db5432165e
Explicitly walk the host page tables to identify THP mappings instead
of relying solely on the metadata in struct page. This sets the stage
for using a common method of identifying huge mappings regardless of the
underlying implementation (HugeTLB vs THB vs DAX), and hopefully avoids
the pitfalls of relying on metadata to identify THP mappings, e.g. see
commit 169226f7e0d2 ("mm: thp: handle page cache THP correctly in
PageTransCompoundMap") and the need for KVM to explicitly check for a
THP compound page. KVM will also naturally work with 1gb THP pages, if
they are ever supported.
Walking the tables for THP mappings is likely marginally slower than
querying metadata, but a future patch will reuse the walk to identify
HugeTLB mappings, at which point eliminating the existing VMA lookup for
HugeTLB will make this a net positive.
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Barret Rhoden <brho@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@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.