linux/mm/debug_vm_pgtable.c, branch v6.4

mm, treewide: redefine MAX_ORDER sanely

2023-04-06T02:42:46Z

MAX_ORDER currently defined as number of orders page allocator supports: user can ask buddy allocator for page order between 0 and MAX_ORDER-1. This definition is counter-intuitive and lead to number of bugs all over the kernel. Change the definition of MAX_ORDER to be inclusive: the range of orders user can ask from buddy allocator is 0..MAX_ORDER now. [kirill@shutemov.name: fix min() warning] Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box [akpm@linux-foundation.org: fix another min_t warning] [kirill@shutemov.name: fixups per Zi Yan] Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name [akpm@linux-foundation.org: fix underlining in docs] Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/ Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Reviewed-by: Michael Ellerman [powerpc] Cc: "Kirill A. Shutemov" Cc: Zi Yan Signed-off-by: Andrew Morton

mm: prefer xxx_page() alloc/free functions for order-0 pages

2023-03-28T23:20:16Z

Update instances of alloc_pages(..., 0), __get_free_pages(..., 0) and __free_pages(..., 0) to use alloc_page(), __get_free_page() and __free_page() respectively in core code. Link: https://lkml.kernel.org/r/50c48ca4789f1da2a65795f2346f5ae3eff7d665.1678710232.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Reviewed-by: David Hildenbrand Reviewed-by: Mike Rapoport (IBM) Acked-by: Mel Gorman Cc: Arnd Bergmann Cc: Christoph Hellwig Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Uladzislau Rezki (Sony) Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/debug_vm_pgtable: replace pte_mkhuge() with arch_make_huge_pte()

2023-03-28T23:20:11Z

Since the following commit arch_make_huge_pte() should be used directly in generic memory subsystem as a platform provided page table helper, instead of pte_mkhuge(). Change hugetlb_basic_tests() to call arch_make_huge_pte() directly, and update its relevant documentation entry as required. 'commit 16785bd77431 ("mm: merge pte_mkhuge() call into arch_make_huge_pte()")' Link: https://lkml.kernel.org/r/20230302114845.421674-1-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual Reported-by: Christophe Leroy Link: https://lore.kernel.org/all/1ea45095-0926-a56a-a273-816709e9075e@csgroup.eu/ Cc: Jonathan Corbet Cc: David Hildenbrand Cc: Mike Kravetz Cc: Mike Rapoport Signed-off-by: Andrew Morton

mm: remove __HAVE_ARCH_PTE_SWP_EXCLUSIVE

2023-02-03T06:33:11Z

__HAVE_ARCH_PTE_SWP_EXCLUSIVE is now supported by all architectures that support swp PTEs, so let's drop it. Link: https://lkml.kernel.org/r/20230113171026.582290-27-david@redhat.com Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton

mm/debug_vm_pgtable: more pte_swp_exclusive() sanity checks

2023-02-03T06:33:05Z

Patch series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". This is the follow-up on [1]: [PATCH v2 0/8] mm: COW fixes part 3: reliable GUP R/W FOLL_GET of anonymous pages After we implemented __HAVE_ARCH_PTE_SWP_EXCLUSIVE on most prominent enterprise architectures, implement __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all remaining architectures that support swap PTEs. This makes sure that exclusive anonymous pages will stay exclusive, even after they were swapped out -- for example, making GUP R/W FOLL_GET of anonymous pages reliable. Details can be found in [1]. This primarily fixes remaining known O_DIRECT memory corruptions that can happen on concurrent swapout, whereby we can lose DMA reads to a page (modifying the user page by writing to it). To verify, there are two test cases (requiring swap space, obviously): (1) The O_DIRECT+swapout test case [2] from Andrea. This test case tries triggering a race condition. (2) My vmsplice() test case [3] that tries to detect if the exclusive marker was lost during swapout, not relying on a race condition. For example, on 32bit x86 (with and without PAE), my test case fails without these patches: $ ./test_swp_exclusive FAIL: page was replaced during COW But succeeds with these patches: $ ./test_swp_exclusive PASS: page was not replaced during COW Why implement __HAVE_ARCH_PTE_SWP_EXCLUSIVE for all architectures, even the ones where swap support might be in a questionable state? This is the first step towards removing "readable_exclusive" migration entries, and instead using pte_swp_exclusive() also with (readable) migration entries instead (as suggested by Peter). The only missing piece for that is supporting pmd_swp_exclusive() on relevant architectures with THP migration support. As all relevant architectures now implement __HAVE_ARCH_PTE_SWP_EXCLUSIVE,, we can drop __HAVE_ARCH_PTE_SWP_EXCLUSIVE in the last patch. I tried cross-compiling all relevant setups and tested on x86 and sparc64 so far. CCing arch maintainers only on this cover letter and on the respective patch(es). [1] https://lkml.kernel.org/r/20220329164329.208407-1-david@redhat.com [2] https://gitlab.com/aarcange/kernel-testcases-for-v5.11/-/blob/main/page_count_do_wp_page-swap.c [3] https://gitlab.com/davidhildenbrand/scratchspace/-/blob/main/test_swp_exclusive.c This patch (of 26): We want to implement __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures. Let's extend our sanity checks, especially testing that our PTE bit does not affect: * is_swap_pte() -> pte_present() and pte_none() * the swap entry + type * pte_swp_soft_dirty() Especially, the pfn_pte() is dodgy when the swap PTE layout differs heavily from ordinary PTEs. Let's properly construct a swap PTE from swap type+offset. [david@redhat.com: fix build] Link: https://lkml.kernel.org/r/6aaad548-cf48-77fa-9d6c-db83d724b2eb@redhat.com Link: https://lkml.kernel.org/r/20230113171026.582290-1-david@redhat.com Link: https://lkml.kernel.org/r/20230113171026.582290-2-david@redhat.com Signed-off-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Anton Ivanov Cc: Cc: Borislav Petkov (AMD) Cc: Brian Cain Cc: Christophe Leroy Cc: Chris Zankel Cc: Dave Hansen Cc: David S. Miller Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Greg Ungerer Cc: Guo Ren Cc: Helge Deller Cc: H. Peter Anvin (Intel) Cc: Huacai Chen Cc: Hugh Dickins Cc: Ingo Molnar Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jason Gunthorpe Cc: Johannes Berg Cc: John Hubbard Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Mike Rapoport Cc: Nadav Amit Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Xu Cc: Richard Henderson Cc: Richard Weinberger Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Stefan Kristiansson Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Vineet Gupta Cc: Vlastimil Babka Cc: Xuerui Wang Cc: Yang Shi Cc: Yoshinori Sato Signed-off-by: Andrew Morton

mm/debug: use valid physical memory for pmd/pud tests

2023-01-19T01:12:59Z

The page table debug tests need a physical address to validate low-level page table manipulation with. The memory at this address is not actually touched, it just encoded in the page table entries at various levels during the tests only. Since the memory is not used, the code just picks the physical address of the start_kernel symbol. This value is then truncated to get a properly aligned address that is to be used for various tests. Because of the truncation, the address might not actually exist, or might not describe a complete huge page. That's not a problem for most tests, but the arch-specific code may check for attribute validity and consistency. The x86 version of {pud,pmd}_set_huge actually validates the MTRRs for the PMD/PUD range. This may fail with an address derived from start_kernel, depending on where the kernel was loaded and what the physical memory layout of the system is. This then leads to false negatives for the {pud,pmd}_set_huge tests. Avoid this by finding a properly aligned memory range that exists and is usable. If such a range is not found, skip the tests that needed it. [fvdl@google.com: v3] Link: https://lkml.kernel.org/r/20230110181208.1633879-1-fvdl@google.com Link: https://lkml.kernel.org/r/20230109174332.329366-1-fvdl@google.com Fixes: 399145f9eb6c ("mm/debug: add tests validating architecture page table helpers") Signed-off-by: Frank van der Linden Reviewed-by: Anshuman Khandual Signed-off-by: Andrew Morton

mm: remove unused savedwrite infrastructure

2022-11-30T23:58:49Z

NUMA hinting no longer uses savedwrite, let's rip it out. ... and while at it, drop __pte_write() and __pmd_write() on ppc64. Link: https://lkml.kernel.org/r/20221108174652.198904-7-david@redhat.com Signed-off-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Anshuman Khandual Cc: Dave Chinner Cc: Hugh Dickins Cc: Linus Torvalds Cc: Mel Gorman Cc: Michael Ellerman Cc: Mike Rapoport Cc: Nadav Amit Cc: Nicholas Piggin Cc: Peter Xu Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: debug_vm_pgtable: use VM_ACCESS_FLAGS

2022-11-09T01:37:19Z

Directly use VM_ACCESS_FLAGS instead VMFLAGS. Link: https://lkml.kernel.org/r/20221019034945.93081-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: Alex Deucher Cc: "Christian König" Cc: Daniel Vetter Cc: Dave Hansen Cc: David Airlie Cc: Dinh Nguyen Cc: Jarkko Sakkinen Cc: "Pan, Xinhui" Signed-off-by: Andrew Morton

docs: rename Documentation/vm to Documentation/mm

2022-06-27T19:52:53Z

so it will be consistent with code mm directory and with Documentation/admin-guide/mm and won't be confused with virtual machines. Signed-off-by: Mike Rapoport Suggested-by: Matthew Wilcox Tested-by: Ira Weiny Acked-by: Jonathan Corbet Acked-by: Wu XiangCheng

mm/debug_vm_pgtable: add tests for __HAVE_ARCH_PTE_SWP_EXCLUSIVE

2022-05-10T01:20:45Z

Let's test that __HAVE_ARCH_PTE_SWP_EXCLUSIVE works as expected. Link: https://lkml.kernel.org/r/20220329164329.208407-3-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Andrea Arcangeli Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Dave Hansen Cc: Don Dutile Cc: Gerald Schaefer Cc: Heiko Carstens Cc: Hugh Dickins Cc: Ingo Molnar Cc: Jan Kara Cc: Jann Horn Cc: Jason Gunthorpe Cc: John Hubbard Cc: "Kirill A. Shutemov" Cc: Liang Zhang Cc: Matthew Wilcox (Oracle) Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Cc: Oded Gabbay Cc: Oleg Nesterov Cc: Paul Mackerras Cc: Pedro Demarchi Gomes Cc: Peter Xu Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Will Deacon Signed-off-by: Andrew Morton