kernel/linux.git/include/linux/huge_mm.h, branch v5.10.257

mm/userfaultfd: fix uffd-wp special cases for fork()

2021-07-25T12:36:18+00:00

commit 8f34f1eac3820fc2722e5159acceb22545b30b0d upstream. We tried to do something similar in b569a1760782 ("userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork") previously, but it's not doing it all right.. A few fixes around the code path: 1. We were referencing VM_UFFD_WP vm_flags on the _old_ vma rather than the new vma. That's overlooked in b569a1760782, so it won't work as expected. Thanks to the recent rework on fork code (7a4830c380f3a8b3), we can easily get the new vma now, so switch the checks to that. 2. Dropping the uffd-wp bit in copy_huge_pmd() could be wrong if the huge pmd is a migration huge pmd. When it happens, instead of using pmd_uffd_wp(), we should use pmd_swp_uffd_wp(). The fix is simply to handle them separately. 3. Forget to carry over uffd-wp bit for a write migration huge pmd entry. This also happens in copy_huge_pmd(), where we converted a write huge migration entry into a read one. 4. In copy_nonpresent_pte(), drop uffd-wp if necessary for swap ptes. 5. In copy_present_page() when COW is enforced when fork(), we also need to pass over the uffd-wp bit if VM_UFFD_WP is armed on the new vma, and when the pte to be copied has uffd-wp bit set. Remove the comment in copy_present_pte() about this. It won't help a huge lot to only comment there, but comment everywhere would be an overkill. Let's assume the commit messages would help. [peterx@redhat.com: fix a few thp pmd missing uffd-wp bit] Link: https://lkml.kernel.org/r/20210428225030.9708-4-peterx@redhat.com Link: https://lkml.kernel.org/r/20210428225030.9708-3-peterx@redhat.com Fixes: b569a1760782f ("userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork") Signed-off-by: Peter Xu Cc: Jerome Glisse Cc: Mike Rapoport Cc: Alexander Viro Cc: Andrea Arcangeli Cc: Axel Rasmussen Cc: Brian Geffon Cc: "Dr . David Alan Gilbert" Cc: Hugh Dickins Cc: Joe Perches Cc: Kirill A. Shutemov Cc: Lokesh Gidra Cc: Mike Kravetz Cc: Mina Almasry Cc: Oliver Upton Cc: Shaohua Li Cc: Shuah Khan Cc: Stephen Rothwell Cc: Wang Qing Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

include/linux/huge_mm.h: remove extern keyword

2021-07-14T14:56:51+00:00

[ Upstream commit ebfe1b8f6ea5d83d8c1aa18ddd8ede432a7414e7 ] The external function definitions don't need the "extern" keyword. Remove them so future changes don't copy the function definition style. Link: https://lkml.kernel.org/r/20201106235135.32109-1-rcampbell@nvidia.com Signed-off-by: Ralph Campbell Reviewed-by: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

mm/huge_memory.c: add missing read-only THP checking in transparent_hugepage_enabled()

2021-07-14T14:56:50+00:00

[ Upstream commit e6be37b2e7bddfe0c76585ee7c7eee5acc8efeab ] Since commit 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS"), read-only THP file mapping is supported. But it forgot to add checking for it in transparent_hugepage_enabled(). To fix it, we add checking for read-only THP file mapping and also introduce helper transhuge_vma_enabled() to check whether thp is enabled for specified vma to reduce duplicated code. We rename transparent_hugepage_enabled to transparent_hugepage_active to make the code easier to follow as suggested by David Hildenbrand. [linmiaohe@huawei.com: define transhuge_vma_enabled next to transhuge_vma_suitable] Link: https://lkml.kernel.org/r/20210514093007.4117906-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210511134857.1581273-4-linmiaohe@huawei.com Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Signed-off-by: Miaohe Lin Reviewed-by: Yang Shi Cc: Alexey Dobriyan Cc: "Aneesh Kumar K . V" Cc: Anshuman Khandual Cc: David Hildenbrand Cc: Hugh Dickins Cc: Johannes Weiner Cc: Kirill A. Shutemov Cc: Matthew Wilcox Cc: Minchan Kim Cc: Ralph Campbell Cc: Rik van Riel Cc: Song Liu Cc: William Kucharski Cc: Zi Yan Cc: Mike Kravetz Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

mm/huge_memory.c: remove dedicated macro HPAGE_CACHE_INDEX_MASK

2021-07-14T14:56:50+00:00

[ Upstream commit b2bd53f18bb7f7cfc91b3bb527d7809376700a8e ] Patch series "Cleanup and fixup for huge_memory:, v3. This series contains cleanups to remove dedicated macro and remove unnecessary tlb_remove_page_size() for huge zero pmd. Also this adds missing read-only THP checking for transparent_hugepage_enabled() and avoids discarding hugepage if other processes are mapping it. More details can be found in the respective changelogs. Thi patch (of 5): Rewrite the pgoff checking logic to remove macro HPAGE_CACHE_INDEX_MASK which is only used here to simplify the code. Link: https://lkml.kernel.org/r/20210511134857.1581273-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210511134857.1581273-2-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reviewed-by: Yang Shi Reviewed-by: Anshuman Khandual Reviewed-by: David Hildenbrand Cc: Zi Yan Cc: William Kucharski Cc: Matthew Wilcox Cc: "Aneesh Kumar K . V" Cc: Ralph Campbell Cc: Song Liu Cc: Kirill A. Shutemov Cc: Rik van Riel Cc: Johannes Weiner Cc: Minchan Kim Cc: Hugh Dickins Cc: Alexey Dobriyan Cc: Mike Kravetz Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

mm/pmem: avoid inserting hugepage PTE entry with fsdax if hugepage support is disabled

2021-07-14T14:56:50+00:00

[ Upstream commit bae84953815793f68ddd8edeadd3f4e32676a2c8 ] Differentiate between hardware not supporting hugepages and user disabling THP via 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' For the devdax namespace, the kernel handles the above via the supported_alignment attribute and failing to initialize the namespace if the namespace align value is not supported on the platform. For the fsdax namespace, the kernel will continue to initialize the namespace. This can result in the kernel creating a huge pte entry even though the hardware don't support the same. We do want hugepage support with pmem even if the end-user disabled THP via sysfs file (/sys/kernel/mm/transparent_hugepage/enabled). Hence differentiate between hardware/firmware lacking support vs user-controlled disable of THP and prevent a huge fault if the hardware lacks hugepage support. Link: https://lkml.kernel.org/r/20210205023956.417587-1-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: Dan Williams Cc: "Kirill A . Shutemov" Cc: Jan Kara Cc: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

mm/thp: make is_huge_zero_pmd() safe and quicker

2021-06-30T12:47:27+00:00

commit 3b77e8c8cde581dadab9a0f1543a347e24315f11 upstream. Most callers of is_huge_zero_pmd() supply a pmd already verified present; but a few (notably zap_huge_pmd()) do not - it might be a pmd migration entry, in which the pfn is encoded differently from a present pmd: which might pass the is_huge_zero_pmd() test (though not on x86, since L1TF forced us to protect against that); or perhaps even crash in pmd_page() applied to a swap-like entry. Make it safe by adding pmd_present() check into is_huge_zero_pmd() itself; and make it quicker by saving huge_zero_pfn, so that is_huge_zero_pmd() will not need to do that pmd_page() lookup each time. __split_huge_pmd_locked() checked pmd_trans_huge() before: that worked, but is unnecessary now that is_huge_zero_pmd() checks present. Link: https://lkml.kernel.org/r/21ea9ca-a1f5-8b90-5e88-95fb1c49bbfa@google.com Fixes: e71769ae5260 ("mm: enable thp migration for shmem thp") Signed-off-by: Hugh Dickins Acked-by: Kirill A. Shutemov Reviewed-by: Yang Shi Cc: Alistair Popple Cc: Jan Kara Cc: Jue Wang Cc: "Matthew Wilcox (Oracle)" Cc: Miaohe Lin Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Peter Xu Cc: Ralph Campbell Cc: Shakeel Butt Cc: Wang Yugui Cc: Zi Yan Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

include/linux/huge_mm.h: remove mincore_huge_pmd declaration

2020-10-14T01:38:32+00:00

As mincore_huge_pmd() was dropped, remove the declaration from the header file. Signed-off-by: Yulei Zhang Signed-off-by: Andrew Morton Reviewed-by: Zi Yan Link: https://lkml.kernel.org/r/20200922083423.15074-1-yuleixzhang@tencent.com Signed-off-by: Linus Torvalds

mm: add thp_head

2020-08-15T02:56:56+00:00

This is like compound_head() but compiles away when CONFIG_TRANSPARENT_HUGEPAGE is not enabled. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Reviewed-by: William Kucharski Reviewed-by: Zi Yan Cc: David Hildenbrand Cc: Mike Kravetz Cc: "Kirill A. Shutemov" Link: http://lkml.kernel.org/r/20200629151959.15779-7-willy@infradead.org Signed-off-by: Linus Torvalds

mm: replace hpage_nr_pages with thp_nr_pages

2020-08-15T02:56:56+00:00

The thp prefix is more frequently used than hpage and we should be consistent between the various functions. [akpm@linux-foundation.org: fix mm/migrate.c] Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Reviewed-by: William Kucharski Reviewed-by: Zi Yan Cc: Mike Kravetz Cc: David Hildenbrand Cc: "Kirill A. Shutemov" Link: http://lkml.kernel.org/r/20200629151959.15779-6-willy@infradead.org Signed-off-by: Linus Torvalds

mm: add thp_size

2020-08-15T02:56:56+00:00

This function returns the number of bytes in a THP. It is like page_size(), but compiles to just PAGE_SIZE if CONFIG_TRANSPARENT_HUGEPAGE is disabled. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Reviewed-by: William Kucharski Reviewed-by: Zi Yan Cc: David Hildenbrand Cc: Mike Kravetz Cc: "Kirill A. Shutemov" Link: http://lkml.kernel.org/r/20200629151959.15779-5-willy@infradead.org Signed-off-by: Linus Torvalds