daandemeyer / rpms / systemd

Forked from rpms/systemd 2 years ago
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From 45d093a37b6f8c2ceae9bfd090c5265f35413b46 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Michal=20Sekleta=CC=81r?= <msekleta@redhat.com>
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Date: Tue, 8 Sep 2020 14:51:39 +0200
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Subject: [PATCH] cgroup: freezer action must be NOP when cgroup v2 freezer is
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 not available
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Low-level cgroup freezer state manipulation is invoked directly from the
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job engine when we are about to execute the job in order to make sure
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the unit is not frozen and job execution is not blocked because of
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that.
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Currently with cgroup v1 we would needlessly do a bunch of work in the
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function and even falsely update the freezer state. Don't do any of this
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and skip the function silently when v2 freezer is not available.
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Following bug is fixed by this commit,
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$ systemd-run --unit foo.service /bin/sleep infinity
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$ systemctl restart foo.service
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$ systemctl show -p FreezerState foo.service
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Before (cgroup v1, i.e. full "legacy" mode):
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FreezerState=thawing
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After:
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FreezerState=running
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(cherry picked from commit 9a1e90aee556b7a30d87553a891a4175ae77ed68)
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Resolves: #1868831
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---
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 src/core/cgroup.c | 3 +++
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 1 file changed, 3 insertions(+)
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diff --git a/src/core/cgroup.c b/src/core/cgroup.c
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index e0eb184fd2..f1ce070f9a 100644
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--- a/src/core/cgroup.c
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+++ b/src/core/cgroup.c
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@@ -2936,6 +2936,9 @@ int unit_cgroup_freezer_action(Unit *u, FreezerAction action) {
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         assert(u);
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         assert(IN_SET(action, FREEZER_FREEZE, FREEZER_THAW));
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+        if (!cg_freezer_supported())
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+                return 0;
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+
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         if (!u->cgroup_realized)
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                 return -EBUSY;
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