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Mainline Linux tree for various devices, only for fun :)
0061270307
Found an issue within cgroup_attach_task_all() fn which seem to exclude cgrp_dfl_root (cgroupv2) while attaching tasks to the given cgroup. This was noticed when the system was running qemu/kvm with kernel vhost helper threads. It appears that the vhost layer which uses cgroup_attach_task_all() fn to assign the vhost kthread to the right qemu cgroup works fine with cgroupv1 based configuration but not in cgroupv2. With cgroupv2, the vhost helper thread ends up just belonging to the root cgroup as is shown below: $ stat -fc %T /sys/fs/cgroup/ cgroup2fs $ sudo pgrep qemu 1916421 $ ps -eL | grep 1916421 1916421 1916421 ? 00:00:01 qemu-system-x86 1916421 1916431 ? 00:00:00 call_rcu 1916421 1916435 ? 00:00:00 IO mon_iothread 1916421 1916436 ? 00:00:34 CPU 0/KVM 1916421 1916439 ? 00:00:00 SPICE Worker 1916421 1916440 ? 00:00:00 vnc_worker 1916433 1916433 ? 00:00:00 vhost-1916421 1916437 1916437 ? 00:00:00 kvm-pit/1916421 $ cat /proc/1916421/cgroup 0::/machine.slice/machine-qemu\x2d18\x2dDroplet\x2d7572850.scope/emulator $ cat /proc/1916439/cgroup 0::/machine.slice/machine-qemu\x2d18\x2dDroplet\x2d7572850.scope/emulator $ cat /proc/1916433/cgroup 0::/ From above, it can be seen that the vhost kthread (PID: 1916433) doesn't seem to belong the qemu cgroup like other qemu PIDs. After applying this patch: $ pgrep qemu 1643 $ ps -eL | grep 1643 1643 1643 ? 00:00:00 qemu-system-x86 1643 1645 ? 00:00:00 call_rcu 1643 1648 ? 00:00:00 IO mon_iothread 1643 1649 ? 00:00:00 CPU 0/KVM 1643 1652 ? 00:00:00 SPICE Worker 1643 1653 ? 00:00:00 vnc_worker 1647 1647 ? 00:00:00 vhost-1643 1651 1651 ? 00:00:00 kvm-pit/1643 $ cat /proc/1647/cgroup 0::/machine.slice/machine-qemu\x2d18\x2dDroplet\x2d7572850.scope/emulator Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Vishal Verma <vverma@digitalocean.com> Signed-off-by: Tejun Heo <tj@kernel.org> |
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.