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Waiman Long ee9707e859 cgroup/cpuset: Enable memory migration for cpuset v2
When a user changes cpuset.cpus, each task in a v2 cpuset will be moved
to one of the new cpus if it is not there already. For memory, however,
they won't be migrated to the new nodes when cpuset.mems changes. This is
an inconsistency in behavior.

In cpuset v1, there is a memory_migrate control file to enable such
behavior by setting the CS_MEMORY_MIGRATE flag. Make it the default
for cpuset v2 so that we have a consistent set of behavior for both
cpus and memory.

There is certainly a cost to make memory migration the default, but it
is a one time cost that shouldn't really matter as long as cpuset.mems
isn't changed frequenty.  Update the cgroup-v2.rst file to document the
new behavior and recommend against changing cpuset.mems frequently.

Since there won't be any concurrent access to the newly allocated cpuset
structure in cpuset_css_alloc(), we can use the cheaper non-atomic
__set_bit() instead of the more expensive atomic set_bit().

Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2021-08-12 11:40:20 -10:00
arch fallthrough fixes for Clang for 5.14-rc2 2021-07-15 13:57:31 -07:00
block block-5.14-2021-07-08 2021-07-09 12:05:33 -07:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-07-09 11:00:44 -07:00
Documentation cgroup/cpuset: Enable memory migration for cpuset v2 2021-08-12 11:40:20 -10:00
drivers pwm: Fixes for v5.14-rc2 2021-07-15 17:29:44 -07:00
fs configfs fix for Linux 5.14 2021-07-15 17:36:36 -07:00
include fallthrough fixes for Clang for 5.14-rc2 2021-07-15 13:57:31 -07:00
init Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
ipc Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
kernel cgroup/cpuset: Enable memory migration for cpuset v2 2021-08-12 11:40:20 -10:00
lib lib/test_hmm: remove set but unused page variable 2021-07-15 10:13:49 -07:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm/hugetlb: fix refs calculation from unaligned @vaddr 2021-07-15 10:13:49 -07:00
net Networking fixes for 5.14-rc2, including fixes from bpf and netfilter. 2021-07-14 09:24:32 -07:00
samples Networking fixes for 5.14-rc2, including fixes from bpf and netfilter. 2021-07-14 09:24:32 -07:00
scripts Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
security asm-generic/unaligned: Unify asm/unaligned.h around struct helper 2021-07-02 12:43:40 -07:00
sound ASoC: Mediatek: MT8183: Fix fall-through warning for Clang 2021-07-13 14:58:18 -05:00
tools * Allow again loading KVM on 32-bit non-PAE builds 2021-07-15 11:56:07 -07:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt * Allow again loading KVM on 32-bit non-PAE builds 2021-07-15 11:56:07 -07:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +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 .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap m68k updates for v5.14 2021-06-28 14:01:03 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
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 IOMMU Fixes for Linux v5.14-rc1 2021-07-15 11:50:15 -07:00
Makefile Revert "Makefile: Enable -Wimplicit-fallthrough for Clang" 2021-07-15 18:05:31 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.