kernel/linux.git/mm/truncate.c, branch v6.6.141

mm/truncate: unmap large folio on split failure

2025-11-24T09:30:13+00:00

commit fa04f5b60fda62c98a53a60de3a1e763f11feb41 upstream. Accesses within VMA, but beyond i_size rounded up to PAGE_SIZE are supposed to generate SIGBUS. This behavior might not be respected on truncation. During truncation, the kernel splits a large folio in order to reclaim memory. As a side effect, it unmaps the folio and destroys PMD mappings of the folio. The folio will be refaulted as PTEs and SIGBUS semantics are preserved. However, if the split fails, PMD mappings are preserved and the user will not receive SIGBUS on any accesses within the PMD. Unmap the folio on split failure. It will lead to refault as PTEs and preserve SIGBUS semantics. Make an exception for shmem/tmpfs that for long time intentionally mapped with PMDs across i_size. Link: https://lkml.kernel.org/r/20251027115636.82382-3-kirill@shutemov.name Fixes: b9a8a4195c7d ("truncate,shmem: Handle truncates that split large folios") Signed-off-by: Kiryl Shutsemau Cc: Al Viro Cc: Baolin Wang Cc: Christian Brauner Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: David Hildenbrand Cc: Hugh Dickins Cc: Johannes Weiner Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Rik van Riel Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton Signed-off-by: Kiryl Shutsemau Signed-off-by: Greg Kroah-Hartman

mm: Fix missing folio invalidation calls during truncation

2024-09-04T11:28:23+00:00

[ Upstream commit 0aa2e1b2fb7a75aa4b5b4347055ccfea6f091769 ] When AS_RELEASE_ALWAYS is set on a mapping, the ->release_folio() and ->invalidate_folio() calls should be invoked even if PG_private and PG_private_2 aren't set. This is used by netfslib to keep track of the point above which reads can be skipped in favour of just zeroing pagecache locally. There are a couple of places in truncation in which invalidation is only called when folio_has_private() is true. Fix these to check folio_needs_release() instead. Without this, the generic/075 and generic/112 xfstests (both fsx-based tests) fail with minimum folio size patches applied[1]. Fixes: b4fa966f03b7 ("mm, netfs, fscache: stop read optimisation when folio removed from pagecache") Signed-off-by: David Howells Link: https://lore.kernel.org/r/20240815090849.972355-1-kernel@pankajraghav.com/ [1] Link: https://lore.kernel.org/r/20240823200819.532106-2-dhowells@redhat.com Reviewed-by: Matthew Wilcox (Oracle) cc: Matthew Wilcox (Oracle) cc: Pankaj Raghav cc: Jeff Layton cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: netfs@lists.linux.dev cc: linux-mm@kvack.org cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

Merge tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-29T21:25:26+00:00

Pull MM updates from Andrew Morton: - Some swap cleanups from Ma Wupeng ("fix WARN_ON in add_to_avail_list") - Peter Xu has a series (mm/gup: Unify hugetlb, speed up thp") which reduces the special-case code for handling hugetlb pages in GUP. It also speeds up GUP handling of transparent hugepages. - Peng Zhang provides some maple tree speedups ("Optimize the fast path of mas_store()"). - Sergey Senozhatsky has improved te performance of zsmalloc during compaction (zsmalloc: small compaction improvements"). - Domenico Cerasuolo has developed additional selftest code for zswap ("selftests: cgroup: add zswap test program"). - xu xin has doe some work on KSM's handling of zero pages. These changes are mainly to enable the user to better understand the effectiveness of KSM's treatment of zero pages ("ksm: support tracking KSM-placed zero-pages"). - Jeff Xu has fixes the behaviour of memfd's MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED sysctl ("mm/memfd: fix sysctl MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED"). - David Howells has fixed an fscache optimization ("mm, netfs, fscache: Stop read optimisation when folio removed from pagecache"). - Axel Rasmussen has given userfaultfd the ability to simulate memory poisoning ("add UFFDIO_POISON to simulate memory poisoning with UFFD"). - Miaohe Lin has contributed some routine maintenance work on the memory-failure code ("mm: memory-failure: remove unneeded PageHuge() check"). - Peng Zhang has contributed some maintenance work on the maple tree code ("Improve the validation for maple tree and some cleanup"). - Hugh Dickins has optimized the collapsing of shmem or file pages into THPs ("mm: free retracted page table by RCU"). - Jiaqi Yan has a patch series which permits us to use the healthy subpages within a hardware poisoned huge page for general purposes ("Improve hugetlbfs read on HWPOISON hugepages"). - Kemeng Shi has done some maintenance work on the pagetable-check code ("Remove unused parameters in page_table_check"). - More folioification work from Matthew Wilcox ("More filesystem folio conversions for 6.6"), ("Followup folio conversions for zswap"). And from ZhangPeng ("Convert several functions in page_io.c to use a folio"). - page_ext cleanups from Kemeng Shi ("minor cleanups for page_ext"). - Baoquan He has converted some architectures to use the GENERIC_IOREMAP ioremap()/iounmap() code ("mm: ioremap: Convert architectures to take GENERIC_IOREMAP way"). - Anshuman Khandual has optimized arm64 tlb shootdown ("arm64: support batched/deferred tlb shootdown during page reclamation/migration"). - Better maple tree lockdep checking from Liam Howlett ("More strict maple tree lockdep"). Liam also developed some efficiency improvements ("Reduce preallocations for maple tree"). - Cleanup and optimization to the secondary IOMMU TLB invalidation, from Alistair Popple ("Invalidate secondary IOMMU TLB on permission upgrade"). - Ryan Roberts fixes some arm64 MM selftest issues ("selftests/mm fixes for arm64"). - Kemeng Shi provides some maintenance work on the compaction code ("Two minor cleanups for compaction"). - Some reduction in mmap_lock pressure from Matthew Wilcox ("Handle most file-backed faults under the VMA lock"). - Aneesh Kumar contributes code to use the vmemmap optimization for DAX on ppc64, under some circumstances ("Add support for DAX vmemmap optimization for ppc64"). - page-ext cleanups from Kemeng Shi ("add page_ext_data to get client data in page_ext"), ("minor cleanups to page_ext header"). - Some zswap cleanups from Johannes Weiner ("mm: zswap: three cleanups"). - kmsan cleanups from ZhangPeng ("minor cleanups for kmsan"). - VMA handling cleanups from Kefeng Wang ("mm: convert to vma_is_initial_heap/stack()"). - DAMON feature work from SeongJae Park ("mm/damon/sysfs-schemes: implement DAMOS tried total bytes file"), ("Extend DAMOS filters for address ranges and DAMON monitoring targets"). - Compaction work from Kemeng Shi ("Fixes and cleanups to compaction"). - Liam Howlett has improved the maple tree node replacement code ("maple_tree: Change replacement strategy"). - ZhangPeng has a general code cleanup - use the K() macro more widely ("cleanup with helper macro K()"). - Aneesh Kumar brings memmap-on-memory to ppc64 ("Add support for memmap on memory feature on ppc64"). - pagealloc cleanups from Kemeng Shi ("Two minor cleanups for pcp list in page_alloc"), ("Two minor cleanups for get pageblock migratetype"). - Vishal Moola introduces a memory descriptor for page table tracking, "struct ptdesc" ("Split ptdesc from struct page"). - memfd selftest maintenance work from Aleksa Sarai ("memfd: cleanups for vm.memfd_noexec"). - MM include file rationalization from Hugh Dickins ("arch: include asm/cacheflush.h in asm/hugetlb.h"). - THP debug output fixes from Hugh Dickins ("mm,thp: fix sloppy text output"). - kmemleak improvements from Xiaolei Wang ("mm/kmemleak: use object_cache instead of kmemleak_initialized"). - More folio-related cleanups from Matthew Wilcox ("Remove _folio_dtor and _folio_order"). - A VMA locking scalability improvement from Suren Baghdasaryan ("Per-VMA lock support for swap and userfaults"). - pagetable handling cleanups from Matthew Wilcox ("New page table range API"). - A batch of swap/thp cleanups from David Hildenbrand ("mm/swap: stop using page->private on tail pages for THP_SWAP + cleanups"). - Cleanups and speedups to the hugetlb fault handling from Matthew Wilcox ("Change calling convention for ->huge_fault"). - Matthew Wilcox has also done some maintenance work on the MM subsystem documentation ("Improve mm documentation"). * tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (489 commits) maple_tree: shrink struct maple_tree maple_tree: clean up mas_wr_append() secretmem: convert page_is_secretmem() to folio_is_secretmem() nios2: fix flush_dcache_page() for usage from irq context hugetlb: add documentation for vma_kernel_pagesize() mm: add orphaned kernel-doc to the rst files. mm: fix clean_record_shared_mapping_range kernel-doc mm: fix get_mctgt_type() kernel-doc mm: fix kernel-doc warning from tlb_flush_rmaps() mm: remove enum page_entry_size mm: allow ->huge_fault() to be called without the mmap_lock held mm: move PMD_ORDER to pgtable.h mm: remove checks for pte_index memcg: remove duplication detection for mem_cgroup_uncharge_swap mm/huge_memory: work on folio->swap instead of page->private when splitting folio mm/swap: inline folio_set_swap_entry() and folio_swap_entry() mm/swap: use dedicated entry for swap in folio mm/swap: stop using page->private on tail pages for THP_SWAP selftests/mm: fix WARNING comparing pointer to 0 selftests: cgroup: fix test_kmem_memcg_deletion kernel mem check ...

mm: merge folio_has_private()/filemap_release_folio() call pairs

2023-08-18T17:12:12+00:00

Patch series "mm, netfs, fscache: Stop read optimisation when folio removed from pagecache", v7. This fixes an optimisation in fscache whereby we don't read from the cache for a particular file until we know that there's data there that we don't have in the pagecache. The problem is that I'm no longer using PG_fscache (aka PG_private_2) to indicate that the page is cached and so I don't get a notification when a cached page is dropped from the pagecache. The first patch merges some folio_has_private() and filemap_release_folio() pairs and introduces a helper, folio_needs_release(), to indicate if a release is required. The second patch is the actual fix. Following Willy's suggestions[1], it adds an AS_RELEASE_ALWAYS flag to an address_space that will make filemap_release_folio() always call ->release_folio(), even if PG_private/PG_private_2 aren't set. folio_needs_release() is altered to add a check for this. This patch (of 2): Make filemap_release_folio() check folio_has_private(). Then, in most cases, where a call to folio_has_private() is immediately followed by a call to filemap_release_folio(), we can get rid of the test in the pair. There are a couple of sites in mm/vscan.c that this can't so easily be done. In shrink_folio_list(), there are actually three cases (something different is done for incompletely invalidated buffers), but filemap_release_folio() elides two of them. In shrink_active_list(), we don't have have the folio lock yet, so the check allows us to avoid locking the page unnecessarily. A wrapper function to check if a folio needs release is provided for those places that still need to do it in the mm/ directory. This will acquire additional parts to the condition in a future patch. After this, the only remaining caller of folio_has_private() outside of mm/ is a check in fuse. Link: https://lkml.kernel.org/r/20230628104852.3391651-1-dhowells@redhat.com Link: https://lkml.kernel.org/r/20230628104852.3391651-2-dhowells@redhat.com Reported-by: Rohith Surabattula Suggested-by: Matthew Wilcox Signed-off-by: David Howells Cc: Matthew Wilcox Cc: Linus Torvalds Cc: Steve French Cc: Shyam Prasad N Cc: Rohith Surabattula Cc: Dave Wysochanski Cc: Dominique Martinet Cc: Ilya Dryomov Cc: "Theodore Ts'o" Cc: Andreas Dilger Cc: Xiubo Li Cc: Jingbo Xu Signed-off-by: Andrew Morton

mm: increase usage of folio_next_index() helper

2023-08-18T17:12:00+00:00

Simplify code pattern of 'folio->index + folio_nr_pages(folio)' by using the existing helper folio_next_index(). Link: https://lkml.kernel.org/r/20230627174349.491803-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Suggested-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Cc: Andreas Dilger Cc: Christoph Hellwig Cc: Hugh Dickins Cc: Matthew Wilcox Cc: Theodore Ts'o Signed-off-by: Andrew Morton

mm: invalidation check mapping before folio_contains

2023-08-11T11:48:55+00:00

Enabling tmpfs "direct IO" exposes it to invalidate_inode_pages2_range(), which when swapping can hit the VM_BUG_ON_FOLIO(!folio_contains()): the folio has been moved from page cache to swap cache (with folio->mapping reset to NULL), but the folio_index() embedded in folio_contains() sees swapcache, and so returns the swapcache_index() - whereas folio->index would be the right one to check against the index from mapping's xarray. There are different ways to fix this, but my preference is just to order the checks in invalidate_inode_pages2_range() the same way that they are in __filemap_get_folio() and find_lock_entries() and filemap_fault(): check folio->mapping before folio_contains(). Signed-off-by: Hugh Dickins Reviewed-by: Jan Kara Message-Id: Signed-off-by: Christian Brauner

mm: remove references to pagevec

2023-06-23T23:59:30+00:00

Most of these should just refer to the LRU cache rather than the data structure used to implement the LRU cache. Link: https://lkml.kernel.org/r/20230621164557.3510324-13-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

mm: rename invalidate_mapping_pagevec to mapping_try_invalidate

2023-06-23T23:59:30+00:00

We don't use pagevecs for the LRU cache any more, and we don't know that the failed invalidations were due to the folio being in an LRU cache. So rename it to be more accurate. Link: https://lkml.kernel.org/r/20230621164557.3510324-12-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

mm: return an ERR_PTR from __filemap_get_folio

2023-04-06T02:42:42+00:00

Instead of returning NULL for all errors, distinguish between: - no entry found and not asked to allocated (-ENOENT) - failed to allocate memory (-ENOMEM) - would block (-EAGAIN) so that callers don't have to guess the error based on the passed in flags. Also pass through the error through the direct callers: filemap_get_folio, filemap_lock_folio filemap_grab_folio and filemap_get_incore_folio. [hch@lst.de: fix null-pointer deref] Link: https://lkml.kernel.org/r/20230310070023.GA13563@lst.de Link: https://lkml.kernel.org/r/20230310043137.GA1624890@u2004 Link: https://lkml.kernel.org/r/20230307143410.28031-8-hch@lst.de Signed-off-by: Christoph Hellwig Acked-by: Ryusuke Konishi [nilfs2] Cc: Andreas Gruenbacher Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Naoya Horiguchi Signed-off-by: Andrew Morton

folio-compat: remove lru_cache_add()

2022-12-12T02:12:13+00:00

There are no longer any callers of lru_cache_add(), so remove it. This saves 79 bytes of kernel text. Also cleanup some comments such that they reference the new folio_add_lru() instead. Link: https://lkml.kernel.org/r/20221101175326.13265-6-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Reviewed-by: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Miklos Szeredi Signed-off-by: Andrew Morton