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Linux kernel source tree
9709eb0f84
Patch series "sched/numa: add statistics of numa balance task migration",
v6.
Introduce task migration and swap statistics in the following places:
/sys/fs/cgroup/{GROUP}/memory.stat
/proc/{PID}/sched
/proc/vmstat
These statistics facilitate a rapid evaluation of the performance and
resource utilization of the target workload.
This patch (of 2):
Task swapping is triggered when there are no idle CPUs in task A's
preferred node. In this case, the NUMA load balancer chooses a task B
on A's preferred node and swaps B with A. This helps improve NUMA
locality without introducing load imbalance between nodes. In the
current implementation, B's NUMA node preference is not mandatory.
That is to say, a kernel thread might be incorrectly chosen as B.
However, kernel thread and user space thread that does not have mm are
not supposed to be covered by NUMA balancing because NUMA balancing
only considers user pages via VMAs.
According to Peter's suggestion for fixing this issue, we use
PF_KTHREAD to skip the kernel thread. curr->mm is also checked because
it is possible that user_mode_thread() might create a user thread
without an mm. As per Prateek's analysis, after adding the PF_KTHREAD
check, there is no need to further check the PF_IDLE flag:
: - play_idle_precise() already ensures PF_KTHREAD is set before adding
: PF_IDLE
:
: - cpu_startup_entry() is only called from the startup thread which
: should be marked with PF_KTHREAD (based on my understanding looking at
: commit
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| 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 reStructuredText 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.