Skip to content

cgroupv1 freezer: thaw to increase freeze chances #2791

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
cyphar merged 1 commit into from
Feb 7, 2021
Merged

cgroupv1 freezer: thaw to increase freeze chances #2791

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 13 additions & 3 deletions libcontainer/cgroups/fs/freezer.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@ import (
"github.com/opencontainers/runc/libcontainer/cgroups"
"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
"github.com/opencontainers/runc/libcontainer/configs"
"github.com/sirupsen/logrus"
"golang.org/x/sys/unix"
)

Expand All @@ -38,13 +39,19 @@ func (s *FreezerGroup) Set(path string, cgroup *configs.Cgroup) error {
// (either via fork/clone or by writing new PIDs to
// cgroup.procs).
//
// The number of retries below is chosen to have a decent
// chance to succeed even in the worst case scenario (runc
// pause/unpause with parallel runc exec).
// The numbers below are chosen to have a decent chance to
// succeed even in the worst case scenario (runc pause/unpause
// with parallel runc exec).
//
// Adding any amount of sleep in between retries did not
// increase the chances of successful freeze.
for i := 0; i < 1000; i++ {
if i%50 == 49 {
// Briefly thawing the cgroup also helps.
_ = fscommon.WriteFile(path, "freezer.state", string(configs.Thawed))
time.Sleep(10 * time.Millisecond)
}

if err := fscommon.WriteFile(path, "freezer.state", string(configs.Frozen)); err != nil {
return err
}
Expand All @@ -58,6 +65,9 @@ func (s *FreezerGroup) Set(path string, cgroup *configs.Cgroup) error {
case "FREEZING":
continue
case string(configs.Frozen):
if i > 1 {
logrus.Debugf("frozen after %d retries", i)
}
return nil
default:
// should never happen
Expand Down