b78a50c378
docker pause/unpause with parallel docker exec can lead to freezing state, set freezer.state to Thawed to increase freeze chances
55 lines
2.2 KiB
Diff
55 lines
2.2 KiB
Diff
From a1e170db821863c8a8062f599fab64d6c1d95210 Mon Sep 17 00:00:00 2001
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From: chenjiankun <chenjiankun1@huawei.com>
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Date: Fri, 13 Jan 2023 17:13:22 +0800
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Subject: [PATCH] docker: set freezer.state to Thawed to increase freeze
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chances
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docker pause/unpause with parallel docker exec can lead to freezing
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state, set freezer.state to Thawed to increase freeze chances
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---
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components/engine/daemon/freezer/freezer.go | 21 +++++++++++++++++++++
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1 file changed, 21 insertions(+)
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diff --git a/components/engine/daemon/freezer/freezer.go b/components/engine/daemon/freezer/freezer.go
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index 6df176f2f..fde134887 100644
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--- a/components/engine/daemon/freezer/freezer.go
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+++ b/components/engine/daemon/freezer/freezer.go
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@@ -186,6 +186,7 @@ func (f *freezer) updateCgroup(state string) error {
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timeout := time.After(30 * time.Second)
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ticker := time.NewTicker(1 * time.Millisecond)
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defer ticker.Stop()
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+ count := 0
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for {
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select {
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case <-timeout:
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@@ -194,6 +195,26 @@ func (f *freezer) updateCgroup(state string) error {
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}
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return fmt.Errorf("update freezer cgroup timeout for 30s")
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case <-ticker.C:
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+ // As per older kernel docs (freezer-subsystem.txt before
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+ // kernel commit ef9fe980c6fcc1821), if FREEZING is seen,
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+ // userspace should either retry or thaw. While current
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+ // kernel cgroup v1 docs no longer mention a need to retry,
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+ // the kernel (tested on v5.4, Ubuntu 20.04) can't reliably
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+ // freeze a cgroup while new processes keep appearing in it
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+ // (either via fork/clone or by writing new PIDs to
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+ // cgroup.procs).
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+ //
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+ // The numbers below are chosen to have a decent chance to
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+ // succeed even in the worst case scenario (docker pause/unpause
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+ // with parallel docker exec).
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+ //
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+ // Adding any amount of sleep in between retries did not
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+ // increase the chances of successful freeze.
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+ if count++; count % 50 == 0 && state == string(configs.Frozen) {
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+ writeFile(f.path, "freezer.state", string(configs.Thawed))
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+ time.Sleep(10 * time.Millisecond)
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+ }
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+
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// In case this loop does not exit because it doesn't get the expected
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// state, let's write again this state, hoping it's going to be properly
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// set this time. Otherwise, this loop could run infinitely, waiting for
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--
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2.23.0
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