diff options
| author | Peter Xu <peterx@redhat.com> | 2024-03-27 18:23:24 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-04-26 06:56:21 +0300 |
| commit | 35a76f5c0863fc6b570bf02ab6dbf4cd65d1e001 (patch) | |
| tree | eb6e69c63a674b1660a68cfcbb0c447196b0c5c3 /include/linux/pgtable.h | |
| parent | 239e9a90c887d33e9339870a650d2bd621b95674 (diff) | |
| download | linux-35a76f5c0863fc6b570bf02ab6dbf4cd65d1e001.tar.xz | |
mm/arch: provide pud_pfn() fallback
The comment in the code explains the reasons. We took a different
approach comparing to pmd_pfn() by providing a fallback function.
Another option is to provide some lower level config options (compare to
HUGETLB_PAGE or THP) to identify which layer an arch can support for such
huge mappings. However that can be an overkill.
[peterx@redhat.com: fix loongson defconfig]
Link: https://lkml.kernel.org/r/20240403013249.1418299-4-peterx@redhat.com
Link: https://lkml.kernel.org/r/20240327152332.950956-6-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Jones <andrew.jones@linux.dev>
Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/pgtable.h')
| -rw-r--r-- | include/linux/pgtable.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 09c85c7bf9c2..f108c7a3c1d9 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1820,6 +1820,20 @@ typedef unsigned int pgtbl_mod_mask; #endif /* + * We always define pmd_pfn for all archs as it's used in lots of generic + * code. Now it happens too for pud_pfn (and can happen for larger + * mappings too in the future; we're not there yet). Instead of defining + * it for all archs (like pmd_pfn), provide a fallback. + * + * Note that returning 0 here means any arch that didn't define this can + * get severely wrong when it hits a real pud leaf. It's arch's + * responsibility to properly define it when a huge pud is possible. + */ +#ifndef pud_pfn +#define pud_pfn(x) 0 +#endif + +/* * Some architectures have MMUs that are configurable or selectable at boot * time. These lead to variable PTRS_PER_x. For statically allocated arrays it * helps to have a static maximum value. |