mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-03 18:12:25 -04:00
9067d90006
The cgroup root_list is already RCU-safe. Therefore, we can replace the
cgroup_mutex with the RCU read lock in some particular paths. This change
will be particularly beneficial for frequent operations, such as
`cat /proc/self/cgroup`, in a cgroup1-based container environment.
I did stress tests with this change, as outlined below
(with CONFIG_PROVE_RCU_LIST enabled):
- Continuously mounting and unmounting named cgroups in some tasks,
for example:
cgrp_name=$1
while true
do
mount -t cgroup -o none,name=$cgrp_name none /$cgrp_name
umount /$cgrp_name
done
- Continuously triggering proc_cgroup_show() in some tasks concurrently,
for example:
while true; do cat /proc/self/cgroup > /dev/null; done
They can ran successfully after implementing this change, with no RCU
warnings in dmesg.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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.