8d400913c2
When sizeof(struct page) is not a power of 2, sections do not span a PMD anymore and so when populating them some parts of the PMD will remain unused. Because of this, PMDs will be left behind when depopulating sections since remove_pmd_table() thinks that those unused parts are still in use. Fix this by marking the unused parts with PAGE_UNUSED, so memchr_inv() will do the right thing and will let us free the PMD when the last user of it is gone. This patch is based on a similar patch by David Hildenbrand: https://lore.kernel.org/linux-mm/20200722094558.9828-9-david@redhat.com/ [osalvador@suse.de: go back to the ifdef version] Link: https://lkml.kernel.org/r/YGy++mSft7K4u+88@localhost.localdomain Link: https://lkml.kernel.org/r/20210309214050.4674-4-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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.