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Jeremy Linton e156ab71a9 arm64: topology: Avoid checking numa mask for scheduler MC selection
The numa mask subset check can often lead to system hang or crash during
CPU hotplug and system suspend operation if NUMA is disabled. This is
mostly observed on HMP systems where the CPU compute capacities are
different and ends up in different scheduler domains. Since
cpumask_of_node is returned instead core_sibling, the scheduler is
confused with incorrect cpumasks(e.g. one CPU in two different sched
domains at the same time) on CPU hotplug.

Lets disable the NUMA siblings checks for the time being, as NUMA in
socket machines have LLC's that will assure that the scheduler topology
isn't "borken".

The NUMA check exists to assure that if a LLC within a socket crosses
NUMA nodes/chiplets the scheduler domains remain consistent. This code will
likely have to be re-enabled in the near future once the NUMA mask story
is sorted.  At the moment its not necessary because the NUMA in socket
machines LLC's are contained within the NUMA domains.

Further, as a defensive mechanism during hot-plug, lets assure that the
LLC siblings are also masked.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-06-07 17:42:11 +01:00
Documentation arm64: Add 'ssbd' command-line option 2018-05-31 17:34:49 +01:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
arch arm64: topology: Avoid checking numa mask for scheduler MC selection 2018-06-07 17:42:11 +01:00
block blk-mq: fix sysfs inflight counter 2018-04-26 09:02:01 -06:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto crypto: drbg - set freed buffers to NULL 2018-04-21 00:57:00 +08:00
drivers Merge branch 'for-next/perf' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux 2018-05-31 18:09:38 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs First pull request for 4.17-rc 2018-05-04 20:51:10 -10:00
include ACPI / PPTT: fix build when CONFIG_ACPI_PPTT is not enabled 2018-06-05 18:06:24 +01:00
init Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-15 16:12:35 -07:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-13 17:10:27 -07:00
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-05-06 05:35:23 -10:00
lib swiotlb: fix inversed DMA_ATTR_NO_WARN test 2018-05-02 14:48:55 +02:00
mm for-linus-20180504 2018-05-04 20:41:44 -10:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-05-03 18:57:03 -10:00
samples bpf: sockmap sample use clang flag, -target bpf 2018-04-23 23:42:21 +02:00
scripts Kbuild fixes for v4.17 2018-05-04 21:15:25 -10:00
security Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-24 17:58:51 -07:00
sound ALSA: pcm: Check PCM state at xfern compat ioctl 2018-05-02 08:54:54 +02:00
tools ACPI fix for 4.17-rc4 2018-05-04 05:43:33 -10:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt arm64: KVM: Add ARCH_WORKAROUND_2 discovery through ARCH_FEATURES_FUNC_ID 2018-05-31 18:00:59 +01:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Kbuild fixes for v4.17 2018-05-04 21:15:25 -10:00
Makefile Linux 4.17-rc4 2018-05-06 16:57:38 -10:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.