53cdc1cb29
We see multiple issues with the implementation/interface to compute
whether a memory block can be offlined (exposed via
/sys/devices/system/memory/memoryX/removable) and would like to simplify
it (remove the implementation).
1. It runs basically lockless. While this might be good for performance,
we see possible races with memory offlining that will require at
least some sort of locking to fix.
2. Nowadays, more false positives are possible. No arch-specific checks
are performed that validate if memory offlining will not be denied
right away (and such check will require locking). For example, arm64
won't allow to offline any memory block that was added during boot -
which will imply a very high error rate. Other archs have other
constraints.
3. The interface is inherently racy. E.g., if a memory block is detected
to be removable (and was not a false positive at that time), there is
still no guarantee that offlining will actually succeed. So any
caller already has to deal with false positives.
4. It is unclear which performance benefit this interface actually
provides. The introducing commit
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| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.