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sys-kernel/coreos-modules: enable CONFIG_CPUSETS_V1#3263

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Sep 11, 2025
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sys-kernel/coreos-modules: enable CONFIG_CPUSETS_V1#3263
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@tormath1 tormath1 commented Sep 11, 2025 •
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With Kernel 6.12 this is disabled by default and this can cause breakage for existing workloads relying on this like the JVM.

Related to: flatcar/Flatcar#1884

diff --git a/tmp/4426.0.0-7E5TbI b/tmp/.-58Genq
index 10139482c2..16c6201253 100644
--- a/tmp/4426.0.0-7E5TbI
+++ b/tmp/.-58Genq
@@ -1,5 +1,5 @@
 File    Size  Used Avail Use% Type
 /boot   127M   64M   63M  51% vfat
-/usr   1016M  455M  331M  58% btrfs
+/usr   1016M  452M  331M  58% btrfs
 /       2.0G  576K  1.8G   1% ext4
-SUM     3.1G  519M  2.2G  19% -
+SUM     3.1G  515M  2.2G  19% -

Before (Max heap size is ~2Gb (half of the host system) while it should be ~1Gb):

core@localhost ~ $ docker run -it -m 2g fedora:41 bash -c "dnf install -y java-headless && java -XX:MaxRAMPercentage=50 -XshowSettings -Xlog:os+container=debug --version"

...
    Max. Heap Size (Estimated): 1.92G
...
core@localhost ~ $ free -m
               total        used        free      shared  buff/cache   available
Mem:            3922         428        2397           0        1329        3493
Swap:              0           0           0

After (Max heap size is now correctly set to ~1Gb):

core@localhost ~ $ docker run -it -m 2g fedora:41 bash -c "dnf install -y java-headless && java -XX:MaxRAMPercentage=50 -XshowSettings -Xlog:os+container=debug --version"
...
    Max. Heap Size (Estimated): 988.00M
...

@tormath1
sys-kernel/coreos-modules: enable CONFIG_CPUSETS_V1
09a66bd 
With Kernel 6.12 this is disabled by default and this can cause breakage
for existing workloads relying on this like the JVM.

Signed-off-by: Mathieu Tortuyaux <mtortuyaux@microsoft.com>
@tormath1 tormath1 self-assigned this Sep 11, 2025
@tormath1 tormath1 moved this to ✅ Testing / in Review in Flatcar tactical, release planning, and roadmap Sep 11, 2025
@tormath1
changelog: add entry
ce7f40a 
Signed-off-by: Mathieu Tortuyaux <mtortuyaux@microsoft.com>
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github-actions bot commented Sep 11, 2025 •
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Build action triggered: https://github.com/flatcar/scripts/actions/runs/17649374789

@tormath1 tormath1 marked this pull request as ready for review September 11, 2025 13:47
@tormath1 tormath1 requested a review from a team as a code owner September 11, 2025 13:47
@tormath1 tormath1 merged commit 24fc49b into main Sep 11, 2025
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@github-project-automation github-project-automation bot moved this from ✅ Testing / in Review to Implemented in Flatcar tactical, release planning, and roadmap Sep 11, 2025
@tormath1 tormath1 deleted the tormath1/cpuset branch September 11, 2025 15:22
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tormath1 commented Sep 11, 2025

Cherry-picked to:

  • flatcar-4426
  • flatcar-4372

@tormath1 tormath1 mentioned this pull request Sep 16, 2025
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@thechristschn thechristschn mentioned this pull request Sep 19, 2025
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@github-actions github-actions bot mentioned this pull request Sep 26, 2025
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