Bug 78738

Summary:	DOC: Setting MemoryLimit does not imply "MemoryAccounting=true"
Product:	systemd	Reporter:	Andy Melnikov <andy.melnikov>
Component:	general	Assignee:	systemd-bugs
Status:	RESOLVED FIXED	QA Contact:	systemd-bugs
Severity:	normal
Priority:	medium
Version:	unspecified
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Andy Melnikov 2014-05-15 12:20:30 UTC

http://www.freedesktop.org/software/systemd/man/systemd.resource-control.html says that MemoryLimit implies "MemoryAccounting=true".

But it's not the case. If I don't put an explicit "MemoryAccounting=true" in the unit file below, service control groups under memory is not created and memory limit doesn't work.

----
[Unit]
Description=foo
After=network.target

[Service]
User=bar
WorkingDirectory=/home/bar
ExecStart=/usr/bin/foo
Restart=always
RestartSec=5min
MemoryLimit=256M

[Install]
WantedBy=multi-user.target
----

[root@quux ~]# systemctl show foo -p MemoryLimit
MemoryLimit=268435456
[root@quux ~]# systemctl show foo -p MemoryAccounting
MemoryAccounting=no

Comment 1 Lennart Poettering 2014-05-24 06:56:38 UTC

Note that setting MemoryLimit= effectively turns on MemoryAccounting= but it won't show it with "systemctl show", since that actually shows the original MemoryAccounting= setting.

Or in other words, there's a distinction between the MemoryAccounting= setting (which is unaffected by MemoryLimit=, as you experienced), and the actual memory accounting which is turned on in the kernel either by using MemoryAccounting= or by MemoryLimit=. If you follow wht I mean.

Anyway, this is actually intended behaviour, but certainly something we could document better. Hence renaming the bug accordingly.

Comment 2 Lennart Poettering 2018-07-20 14:46:43 UTC

We dropped the offending sentences now from the man page. Closing.

See: https://github.com/systemd/systemd/pull/9669

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