Aneesh Kumar K.V
368a0590d9
This is in preparation to update radix to implement vmemmap optimization for devdax. Below are the rules w.r.t radix vmemmap mapping 1. First try to map things using PMD (2M) 2. With altmap if altmap cross-boundary check returns true, fall back to PAGE_SIZE 3. If we can't allocate PMD_SIZE backing memory for vmemmap, fallback to PAGE_SIZE On removing vmemmap mapping, check if every subsection that is using the vmemmap area is invalid. If found to be invalid, that implies we can safely free the vmemmap area. We don't use the PAGE_UNUSED pattern used by x86 because with 64K page size, we need to do the above check even at the PAGE_SIZE granularity. [aneesh.kumar@linux.ibm.com: fix section mismatch warning] Link: https://lkml.kernel.org/r/87h6pqvu5g.fsf@linux.ibm.com [aneesh.kumar@linux.ibm.com: fix kernel build error] Link: https://lkml.kernel.org/r/877cqkwd20.fsf@linux.ibm.com Link: https://lkml.kernel.org/r/20230724190759.483013-11-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@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.