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* mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_wpOscar Salvador2024-05-111-1/+1
| | | | | | | | | | | | | | | | | commit 1cb9dc4b475c ("mm: hwpoison: support recovery from HugePage copy-on-write faults") added support to use the mc variants when coping hugetlb pages on CoW faults. Add the missing VM_FAULT_SET_HINDEX, so the right si_addr_lsb will be passed to userspace to report the extension of the faulty area. Link: https://lkml.kernel.org/r/20240509100148.22384-3-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Peter Xu <peterx@redhat.com> Acked-by: Axel Rasmussen <axelrasmussen@google.com> Cc: Liu Shixin <liushixin2@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_faultOscar Salvador2024-05-111-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "Minor fixups for hugetlb fault path". This series contains a couple of fixups for hugetlb_fault and hugetlb_wp respectively, where a VM_FAULT_SET_HINDEX call was missing. I did not bother with a Fixes tag because the missing piece here is that we will not report to userspace the right extension of the faulty area by adjusting struct kernel_siginfo.si_addr_lsb, but I do not consider that to be a big issue because I assume that userspace already knows the size of the mapping anyway. This patch (of 2): commit af19487f00f3 ("mm: make PTE_MARKER_SWAPIN_ERROR more general") added the code to handle pte_markers in hugetlb faulting path. In case of an UFFD_POISON event, a PTE_MARKER_POISONED will be created and we will return VM_FAULT_HWPOISON_LARGE upon detecting that in the fault path. Add the missing VM_FAULT_SET_HINDEX, so the right si_addr_lsb will be passed to userspace to report the extension of the faulty area. Link: https://lkml.kernel.org/r/20240509100148.22384-1-osalvador@suse.de Link: https://lkml.kernel.org/r/20240509100148.22384-2-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Peter Xu <peterx@redhat.com> Acked-by: Axel Rasmussen <axelrasmussen@google.com> Cc: Liu Shixin <liushixin2@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: align cma on allocation order, not demotion orderFrank van der Linden2024-05-071-1/+1
| | | | | | | | | | | | | | | Align the CMA area for hugetlb gigantic pages to their size, not the size that they can be demoted to. Otherwise there might be misaligned sections at the start and end of the CMA area that will never be used for hugetlb page allocations. Link: https://lkml.kernel.org/r/20240430161437.2100295-1-fvdl@google.com Fixes: a01f43901cfb ("hugetlb: be sure to free demoted CMA pages to CMA") Signed-off-by: Frank van der Linden <fvdl@google.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: document why hugetlb uses folio_mapcount() for COW reuse decisionsDavid Hildenbrand2024-05-071-0/+7
| | | | | | | | | | | | | | | | | | | Let's document why hugetlb still uses folio_mapcount() and is prone to leaking memory between processes, for example using vmsplice() that still uses FOLL_GET. More details can be found in [1], especially around how hugetlb pages cannot really be overcommitted, and why we don't particularly care about these vmsplice() leaks for hugetlb -- in contrast to ordinary memory. [1] https://lore.kernel.org/all/8b42a24d-caf0-46ef-9e15-0f88d47d2f21@redhat.com/ Link: https://lkml.kernel.org/r/20240502085259.103784-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Suggested-by: Peter Xu <peterx@redhat.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: convert hugetlb_page_mapping_lock_write to folioMatthew Wilcox (Oracle)2024-05-051-3/+3
| | | | | | | | | | | | | | The page is only used to get the mapping, so the folio will do just as well. Both callers already have a folio available, so this saves a call to compound_head(). Link: https://lkml.kernel.org/r/20240412193510.2356957-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Jane Chu  <jane.chu@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: rename dissolve_free_huge_pages() to dissolve_free_hugetlb_folios()Sidhartha Kumar2024-05-051-1/+1
| | | | | | | | | | | | | | | | dissolve_free_huge_pages() only uses folios internally, rename it to dissolve_free_hugetlb_folios() and change the comments which reference it. [akpm@linux-foundation.org: remove unneeded `extern'] Link: https://lkml.kernel.org/r/20240412182139.120871-2-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: convert dissolve_free_huge_pages() to foliosSidhartha Kumar2024-05-051-9/+8
| | | | | | | | | | | | | | | | | | | | Allows us to rename dissolve_free_huge_pages() to dissolve_free_hugetlb_folio(). Convert one caller to pass in a folio directly and use page_folio() to convert the caller in mm/memory-failure. [sidhartha.kumar@oracle.com: remove unneeded `extern'] Link: https://lkml.kernel.org/r/71760ed4-e80d-493a-95ea-2545414b1aba@oracle.com [sidhartha.kumar@oracle.com: v2] Link: https://lkml.kernel.org/r/20240412182139.120871-1-sidhartha.kumar@oracle.com Link: https://lkml.kernel.org/r/20240411164756.261178-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: track mapcount of large folios in single valueDavid Hildenbrand2024-05-051-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's track the mapcount of large folios in a single value. The mapcount of a large folio currently corresponds to the sum of the entire mapcount and all page mapcounts. This sum is what we actually want to know in folio_mapcount() and it is also sufficient for implementing folio_mapped(). With PTE-mapped THP becoming more important and more widely used, we want to avoid looping over all pages of a folio just to obtain the mapcount of large folios. The comment "In the common case, avoid the loop when no pages mapped by PTE" in folio_total_mapcount() does no longer hold for mTHP that are always mapped by PTE. Further, we are planning on using folio_mapcount() more frequently, and might even want to remove page mapcounts for large folios in some kernel configs. Therefore, allow for reading the mapcount of large folios efficiently and atomically without looping over any pages. Maintain the mapcount also for hugetlb pages for simplicity. Use the new mapcount to implement folio_mapcount() and folio_mapped(). Make page_mapped() simply call folio_mapped(). We can now get rid of folio_large_is_mapped(). _nr_pages_mapped is now only used in rmap code and for debugging purposes. Keep folio_nr_pages_mapped() around, but document that its use should be limited to rmap internals and debugging purposes. This change implies one additional atomic add/sub whenever mapping/unmapping (parts of) a large folio. As we now batch RMAP operations for PTE-mapped THP during fork(), during unmap/zap, and when PTE-remapping a PMD-mapped THP, and we adjust the large mapcount for a PTE batch only once, the added overhead in the common case is small. Only when unmapping individual pages of a large folio (e.g., during COW), the overhead might be bigger in comparison, but it's essentially one additional atomic operation. Note that before the new mapcount would overflow, already our refcount would overflow: each mapping requires a folio reference. Extend the focumentation of folio_mapcount(). Link: https://lkml.kernel.org/r/20240409192301.907377-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Cc: Chris Zankel <chris@zankel.net> Cc: Hugh Dickins <hughd@google.com> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Richard Chang <richardycc@google.com> Cc: Rich Felker <dalias@libc.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: pass correct order_per_bit to cma_declare_contiguous_nidFrank van der Linden2024-04-251-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The hugetlb_cma code passes 0 in the order_per_bit argument to cma_declare_contiguous_nid (the alignment, computed using the page order, is correctly passed in). This causes a bit in the cma allocation bitmap to always represent a 4k page, making the bitmaps potentially very large, and slower. It would create bitmaps that would be pretty big. E.g. for a 4k page size on x86, hugetlb_cma=64G would mean a bitmap size of (64G / 4k) / 8 == 2M. With HUGETLB_PAGE_ORDER as order_per_bit, as intended, this would be (64G / 2M) / 8 == 4k. So, that's quite a difference. Also, this restricted the hugetlb_cma area to ((PAGE_SIZE << MAX_PAGE_ORDER) * 8) * PAGE_SIZE (e.g. 128G on x86) , since bitmap_alloc uses normal page allocation, and is thus restricted by MAX_PAGE_ORDER. Specifying anything about that would fail the CMA initialization. So, correctly pass in the order instead. Link: https://lkml.kernel.org/r/20240404162515.527802-2-fvdl@google.com Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma") Signed-off-by: Frank van der Linden <fvdl@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: convert hugetlb_wp() to use struct vm_faultVishal Moola (Oracle)2024-04-251-32/+32
| | | | | | | | | | | | | | | hugetlb_wp() can use the struct vm_fault passed in from hugetlb_fault(). This alleviates the stack by consolidating 5 variables into a single struct. [vishal.moola@gmail.com: simplify hugetlb_wp() arguments] Link: https://lkml.kernel.org/r/ZhQtoFNZBNwBCeXn@fedora Link: https://lkml.kernel.org/r/20240401202651.31440-4-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: convert hugetlb_no_page() to use struct vm_faultVishal Moola (Oracle)2024-04-251-32/+31
| | | | | | | | | | | | | | | hugetlb_no_page() can use the struct vm_fault passed in from hugetlb_fault(). This alleviates the stack by consolidating 7 variables into a single struct. [vishal.moola@gmail.com: simplify hugetlb_no_page() arguments] Link: https://lkml.kernel.org/r/ZhQtN8y5zud8iI1u@fedora Link: https://lkml.kernel.org/r/20240401202651.31440-3-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: convert hugetlb_fault() to use struct vm_faultVishal Moola (Oracle)2024-04-251-43/+41
| | | | | | | | | | | | | | | | | | | | | | | | Patch series "Hugetlb fault path to use struct vm_fault", v2. This patchset converts the hugetlb fault path to use struct vm_fault. This helps make the code more readable, and alleviates the stack by allowing us to consolidate many fault-related variables into an individual pointer. This patch (of 3): Now that hugetlb_fault() has a vm_fault available for fault tracking, use it throughout. This cleans up the code by removing 2 variables, and prepares hugetlb_fault() to take in a struct vm_fault argument. Link: https://lkml.kernel.org/r/20240401202651.31440-1-vishal.moola@gmail.com Link: https://lkml.kernel.org/r/20240401202651.31440-2-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Muchun Song <muchun.song@linux.dev> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: convert alloc_buddy_hugetlb_folio to use a folioMatthew Wilcox (Oracle)2024-04-251-17/+16
| | | | | | | | | | | | | | While this function returned a folio, it was still using __alloc_pages() and __free_pages(). Use __folio_alloc() and put_folio() instead. This actually removes a call to compound_head(), but more importantly, it prepares us for the move to memdescs. Link: https://lkml.kernel.org/r/20240402200656.913841-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* memory: remove the now superfluous sentinel element from ctl_table arrayJoel Granados2024-04-251-1/+0
| | | | | | | | | | | | | | | | This commit comes at the tail end of a greater effort to remove the empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) Remove sentinel from all files under mm/ that register a sysctl table. Link: https://lkml.kernel.org/r/20240328-jag-sysctl_remset_misc-v1-1-47c1463b3af2@samsung.com Signed-off-by: Joel Granados <j.granados@samsung.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/gup: handle hugetlb in the generic follow_page_mask codePeter Xu2024-04-251-71/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now follow_page() is ready to handle hugetlb pages in whatever form, and over all architectures. Switch to the generic code path. Time to retire hugetlb_follow_page_mask(), following the previous retirement of follow_hugetlb_page() in 4849807114b8. There may be a slight difference of how the loops run when processing slow GUP over a large hugetlb range on cont_pte/cont_pmd supported archs: each loop of __get_user_pages() will resolve one pgtable entry with the patch applied, rather than relying on the size of hugetlb hstate, the latter may cover multiple entries in one loop. A quick performance test on an aarch64 VM on M1 chip shows 15% degrade over a tight loop of slow gup after the path switched. That shouldn't be a problem because slow-gup should not be a hot path for GUP in general: when page is commonly present, fast-gup will already succeed, while when the page is indeed missing and require a follow up page fault, the slow gup degrade will probably buried in the fault paths anyway. It also explains why slow gup for THP used to be very slow before 57edfcfd3419 ("mm/gup: accelerate thp gup even for "pages != NULL"") lands, the latter not part of a performance analysis but a side benefit. If the performance will be a concern, we can consider handle CONT_PTE in follow_page(). Before that is justified to be necessary, keep everything clean and simple. Link: https://lkml.kernel.org/r/20240327152332.950956-14-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: 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: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> 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>
* mm/hugetlb: declare hugetlbfs_pagecache_present() non-staticPeter Xu2024-04-251-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | It will be used outside hugetlb.c soon. Link: https://lkml.kernel.org/r/20240327152332.950956-3-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Tested-by: Ryan Roberts <ryan.roberts@arm.com> 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: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> 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>
* mm: convert arch_clear_hugepage_flags to take a folioMatthew Wilcox (Oracle)2024-04-251-2/+2
| | | | | | | | | | | | | | All implementations that aren't no-ops just set a bit in the flags, and we want to use the folio flags rather than the page flags for that. Rename it to arch_clear_hugetlb_flags() while we're touching it so nobody thinks it's used for THP. [willy@infradead.org: fix arm64 build] Link: https://lkml.kernel.org/r/ZgQvNKGdlDkwhQEX@casper.infradead.org Link: https://lkml.kernel.org/r/20240326171045.410737-8-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: hugetlb: make the hugetlb migration strategy consistentBaolin Wang2024-04-251-2/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As discussed in previous thread [1], there is an inconsistency when handing hugetlb migration. When handling the migration of freed hugetlb, it prevents fallback to other NUMA nodes in alloc_and_dissolve_hugetlb_folio(). However, when dealing with in-use hugetlb, it allows fallback to other NUMA nodes in alloc_hugetlb_folio_nodemask(), which can break the per-node hugetlb pool and might result in unexpected failures when node bound workloads doesn't get what is asssumed available. To make hugetlb migration strategy more clear, we should list all the scenarios of hugetlb migration and analyze whether allocation fallback is permitted: 1) Memory offline: will call dissolve_free_huge_pages() to free the freed hugetlb, and call do_migrate_range() to migrate the in-use hugetlb. Both can break the per-node hugetlb pool, but as this is an explicit offlining operation, no better choice. So should allow the hugetlb allocation fallback. 2) Memory failure: same as memory offline. Should allow fallback to a different node might be the only option to handle it, otherwise the impact of poisoned memory can be amplified. 3) Longterm pinning: will call migrate_longterm_unpinnable_pages() to migrate in-use and not-longterm-pinnable hugetlb, which can break the per-node pool. But we should fail to longterm pinning if can not allocate on current node to avoid breaking the per-node pool. 4) Syscalls (mbind, migrate_pages, move_pages): these are explicit users operation to move pages to other nodes, so fallback to other nodes should not be prohibited. 5) alloc_contig_range: used by CMA allocation and virtio-mem fake-offline to allocate given range of pages. Now the freed hugetlb migration is not allowed to fallback, to keep consistency, the in-use hugetlb migration should be also not allowed to fallback. 6) alloc_contig_pages: used by kfence, pgtable_debug etc. The strategy should be consistent with that of alloc_contig_range(). Based on the analysis of the various scenarios above, introducing a new helper to determine whether fallback is permitted according to the migration reason.. [1] https://lore.kernel.org/all/6f26ce22d2fcd523418a085f2c588fe0776d46e7.1706794035.git.baolin.wang@linux.alibaba.com/ Link: https://lkml.kernel.org/r/3519fcd41522817307a05b40fb551e2e17e68101.1709719720.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: remove mention of destructorsMatthew Wilcox (Oracle)2024-04-251-24/+16
| | | | | | | | | | | | | | | | We no longer have destructors or dtors, merely a page flag (technically a page type flag, but that's an implementation detail). Remove __clear_hugetlb_destructor, fix up comments and the occasional variable name. Link: https://lkml.kernel.org/r/20240321142448.1645400-10-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: always initialise folio->_deferred_listMatthew Wilcox (Oracle)2024-04-251-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "Various significant MM patches". These patches all interact in annoying ways which make it tricky to send them out in any way other than a big batch, even though there's not really an overarching theme to connect them. The big effects of this patch series are: - folio_test_hugetlb() becomes reliable, even when called without a page reference - We free up PG_slab, and we could always use more page flags - We no longer need to check PageSlab before calling page_mapcount() This patch (of 9): For compound pages which are at least order-2 (and hence have a deferred_list), initialise it and then we can check at free that the page is not part of a deferred list. We recently found this useful to rule out a source of corruption. [peterx@redhat.com: always initialise folio->_deferred_list] Link: https://lkml.kernel.org/r/20240417211836.2742593-2-peterx@redhat.com Link: https://lkml.kernel.org/r/20240321142448.1645400-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240321142448.1645400-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: fix DEBUG_LOCKS_WARN_ON(1) when dissolve_free_hugetlb_folio()Miaohe Lin2024-04-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When I did memory failure tests recently, below warning occurs: DEBUG_LOCKS_WARN_ON(1) WARNING: CPU: 8 PID: 1011 at kernel/locking/lockdep.c:232 __lock_acquire+0xccb/0x1ca0 Modules linked in: mce_inject hwpoison_inject CPU: 8 PID: 1011 Comm: bash Kdump: loaded Not tainted 6.9.0-rc3-next-20240410-00012-gdb69f219f4be #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 RIP: 0010:__lock_acquire+0xccb/0x1ca0 RSP: 0018:ffffa7a1c7fe3bd0 EFLAGS: 00000082 RAX: 0000000000000000 RBX: eb851eb853975fcf RCX: ffffa1ce5fc1c9c8 RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffffa1ce5fc1c9c0 RBP: ffffa1c6865d3280 R08: ffffffffb0f570a8 R09: 0000000000009ffb R10: 0000000000000286 R11: ffffffffb0f2ad50 R12: ffffa1c6865d3d10 R13: ffffa1c6865d3c70 R14: 0000000000000000 R15: 0000000000000004 FS: 00007ff9f32aa740(0000) GS:ffffa1ce5fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff9f3134ba0 CR3: 00000008484e4000 CR4: 00000000000006f0 Call Trace: <TASK> lock_acquire+0xbe/0x2d0 _raw_spin_lock_irqsave+0x3a/0x60 hugepage_subpool_put_pages.part.0+0xe/0xc0 free_huge_folio+0x253/0x3f0 dissolve_free_huge_page+0x147/0x210 __page_handle_poison+0x9/0x70 memory_failure+0x4e6/0x8c0 hard_offline_page_store+0x55/0xa0 kernfs_fop_write_iter+0x12c/0x1d0 vfs_write+0x380/0x540 ksys_write+0x64/0xe0 do_syscall_64+0xbc/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff9f3114887 RSP: 002b:00007ffecbacb458 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007ff9f3114887 RDX: 000000000000000c RSI: 0000564494164e10 RDI: 0000000000000001 RBP: 0000564494164e10 R08: 00007ff9f31d1460 R09: 000000007fffffff R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000c R13: 00007ff9f321b780 R14: 00007ff9f3217600 R15: 00007ff9f3216a00 </TASK> Kernel panic - not syncing: kernel: panic_on_warn set ... CPU: 8 PID: 1011 Comm: bash Kdump: loaded Not tainted 6.9.0-rc3-next-20240410-00012-gdb69f219f4be #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> panic+0x326/0x350 check_panic_on_warn+0x4f/0x50 __warn+0x98/0x190 report_bug+0x18e/0x1a0 handle_bug+0x3d/0x70 exc_invalid_op+0x18/0x70 asm_exc_invalid_op+0x1a/0x20 RIP: 0010:__lock_acquire+0xccb/0x1ca0 RSP: 0018:ffffa7a1c7fe3bd0 EFLAGS: 00000082 RAX: 0000000000000000 RBX: eb851eb853975fcf RCX: ffffa1ce5fc1c9c8 RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffffa1ce5fc1c9c0 RBP: ffffa1c6865d3280 R08: ffffffffb0f570a8 R09: 0000000000009ffb R10: 0000000000000286 R11: ffffffffb0f2ad50 R12: ffffa1c6865d3d10 R13: ffffa1c6865d3c70 R14: 0000000000000000 R15: 0000000000000004 lock_acquire+0xbe/0x2d0 _raw_spin_lock_irqsave+0x3a/0x60 hugepage_subpool_put_pages.part.0+0xe/0xc0 free_huge_folio+0x253/0x3f0 dissolve_free_huge_page+0x147/0x210 __page_handle_poison+0x9/0x70 memory_failure+0x4e6/0x8c0 hard_offline_page_store+0x55/0xa0 kernfs_fop_write_iter+0x12c/0x1d0 vfs_write+0x380/0x540 ksys_write+0x64/0xe0 do_syscall_64+0xbc/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff9f3114887 RSP: 002b:00007ffecbacb458 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007ff9f3114887 RDX: 000000000000000c RSI: 0000564494164e10 RDI: 0000000000000001 RBP: 0000564494164e10 R08: 00007ff9f31d1460 R09: 000000007fffffff R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000c R13: 00007ff9f321b780 R14: 00007ff9f3217600 R15: 00007ff9f3216a00 </TASK> After git bisecting and digging into the code, I believe the root cause is that _deferred_list field of folio is unioned with _hugetlb_subpool field. In __update_and_free_hugetlb_folio(), folio->_deferred_list is initialized leading to corrupted folio->_hugetlb_subpool when folio is hugetlb. Later free_huge_folio() will use _hugetlb_subpool and above warning happens. But it is assumed hugetlb flag must have been cleared when calling folio_put() in update_and_free_hugetlb_folio(). This assumption is broken due to below race: CPU1 CPU2 dissolve_free_huge_page update_and_free_pages_bulk update_and_free_hugetlb_folio hugetlb_vmemmap_restore_folios folio_clear_hugetlb_vmemmap_optimized clear_flag = folio_test_hugetlb_vmemmap_optimized if (clear_flag) <-- False, it's already cleared. __folio_clear_hugetlb(folio) <-- Hugetlb is not cleared. folio_put free_huge_folio <-- free_the_page is expected. list_for_each_entry() __folio_clear_hugetlb <-- Too late. Fix this issue by checking whether folio is hugetlb directly instead of checking clear_flag to close the race window. Link: https://lkml.kernel.org/r/20240419085819.1901645-1-linmiaohe@huawei.com Fixes: 32c877191e02 ("hugetlb: do not clear hugetlb dtor until allocating vmemmap") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: check for anon_vma prior to folio allocationVishal Moola (Oracle)2024-04-241-4/+7
| | | | | | | | | | | | | | | | | | | Commit 9acad7ba3e25 ("hugetlb: use vmf_anon_prepare() instead of anon_vma_prepare()") may bailout after allocating a folio if we do not hold the mmap lock. When this occurs, vmf_anon_prepare() will release the vma lock. Hugetlb then attempts to call restore_reserve_on_error(), which depends on the vma lock being held. We can move vmf_anon_prepare() prior to the folio allocation in order to avoid calling restore_reserve_on_error() without the vma lock. Link: https://lkml.kernel.org/r/ZiFqSrSRLhIV91og@fedora Fixes: 9acad7ba3e25 ("hugetlb: use vmf_anon_prepare() instead of anon_vma_prepare()") Reported-by: syzbot+ad1b592fc4483655438b@syzkaller.appspotmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: turn folio_test_hugetlb into a PageTypeMatthew Wilcox (Oracle)2024-04-241-19/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current folio_test_hugetlb() can be fooled by a concurrent folio split into returning true for a folio which has never belonged to hugetlbfs. This can't happen if the caller holds a refcount on it, but we have a few places (memory-failure, compaction, procfs) which do not and should not take a speculative reference. Since hugetlb pages do not use individual page mapcounts (they are always fully mapped and use the entire_mapcount field to record the number of mappings), the PageType field is available now that page_mapcount() ignores the value in this field. In compaction and with CONFIG_DEBUG_VM enabled, the current implementation can result in an oops, as reported by Luis. This happens since 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR") effectively added some VM_BUG_ON() checks in the PageHuge() testing path. [willy@infradead.org: update vmcoreinfo] Link: https://lkml.kernel.org/r/ZgGZUvsdhaT1Va-T@casper.infradead.org Link: https://lkml.kernel.org/r/20240321142448.1645400-6-willy@infradead.org Fixes: 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Luis Chamberlain <mcgrof@kernel.org> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218227 Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: fix missing hugetlb_lock for resv unchargePeter Xu2024-04-241-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | There is a recent report on UFFDIO_COPY over hugetlb: https://lore.kernel.org/all/000000000000ee06de0616177560@google.com/ 350: lockdep_assert_held(&hugetlb_lock); Should be an issue in hugetlb but triggered in an userfault context, where it goes into the unlikely path where two threads modifying the resv map together. Mike has a fix in that path for resv uncharge but it looks like the locking criteria was overlooked: hugetlb_cgroup_uncharge_folio_rsvd() will update the cgroup pointer, so it requires to be called with the lock held. Link: https://lkml.kernel.org/r/20240417211836.2742593-3-peterx@redhat.com Fixes: 79aa925bf239 ("hugetlb_cgroup: fix reservation accounting") Signed-off-by: Peter Xu <peterx@redhat.com> Reported-by: syzbot+4b8077a5fccc61c385a1@syzkaller.appspotmail.com Reviewed-by: Mina Almasry <almasrymina@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/userfaultfd: allow hugetlb change protection upon poison entryPeter Xu2024-04-161-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After UFFDIO_POISON, there can be two kinds of hugetlb pte markers, either the POISON one or UFFD_WP one. Allow change protection to run on a poisoned marker just like !hugetlb cases, ignoring the marker irrelevant of the permission. Here the two bits are mutual exclusive. For example, when install a poisoned entry it must not be UFFD_WP already (by checking pte_none() before such install). And it also means if UFFD_WP is set there must have no POISON bit set. It makes sense because UFFD_WP is a bit to reflect permission, and permissions do not apply if the pte is poisoned and destined to sigbus. So here we simply check uffd_wp bit set first, do nothing otherwise. Attach the Fixes to UFFDIO_POISON work, as before that it should not be possible to have poison entry for hugetlb (e.g., hugetlb doesn't do swap, so no chance of swapin errors). Link: https://lkml.kernel.org/r/20240405231920.1772199-1-peterx@redhat.com Link: https://lore.kernel.org/r/000000000000920d5e0615602dd1@google.com Fixes: fc71884a5f59 ("mm: userfaultfd: add new UFFDIO_POISON ioctl") Signed-off-by: Peter Xu <peterx@redhat.com> Reported-by: syzbot+b07c8ac8eee3d4d8440f@syzkaller.appspotmail.com Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Axel Rasmussen <axelrasmussen@google.com> Cc: <stable@vger.kernel.org> [6.6+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: add an explicit smp_wmb() to UFFDIO_CONTINUEJames Houghton2024-03-121-4/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | Users of UFFDIO_CONTINUE may reasonably assume that a write memory barrier is included as part of UFFDIO_CONTINUE. That is, a user may believe that all writes it has done to a page that it is now UFFDIO_CONTINUE'ing are guaranteed to be visible to anyone subsequently reading the page through the newly mapped virtual memory region. Today, such a user happens to be correct. mmget_not_zero(), for example, is called as part of UFFDIO_CONTINUE (and comes before any PTE updates), and it implicitly gives us a write barrier. To be resilient against future changes, include an explicit smp_wmb(). While we're at it, optimize the smp_wmb() that is already incidentally present for the HugeTLB case. Merely making a syscall does not generally imply the memory ordering constraints that we need (including on x86). Link: https://lkml.kernel.org/r/20240307010250.3847179-1-jthoughton@google.com Signed-off-by: James Houghton <jthoughton@google.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: constify more page/folio testsMatthew Wilcox (Oracle)2024-03-061-2/+2
| | | | | | | | | | Constify the flag tests that aren't automatically generated and the tests that look like flag tests but are more complicated. Link: https://lkml.kernel.org/r/20240227192337.757313-8-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: parallelize 1G hugetlb initializationGang Li2024-03-061-8/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Optimizing the initialization speed of 1G huge pages through parallelization. 1G hugetlbs are allocated from bootmem, a process that is already very fast and does not currently require optimization. Therefore, we focus on parallelizing only the initialization phase in `gather_bootmem_prealloc`. Here are some test results: test case no patch(ms) patched(ms) saved ------------------- -------------- ------------- -------- 256c2T(4 node) 1G 4745 2024 57.34% 128c1T(2 node) 1G 3358 1712 49.02% 12T 1G 77000 18300 76.23% [akpm@linux-foundation.org: s/initialied/initialized/, per Alexey] Link: https://lkml.kernel.org/r/20240222140422.393911-9-gang.li@linux.dev Signed-off-by: Gang Li <ligang.bdlg@bytedance.com> Tested-by: David Rientjes <rientjes@google.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: parallelize 2M hugetlb allocation and initializationGang Li2024-03-061-17/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | By distributing both the allocation and the initialization tasks across multiple threads, the initialization of 2M hugetlb will be faster, thereby improving the boot speed. Here are some test results: test case no patch(ms) patched(ms) saved ------------------- -------------- ------------- -------- 256c2T(4 node) 2M 3336 1051 68.52% 128c1T(2 node) 2M 1943 716 63.15% Link: https://lkml.kernel.org/r/20240222140422.393911-8-gang.li@linux.dev Signed-off-by: Gang Li <ligang.bdlg@bytedance.com> Tested-by: David Rientjes <rientjes@google.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: pass *next_nid_to_alloc directly to for_each_node_mask_to_allocGang Li2024-03-061-10/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | With parallelization of hugetlb allocation across different threads, each thread works on a differnet node to allocate pages from, instead of all allocating from a common node h->next_nid_to_alloc. To address this, it's necessary to assign a separate next_nid_to_alloc for each thread. Consequently, the hstate_next_node_to_alloc and for_each_node_mask_to_alloc have been modified to directly accept a *next_nid_to_alloc parameter, ensuring thread-specific allocation and avoiding concurrent access issues. Link: https://lkml.kernel.org/r/20240222140422.393911-4-gang.li@linux.dev Signed-off-by: Gang Li <ligang.bdlg@bytedance.com> Tested-by: David Rientjes <rientjes@google.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: split hugetlb_hstate_alloc_pagesGang Li2024-03-061-44/+43
| | | | | | | | | | | | | | | | | | | | | | | | 1G and 2M huge pages have different allocation and initialization logic, which leads to subtle differences in parallelization. Therefore, it is appropriate to split hugetlb_hstate_alloc_pages into gigantic and non-gigantic. This patch has no functional changes. Link: https://lkml.kernel.org/r/20240222140422.393911-3-gang.li@linux.dev Signed-off-by: Gang Li <ligang.bdlg@bytedance.com> Tested-by: David Rientjes <rientjes@google.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: code clean for hugetlb_hstate_alloc_pagesGang Li2024-03-061-17/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "hugetlb: parallelize hugetlb page init on boot", v6. Introduction ------------ Hugetlb initialization during boot takes up a considerable amount of time. For instance, on a 2TB system, initializing 1,800 1GB huge pages takes 1-2 seconds out of 10 seconds. Initializing 11,776 1GB pages on a 12TB Intel host takes more than 1 minute[1]. This is a noteworthy figure. Inspired by [2] and [3], hugetlb initialization can also be accelerated through parallelization. Kernel already has infrastructure like padata_do_multithreaded, this patch uses it to achieve effective results by minimal modifications. [1] https://lore.kernel.org/all/783f8bac-55b8-5b95-eb6a-11a583675000@google.com/ [2] https://lore.kernel.org/all/20200527173608.2885243-1-daniel.m.jordan@oracle.com/ [3] https://lore.kernel.org/all/20230906112605.2286994-1-usama.arif@bytedance.com/ [4] https://lore.kernel.org/all/76becfc1-e609-e3e8-2966-4053143170b6@google.com/ max_threads ----------- This patch use `padata_do_multithreaded` like this: ``` job.max_threads = num_node_state(N_MEMORY) * multiplier; padata_do_multithreaded(&job); ``` To fully utilize the CPU, the number of parallel threads needs to be carefully considered. `max_threads = num_node_state(N_MEMORY)` does not fully utilize the CPU, so we need to multiply it by a multiplier. Tests below indicate that a multiplier of 2 significantly improves performance, and although larger values also provide improvements, the gains are marginal. multiplier 1 2 3 4 5 ------------ ------- ------- ------- ------- ------- 256G 2node 358ms 215ms 157ms 134ms 126ms 2T 4node 979ms 679ms 543ms 489ms 481ms 50G 2node 71ms 44ms 37ms 30ms 31ms Therefore, choosing 2 as the multiplier strikes a good balance between enhancing parallel processing capabilities and maintaining efficient resource management. Test result ----------- test case no patch(ms) patched(ms) saved ------------------- -------------- ------------- -------- 256c2T(4 node) 1G 4745 2024 57.34% 128c1T(2 node) 1G 3358 1712 49.02% 12T 1G 77000 18300 76.23% 256c2T(4 node) 2M 3336 1051 68.52% 128c1T(2 node) 2M 1943 716 63.15% This patch (of 8): The readability of `hugetlb_hstate_alloc_pages` is poor. By cleaning the code, its readability can be improved, facilitating future modifications. This patch extracts two functions to reduce the complexity of `hugetlb_hstate_alloc_pages` and has no functional changes. - hugetlb_hstate_alloc_pages_node_specific() to handle iterates through each online node and performs allocation if necessary. - hugetlb_hstate_alloc_pages_report() report error during allocation. And the value of h->max_huge_pages is updated accordingly. Link: https://lkml.kernel.org/r/20240222140422.393911-1-gang.li@linux.dev Link: https://lkml.kernel.org/r/20240222140422.393911-2-gang.li@linux.dev Signed-off-by: Gang Li <ligang.bdlg@bytedance.com> Tested-by: David Rientjes <rientjes@google.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: allow faults to be handled under the VMA lockVishal Moola (Oracle)2024-03-041-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | Hugetlb can now safely handle faults under the VMA lock, so allow it to do so. This patch may cause ltp hugemmap10 to "fail". Hugemmap10 tests hugetlb counters, and expects the counters to remain unchanged on failure to handle a fault. In hugetlb_no_page(), vmf_anon_prepare() may bailout with no anon_vma under the VMA lock after allocating a folio for the hugepage. In free_huge_folio(), this folio is completely freed on bailout iff there is a surplus of hugetlb pages. This will remove a folio off the freelist and decrement the number of hugepages while ltp expects these counters to remain unchanged on failure. Originally this could only happen due to OOM failures, but now it may also occur after we allocate a hugetlb folio without a suitable anon_vma under the VMA lock. This should only happen for the first freshly allocated hugepage in this vma. Link: https://lkml.kernel.org/r/20240221234732.187629-6-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: use vmf_anon_prepare() instead of anon_vma_prepare()Vishal Moola (Oracle)2024-03-041-9/+9
| | | | | | | | | | | | | | | | hugetlb_no_page() and hugetlb_wp() call anon_vma_prepare(). In preparation for hugetlb to safely handle faults under the VMA lock, use vmf_anon_prepare() here instead. Additionally, passing hugetlb_wp() the vm_fault struct from hugetlb_fault() works toward cleaning up the hugetlb code and function stack. Link: https://lkml.kernel.org/r/20240221234732.187629-5-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: pass struct vm_fault through to hugetlb_handle_userfault()Vishal Moola (Oracle)2024-03-041-29/+9
| | | | | | | | | | | | | | Now that hugetlb_fault() has a struct vm_fault, have hugetlb_handle_userfault() use it instead of creating one of its own. This lets us reduce the number of arguments passed to hugetlb_handle_userfault() from 7 to 3, cleaning up the code and stack. Link: https://lkml.kernel.org/r/20240221234732.187629-4-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb: move vm_fault declaration to the top of hugetlb_fault()Vishal Moola (Oracle)2024-03-041-13/+19
| | | | | | | | | | | | | | | | | hugetlb_fault() currently defines a vm_fault to pass to the generic handle_userfault() function. We can move this definition to the top of hugetlb_fault() so that it can be used throughout the rest of the hugetlb fault path. This will help cleanup a number of excess variables and function arguments throughout the stack. Also, since vm_fault already has space to store the page offset, use that instead and get rid of idx. Link: https://lkml.kernel.org/r/20240221234732.187629-3-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: move page order check inside hugetlb_cma_reserve()Anshuman Khandual2024-02-221-0/+7
| | | | | | | | | | | | | | | | All platforms could benefit from page order check against MAX_PAGE_ORDER before allocating a CMA area for gigantic hugetlb pages. Let's move this check from individual platforms to generic hugetlb. Link: https://lkml.kernel.org/r/20240209054221.1403364-1-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: hugetlb: improve the handling of hugetlb allocation failure for freed or ↵Baolin Wang2024-02-221-16/+16
| | | | | | | | | | | | | | | | | | | | | | | | in-use hugetlb alloc_and_dissolve_hugetlb_folio() preallocates a new hugetlb page before it takes hugetlb_lock. In 3 out of 4 cases the page is not really used and therefore the newly allocated page is just freed right away. This is wasteful and it might cause pre-mature failures in those cases. Address that by moving the allocation down to the only case (hugetlb page is really in the free pages pool). We need to drop hugetlb_lock to do so and therefore need to recheck the page state after regaining it. The patch is more of a cleanup than an actual fix to an existing problem. There are no known reports about pre-mature failures. Link: https://lkml.kernel.org/r/62890fd60b1ecd5bf1cdc476c973f60fe37aa0cb.1707181934.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Cc: David Hildenbrand <david@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: restore the reservation if neededBreno Leitao2024-02-221-0/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm/hugetlb: Restore the reservation", v2. This is a fix for a case where a backing huge page could stolen after madvise(MADV_DONTNEED). A full reproducer is in selftest. See https://lore.kernel.org/all/20240105155419.1939484-1-leitao@debian.org/ In order to test this patch, I instrumented the kernel with LOCKDEP and KASAN, and run the following tests, without any regression: * The self test that reproduces the problem * All mm hugetlb selftests SUMMARY: PASS=9 SKIP=0 FAIL=0 * All libhugetlbfs tests PASS: 0 86 FAIL: 0 0 This patch (of 2): Currently there is a bug that a huge page could be stolen, and when the original owner tries to fault in it, it causes a page fault. You can achieve that by: 1) Creating a single page echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages 2) mmap() the page above with MAP_HUGETLB into (void *ptr1). * This will mark the page as reserved 3) touch the page, which causes a page fault and allocates the page * This will move the page out of the free list. * It will also unreserved the page, since there is no more free page 4) madvise(MADV_DONTNEED) the page * This will free the page, but not mark it as reserved. 5) Allocate a secondary page with mmap(MAP_HUGETLB) into (void *ptr2). * it should fail, but, since there is no more available page. * But, since the page above is not reserved, this mmap() succeed. 6) Faulting at ptr1 will cause a SIGBUS * it will try to allocate a huge page, but there is none available A full reproducer is in selftest. See https://lore.kernel.org/all/20240105155419.1939484-1-leitao@debian.org/ Fix this by restoring the reserved page if necessary. These are the condition for the page restore: * The system is not using surplus pages. The goal is to reduce the surplus usage for this case. * If the VMA has the HPAGE_RESV_OWNER flag set, and is PRIVATE. This is safely checked using __vma_private_lock() * The page is anonymous Once this is scenario is found, set the `hugetlb_restore_reserve` bit in the folio. Then check if the resv reservations need to be adjusted later, done later, after the spinlock, since the vma_xxxx_reservation() might touch the file system lock. Link: https://lkml.kernel.org/r/20240205191843.4009640-1-leitao@debian.org Link: https://lkml.kernel.org/r/20240205191843.4009640-2-leitao@debian.org Signed-off-by: Breno Leitao <leitao@debian.org> Suggested-by: Rik van Riel <riel@surriel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* Merge tag 'mm-stable-2024-01-08-15-31' of ↵Linus Torvalds2024-01-091-13/+12
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "Many singleton patches against the MM code. The patch series which are included in this merge do the following: - Peng Zhang has done some mapletree maintainance work in the series 'maple_tree: add mt_free_one() and mt_attr() helpers' 'Some cleanups of maple tree' - In the series 'mm: use memmap_on_memory semantics for dax/kmem' Vishal Verma has altered the interworking between memory-hotplug and dax/kmem so that newly added 'device memory' can more easily have its memmap placed within that newly added memory. - Matthew Wilcox continues folio-related work (including a few fixes) in the patch series 'Add folio_zero_tail() and folio_fill_tail()' 'Make folio_start_writeback return void' 'Fix fault handler's handling of poisoned tail pages' 'Convert aops->error_remove_page to ->error_remove_folio' 'Finish two folio conversions' 'More swap folio conversions' - Kefeng Wang has also contributed folio-related work in the series 'mm: cleanup and use more folio in page fault' - Jim Cromie has improved the kmemleak reporting output in the series 'tweak kmemleak report format'. - In the series 'stackdepot: allow evicting stack traces' Andrey Konovalov to permits clients (in this case KASAN) to cause eviction of no longer needed stack traces. - Charan Teja Kalla has fixed some accounting issues in the page allocator's atomic reserve calculations in the series 'mm: page_alloc: fixes for high atomic reserve caluculations'. - Dmitry Rokosov has added to the samples/ dorectory some sample code for a userspace memcg event listener application. See the series 'samples: introduce cgroup events listeners'. - Some mapletree maintanance work from Liam Howlett in the series 'maple_tree: iterator state changes'. - Nhat Pham has improved zswap's approach to writeback in the series 'workload-specific and memory pressure-driven zswap writeback'. - DAMON/DAMOS feature and maintenance work from SeongJae Park in the series 'mm/damon: let users feed and tame/auto-tune DAMOS' 'selftests/damon: add Python-written DAMON functionality tests' 'mm/damon: misc updates for 6.8' - Yosry Ahmed has improved memcg's stats flushing in the series 'mm: memcg: subtree stats flushing and thresholds'. - In the series 'Multi-size THP for anonymous memory' Ryan Roberts has added a runtime opt-in feature to transparent hugepages which improves performance by allocating larger chunks of memory during anonymous page faults. - Matthew Wilcox has also contributed some cleanup and maintenance work against eh buffer_head code int he series 'More buffer_head cleanups'. - Suren Baghdasaryan has done work on Andrea Arcangeli's series 'userfaultfd move option'. UFFDIO_MOVE permits userspace heap compaction algorithms to move userspace's pages around rather than UFFDIO_COPY'a alloc/copy/free. - Stefan Roesch has developed a 'KSM Advisor', in the series 'mm/ksm: Add ksm advisor'. This is a governor which tunes KSM's scanning aggressiveness in response to userspace's current needs. - Chengming Zhou has optimized zswap's temporary working memory use in the series 'mm/zswap: dstmem reuse optimizations and cleanups'. - Matthew Wilcox has performed some maintenance work on the writeback code, both code and within filesystems. The series is 'Clean up the writeback paths'. - Andrey Konovalov has optimized KASAN's handling of alloc and free stack traces for secondary-level allocators, in the series 'kasan: save mempool stack traces'. - Andrey also performed some KASAN maintenance work in the series 'kasan: assorted clean-ups'. - David Hildenbrand has gone to town on the rmap code. Cleanups, more pte batching, folio conversions and more. See the series 'mm/rmap: interface overhaul'. - Kinsey Ho has contributed some maintenance work on the MGLRU code in the series 'mm/mglru: Kconfig cleanup'. - Matthew Wilcox has contributed lruvec page accounting code cleanups in the series 'Remove some lruvec page accounting functions'" * tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (361 commits) mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER mm, treewide: introduce NR_PAGE_ORDERS selftests/mm: add separate UFFDIO_MOVE test for PMD splitting selftests/mm: skip test if application doesn't has root privileges selftests/mm: conform test to TAP format output selftests: mm: hugepage-mmap: conform to TAP format output selftests/mm: gup_test: conform test to TAP format output mm/selftests: hugepage-mremap: conform test to TAP format output mm/vmstat: move pgdemote_* out of CONFIG_NUMA_BALANCING mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large mm/memcontrol: remove __mod_lruvec_page_state() mm/khugepaged: use a folio more in collapse_file() slub: use a folio in __kmalloc_large_node slub: use folio APIs in free_large_kmalloc() slub: use alloc_pages_node() in alloc_slab_page() mm: remove inc/dec lruvec page state functions mm: ratelimit stat flush from workingset shrinker kasan: stop leaking stack trace handles mm/mglru: remove CONFIG_TRANSPARENT_HUGEPAGE mm/mglru: add dummy pmd_dirty() ...
| * mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDERKirill A. Shutemov2024-01-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely") has changed the definition of MAX_ORDER to be inclusive. This has caused issues with code that was not yet upstream and depended on the previous definition. To draw attention to the altered meaning of the define, rename MAX_ORDER to MAX_PAGE_ORDER. Link: https://lkml.kernel.org/r/20231228144704.14033-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm/rmap: introduce and use hugetlb_try_dup_anon_rmap()David Hildenbrand2023-12-291-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hugetlb rmap handling differs quite a lot from "ordinary" rmap code. For example, hugetlb currently only supports entire mappings, and treats any mapping as mapped using a single "logical PTE". Let's move it out of the way so we can overhaul our "ordinary" rmap. implementation/interface. So let's introduce and use hugetlb_try_dup_anon_rmap() to make all hugetlb handling use dedicated hugetlb_* rmap functions. Add sanity checks that we end up with the right folios in the right functions. Note that is_device_private_page() does not apply to hugetlb. Link: https://lkml.kernel.org/r/20231220224504.646757-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm/rmap: introduce and use hugetlb_add_file_rmap()David Hildenbrand2023-12-291-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hugetlb rmap handling differs quite a lot from "ordinary" rmap code. For example, hugetlb currently only supports entire mappings, and treats any mapping as mapped using a single "logical PTE". Let's move it out of the way so we can overhaul our "ordinary" rmap. implementation/interface. Right now we're using page_dup_file_rmap() in some cases where "ordinary" rmap code would have used page_add_file_rmap(). So let's introduce and use hugetlb_add_file_rmap() instead. We won't be adding a "hugetlb_dup_file_rmap()" functon for the fork() case, as it would be doing the same: "dup" is just an optimization for "add". What remains is a single page_dup_file_rmap() call in fork() code. Add sanity checks that we end up with the right folios in the right functions. Link: https://lkml.kernel.org/r/20231220224504.646757-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm/rmap: introduce and use hugetlb_remove_rmap()David Hildenbrand2023-12-291-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hugetlb rmap handling differs quite a lot from "ordinary" rmap code. For example, hugetlb currently only supports entire mappings, and treats any mapping as mapped using a single "logical PTE". Let's move it out of the way so we can overhaul our "ordinary" rmap. implementation/interface. Let's introduce and use hugetlb_remove_rmap() and remove the hugetlb code from page_remove_rmap(). This effectively removes one check on the small-folio path as well. Add sanity checks that we end up with the right folios in the right functions. Note: all possible candidates that need care are page_remove_rmap() that pass compound=true. Link: https://lkml.kernel.org/r/20231220224504.646757-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Hugh Dickins <hughd@google.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm/rmap: rename hugepage_add* to hugetlb_add*David Hildenbrand2023-12-291-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm/rmap: interface overhaul", v2. This series overhauls the rmap interface, to get rid of the "bool compound" / RMAP_COMPOUND parameter with the goal of making the interface less error prone, more future proof, and more natural to extend to "batching". Also, this converts the interface to always consume folio+subpage, which speeds up operations on large folios. Further, this series adds PTE-batching variants for 4 rmap functions, whereby only folio_add_anon_rmap_ptes() is used for batching in this series when PTE-remapping a PMD-mapped THP. folio_remove_rmap_ptes(), folio_try_dup_anon_rmap_ptes() and folio_dup_file_rmap_ptes() will soon come in handy[1,2]. This series performs a lot of folio conversion along the way. Most of the added LOC in the diff are only due to documentation. As we're moving to a pte/pmd interface where we clearly express the mapping granularity we are dealing with, we first get the remainder of hugetlb out of the way, as it is special and expected to remain special: it treats everything as a "single logical PTE" and only currently allows entire mappings. Even if we'd ever support partial mappings, I strongly assume the interface and implementation will still differ heavily: hopefull we can avoid working on subpages/subpage mapcounts completely and only add a "count" parameter for them to enable batching. New (extended) hugetlb interface that operates on entire folio: * hugetlb_add_new_anon_rmap() -> Already existed * hugetlb_add_anon_rmap() -> Already existed * hugetlb_try_dup_anon_rmap() * hugetlb_try_share_anon_rmap() * hugetlb_add_file_rmap() * hugetlb_remove_rmap() New "ordinary" interface for small folios / THP:: * folio_add_new_anon_rmap() -> Already existed * folio_add_anon_rmap_[pte|ptes|pmd]() * folio_try_dup_anon_rmap_[pte|ptes|pmd]() * folio_try_share_anon_rmap_[pte|pmd]() * folio_add_file_rmap_[pte|ptes|pmd]() * folio_dup_file_rmap_[pte|ptes|pmd]() * folio_remove_rmap_[pte|ptes|pmd]() folio_add_new_anon_rmap() will always map at the largest granularity possible (currently, a single PMD to cover a PMD-sized THP). Could be extended if ever required. In the future, we might want "_pud" variants and eventually "_pmds" variants for batching. I ran some simple microbenchmarks on an Intel(R) Xeon(R) Silver 4210R: measuring munmap(), fork(), cow, MADV_DONTNEED on each PTE ... and PTE remapping PMD-mapped THPs on 1 GiB of memory. For small folios, there is barely a change (< 1% improvement for me). For PTE-mapped THP: * PTE-remapping a PMD-mapped THP is more than 10% faster. * fork() is more than 4% faster. * MADV_DONTNEED is 2% faster * COW when writing only a single byte on a COW-shared PTE is 1% faster * munmap() barely changes (< 1%). [1] https://lkml.kernel.org/r/20230810103332.3062143-1-ryan.roberts@arm.com [2] https://lkml.kernel.org/r/20231204105440.61448-1-ryan.roberts@arm.com This patch (of 40): Let's just call it "hugetlb_". Yes, it's all already inconsistent and confusing because we have a lot of "hugepage_" functions for legacy reasons. But "hugetlb" cannot possibly be confused with transparent huge pages, and it matches "hugetlb.c" and "folio_test_hugetlb()". So let's minimize confusion in rmap code. Link: https://lkml.kernel.org/r/20231220224504.646757-1-david@redhat.com Link: https://lkml.kernel.org/r/20231220224504.646757-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | Merge tag 'vfs-6.8.misc' of ↵Linus Torvalds2024-01-081-1/+1
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull misc vfs updates from Christian Brauner: "This contains the usual miscellaneous features, cleanups, and fixes for vfs and individual fses. Features: - Add Jan Kara as VFS reviewer - Show correct device and inode numbers in proc/<pid>/maps for vma files on stacked filesystems. This is now easily doable thanks to the backing file work from the last cycles. This comes with selftests Cleanups: - Remove a redundant might_sleep() from wait_on_inode() - Initialize pointer with NULL, not 0 - Clarify comment on access_override_creds() - Rework and simplify eventfd_signal() and eventfd_signal_mask() helpers - Process aio completions in batches to avoid needless wakeups - Completely decouple struct mnt_idmap from namespaces. We now only keep the actual idmapping around and don't stash references to namespaces - Reformat maintainer entries to indicate that a given subsystem belongs to fs/ - Simplify fput() for files that were never opened - Get rid of various pointless file helpers - Rename various file helpers - Rename struct file members after SLAB_TYPESAFE_BY_RCU switch from last cycle - Make relatime_need_update() return bool - Use GFP_KERNEL instead of GFP_USER when allocating superblocks - Replace deprecated ida_simple_*() calls with their current ida_*() counterparts Fixes: - Fix comments on user namespace id mapping helpers. They aren't kernel doc comments so they shouldn't be using /** - s/Retuns/Returns/g in various places - Add missing parameter documentation on can_move_mount_beneath() - Rename i_mapping->private_data to i_mapping->i_private_data - Fix a false-positive lockdep warning in pipe_write() for watch queues - Improve __fget_files_rcu() code generation to improve performance - Only notify writer that pipe resizing has finished after setting pipe->max_usage otherwise writers are never notified that the pipe has been resized and hang - Fix some kernel docs in hfsplus - s/passs/pass/g in various places - Fix kernel docs in ntfs - Fix kcalloc() arguments order reported by gcc 14 - Fix uninitialized value in reiserfs" * tag 'vfs-6.8.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (36 commits) reiserfs: fix uninit-value in comp_keys watch_queue: fix kcalloc() arguments order ntfs: dir.c: fix kernel-doc function parameter warnings fs: fix doc comment typo fs tree wide selftests/overlayfs: verify device and inode numbers in /proc/pid/maps fs/proc: show correct device and inode numbers in /proc/pid/maps eventfd: Remove usage of the deprecated ida_simple_xx() API fs: super: use GFP_KERNEL instead of GFP_USER for super block allocation fs/hfsplus: wrapper.c: fix kernel-doc warnings fs: add Jan Kara as reviewer fs/inode: Make relatime_need_update return bool pipe: wakeup wr_wait after setting max_usage file: remove __receive_fd() file: stop exposing receive_fd_user() fs: replace f_rcuhead with f_task_work file: remove pointless wrapper file: s/close_fd_get_file()/file_close_fd()/g Improve __fget_files_rcu() code generation (and thus __fget_light()) file: massage cleanup of files that failed to open fs/pipe: Fix lockdep false-positive in watchqueue pipe_write() ...
| * fs: Rename mapping private membersMatthew Wilcox (Oracle)2023-11-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | It is hard to find where mapping->private_lock, mapping->private_list and mapping->private_data are used, due to private_XXX being a relatively common name for variables and structure members in the kernel. To fit with other members of struct address_space, rename them all to have an i_ prefix. Tested with an allmodconfig build. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Link: https://lore.kernel.org/r/20231117215823.2821906-1-willy@infradead.org Acked-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
* | hugetlb: fix null-ptr-deref in hugetlb_vma_lock_writeMike Kravetz2023-12-061-0/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The routine __vma_private_lock tests for the existence of a reserve map associated with a private hugetlb mapping. A pointer to the reserve map is in vma->vm_private_data. __vma_private_lock was checking the pointer for NULL. However, it is possible that the low bits of the pointer could be used as flags. In such instances, vm_private_data is not NULL and not a valid pointer. This results in the null-ptr-deref reported by syzbot: general protection fault, probably for non-canonical address 0xdffffc000000001d: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef] CPU: 0 PID: 5048 Comm: syz-executor139 Not tainted 6.6.0-rc7-syzkaller-00142-g88 8cf78c29e2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 1 0/09/2023 RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5004 ... Call Trace: <TASK> lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718 down_write+0x93/0x200 kernel/locking/rwsem.c:1573 hugetlb_vma_lock_write mm/hugetlb.c:300 [inline] hugetlb_vma_lock_write+0xae/0x100 mm/hugetlb.c:291 __hugetlb_zap_begin+0x1e9/0x2b0 mm/hugetlb.c:5447 hugetlb_zap_begin include/linux/hugetlb.h:258 [inline] unmap_vmas+0x2f4/0x470 mm/memory.c:1733 exit_mmap+0x1ad/0xa60 mm/mmap.c:3230 __mmput+0x12a/0x4d0 kernel/fork.c:1349 mmput+0x62/0x70 kernel/fork.c:1371 exit_mm kernel/exit.c:567 [inline] do_exit+0x9ad/0x2a20 kernel/exit.c:861 __do_sys_exit kernel/exit.c:991 [inline] __se_sys_exit kernel/exit.c:989 [inline] __x64_sys_exit+0x42/0x50 kernel/exit.c:989 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Mask off low bit flags before checking for NULL pointer. In addition, the reserve map only 'belongs' to the OWNER (parent in parent/child relationships) so also check for the OWNER flag. Link: https://lkml.kernel.org/r/20231114012033.259600-1-mike.kravetz@oracle.com Reported-by: syzbot+6ada951e7c0f7bc8a71e@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-mm/00000000000078d1e00608d7878b@google.com/ Fixes: bf4916922c60 ("hugetlbfs: extend hugetlb_vma_lock to private VMAs") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Rik van Riel <riel@surriel.com> Cc: Edward Adam Davis <eadavis@qq.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Tom Rix <trix@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mempolicy: mmap_lock is not needed while migrating foliosHugh Dickins2023-10-251-18/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mbind(2) holds down_write of current task's mmap_lock throughout (exclusive because it needs to set the new mempolicy on the vmas); migrate_pages(2) holds down_read of pid's mmap_lock throughout. They both hold mmap_lock across the internal migrate_pages(), under which all new page allocations (huge or small) are made. I'm nervous about it; and migrate_pages() certainly does not need mmap_lock itself. It's done this way for mbind(2), because its page allocator is vma_alloc_folio() or alloc_hugetlb_folio_vma(), both of which depend on vma and address. Now that we have alloc_pages_mpol(), depending on (refcounted) memory policy and interleave index, mbind(2) can be modified to use that or alloc_hugetlb_folio_nodemask(), and then not need mmap_lock across the internal migrate_pages() at all: add alloc_migration_target_by_mpol() to replace mbind's new_page(). (After that change, alloc_hugetlb_folio_vma() is used by nothing but a userfaultfd function: move it out of hugetlb.h and into the #ifdef.) migrate_pages(2) has chosen its target node before migrating, so can continue to use the standard alloc_migration_target(); but let it take and drop mmap_lock just around migrate_to_node()'s queue_pages_range(): neither the node-to-node calculations nor the page migrations need it. It seems unlikely, but it is conceivable that some userspace depends on the kernel's mmap_lock exclusion here, instead of doing its own locking: more likely in a testsuite than in real life. It is also possible, of course, that some pages on the list will be munmapped by another thread before they are migrated, or a newer memory policy applied to the range by that time: but such races could happen before, as soon as mmap_lock was dropped, so it does not appear to be a concern. Link: https://lkml.kernel.org/r/21e564e8-269f-6a89-7ee2-fd612831c289@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun heo <tj@kernel.org> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* hugetlb_vmemmap: use folio argument for hugetlb_vmemmap_* functionsUsama Arif2023-10-251-7/+7
| | | | | | | | | | | | | | | | | | Most function calls in hugetlb.c are made with folio arguments. This brings hugetlb_vmemmap calls inline with them by using folio instead of head struct page. Head struct page is still needed within these functions. The set/clear/test functions for hugepages are also changed to folio versions. Link: https://lkml.kernel.org/r/20231011144557.1720481-2-usama.arif@bytedance.com Signed-off-by: Usama Arif <usama.arif@bytedance.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Fam Zheng <fam.zheng@bytedance.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-19 03:31:28 +0000