os.Signal) error {

 func (p *setnsProcess) start() (retErr error) {
 	defer p.messageSockPair.parent.Close()
+


unrelated; please remove

libcontainer/utils/utils_unix.go

libcontainer/configs/validate/validator.go

libcontainer/utils/utils_unix.go

kolyshkin · 2023-09-27T01:00:35Z

libcontainer/setns_init_linux.go

+			if errors.Is(err, unix.EPERM) {
+				return fmt.Errorf("error setting scheduler(please check you have appropriate privileges or valid cpus config): %w", err)


If you do want to distinguish between the two cases for EPERM, maybe it makes sense to check if we have cpus set first.

Also, maybe move this code into a separate function (setupScheduler), as we have the same 8 lines of code in both setns_init_linux.go and standard_init_linux.go

maybe it makes sense to check if we have cpus set first.

I also considered it when writing the code, but there is another corner case is that if the cpus value includes all cpus in the machine, it will be no error. So I don't want to check cpus value.

kolyshkin

@lifubang thanks for the carry! Left some comments, mostly minor.

lifubang · 2023-09-28T17:13:11Z

@lifubang thanks for the carry! Left some comments, mostly minor.

Thanks, there are all resolved, PTAL.

kolyshkin · 2023-09-29T17:37:09Z

libcontainer/configs/validate/validator.go

+		return nil
+	}
+	if s.Policy == "" {
+		return fmt.Errorf("scheduler policy is required")


nit: errors.New.

kolyshkin · 2023-09-29T17:37:59Z

libcontainer/configs/validate/validator.go

+	niceValue := s.Nice
+	if niceValue < -20 || niceValue > 19 {
+		return fmt.Errorf("invalid scheduler.nice: %d", niceValue)


I think it's better to use s.Nice directly (drop the intermediate variable) here.

I think the original author used an intermediate variable because repeating config.Scheduler.Nice three times was too much.

But, just in case an intermediate variable is preferred, it is better to limit its scope:

if n := s.Nice; n < -20 || n > 19 { return fmt.Errorf("invalid scheduler.nice: %d", n) }

kolyshkin · 2023-09-29T17:44:40Z

libcontainer/init_linux.go

+			if config.Cgroups.CpusetCpus == "" {
+				return errors.New("please check you have appropriate privileges to set process scheduler")
+			}


Maybe don't make this a special case.

I.e. something like

if err := unix.SchedSetAttr(0, attr, 0); err != nil { if errors.Is(err, unix.EPERM) && config.Cgroups.CpusetCpus != "" { return errors.New("process scheduler can not be used together with AllowedCPUs") } return fmt.Errorf("error setting scheduler: %w", err) }

kolyshkin

Left some nits.

Also, you can add Co-authored-by: ... footer.

kolyshkin

@lifubang I mean, put yourself as a co-author (@utam0k is already marked as the author, no need to add him as a co-author).

kolyshkin

LGTM

Spec: opencontainers/runtime-spec#1188 Fix: opencontainers#3895 Co-authored-by: lifubang <[email protected]> Signed-off-by: utam0k <[email protected]> Signed-off-by: lifubang <[email protected]>

lifubang commented Sep 25, 2023

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libcontainer/specconv/spec_linux.go Outdated Show resolved Hide resolved

lifubang mentioned this pull request Sep 25, 2023

Support process.scheduler #3962

Closed

lifubang requested review from AkihiroSuda and kolyshkin September 25, 2023 10:59

lifubang force-pushed the feat-sched-carry-3962 branch 2 times, most recently from ecd3e1a to 8d1145b Compare September 25, 2023 11:08