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Zqiang 0578e14c94 rcu/nocb: Avoid polling when my_rdp->nocb_head_rdp list is empty
Currently, if the 'rcu_nocb_poll' kernel boot parameter is enabled, all
rcuog kthreads enter polling mode.  However, if all of a given group
of rcuo kthreads correspond to CPUs that have been de-offloaded, the
corresponding rcuog kthread will nonetheless still wake up periodically,
unnecessarily consuming power and perturbing workloads.  Fortunately,
this situation is easily detected by the fact that the rcuog kthread's
CPU's rcu_data structure's ->nocb_head_rdp list is empty.

This commit saves power and avoids unnecessarily perturbing workloads
by putting an rcuog kthread to sleep during any time period when all of
its rcuo kthreads' CPUs are de-offloaded.

Co-developed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
2022-07-19 11:43:55 -07:00
Documentation rcu/nocb: Add an option to offload all CPUs on boot 2022-07-19 11:43:34 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
arch X86 updates: 2022-06-19 09:58:28 -05:00
block block/bfq: Enable I/O statistics 2022-06-16 16:59:28 -06:00
certs certs: fix and refactor CONFIG_SYSTEM_BLACKLIST_HASH_LIST build 2022-06-15 21:52:32 +03:00
crypto crypto: memneq - move into lib/ 2022-06-12 14:51:51 +08:00
drivers A set of interrupt subsystem updates: 2022-06-19 09:45:16 -05:00
fs Fixes for 5.19-rc3: 2022-06-19 09:24:49 -05:00
include Build tool updates: 2022-06-19 09:54:16 -05:00
init gcc-12: disable '-Warray-bounds' universally for now 2022-06-09 10:11:12 -07:00
ipc These changes update the ipc sysctls so that they are fundamentally 2022-06-03 15:54:57 -07:00
kernel rcu/nocb: Avoid polling when my_rdp->nocb_head_rdp list is empty 2022-07-19 11:43:55 -07:00
lib Build tool updates: 2022-06-19 09:54:16 -05:00
mm Merge tag 'fs_for_v5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2022-06-17 10:09:24 -07:00
net NFS Client Fixes for Linux 5.19-rc 2022-06-17 15:17:57 -05:00
samples drm for 5.19-rc1 2022-05-25 16:18:27 -07:00
scripts Build tool updates: 2022-06-19 09:54:16 -05:00
security selinux: free contexts previously transferred in selinux_add_opt() 2022-06-15 21:20:45 -04:00
sound sound fixes for 5.19-rc2 2022-06-10 10:20:57 -07:00
tools Build tool updates: 2022-06-19 09:54:16 -05:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking 2022-06-09 10:52:20 -04:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap Hot fixes for 5.19-rc1. 2022-06-05 17:05:38 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS rectifications and a few minor driver fixes 2022-06-19 09:35:09 -05:00
Makefile Linux 5.19-rc3 2022-06-19 15:06:47 -05:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.