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2024-09-27[tree-wide] finally take no_llseek outAl Viro
no_llseek had been defined to NULL two years ago, in commit 868941b14441 ("fs: remove no_llseek") To quote that commit, At -rc1 we'll need do a mechanical removal of no_llseek - git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/\<no_llseek\>/d' $i done would do it. Unfortunately, that hadn't been done. Linus, could you do that now, so that we could finally put that thing to rest? All instances are of the form .llseek = no_llseek, so it's obviously safe. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-09-21Merge tag 'mm-stable-2024-09-20-02-31' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "Along with the usual shower of singleton patches, notable patch series in this pull request are: - "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds consistency to the APIs and behaviour of these two core allocation functions. This also simplifies/enables Rustification. - "Some cleanups for shmem" from Baolin Wang. No functional changes - mode code reuse, better function naming, logic simplifications. - "mm: some small page fault cleanups" from Josef Bacik. No functional changes - code cleanups only. - "Various memory tiering fixes" from Zi Yan. A small fix and a little cleanup. - "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and simplifications and .text shrinkage. - "Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt. This is a feature, it adds new feilds to /proc/vmstat such as $ grep kstack /proc/vmstat kstack_1k 3 kstack_2k 188 kstack_4k 11391 kstack_8k 243 kstack_16k 0 which tells us that 11391 processes used 4k of stack while none at all used 16k. Useful for some system tuning things, but partivularly useful for "the dynamic kernel stack project". - "kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory. - "mm: memcg: page counters optimizations" from Roman Gushchin. "3 independent small optimizations of page counters". - "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David Hildenbrand. Improves PTE/PMD splitlock detection, makes powerpc/8xx work correctly by design rather than by accident. - "mm: remove arch_make_page_accessible()" from David Hildenbrand. Some folio conversions which make arch_make_page_accessible() unneeded. - "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel. Cleans up and fixes our handling of the resetting of the cgroup/process peak-memory-use detector. - "Make core VMA operations internal and testable" from Lorenzo Stoakes. Rationalizaion and encapsulation of the VMA manipulation APIs. With a view to better enable testing of the VMA functions, even from a userspace-only harness. - "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix issues in the zswap global shrinker, resulting in improved performance. - "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill in some missing info in /proc/zoneinfo. - "mm: replace follow_page() by folio_walk" from David Hildenbrand. Code cleanups and rationalizations (conversion to folio_walk()) resulting in the removal of follow_page(). - "improving dynamic zswap shrinker protection scheme" from Nhat Pham. Some tuning to improve zswap's dynamic shrinker. Significant reductions in swapin and improvements in performance are shown. - "mm: Fix several issues with unaccepted memory" from Kirill Shutemov. Improvements to the new unaccepted memory feature, - "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on DAX PUDs. This was missing, although nobody seems to have notied yet. - "Introduce a store type enum for the Maple tree" from Sidhartha Kumar. Cleanups and modest performance improvements for the maple tree library code. - "memcg: further decouple v1 code from v2" from Shakeel Butt. Move more cgroup v1 remnants away from the v2 memcg code. - "memcg: initiate deprecation of v1 features" from Shakeel Butt. Adds various warnings telling users that memcg v1 features are deprecated. - "mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li. Greatly improves the success rate of the mTHP swap allocation. - "mm: introduce numa_memblks" from Mike Rapoport. Moves various disparate per-arch implementations of numa_memblk code into generic code. - "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly improves the performance of munmap() of swap-filled ptes. - "support large folio swap-out and swap-in for shmem" from Baolin Wang. With this series we no longer split shmem large folios into simgle-page folios when swapping out shmem. - "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice performance improvements and code reductions for gigantic folios. - "support shmem mTHP collapse" from Baolin Wang. Adds support for khugepaged's collapsing of shmem mTHP folios. - "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect() performance regression due to the addition of mseal(). - "Increase the number of bits available in page_type" from Matthew Wilcox. Increases the number of bits available in page_type! - "Simplify the page flags a little" from Matthew Wilcox. Many legacy page flags are now folio flags, so the page-based flags and their accessors/mutators can be removed. - "mm: store zero pages to be swapped out in a bitmap" from Usama Arif. An optimization which permits us to avoid writing/reading zero-filled zswap pages to backing store. - "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race window which occurs when a MAP_FIXED operqtion is occurring during an unrelated vma tree walk. - "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of the vma_merge() functionality, making ot cleaner, more testable and better tested. - "misc fixups for DAMON {self,kunit} tests" from SeongJae Park. Minor fixups of DAMON selftests and kunit tests. - "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang. Code cleanups and folio conversions. - "Shmem mTHP controls and stats improvements" from Ryan Roberts. Cleanups for shmem controls and stats. - "mm: count the number of anonymous THPs per size" from Barry Song. Expose additional anon THP stats to userspace for improved tuning. - "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio conversions and removal of now-unused page-based APIs. - "replace per-quota region priorities histogram buffer with per-context one" from SeongJae Park. DAMON histogram rationalization. - "Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae Park. DAMON documentation updates. - "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve related doc and warn" from Jason Wang: fixes usage of page allocator __GFP_NOFAIL and GFP_ATOMIC flags. - "mm: split underused THPs" from Yu Zhao. Improve THP=always policy. This was overprovisioning THPs in sparsely accessed memory areas. - "zram: introduce custom comp backends API" frm Sergey Senozhatsky. Add support for zram run-time compression algorithm tuning. - "mm: Care about shadow stack guard gap when getting an unmapped area" from Mark Brown. Fix up the various arch_get_unmapped_area() implementations to better respect guard areas. - "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability of mem_cgroup_iter() and various code cleanups. - "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge pfnmap support. - "resource: Fix region_intersects() vs add_memory_driver_managed()" from Huang Ying. Fix a bug in region_intersects() for systems with CXL memory. - "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches a couple more code paths to correctly recover from the encountering of poisoned memry. - "mm: enable large folios swap-in support" from Barry Song. Support the swapin of mTHP memory into appropriately-sized folios, rather than into single-page folios" * tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits) zram: free secondary algorithms names uprobes: turn xol_area->pages[2] into xol_area->page uprobes: introduce the global struct vm_special_mapping xol_mapping Revert "uprobes: use vm_special_mapping close() functionality" mm: support large folios swap-in for sync io devices mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios mm: fix swap_read_folio_zeromap() for large folios with partial zeromap mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries set_memory: add __must_check to generic stubs mm/vma: return the exact errno in vms_gather_munmap_vmas() memcg: cleanup with !CONFIG_MEMCG_V1 mm/show_mem.c: report alloc tags in human readable units mm: support poison recovery from copy_present_page() mm: support poison recovery from do_cow_fault() resource, kunit: add test case for region_intersects() resource: make alloc_free_mem_region() works for iomem_resource mm: z3fold: deprecate CONFIG_Z3FOLD vfio/pci: implement huge_fault support mm/arm64: support large pfn mappings mm/x86: support large pfn mappings ...
2024-09-20Merge tag 'vfs-6.12.blocksize' of ↵Linus Torvalds
gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs Pull vfs blocksize updates from Christian Brauner: "This contains the vfs infrastructure as well as the xfs bits to enable support for block sizes (bs) larger than page sizes (ps) plus a few fixes to related infrastructure. There has been efforts over the last 16 years to enable enable Large Block Sizes (LBS), that is block sizes in filesystems where bs > page size. Through these efforts we have learned that one of the main blockers to supporting bs > ps in filesystems has been a way to allocate pages that are at least the filesystem block size on the page cache where bs > ps. Thanks to various previous efforts it is possible to support bs > ps in XFS with only a few changes in XFS itself. Most changes are to the page cache to support minimum order folio support for the target block size on the filesystem. A motivation for Large Block Sizes today is to support high-capacity (large amount of Terabytes) QLC SSDs where the internal Indirection Unit (IU) are typically greater than 4k to help reduce DRAM and so in turn cost and space. In practice this then allows different architectures to use a base page size of 4k while still enabling support for block sizes aligned to the larger IUs by relying on high order folios on the page cache when needed. It also allows to take advantage of the drive's support for atomics larger than 4k with buffered IO support in Linux. As described this year at LSFMM, supporting large atomics greater than 4k enables databases to remove the need to rely on their own journaling, so they can disable double buffered writes, which is a feature different cloud providers are already enabling through custom storage solutions" * tag 'vfs-6.12.blocksize' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (22 commits) Documentation: iomap: fix a typo iomap: remove the iomap_file_buffered_write_punch_delalloc return value iomap: pass the iomap to the punch callback iomap: pass flags to iomap_file_buffered_write_punch_delalloc iomap: improve shared block detection in iomap_unshare_iter iomap: handle a post-direct I/O invalidate race in iomap_write_delalloc_release docs:filesystems: fix spelling and grammar mistakes in iomap design page filemap: fix htmldoc warning for mapping_align_index() iomap: make zero range flush conditional on unwritten mappings iomap: fix handling of dirty folios over unwritten extents iomap: add a private argument for iomap_file_buffered_write iomap: remove set_memor_ro() on zero page xfs: enable block size larger than page size support xfs: make the calculation generic in xfs_sb_validate_fsb_count() xfs: expose block size in stat xfs: use kvmalloc for xattr buffers iomap: fix iomap_dio_zero() for fs bs > system page size filemap: cap PTE range to be created to allowed zero fill in folio_map_range() mm: split a folio in minimum folio order chunks readahead: allocate folios with mapping_min_order in readahead ...
2024-09-17mm/fork: accept huge pfnmap entriesPeter Xu
Teach the fork code to properly copy pfnmaps for pmd/pud levels. Pud is much easier, the write bit needs to be persisted though for writable and shared pud mappings like PFNMAP ones, otherwise a follow up write in either parent or child process will trigger a write fault. Do the same for pmd level. Link: https://lkml.kernel.org/r/20240826204353.2228736-8-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Gavin Shan <gshan@redhat.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17mm: allow THP orders for PFNMAPsPeter Xu
This enables PFNMAPs to be mapped at either pmd/pud layers. Generalize the dax case into vma_is_special_huge() so as to cover both. Meanwhile, rename the macro to THP_ORDERS_ALL_SPECIAL. Link: https://lkml.kernel.org/r/20240826204353.2228736-5-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Gavin Shan <gshan@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17mm: mark special bits for huge pfn mappings when injectPeter Xu
We need these special bits to be around on pfnmaps. Mark properly for !devmap case, reflecting that there's no page struct backing the entry. Link: https://lkml.kernel.org/r/20240826204353.2228736-4-peterx@redhat.com Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Peter Xu <peterx@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Gavin Shan <gshan@redhat.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17mm: drop is_huge_zero_pud()Peter Xu
It constantly returns false since 2017. One assertion is added in 2019 but it should never have triggered, IOW it means what is checked should be asserted instead. If it didn't exist for 7 years maybe it's good idea to remove it and only add it when it comes. Link: https://lkml.kernel.org/r/20240826204353.2228736-3-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Gavin Shan <gshan@redhat.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17mm/huge_memory: ensure huge_zero_folio won't have large_rmappable flag setMiaohe Lin
Ensure huge_zero_folio won't have large_rmappable flag set. So it can be reported as thp,zero correctly through stable_page_flags(). Link: https://lkml.kernel.org/r/20240914015306.3656791-1-linmiaohe@huawei.com Fixes: 5691753d73a2 ("mm: convert huge_zero_page to huge_zero_folio") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm/codetag: fix pgalloc_tag_split()Yu Zhao
The current assumption is that a large folio can only be split into order-0 folios. That is not the case for hugeTLB demotion, nor for THP split: see commit c010d47f107f ("mm: thp: split huge page to any lower order pages"). When a large folio is split into ones of a lower non-zero order, only the new head pages should be tagged. Tagging tail pages can cause imbalanced "calls" counters, since only head pages are untagged by pgalloc_tag_sub() and the "calls" counts on tail pages are leaked, e.g., # echo 2048kB >/sys/kernel/mm/hugepages/hugepages-1048576kB/demote_size # echo 700 >/sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages # time echo 700 >/sys/kernel/mm/hugepages/hugepages-1048576kB/demote # echo 0 >/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages # grep alloc_gigantic_folio /proc/allocinfo Before this patch: 0 549427200 mm/hugetlb.c:1549 func:alloc_gigantic_folio real 0m2.057s user 0m0.000s sys 0m2.051s After this patch: 0 0 mm/hugetlb.c:1549 func:alloc_gigantic_folio real 0m1.711s user 0m0.000s sys 0m1.704s Not tagging tail pages also improves the splitting time, e.g., by about 15% when demoting 1GB hugeTLB folios to 2MB ones, as shown above. Link: https://lkml.kernel.org/r/20240906042108.1150526-2-yuzhao@google.com Fixes: be25d1d4e822 ("mm: create new codetag references during page splitting") Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Suren Baghdasaryan <surenb@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Muchun Song <muchun.song@linux.dev> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm: thp: simplify split_huge_pages_pid()Nanyong Sun
The helper find_get_task_by_vpid() can totally replace the task_struct find logic in split_huge_pages_pid(), so use it to simplify the code. Also delete the needless comments for the helper function name already explains what it's doing here. Link: https://lkml.kernel.org/r/20240905153028.1205128-1-sunnanyong@huawei.com Signed-off-by: Nanyong Sun <sunnanyong@huawei.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm,tmpfs: consider end of file write in shmem_is_hugeRik van Riel
Take the end of a file write into consideration when deciding whether or not to use huge pages for tmpfs files when the tmpfs filesystem is mounted with huge=within_size This allows large writes that append to the end of a file to automatically use large pages. Doing 4MB sequential writes without fallocate to a 16GB tmpfs file with fio. The numbers without THP or with huge=always stay the same, but the performance with huge=within_size now matches that of huge=always. huge before after 4kB pages 1560 MB/s 1560 MB/s within_size 1560 MB/s 4720 MB/s always: 4720 MB/s 4720 MB/s [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/20240903111928.7171e60c@imladris.surriel.com Signed-off-by: Rik van Riel <riel@surriel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm: add sysfs entry to disable splitting underused THPsUsama Arif
If disabled, THPs faulted in or collapsed will not be added to _deferred_list, and therefore won't be considered for splitting under memory pressure if underused. Link: https://lkml.kernel.org/r/20240830100438.3623486-7-usamaarif642@gmail.com Signed-off-by: Usama Arif <usamaarif642@gmail.com> Cc: Alexander Zhu <alexlzhu@fb.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kairui Song <ryncsn@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Shuang Zhai <zhais@google.com> Cc: Shuang Zhai <szhai2@cs.rochester.edu> Cc: Yu Zhao <yuzhao@google.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm: split underused THPsUsama Arif
This is an attempt to mitigate the issue of running out of memory when THP is always enabled. During runtime whenever a THP is being faulted in (__do_huge_pmd_anonymous_page) or collapsed by khugepaged (collapse_huge_page), the THP is added to _deferred_list. Whenever memory reclaim happens in linux, the kernel runs the deferred_split shrinker which goes through the _deferred_list. If the folio was partially mapped, the shrinker attempts to split it. If the folio is not partially mapped, the shrinker checks if the THP was underused, i.e. how many of the base 4K pages of the entire THP were zero-filled. If this number goes above a certain threshold (decided by /sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none), the shrinker will attempt to split that THP. Then at remap time, the pages that were zero-filled are mapped to the shared zeropage, hence saving memory. Link: https://lkml.kernel.org/r/20240830100438.3623486-6-usamaarif642@gmail.com Signed-off-by: Usama Arif <usamaarif642@gmail.com> Suggested-by: Rik van Riel <riel@surriel.com> Co-authored-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Alexander Zhu <alexlzhu@fb.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kairui Song <ryncsn@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Shuang Zhai <zhais@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Shuang Zhai <szhai2@cs.rochester.edu> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm: introduce a pageflag for partially mapped foliosUsama Arif
Currently folio->_deferred_list is used to keep track of partially_mapped folios that are going to be split under memory pressure. In the next patch, all THPs that are faulted in and collapsed by khugepaged are also going to be tracked using _deferred_list. This patch introduces a pageflag to be able to distinguish between partially mapped folios and others in the deferred_list at split time in deferred_split_scan. Its needed as __folio_remove_rmap decrements _mapcount, _large_mapcount and _entire_mapcount, hence it won't be possible to distinguish between partially mapped folios and others in deferred_split_scan. Eventhough it introduces an extra flag to track if the folio is partially mapped, there is no functional change intended with this patch and the flag is not useful in this patch itself, it will become useful in the next patch when _deferred_list has non partially mapped folios. Link: https://lkml.kernel.org/r/20240830100438.3623486-5-usamaarif642@gmail.com Signed-off-by: Usama Arif <usamaarif642@gmail.com> Cc: Alexander Zhu <alexlzhu@fb.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kairui Song <ryncsn@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Shuang Zhai <zhais@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Shuang Zhai <szhai2@cs.rochester.edu> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm: remap unused subpages to shared zeropage when splitting isolated thpYu Zhao
Patch series "mm: split underused THPs", v5. The current upstream default policy for THP is always. However, Meta uses madvise in production as the current THP=always policy vastly overprovisions THPs in sparsely accessed memory areas, resulting in excessive memory pressure and premature OOM killing. Using madvise + relying on khugepaged has certain drawbacks over THP=always. Using madvise hints mean THPs aren't "transparent" and require userspace changes. Waiting for khugepaged to scan memory and collapse pages into THP can be slow and unpredictable in terms of performance (i.e. you dont know when the collapse will happen), while production environments require predictable performance. If there is enough memory available, its better for both performance and predictability to have a THP from fault time, i.e. THP=always rather than wait for khugepaged to collapse it, and deal with sparsely populated THPs when the system is running out of memory. This patch series is an attempt to mitigate the issue of running out of memory when THP is always enabled. During runtime whenever a THP is being faulted in or collapsed by khugepaged, the THP is added to a list. Whenever memory reclaim happens, the kernel runs the deferred_split shrinker which goes through the list and checks if the THP was underused, i.e. how many of the base 4K pages of the entire THP were zero-filled. If this number goes above a certain threshold, the shrinker will attempt to split that THP. Then at remap time, the pages that were zero-filled are mapped to the shared zeropage, hence saving memory. This method avoids the downside of wasting memory in areas where THP is sparsely filled when THP is always enabled, while still providing the upside THPs like reduced TLB misses without having to use madvise. Meta production workloads that were CPU bound (>99% CPU utilzation) were tested with THP shrinker. The results after 2 hours are as follows: | THP=madvise | THP=always | THP=always | | | + shrinker series | | | + max_ptes_none=409 ----------------------------------------------------------------------------- Performance improvement | - | +1.8% | +1.7% (over THP=madvise) | | | ----------------------------------------------------------------------------- Memory usage | 54.6G | 58.8G (+7.7%) | 55.9G (+2.4%) ----------------------------------------------------------------------------- max_ptes_none=409 means that any THP that has more than 409 out of 512 (80%) zero filled filled pages will be split. To test out the patches, the below commands without the shrinker will invoke OOM killer immediately and kill stress, but will not fail with the shrinker: echo 450 > /sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none mkdir /sys/fs/cgroup/test echo $$ > /sys/fs/cgroup/test/cgroup.procs echo 20M > /sys/fs/cgroup/test/memory.max echo 0 > /sys/fs/cgroup/test/memory.swap.max # allocate twice memory.max for each stress worker and touch 40/512 of # each THP, i.e. vm-stride 50K. # With the shrinker, max_ptes_none of 470 and below won't invoke OOM # killer. # Without the shrinker, OOM killer is invoked immediately irrespective # of max_ptes_none value and kills stress. stress --vm 1 --vm-bytes 40M --vm-stride 50K This patch (of 5): Here being unused means containing only zeros and inaccessible to userspace. When splitting an isolated thp under reclaim or migration, the unused subpages can be mapped to the shared zeropage, hence saving memory. This is particularly helpful when the internal fragmentation of a thp is high, i.e. it has many untouched subpages. This is also a prerequisite for THP low utilization shrinker which will be introduced in later patches, where underutilized THPs are split, and the zero-filled pages are freed saving memory. Link: https://lkml.kernel.org/r/20240830100438.3623486-1-usamaarif642@gmail.com Link: https://lkml.kernel.org/r/20240830100438.3623486-3-usamaarif642@gmail.com Signed-off-by: Yu Zhao <yuzhao@google.com> Signed-off-by: Usama Arif <usamaarif642@gmail.com> Tested-by: Shuang Zhai <zhais@google.com> Cc: Alexander Zhu <alexlzhu@fb.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kairui Song <ryncsn@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Shuang Zhai <szhai2@cs.rochester.edu> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm: count the number of partially mapped anonymous THPs per sizeBarry Song
When a THP is added to the deferred_list due to partially mapped, its partial pages are unused, leading to wasted memory and potentially increasing memory reclamation pressure. Detailing the specifics of how unmapping occurs is quite difficult and not that useful, so we adopt a simple approach: each time a THP enters the deferred_list, we increment the count by 1; whenever it leaves for any reason, we decrement the count by 1. Link: https://lkml.kernel.org/r/20240824010441.21308-3-21cnbao@gmail.com Signed-off-by: Barry Song <v-songbaohua@oppo.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Chris Li <chrisl@kernel.org> Cc: Chuanhua Han <hanchuanhua@oppo.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuai Yuan <yuanshuai@oppo.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm: count the number of anonymous THPs per sizeBarry Song
Patch series "mm: count the number of anonymous THPs per size", v4. Knowing the number of transparent anon THPs in the system is crucial for performance analysis. It helps in understanding the ratio and distribution of THPs versus small folios throughout the system. Additionally, partial unmapping by userspace can lead to significant waste of THPs over time and increase memory reclamation pressure. We need this information for comprehensive system tuning. This patch (of 2): Let's track for each anonymous THP size, how many of them are currently allocated. We'll track the complete lifespan of an anon THP, starting when it becomes an anon THP ("large anon folio") (->mapping gets set), until it gets freed (->mapping gets cleared). Introduce a new "nr_anon" counter per THP size and adjust the corresponding counter in the following cases: * We allocate a new THP and call folio_add_new_anon_rmap() to map it the first time and turn it into an anon THP. * We split an anon THP into multiple smaller ones. * We migrate an anon THP, when we prepare the destination. * We free an anon THP back to the buddy. Note that AnonPages in /proc/meminfo currently tracks the total number of *mapped* anonymous *pages*, and therefore has slightly different semantics. In the future, we might also want to track "nr_anon_mapped" for each THP size, which might be helpful when comparing it to the number of allocated anon THPs (long-term pinning, stuck in swapcache, memory leaks, ...). Further note that for now, we only track anon THPs after they got their ->mapping set, for example via folio_add_new_anon_rmap(). If we would allocate some in the swapcache, they will only show up in the statistics for now after they have been mapped to user space the first time, where we call folio_add_new_anon_rmap(). [akpm@linux-foundation.org: documentation fixups, per David] Link: https://lkml.kernel.org/r/3e8add35-e26b-443b-8a04-1078f4bc78f6@redhat.com Link: https://lkml.kernel.org/r/20240824010441.21308-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20240824010441.21308-2-21cnbao@gmail.com Signed-off-by: Barry Song <v-songbaohua@oppo.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Chris Li <chrisl@kernel.org> Cc: Chuanhua Han <hanchuanhua@oppo.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuai Yuan <yuanshuai@oppo.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09mm: tidy up shmem mTHP controls and statsRyan Roberts
Previously we had a situation where shmem mTHP controls and stats were not exposed for some supported sizes and were exposed for some unsupported sizes. So let's clean that up. Anon mTHP can support all large orders [2, PMD_ORDER]. But shmem can support all large orders [1, MAX_PAGECACHE_ORDER]. However, per-size shmem controls and stats were previously being exposed for all the anon mTHP orders, meaning order-1 was not present, and for arm64 64K base pages, orders 12 and 13 were exposed but were not supported internally. Tidy this all up by defining ctrl and stats attribute groups for anon and file separately. Anon ctrl and stats groups are populated for all orders in THP_ORDERS_ALL_ANON and file ctrl and stats groups are populated for all orders in THP_ORDERS_ALL_FILE_DEFAULT. Additionally, create "any" ctrl and stats attribute groups which are populated for all orders in (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DEFAULT). swpout stats use this since they apply to anon and shmem. The side-effect of all this is that different hugepage-*kB directories contain different sets of controls and stats, depending on which memory types support that size. This approach is preferred over the alternative, which is to populate dummy controls and stats for memory types that do not support a given size. [ryan.roberts@arm.com: file pages and shmem can also be split] Link: https://lkml.kernel.org/r/f7ced14c-8bc5-405f-bee7-94f63980f525@arm.comLink: https://lkml.kernel.org/r/20240808111849.651867-3-ryan.roberts@arm.com Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Tested-by: Barry Song <baohua@kernel.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Gavin Shan <gshan@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-03x86: remove PG_uncachedMatthew Wilcox (Oracle)
Convert x86 to use PG_arch_2 instead of PG_uncached and remove PG_uncached. Link: https://lkml.kernel.org/r/20240821193445.2294269-11-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-03mm: remove PageUnevictableMatthew Wilcox (Oracle)
There is only one caller of PageUnevictable() left; convert it to call folio_test_unevictable() and remove all the page accessors. Link: https://lkml.kernel.org/r/20240821193445.2294269-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-02mm: split a folio in minimum folio order chunksLuis Chamberlain
split_folio() and split_folio_to_list() assume order 0, to support minorder for non-anonymous folios, we must expand these to check the folio mapping order and use that. Set new_order to be at least minimum folio order if it is set in split_huge_page_to_list() so that we can maintain minimum folio order requirement in the page cache. Update the debugfs write files used for testing to ensure the order is respected as well. We simply enforce the min order when a file mapping is used. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> Link: https://lore.kernel.org/r/20240902124931.506061-2-kernel@pankajraghav.com # folded fix Link: https://lore.kernel.org/r/20240822135018.1931258-5-kernel@pankajraghav.com Tested-by: David Howells <dhowells@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-01mm: override mTHP "enabled" defaults at kernel cmdlineRyan Roberts
Add thp_anon= cmdline parameter to allow specifying the default enablement of each supported anon THP size. The parameter accepts the following format and can be provided multiple times to configure each size: thp_anon=<size>,<size>[KMG]:<value>;<size>-<size>[KMG]:<value> An example: thp_anon=16K-64K:always;128K,512K:inherit;256K:madvise;1M-2M:never See Documentation/admin-guide/mm/transhuge.rst for more details. Configuring the defaults at boot time is useful to allow early user space to take advantage of mTHP before its been configured through sysfs. [v-songbaohua@oppo.com: use get_oder() and check size is is_power_of_2] Link: https://lkml.kernel.org/r/20240814224635.43272-1-21cnbao@gmail.com [ryan.roberts@arm.com: some minor cleanup according to David's comments] Link: https://lkml.kernel.org/r/20240820105244.62703-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20240814020247.67297-1-21cnbao@gmail.com Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Co-developed-by: Barry Song <v-songbaohua@oppo.com> Signed-off-by: Barry Song <v-songbaohua@oppo.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lance Yang <ioworker0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm/mprotect: fix dax pud handlingsPeter Xu
This is only relevant to the two archs that support PUD dax, aka, x86_64 and ppc64. PUD THPs do not yet exist elsewhere, and hugetlb PUDs do not count in this case. DAX have had PUD mappings for years, but change protection path never worked. When the path is triggered in any form (a simple test program would be: call mprotect() on a 1G dev_dax mapping), the kernel will report "bad pud". This patch should fix that. The new change_huge_pud() tries to keep everything simple. For example, it doesn't optimize write bit as that will need even more PUD helpers. It's not too bad anyway to have one more write fault in the worst case once for 1G range; may be a bigger thing for each PAGE_SIZE, though. Neither does it support userfault-wp bits, as there isn't such PUD mappings that is supported; file mappings always need a split there. The same to TLB shootdown: the pmd path (which was for x86 only) has the trick of using _ad() version of pmdp_invalidate*() which can avoid one redundant TLB, but let's also leave that for later. Again, the larger the mapping, the smaller of such effect. There's some difference on handling "retry" for change_huge_pud() (where it can return 0): it isn't like change_huge_pmd(), as the pmd version is safe with all conditions handled in change_pte_range() later, thanks to Hugh's new pte_offset_map_lock(). In short, change_pte_range() is simply smarter. For that, change_pud_range() will need proper retry if it races with something else when a huge PUD changed from under us. The last thing to mention is currently the PUD path ignores the huge pte numa counter (NUMA_HUGE_PTE_UPDATES), not only because DAX is not applicable to NUMA, but also that it's ambiguous on its own to decide how to account pud in this case. In one earlier version of this patchset I proposed to remove the counter as it doesn't even look right to do the accounting as of now [1], but then a further discussion suggests we can leave that for later, as that doesn't block this series if we choose to ignore that counter. That's what this patch does, by ignoring it. When at it, touch up the comment in pgtable_split_needed() to make it generic to either pmd or pud file THPs. [1] https://lore.kernel.org/all/20240715192142.3241557-3-peterx@redhat.com/ [2] https://lore.kernel.org/r/added2d0-b8be-4108-82ca-1367a388d0b1@redhat.com Link: https://lkml.kernel.org/r/20240812181225.1360970-8-peterx@redhat.com Fixes: a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent hugepages") Fixes: 27af67f35631 ("powerpc/book3s64/mm: enable transparent pud hugepage") Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm/x86: implement arch_check_zapped_pud()Peter Xu
Introduce arch_check_zapped_pud() to sanity check shadow stack on PUD zaps. It has the same logic as the PMD helper. One thing to mention is, it might be a good idea to use page_table_check in the future for trapping wrong setups of shadow stack pgtable entries [1]. That is left for the future as a separate effort. [1] https://lore.kernel.org/all/59d518698f664e07c036a5098833d7b56b953305.camel@intel.com Link: https://lkml.kernel.org/r/20240812181225.1360970-6-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm/migrate: move common code to numa_migrate_check (was numa_migrate_prep)Zi Yan
do_numa_page() and do_huge_pmd_numa_page() share a lot of common code. To reduce redundancy, move common code to numa_migrate_prep() and rename the function to numa_migrate_check() to reflect its functionality. Now do_huge_pmd_numa_page() also checks shared folios to set TNF_SHARED flag. Link: https://lkml.kernel.org/r/20240809145906.1513458-4-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Suggested-by: David Hildenbrand <david@redhat.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm/huge_memory: convert split_huge_pages_pid() from follow_page() to folio_walkDavid Hildenbrand
Let's remove yet another follow_page() user. Note that we have to do the split without holding the PTL, after folio_walk_end(). We don't care about losing the secretmem check in follow_page(). [david@redhat.com: teach can_split_folio() that we are not holding an additional reference] Link: https://lkml.kernel.org/r/c75d1c6c-8ea6-424f-853c-1ccda6c77ba2@redhat.com Link: https://lkml.kernel.org/r/20240802155524.517137-8-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01memory tiering: introduce folio_use_access_time() checkZi Yan
If memory tiering mode is on and a folio is not in the top tier memory, folio's cpupid field is repurposed to store page access time. Instead of an open coded check, use a function to encapsulate the check. Link: https://lkml.kernel.org/r/20240724130115.793641-3-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01memory tiering: read last_cpupid correctly in do_huge_pmd_numa_page()Zi Yan
Patch series "Various memory tiering fixes", v3. This patch (of 3): last_cpupid is only available when memory tiering is off or the folio is in toptier node. Complete the check to read last_cpupid when it is available. Before the fix, the default last_cpupid will be used even if memory tiering mode is turned off at runtime instead of the actual value. This can prevent task_numa_fault() from getting right numa fault stats, but should not cause any crash. User might see performance changes after the fix. Link: https://lkml.kernel.org/r/20240724130115.793641-1-ziy@nvidia.com Link: https://lkml.kernel.org/r/20240724130115.793641-2-ziy@nvidia.com Fixes: 33024536bafd ("memory tiering: hot page selection with hint page fault latency") Signed-off-by: Zi Yan <ziy@nvidia.com> Reported-by: David Hildenbrand <david@redhat.com> Closes: https://lore.kernel.org/linux-mm/9af34a6b-ca56-4a64-8aa6-ade65f109288@redhat.com/ Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm: shmem: move shmem_huge_global_enabled() into shmem_allowable_huge_orders()Baolin Wang
Move shmem_huge_global_enabled() into shmem_allowable_huge_orders(), so that shmem_allowable_huge_orders() can also help to find the allowable huge orders for tmpfs. Moreover the shmem_huge_global_enabled() can become static. While we are at it, passing the vma instead of mm for shmem_huge_global_enabled() makes code cleaner. No functional changes. Link: https://lkml.kernel.org/r/8e825146bb29ee1a1c7bd64d2968ff3e19be7815.1721626645.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Barry Song <21cnbao@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm: shmem: rename shmem_is_huge() to shmem_huge_global_enabled()Baolin Wang
shmem_is_huge() is now used to check if the top-level huge page is enabled, thus rename it to reflect its usage. Link: https://lkml.kernel.org/r/da53296e0ab6359aa083561d9dc01e4223d60fbe.1721626645.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Barry Song <21cnbao@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-08-15mm/numa: no task_numa_fault() call if PMD is changedZi Yan
When handling a numa page fault, task_numa_fault() should be called by a process that restores the page table of the faulted folio to avoid duplicated stats counting. Commit c5b5a3dd2c1f ("mm: thp: refactor NUMA fault handling") restructured do_huge_pmd_numa_page() and did not avoid task_numa_fault() call in the second page table check after a numa migration failure. Fix it by making all !pmd_same() return immediately. This issue can cause task_numa_fault() being called more than necessary and lead to unexpected numa balancing results (It is hard to tell whether the issue will cause positive or negative performance impact due to duplicated numa fault counting). Link: https://lkml.kernel.org/r/20240809145906.1513458-3-ziy@nvidia.com Fixes: c5b5a3dd2c1f ("mm: thp: refactor NUMA fault handling") Reported-by: "Huang, Ying" <ying.huang@intel.com> Closes: https://lore.kernel.org/linux-mm/87zfqfw0yw.fsf@yhuang6-desk2.ccr.corp.intel.com/ Signed-off-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Yang Shi <shy828301@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-26mm/huge_memory: avoid PMD-size page cache if neededGavin Shan
xarray can't support arbitrary page cache size. the largest and supported page cache size is defined as MAX_PAGECACHE_ORDER by commit 099d90642a71 ("mm/filemap: make MAX_PAGECACHE_ORDER acceptable to xarray"). However, it's possible to have 512MB page cache in the huge memory's collapsing path on ARM64 system whose base page size is 64KB. 512MB page cache is breaking the limitation and a warning is raised when the xarray entry is split as shown in the following example. [root@dhcp-10-26-1-207 ~]# cat /proc/1/smaps | grep KernelPageSize KernelPageSize: 64 kB [root@dhcp-10-26-1-207 ~]# cat /tmp/test.c : int main(int argc, char **argv) { const char *filename = TEST_XFS_FILENAME; int fd = 0; void *buf = (void *)-1, *p; int pgsize = getpagesize(); int ret = 0; if (pgsize != 0x10000) { fprintf(stdout, "System with 64KB base page size is required!\n"); return -EPERM; } system("echo 0 > /sys/devices/virtual/bdi/253:0/read_ahead_kb"); system("echo 1 > /proc/sys/vm/drop_caches"); /* Open the xfs file */ fd = open(filename, O_RDONLY); assert(fd > 0); /* Create VMA */ buf = mmap(NULL, TEST_MEM_SIZE, PROT_READ, MAP_SHARED, fd, 0); assert(buf != (void *)-1); fprintf(stdout, "mapped buffer at 0x%p\n", buf); /* Populate VMA */ ret = madvise(buf, TEST_MEM_SIZE, MADV_NOHUGEPAGE); assert(ret == 0); ret = madvise(buf, TEST_MEM_SIZE, MADV_POPULATE_READ); assert(ret == 0); /* Collapse VMA */ ret = madvise(buf, TEST_MEM_SIZE, MADV_HUGEPAGE); assert(ret == 0); ret = madvise(buf, TEST_MEM_SIZE, MADV_COLLAPSE); if (ret) { fprintf(stdout, "Error %d to madvise(MADV_COLLAPSE)\n", errno); goto out; } /* Split xarray entry. Write permission is needed */ munmap(buf, TEST_MEM_SIZE); buf = (void *)-1; close(fd); fd = open(filename, O_RDWR); assert(fd > 0); fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, TEST_MEM_SIZE - pgsize, pgsize); out: if (buf != (void *)-1) munmap(buf, TEST_MEM_SIZE); if (fd > 0) close(fd); return ret; } [root@dhcp-10-26-1-207 ~]# gcc /tmp/test.c -o /tmp/test [root@dhcp-10-26-1-207 ~]# /tmp/test ------------[ cut here ]------------ WARNING: CPU: 25 PID: 7560 at lib/xarray.c:1025 xas_split_alloc+0xf8/0x128 Modules linked in: nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib \ nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct \ nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 \ ip_set rfkill nf_tables nfnetlink vfat fat virtio_balloon drm fuse \ xfs libcrc32c crct10dif_ce ghash_ce sha2_ce sha256_arm64 virtio_net \ sha1_ce net_failover virtio_blk virtio_console failover dimlib virtio_mmio CPU: 25 PID: 7560 Comm: test Kdump: loaded Not tainted 6.10.0-rc7-gavin+ #9 Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20240524-1.el9 05/24/2024 pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : xas_split_alloc+0xf8/0x128 lr : split_huge_page_to_list_to_order+0x1c4/0x780 sp : ffff8000ac32f660 x29: ffff8000ac32f660 x28: ffff0000e0969eb0 x27: ffff8000ac32f6c0 x26: 0000000000000c40 x25: ffff0000e0969eb0 x24: 000000000000000d x23: ffff8000ac32f6c0 x22: ffffffdfc0700000 x21: 0000000000000000 x20: 0000000000000000 x19: ffffffdfc0700000 x18: 0000000000000000 x17: 0000000000000000 x16: ffffd5f3708ffc70 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: ffffffffffffffc0 x10: 0000000000000040 x9 : ffffd5f3708e692c x8 : 0000000000000003 x7 : 0000000000000000 x6 : ffff0000e0969eb8 x5 : ffffd5f37289e378 x4 : 0000000000000000 x3 : 0000000000000c40 x2 : 000000000000000d x1 : 000000000000000c x0 : 0000000000000000 Call trace: xas_split_alloc+0xf8/0x128 split_huge_page_to_list_to_order+0x1c4/0x780 truncate_inode_partial_folio+0xdc/0x160 truncate_inode_pages_range+0x1b4/0x4a8 truncate_pagecache_range+0x84/0xa0 xfs_flush_unmap_range+0x70/0x90 [xfs] xfs_file_fallocate+0xfc/0x4d8 [xfs] vfs_fallocate+0x124/0x2f0 ksys_fallocate+0x4c/0xa0 __arm64_sys_fallocate+0x24/0x38 invoke_syscall.constprop.0+0x7c/0xd8 do_el0_svc+0xb4/0xd0 el0_svc+0x44/0x1d8 el0t_64_sync_handler+0x134/0x150 el0t_64_sync+0x17c/0x180 Fix it by correcting the supported page cache orders, different sets for DAX and other files. With it corrected, 512MB page cache becomes disallowed on all non-DAX files on ARM64 system where the base page size is 64KB. After this patch is applied, the test program fails with error -EINVAL returned from __thp_vma_allowable_orders() and the madvise() system call to collapse the page caches. Link: https://lkml.kernel.org/r/20240715000423.316491-1-gshan@redhat.com Fixes: 6b24ca4a1a8d ("mm: Use multi-index entries in the page cache") Signed-off-by: Gavin Shan <gshan@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Acked-by: Zi Yan <ziy@nvidia.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Don Dutile <ddutile@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: <stable@vger.kernel.org> [5.17+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-26mm: huge_memory: use !CONFIG_64BIT to relax huge page alignment on 32 bit ↵Yang Shi
machines Yves-Alexis Perez reported commit 4ef9ad19e176 ("mm: huge_memory: don't force huge page alignment on 32 bit") didn't work for x86_32 [1]. It is because x86_32 uses CONFIG_X86_32 instead of CONFIG_32BIT. !CONFIG_64BIT should cover all 32 bit machines. [1] https://lore.kernel.org/linux-mm/CAHbLzkr1LwH3pcTgM+aGQ31ip2bKqiqEQ8=FQB+t2c3dhNKNHA@mail.gmail.com/ Link: https://lkml.kernel.org/r/20240712155855.1130330-1-yang@os.amperecomputing.com Fixes: 4ef9ad19e176 ("mm: huge_memory: don't force huge page alignment on 32 bit") Signed-off-by: Yang Shi <yang@os.amperecomputing.com> Reported-by: Yves-Alexis Perez <corsac@debian.org> Tested-by: Yves-Alexis Perez <corsac@debian.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Christoph Lameter <cl@linux.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Salvatore Bonaccorso <carnil@debian.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: <stable@vger.kernel.org> [6.8+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12mm: shmem: rename mTHP shmem countersRyan Roberts
The legacy PMD-sized THP counters at /proc/vmstat include thp_file_alloc, thp_file_fallback and thp_file_fallback_charge, which rather confusingly refer to shmem THP and do not include any other types of file pages. This is inconsistent since in most other places in the kernel, THP counters are explicitly separated for anon, shmem and file flavours. However, we are stuck with it since it constitutes a user ABI. Recently, commit 66f44583f9b6 ("mm: shmem: add mTHP counters for anonymous shmem") added equivalent mTHP stats for shmem, keeping the same "file_" prefix in the names. But in future, we may want to add extra stats to cover actual file pages, at which point, it would all become very confusing. So let's take the opportunity to rename these new counters "shmem_" before the change makes it upstream and the ABI becomes immutable. While we are at it, let's improve the documentation for the legacy counters to make it clear that they count shmem pages only. Link: https://lkml.kernel.org/r/20240710095503.3193901-1-ryan.roberts@arm.com Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Lance Yang <ioworker0@gmail.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Barry Song <baohua@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Daniel Gomez <da.gomez@samsung.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12mm: thp: support "THPeligible" semantics for mTHP with anonymous shmemBang Li
After the commit 7fb1b252afb5 ("mm: shmem: add mTHP support for anonymous shmem"), we can configure different policies through the multi-size THP sysfs interface for anonymous shmem. But currently "THPeligible" indicates only whether the mapping is eligible for allocating THP-pages as well as the THP is PMD mappable or not for anonymous shmem, we need to support semantics for mTHP with anonymous shmem similar to those for mTHP with anonymous memory. Link: https://lkml.kernel.org/r/20240705032309.24933-1-libang.li@antgroup.com Signed-off-by: Bang Li <libang.li@antgroup.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12mm: fix khugepaged activation policyRyan Roberts
Since the introduction of mTHP, the docuementation has stated that khugepaged would be enabled when any mTHP size is enabled, and disabled when all mTHP sizes are disabled. There are 2 problems with this; 1. this is not what was implemented by the code and 2. this is not the desirable behavior. Desirable behavior is for khugepaged to be enabled when any PMD-sized THP is enabled, anon or file. (Note that file THP is still controlled by the top-level control so we must always consider that, as well as the PMD-size mTHP control for anon). khugepaged only supports collapsing to PMD-sized THP so there is no value in enabling it when PMD-sized THP is disabled. So let's change the code and documentation to reflect this policy. Further, per-size enabled control modification events were not previously forwarded to khugepaged to give it an opportunity to start or stop. Consequently the following was resulting in khugepaged eroneously not being activated: echo never > /sys/kernel/mm/transparent_hugepage/enabled echo always > /sys/kernel/mm/transparent_hugepage/hugepages-2048kB/enabled [ryan.roberts@arm.com: v3] Link: https://lkml.kernel.org/r/20240705102849.2479686-1-ryan.roberts@arm.com Link: https://lkml.kernel.org/r/20240705102849.2479686-1-ryan.roberts@arm.com Link: https://lkml.kernel.org/r/20240704091051.2411934-1-ryan.roberts@arm.com Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Fixes: 3485b88390b0 ("mm: thp: introduce multi-size THP sysfs interface") Closes: https://lore.kernel.org/linux-mm/7a0bbe69-1e3d-4263-b206-da007791a5c4@redhat.com/ Acked-by: David Hildenbrand <david@redhat.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lance Yang <ioworker0@gmail.com> Cc: Yang Shi <shy828301@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12mm: add per-order mTHP split countersLance Yang
Patch series "mm: introduce per-order mTHP split counters", v3. At present, the split counters in THP statistics no longer include PTE-mapped mTHP. Therefore, we want to introduce per-order mTHP split counters to monitor the frequency of mTHP splits. This will assist developers in better analyzing and optimizing system performance. /sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats split split_failed split_deferred This patch (of 2): Currently, the split counters in THP statistics no longer include PTE-mapped mTHP. Therefore, we propose introducing per-order mTHP split counters to monitor the frequency of mTHP splits. This will help developers better analyze and optimize system performance. /sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats split split_failed split_deferred [ioworker0@gmail.com: make things more readable, per Barry and Baolin] Link: https://lkml.kernel.org/r/20240704012905.42971-2-ioworker0@gmail.com [ioworker0@gmail.com: use == for `order' test, per David] Link: https://lkml.kernel.org/r/20240705113119.82210-1-ioworker0@gmail.com Link: https://lkml.kernel.org/r/20240704012905.42971-1-ioworker0@gmail.com Link: https://lkml.kernel.org/r/20240704012905.42971-2-ioworker0@gmail.com Link: https://lkml.kernel.org/r/20240628130750.73097-1-ioworker0@gmail.com Link: https://lkml.kernel.org/r/20240628130750.73097-2-ioworker0@gmail.com Signed-off-by: Mingzhe Yang <mingzhe.yang@ly.com> Signed-off-by: Lance Yang <ioworker0@gmail.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Acked-by: Barry Song <baohua@kernel.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Bang Li <libang.li@antgroup.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-06Merge branch 'mm-hotfixes-stable' into mm-stable to pick up "mm: fixAndrew Morton
crashes from deferred split racing folio migration", needed by "mm: migrate: split folio_migrate_mapping()".
2024-07-06mm: gup: stop abusing try_grab_folioYang Shi
A kernel warning was reported when pinning folio in CMA memory when launching SEV virtual machine. The splat looks like: [ 464.325306] WARNING: CPU: 13 PID: 6734 at mm/gup.c:1313 __get_user_pages+0x423/0x520 [ 464.325464] CPU: 13 PID: 6734 Comm: qemu-kvm Kdump: loaded Not tainted 6.6.33+ #6 [ 464.325477] RIP: 0010:__get_user_pages+0x423/0x520 [ 464.325515] Call Trace: [ 464.325520] <TASK> [ 464.325523] ? __get_user_pages+0x423/0x520 [ 464.325528] ? __warn+0x81/0x130 [ 464.325536] ? __get_user_pages+0x423/0x520 [ 464.325541] ? report_bug+0x171/0x1a0 [ 464.325549] ? handle_bug+0x3c/0x70 [ 464.325554] ? exc_invalid_op+0x17/0x70 [ 464.325558] ? asm_exc_invalid_op+0x1a/0x20 [ 464.325567] ? __get_user_pages+0x423/0x520 [ 464.325575] __gup_longterm_locked+0x212/0x7a0 [ 464.325583] internal_get_user_pages_fast+0xfb/0x190 [ 464.325590] pin_user_pages_fast+0x47/0x60 [ 464.325598] sev_pin_memory+0xca/0x170 [kvm_amd] [ 464.325616] sev_mem_enc_register_region+0x81/0x130 [kvm_amd] Per the analysis done by yangge, when starting the SEV virtual machine, it will call pin_user_pages_fast(..., FOLL_LONGTERM, ...) to pin the memory. But the page is in CMA area, so fast GUP will fail then fallback to the slow path due to the longterm pinnalbe check in try_grab_folio(). The slow path will try to pin the pages then migrate them out of CMA area. But the slow path also uses try_grab_folio() to pin the page, it will also fail due to the same check then the above warning is triggered. In addition, the try_grab_folio() is supposed to be used in fast path and it elevates folio refcount by using add ref unless zero. We are guaranteed to have at least one stable reference in slow path, so the simple atomic add could be used. The performance difference should be trivial, but the misuse may be confusing and misleading. Redefined try_grab_folio() to try_grab_folio_fast(), and try_grab_page() to try_grab_folio(), and use them in the proper paths. This solves both the abuse and the kernel warning. The proper naming makes their usecase more clear and should prevent from abusing in the future. peterx said: : The user will see the pin fails, for gpu-slow it further triggers the WARN : right below that failure (as in the original report): : : folio = try_grab_folio(page, page_increm - 1, : foll_flags); : if (WARN_ON_ONCE(!folio)) { <------------------------ here : /* : * Release the 1st page ref if the : * folio is problematic, fail hard. : */ : gup_put_folio(page_folio(page), 1, : foll_flags); : ret = -EFAULT; : goto out; : } [1] https://lore.kernel.org/linux-mm/1719478388-31917-1-git-send-email-yangge1116@126.com/ [shy828301@gmail.com: fix implicit declaration of function try_grab_folio_fast] Link: https://lkml.kernel.org/r/CAHbLzkowMSso-4Nufc9hcMehQsK9PNz3OSu-+eniU-2Mm-xjhA@mail.gmail.com Link: https://lkml.kernel.org/r/20240628191458.2605553-1-yang@os.amperecomputing.com Fixes: 57edfcfd3419 ("mm/gup: accelerate thp gup even for "pages != NULL"") Signed-off-by: Yang Shi <yang@os.amperecomputing.com> Reported-by: yangge <yangge1116@126.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: <stable@vger.kernel.org> [6.6+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-04mm: refactor folio_undo_large_rmappable()Kefeng Wang
Folios of order <= 1 are not in deferred list, the check of order is added into folio_undo_large_rmappable() from commit 8897277acfef ("mm: support order-1 folios in the page cache"), but there is a repeated check for small folio (order 0) during each call of the folio_undo_large_rmappable(), so only keep folio_order() check inside the function. In addition, move all the checks into header file to save a function call for non-large-rmappable or empty deferred_list folio. Link: https://lkml.kernel.org/r/20240521130315.46072-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lance Yang <ioworker0@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: Shakeel Butt <shakeel.butt@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm/migrate: move NUMA hinting fault folio isolation + checks under PTLDavid Hildenbrand
Currently we always take a folio reference even if migration will not even be tried or isolation failed, requiring us to grab+drop an additional reference. Further, we end up calling folio_likely_mapped_shared() while the folio might have already been unmapped, because after we dropped the PTL, that can easily happen. We want to stop touching mapcounts and friends from such context, and only call folio_likely_mapped_shared() while the folio is still mapped: mapcount information is pretty much stale and unreliable otherwise. So let's move checks into numamigrate_isolate_folio(), rename that function to migrate_misplaced_folio_prepare(), and call that function from callsites where we call migrate_misplaced_folio(), but still with the PTL held. We can now stop taking temporary folio references, and really only take a reference if folio isolation succeeded. Doing the folio_likely_mapped_shared() + folio isolation under PT lock is now similar to how we handle MADV_PAGEOUT. While at it, combine the folio_is_file_lru() checks. [david@redhat.com: fix list_del() corruption] Link: https://lkml.kernel.org/r/8f85c31a-e603-4578-bf49-136dae0d4b69@redhat.com Link: https://lkml.kernel.org/r/20240626191129.658CFC32782@smtp.kernel.org Link: https://lkml.kernel.org/r/20240620212935.656243-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Tested-by: Donet Tom <donettom@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm/migrate: make migrate_misplaced_folio() return 0 on successDavid Hildenbrand
Patch series "mm/migrate: move NUMA hinting fault folio isolation + checks under PTL". Let's just return 0 on success, which is less confusing. ... especially because we got it wrong in the migrate.h stub where we have "return -EAGAIN; /* can't migrate now */" instead of "return 0;". Likely this wrong return value doesn't currently matter, but it certainly adds confusion. We'll add migrate_misplaced_folio_prepare() next, where we want to use the same "return 0 on success" approach, so let's just clean this up. Link: https://lkml.kernel.org/r/20240620212935.656243-1-david@redhat.com Link: https://lkml.kernel.org/r/20240620212935.656243-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Donet Tom <donettom@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm: memory: convert clear_huge_page() to folio_zero_user()Kefeng Wang
Patch series "mm: improve clear and copy user folio", v2. Some folio conversions. An improvement is to move address alignment into the caller as it is only needed if we don't know which address will be accessed when clearing/copying user folios. This patch (of 4): Replace clear_huge_page() with folio_zero_user(), and take a folio instead of a page. Directly get number of pages by folio_nr_pages() to remove pages_per_huge_page argument, furthermore, move the address alignment from folio_zero_user() to the callers since the alignment is only needed when we don't know which address will be accessed. Link: https://lkml.kernel.org/r/20240618091242.2140164-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20240618091242.2140164-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm: extend rmap flags arguments for folio_add_new_anon_rmapBarry Song
Patch series "mm: clarify folio_add_new_anon_rmap() and __folio_add_anon_rmap()", v2. This patchset is preparatory work for mTHP swapin. folio_add_new_anon_rmap() assumes that new anon rmaps are always exclusive. However, this assumption doesn’t hold true for cases like do_swap_page(), where a new anon might be added to the swapcache and is not necessarily exclusive. The patchset extends the rmap flags to allow folio_add_new_anon_rmap() to handle both exclusive and non-exclusive new anon folios. The do_swap_page() function is updated to use this extended API with rmap flags. Consequently, all new anon folios now consistently use folio_add_new_anon_rmap(). The special case for !folio_test_anon() in __folio_add_anon_rmap() can be safely removed. In conclusion, new anon folios always use folio_add_new_anon_rmap(), regardless of exclusivity. Old anon folios continue to use __folio_add_anon_rmap() via folio_add_anon_rmap_pmd() and folio_add_anon_rmap_ptes(). This patch (of 3): In the case of a swap-in, a new anonymous folio is not necessarily exclusive. This patch updates the rmap flags to allow a new anonymous folio to be treated as either exclusive or non-exclusive. To maintain the existing behavior, we always use EXCLUSIVE as the default setting. [akpm@linux-foundation.org: cleanup and constifications per David and akpm] [v-songbaohua@oppo.com: fix missing doc for flags of folio_add_new_anon_rmap()] Link: https://lkml.kernel.org/r/20240619210641.62542-1-21cnbao@gmail.com [v-songbaohua@oppo.com: enhance doc for extend rmap flags arguments for folio_add_new_anon_rmap] Link: https://lkml.kernel.org/r/20240622030256.43775-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20240617231137.80726-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20240617231137.80726-2-21cnbao@gmail.com Signed-off-by: Barry Song <v-songbaohua@oppo.com> Suggested-by: David Hildenbrand <david@redhat.com> Tested-by: Shuai Yuan <yuanshuai@oppo.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Chris Li <chrisl@kernel.org> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm/huge_memory.c: fix used-uninitializedAndrew Morton
Fix used-uninitialized of `page'. Fixes: dce7d10be4bb ("mm/madvise: optimize lazyfreeing with mTHP in madvise_free") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202406260514.SLhNM9kQ-lkp@intel.com Cc: Lance Yang <ioworker0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm/vmscan: avoid split lazyfree THP during shrink_folio_list()Lance Yang
When the user no longer requires the pages, they would use madvise(MADV_FREE) to mark the pages as lazy free. Subsequently, they typically would not re-write to that memory again. During memory reclaim, if we detect that the large folio and its PMD are both still marked as clean and there are no unexpected references (such as GUP), so we can just discard the memory lazily, improving the efficiency of memory reclamation in this case. On an Intel i5 CPU, reclaiming 1GiB of lazyfree THPs using mem_cgroup_force_empty() results in the following runtimes in seconds (shorter is better): -------------------------------------------- | Old | New | Change | -------------------------------------------- | 0.683426 | 0.049197 | -92.80% | -------------------------------------------- [ioworker0@gmail.com: minor changes per David] Link: https://lkml.kernel.org/r/20240622100057.3352-1-ioworker0@gmail.com Link: https://lkml.kernel.org/r/20240614015138.31461-4-ioworker0@gmail.com Signed-off-by: Lance Yang <ioworker0@gmail.com> Suggested-by: Zi Yan <ziy@nvidia.com> Suggested-by: David Hildenbrand <david@redhat.com> Cc: Bang Li <libang.li@antgroup.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Fangrui Song <maskray@google.com> Cc: Jeff Xie <xiehuan09@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yin Fengwei <fengwei.yin@intel.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm/rmap: integrate PMD-mapped folio splitting into pagewalk loopLance Yang
In preparation for supporting try_to_unmap_one() to unmap PMD-mapped folios, start the pagewalk first, then call split_huge_pmd_address() to split the folio. Link: https://lkml.kernel.org/r/20240614015138.31461-3-ioworker0@gmail.com Signed-off-by: Lance Yang <ioworker0@gmail.com> Suggested-by: David Hildenbrand <david@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Suggested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: Zi Yan <ziy@nvidia.com> Cc: Bang Li <libang.li@antgroup.com> Cc: Barry Song <baohua@kernel.org> Cc: Fangrui Song <maskray@google.com> Cc: Jeff Xie <xiehuan09@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yin Fengwei <fengwei.yin@intel.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm: introduce pmd|pte_needs_soft_dirty_wp helpers for softdirty write-protectBarry Song
Patch series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers and utilize them", v2. This patchset introduces the pte_need_soft_dirty_wp and pmd_need_soft_dirty_wp helpers to determine if write protection is required for softdirty tracking. These helpers enhance code readability and improve the overall appearance. They are then utilized in gup, mprotect, swap, and other related functions. This patch (of 2): This patch introduces the pte_needs_soft_dirty_wp and pmd_needs_soft_dirty_wp helpers to determine if write protection is required for softdirty tracking. This can enhance code readability and improve its overall appearance. These new helpers are then utilized in gup, huge_memory, and mprotect. Link: https://lkml.kernel.org/r/20240607211358.4660-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20240607211358.4660-2-21cnbao@gmail.com Signed-off-by: Barry Song <v-songbaohua@oppo.com> Suggested-by: David Hildenbrand <david@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <kasong@tencent.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm: shmem: add mTHP counters for anonymous shmemBaolin Wang
Add mTHP counters for anonymous shmem. [baolin.wang@linux.alibaba.com: update Documentation/admin-guide/mm/transhuge.rst] Link: https://lkml.kernel.org/r/d86e2e7f-4141-432b-b2ba-c6691f36ef0b@linux.alibaba.com Link: https://lkml.kernel.org/r/4fd9e467d49ae4a747e428bcd821c7d13125ae67.1718090413.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Lance Yang <ioworker0@gmail.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Daniel Gomez <da.gomez@samsung.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03mm: shmem: add multi-size THP sysfs interface for anonymous shmemBaolin Wang
To support the use of mTHP with anonymous shmem, add a new sysfs interface 'shmem_enabled' in the '/sys/kernel/mm/transparent_hugepage/hugepages-kB/' directory for each mTHP to control whether shmem is enabled for that mTHP, with a value similar to the top level 'shmem_enabled', which can be set to: "always", "inherit (to inherit the top level setting)", "within_size", "advise", "never". An 'inherit' option is added to ensure compatibility with these global settings, and the options 'force' and 'deny' are dropped, which are rather testing artifacts from the old ages. By default, PMD-sized hugepages have enabled="inherit" and all other hugepage sizes have enabled="never" for '/sys/kernel/mm/transparent_hugepage/hugepages-xxkB/shmem_enabled'. In addition, if top level value is 'force', then only PMD-sized hugepages have enabled="inherit", otherwise configuration will be failed and vice versa. That means now we will avoid using non-PMD sized THP to override the global huge allocation. [baolin.wang@linux.alibaba.com: fix transhuge.rst indentation] Link: https://lkml.kernel.org/r/b189d815-998b-4dfd-ba89-218ff51313f8@linux.alibaba.com [akpm@linux-foundation.org: reflow transhuge.rst addition to 80 cols] [baolin.wang@linux.alibaba.com: move huge_shmem_orders_lock under CONFIG_SYSFS] Link: https://lkml.kernel.org/r/eb34da66-7f12-44f3-a39e-2bcc90c33354@linux.alibaba.com [akpm@linux-foundation.org: huge_memory.c needs mm_types.h] Link: https://lkml.kernel.org/r/ffddfa8b3cb4266ff963099ab78cfd7184c57ac7.1718090413.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Daniel Gomez <da.gomez@samsung.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>