8fea0f59e9
DEBUG_HOTPLUG_CPU0 debug feature offlines a CPU as early as possible allowing userspace to boot up without that CPU (so that it is possible to check for unwanted dependencies towards the offlined CPU). After doing so it emits a "CPU %u is now offline" pr_info, which is not enough descriptive of why the CPU was offlined (e.g., one might be running with a config that triggered some problem, not being aware that CONFIG_DEBUG_ HOTPLUG_CPU0 is set). Add a bit more of informative text to the pr_info, so that it is immediately obvious why a CPU has been offlined in early boot stages. Background: Got to scratch my head a bit while debugging a WARNING splat related to the offlining of CPU0. Without being aware yet of this debug option it wasn't immediately obvious why CPU0 was being offlined by the kernel. Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Link: http://lkml.kernel.org/r/20181219151647.15073-1-juri.lelli@redhat.com [ Merge line-broken line. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.