JDK-8253797 : [cgroups v2] Account for the fact that swap accounting is disabled on some systems
  • Type: Bug
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 16
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: linux
  • CPU: generic
  • Submitted: 2020-09-29
  • Updated: 2022-12-15
  • Resolved: 2020-12-10
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JDK 11 JDK 17 Other
11.0.16Fixed 17 b01Fixed openjdk8u372Fixed
Related Reports
Relates :  
JDK-8250984 - Memory Docker tests fail on some Linux kernels w/o cgroupv1 swap limit capabilities
Relates :  
JDK-8257746 - Regression introduced with JDK-8250984 - memory might be null in some machines
Description
This is similar to JDK-8250984, but for cgroups v2.

If no swap limit files are available the memory limit should be returned. That makes cgroups v1 and cgroups v2 consistent again.
Comments
Fix request (8u) Please consider this as part of the cgroups v2 backport to jdk8u. This is a clean patch. Thanks!
08-12-2022
A pull request was submitted for review. URL: https://git.openjdk.org/jdk8u-dev/pull/185 Date: 2022-11-18 09:56:24 +0000
18-11-2022
Fix Request 11u Requesting a backport to 11u as part of CGroups v2 support. The patch applies cleanly and passes tier 1 and container tests.
13-04-2022
A pull request was submitted for review. URL: https://git.openjdk.java.net/jdk11u-dev/pull/987 Date: 2022-04-01 20:19:16 +0000
01-04-2022
Changeset: 66936111 Author: Severin Gehwolf <sgehwolf@openjdk.org> Date: 2020-12-10 16:47:02 +0000 URL: https://git.openjdk.java.net/jdk/commit/66936111
10-12-2020
Without this fix and with JDK-8250984 in place only one test fails for me on cgroups v2 with swapaccount=0 FAILED: jdk/internal/platform/docker/TestDockerMemoryMetrics.java More specifically, containers/docker/TestMemoryAwareness.java test passes without the fix.
07-12-2020
Before: ---------- $ podman run --rm -it -v $(pwd)/openjdk-16-jdk:/jdk --memory=300m fedora:33 /bin/bash Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap. [root@206dcc27af24 /]# ./jdk/bin/java -XshowSettings:system -version Operating System Metrics: Provider: cgroupv2 Effective CPU Count: 4 CPU Period: 100000us CPU Quota: -1 CPU Shares: -1 List of Processors: N/A List of Effective Processors, 4 total: 0 1 2 3 List of Memory Nodes: N/A List of Available Memory Nodes, 1 total: 0 Memory Limit: 300.00M Memory Soft Limit: 0.00K Memory & Swap Limit: Unlimited openjdk version "16-internal" 2021-03-16 OpenJDK Runtime Environment (fastdebug build 16-internal+0-adhoc.sgehwolf.jdk-jdk) OpenJDK 64-Bit Server VM (fastdebug build 16-internal+0-adhoc.sgehwolf.jdk-jdk, mixed mode, sharing) After: ------- $ podman run --rm -ti --memory=300m -v $(pwd)/openjdk-16-jdk:/jdk fedora:33 Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap. [root@fdd2aed99d39 /]# /jdk/bin/java -XshowSettings:system -version Operating System Metrics: Provider: cgroupv2 Effective CPU Count: 4 CPU Period: 100000us CPU Quota: -1 CPU Shares: -1 List of Processors: N/A List of Effective Processors, 4 total: 0 1 2 3 List of Memory Nodes: N/A List of Available Memory Nodes, 1 total: 0 Memory Limit: 300.00M Memory Soft Limit: 0.00K Memory & Swap Limit: 300.00M Note the difference in "Memory & Swap Limit" output.
07-12-2020
Fedora 33 has podman 2.2.0 so this should be ready now for development: $ podman --version podman version 2.2.0 $ grep swapaccount /proc/cmdline BOOT_IMAGE=(hd0,msdos1)/vmlinuz-5.9.12-200.fc33.x86_64 root=UUID=be19c1c6-2985-4a4b-add9-011cd5ae0e1c ro rootflags=subvol=root rhgb quiet swapaccount=0 $ podman run --rm -it --memory-reservation=200m --memory=300m --memory-swap=300m fedora:33 /bin/bash Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap. [root@6c381aa047f6 /]#
07-12-2020
Looks like this will be part of podman 2.2 and better.
07-12-2020
PR for podman to fix this: https://github.com/containers/podman/pull/8197
30-10-2020
Right now this case is impossible on systems I've access to. $ grep swapaccount= /proc/cmdline BOOT_IMAGE=(hd0,msdos1)/vmlinuz-5.8.11-300.fc33.x86_64 root=UUID=be19c1c6-2985-4a4b-add9-011cd5ae0e1c ro rootflags=subvol=root rhgb quiet swapaccount=0 $ podman run --rm -it --memory-reservation=200m --memory=300m --memory-swap=300m fedora:33 /bin/bash Error: opening file `memory.swap.max` for writing: Permission denied: OCI runtime permission denied error This is different for cgroups v1 where 'docker' allows one to start a container on such systems. In contrast, podman on such cgroups v1 systems doesn't allow that[1]: # grep swapaccount= /proc/cmdline BOOT_IMAGE=(hd0,msdos1)/vmlinuz-5.6.6-300.fc32.x86_64 root=/dev/mapper/fedora_localhost--live-root ro resume=/dev/mapper/fedora_localhost--live-swap rd.lvm.lv=fedora_localhost-live/root rd.lvm.lv=fedora_localhost-live/swap rhgb quiet systemd.unified_cgroup_hierarchy=0 swapaccount=0 # docker run --rm -it --memory-reservation=200m --memory=300m --memory-swap=300m fedora:32 /bin/bash WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap. [root@7b583400a1f2 /]# # podman run --rm -it --memory-reservation=200m --memory=300m --memory-swap=300m fedora:32 /bin/bash Your kernel does not support swap limit capabilities,or the cgroup is not mounted. Memory limited without swap. Error: writing file `memory.memsw.limit_in_bytes`: Permission denied: OCI runtime permission denied error [1] https://github.com/containers/podman/issues/6365 Once the podman issue is properly resolved this could be looked at.
01-10-2020