f504e15b94
When "unsafe unplug" is enabled, we don't fake-offline all memory ahead of actual memory offlining using alloc_contig_range(). Instead, we rely on offline_pages() to also perform actual page migration, which might fail or take a very long time. In that case, it's possible to easily run into endless loops that cannot be aborted anymore (as offlining is triggered by a workqueue then): For example, a single (accidentally) permanently unmovable page in ZONE_MOVABLE results in an endless loop. For ZONE_NORMAL, races between isolating the pageblock (and checking for unmovable pages) and concurrent page allocation are possible and similarly result in endless loops. The idea of the unsafe unplug mode was to make it possible to more reliably unplug large memory blocks. However, (a) we really should be tackling that differently, by extending the alloc_contig_range()-based mechanism; and (b) this mode is not the default and as far as I know, it's unused either way. So let's simply get rid of it. Signed-off-by: David Hildenbrand <david@redhat.com> Message-Id: <20230713145551.2824980-2-david@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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.