kernel/linux.git/include/linux/shmem_fs.h, branch v6.18.21

mm: constify shmem related test functions for improved const-correctness

2025-09-21T21:22:12+00:00

Patch series "mm: establish const-correctness for pointer parameters", v6. This series is to improved const-correctness in the low-level memory-management subsystem, which provides a basis for further constification further up the call stack (e.g. filesystems). I started this work when I tried to constify the Ceph filesystem code, but found that to be impossible because many "mm" functions accept non-const pointers, even though they modify nothing. This patch (of 12): We select certain test functions which either invoke each other, functions that are already const-ified, or no further functions. It is therefore relatively trivial to const-ify them, which provides a basis for further const-ification further up the call stack. Link: https://lkml.kernel.org/r/20250901205021.3573313-1-max.kellermann@ionos.com Link: https://lkml.kernel.org/r/20250901205021.3573313-2-max.kellermann@ionos.com Signed-off-by: Max Kellermann Reviewed-by: Vishal Moola (Oracle) Reviewed-by: Lorenzo Stoakes Acked-by: David Hildenbrand Acked-by: Vlastimil Babka Acked-by: Mike Rapoport (Microsoft) Acked-by: Shakeel Butt Cc: Alexander Gordeev Cc: Al Viro Cc: Andreas Larsson Cc: Andy Lutomirski Cc: Axel Rasmussen Cc: Baolin Wang Cc: Borislav Betkov Cc: Christian Borntraeger Cc: Christian Brauner Cc: Christian Zankel Cc: David Rientjes Cc: David S. Miller Cc: Gerald Schaefer Cc: Heiko Carstens Cc: Helge Deller Cc: "H. Peter Anvin" Cc: Hugh Dickins Cc: Ingo Molnar Cc: James Bottomley Cc: Jan Kara Cc: Jocelyn Falempe Cc: Liam Howlett Cc: Mark Brown Cc: Matthew Wilcox (Oracle) Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Hocko Cc: "Nysal Jan K.A" Cc: Oscar Salvador Cc: Peter Zijlstra Cc: Russel King Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Thomas Gleinxer Cc: Thomas Huth Cc: Vasily Gorbik Cc: Wei Xu Cc: Yuanchu Xie Signed-off-by: Andrew Morton

mm: stop passing a writeback_control structure to shmem_writeout

2025-07-10T05:41:57+00:00

shmem_writeout only needs the swap_iocb cookie and the split folio list. Pass those explicitly and remove the now unused list member from struct writeback_control. Link: https://lkml.kernel.org/r/20250610054959.2057526-3-hch@lst.de Signed-off-by: Christoph Hellwig Cc: Baolin Wang Cc: Chengming Zhou Cc: Hugh Dickins Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Nhat Pham Signed-off-by: Andrew Morton

shmem: Add shmem_writeout()

2025-04-07T07:36:49+00:00

This will be the replacement for shmem_writepage(). Signed-off-by: "Matthew Wilcox (Oracle)" Link: https://lore.kernel.org/r/20250402150005.2309458-6-willy@infradead.org Reviewed-by: Baolin Wang Signed-off-by: Christian Brauner

Merge tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-11-23T17:58:07+00:00

Pull MM updates from Andrew Morton: - The series "zram: optimal post-processing target selection" from Sergey Senozhatsky improves zram's post-processing selection algorithm. This leads to improved memory savings. - Wei Yang has gone to town on the mapletree code, contributing several series which clean up the implementation: - "refine mas_mab_cp()" - "Reduce the space to be cleared for maple_big_node" - "maple_tree: simplify mas_push_node()" - "Following cleanup after introduce mas_wr_store_type()" - "refine storing null" - The series "selftests/mm: hugetlb_fault_after_madv improvements" from David Hildenbrand fixes this selftest for s390. - The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng implements some rationaizations and cleanups in the page mapping code. - The series "mm: optimize shadow entries removal" from Shakeel Butt optimizes the file truncation code by speeding up the handling of shadow entries. - The series "Remove PageKsm()" from Matthew Wilcox completes the migration of this flag over to being a folio-based flag. - The series "Unify hugetlb into arch_get_unmapped_area functions" from Oscar Salvador implements a bunch of consolidations and cleanups in the hugetlb code. - The series "Do not shatter hugezeropage on wp-fault" from Dev Jain takes away the wp-fault time practice of turning a huge zero page into small pages. Instead we replace the whole thing with a THP. More consistent cleaner and potentiall saves a large number of pagefaults. - The series "percpu: Add a test case and fix for clang" from Andy Shevchenko enhances and fixes the kernel's built in percpu test code. - The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett optimizes mremap() by avoiding doing things which we didn't need to do. - The series "Improve the tmpfs large folio read performance" from Baolin Wang teaches tmpfs to copy data into userspace at the folio size rather than as individual pages. A 20% speedup was observed. - The series "mm/damon/vaddr: Fix issue in damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON splitting. - The series "memcg-v1: fully deprecate charge moving" from Shakeel Butt removes the long-deprecated memcgv2 charge moving feature. - The series "fix error handling in mmap_region() and refactor" from Lorenzo Stoakes cleanup up some of the mmap() error handling and addresses some potential performance issues. - The series "x86/module: use large ROX pages for text allocations" from Mike Rapoport teaches x86 to use large pages for read-only-execute module text. - The series "page allocation tag compression" from Suren Baghdasaryan is followon maintenance work for the new page allocation profiling feature. - The series "page->index removals in mm" from Matthew Wilcox remove most references to page->index in mm/. A slow march towards shrinking struct page. - The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs interface tests" from Andrew Paniakin performs maintenance work for DAMON's self testing code. - The series "mm: zswap swap-out of large folios" from Kanchana Sridhar improves zswap's batching of compression and decompression. It is a step along the way towards using Intel IAA hardware acceleration for this zswap operation. - The series "kasan: migrate the last module test to kunit" from Sabyrzhan Tasbolatov completes the migration of the KASAN built-in tests over to the KUnit framework. - The series "implement lightweight guard pages" from Lorenzo Stoakes permits userapace to place fault-generating guard pages within a single VMA, rather than requiring that multiple VMAs be created for this. Improved efficiencies for userspace memory allocators are expected. - The series "memcg: tracepoint for flushing stats" from JP Kobryn uses tracepoints to provide increased visibility into memcg stats flushing activity. - The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky fixes a zram buglet which potentially affected performance. - The series "mm: add more kernel parameters to control mTHP" from Maíra Canal enhances our ability to control/configuremultisize THP from the kernel boot command line. - The series "kasan: few improvements on kunit tests" from Sabyrzhan Tasbolatov has a couple of fixups for the KASAN KUnit tests. - The series "mm/list_lru: Split list_lru lock into per-cgroup scope" from Kairui Song optimizes list_lru memory utilization when lockdep is enabled. * tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (215 commits) cma: enforce non-zero pageblock_order during cma_init_reserved_mem() mm/kfence: add a new kunit test test_use_after_free_read_nofault() zram: fix NULL pointer in comp_algorithm_show() memcg/hugetlb: add hugeTLB counters to memcg vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event mm: mmap_lock: check trace_mmap_lock_$type_enabled() instead of regcount zram: ZRAM_DEF_COMP should depend on ZRAM MAINTAINERS/MEMORY MANAGEMENT: add document files for mm Docs/mm/damon: recommend academic papers to read and/or cite mm: define general function pXd_init() kmemleak: iommu/iova: fix transient kmemleak false positive mm/list_lru: simplify the list_lru walk callback function mm/list_lru: split the lock to per-cgroup scope mm/list_lru: simplify reparenting and initial allocation mm/list_lru: code clean up for reparenting mm/list_lru: don't export list_lru_add mm/list_lru: don't pass unnecessary key parameters kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller kasan: change kasan_atomics kunit test as KUNIT_CASE_SLOW kasan: use EXPORT_SYMBOL_IF_KUNIT to export symbols ...

mm: shmem: fix khugepaged activation policy for shmem

2024-11-06T00:56:20+00:00

Shmem has a separate interface (different from anonymous pages) to control huge page allocation, that means shmem THP can be enabled while anonymous THP is disabled. However, in this case, khugepaged will not start to collapse shmem THP, which is unreasonable. To fix this issue, we should call start_stop_khugepaged() to activate or deactivate the khugepaged thread when setting shmem mTHP interfaces. Moreover, add a new helper shmem_hpage_pmd_enabled() to help to check whether shmem THP is enabled, which will determine if khugepaged should be activated. Link: https://lkml.kernel.org/r/9b9c6cbc4499bf44c6455367fd9e0f6036525680.1726978977.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Reported-by: Ryan Roberts Reviewed-by: Ryan Roberts Cc: David Hildenbrand Cc: Hugh Dickins Cc: Matthew Wilcox Signed-off-by: Andrew Morton

tmpfs: Add flag FS_CASEFOLD_FL support for tmpfs dirs

2024-10-28T12:36:55+00:00

Enable setting flag FS_CASEFOLD_FL for tmpfs directories, when tmpfs is mounted with casefold support. A special check is need for this flag, since it can't be set for non-empty directories. Reviewed-by: Gabriel Krisman Bertazi Reviewed-by: Gabriel Krisman Bertazi Signed-off-by: André Almeida Link: https://lore.kernel.org/r/20241021-tonyk-tmpfs-v8-7-f443d5814194@igalia.com Signed-off-by: Christian Brauner

mm,tmpfs: consider end of file write in shmem_is_huge

2024-09-09T23:39:12+00:00

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 Reviewed-by: Baolin Wang Tested-by: Baolin Wang Cc: Darrick J. Wong Cc: Hugh Dickins Cc: Matthew Wilcox Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: shmem: move shmem_huge_global_enabled() into shmem_allowable_huge_orders()

2024-09-02T03:25:44+00:00

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 Reviewed-by: Ryan Roberts Acked-by: David Hildenbrand Cc: Barry Song <21cnbao@gmail.com> Cc: Hugh Dickins Cc: Lance Yang Cc: Matthew Wilcox (Oracle) Cc: Zi Yan Signed-off-by: Andrew Morton

mm: shmem: rename shmem_is_huge() to shmem_huge_global_enabled()

2024-09-02T03:25:44+00:00

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 Reviewed-by: Ryan Roberts Acked-by: David Hildenbrand Cc: Barry Song <21cnbao@gmail.com> Cc: Hugh Dickins Cc: Lance Yang Cc: Matthew Wilcox (Oracle) Cc: Zi Yan Signed-off-by: Andrew Morton

mm: thp: support "THPeligible" semantics for mTHP with anonymous shmem

2024-07-12T22:52:21+00:00

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 Reviewed-by: Baolin Wang Cc: David Hildenbrand Cc: Hugh Dickins Cc: Kefeng Wang Cc: Lance Yang Cc: Ryan Roberts Cc: Zi Yan Signed-off-by: Andrew Morton