lwn.git/fs/iomap, branch docs-6.8

Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-11-03T05:38:47+00:00

Pull MM updates from Andrew Morton: "Many singleton patches against the MM code. The patch series which are included in this merge do the following: - Kemeng Shi has contributed some compation maintenance work in the series 'Fixes and cleanups to compaction' - Joel Fernandes has a patchset ('Optimize mremap during mutual alignment within PMD') which fixes an obscure issue with mremap()'s pagetable handling during a subsequent exec(), based upon an implementation which Linus suggested - More DAMON/DAMOS maintenance and feature work from SeongJae Park i the following patch series: mm/damon: misc fixups for documents, comments and its tracepoint mm/damon: add a tracepoint for damos apply target regions mm/damon: provide pseudo-moving sum based access rate mm/damon: implement DAMOS apply intervals mm/damon/core-test: Fix memory leaks in core-test mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval - In the series 'Do not try to access unaccepted memory' Adrian Hunter provides some fixups for the recently-added 'unaccepted memory' feature. To increase the feature's checking coverage. 'Plug a few gaps where RAM is exposed without checking if it is unaccepted memory' - In the series 'cleanups for lockless slab shrink' Qi Zheng has done some maintenance work which is preparation for the lockless slab shrinking code - Qi Zheng has redone the earlier (and reverted) attempt to make slab shrinking lockless in the series 'use refcount+RCU method to implement lockless slab shrink' - David Hildenbrand contributes some maintenance work for the rmap code in the series 'Anon rmap cleanups' - Kefeng Wang does more folio conversions and some maintenance work in the migration code. Series 'mm: migrate: more folio conversion and unification' - Matthew Wilcox has fixed an issue in the buffer_head code which was causing long stalls under some heavy memory/IO loads. Some cleanups were added on the way. Series 'Add and use bdev_getblk()' - In the series 'Use nth_page() in place of direct struct page manipulation' Zi Yan has fixed a potential issue with the direct manipulation of hugetlb page frames - In the series 'mm: hugetlb: Skip initialization of gigantic tail struct pages if freed by HVO' has improved our handling of gigantic pages in the hugetlb vmmemmep optimizaton code. This provides significant boot time improvements when significant amounts of gigantic pages are in use - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code rationalization and folio conversions in the hugetlb code - Yin Fengwei has improved mlock()'s handling of large folios in the series 'support large folio for mlock' - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has added statistics for memcg v1 users which are available (and useful) under memcg v2 - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable) prctl so that userspace may direct the kernel to not automatically propagate the denial to child processes. The series is named 'MDWE without inheritance' - Kefeng Wang has provided the series 'mm: convert numa balancing functions to use a folio' which does what it says - In the series 'mm/ksm: add fork-exec support for prctl' Stefan Roesch makes is possible for a process to propagate KSM treatment across exec() - Huang Ying has enhanced memory tiering's calculation of memory distances. This is used to permit the dax/kmem driver to use 'high bandwidth memory' in addition to Optane Data Center Persistent Memory Modules (DCPMM). The series is named 'memory tiering: calculate abstract distance based on ACPI HMAT' - In the series 'Smart scanning mode for KSM' Stefan Roesch has optimized KSM by teaching it to retain and use some historical information from previous scans - Yosry Ahmed has fixed some inconsistencies in memcg statistics in the series 'mm: memcg: fix tracking of pending stats updates values' - In the series 'Implement IOCTL to get and optionally clear info about PTEs' Peter Xu has added an ioctl to /proc//pagemap which permits us to atomically read-then-clear page softdirty state. This is mainly used by CRIU - Hugh Dickins contributed the series 'shmem,tmpfs: general maintenance', a bunch of relatively minor maintenance tweaks to this code - Matthew Wilcox has increased the use of the VMA lock over file-backed page faults in the series 'Handle more faults under the VMA lock'. Some rationalizations of the fault path became possible as a result - In the series 'mm/rmap: convert page_move_anon_rmap() to folio_move_anon_rmap()' David Hildenbrand has implemented some cleanups and folio conversions - In the series 'various improvements to the GUP interface' Lorenzo Stoakes has simplified and improved the GUP interface with an eye to providing groundwork for future improvements - Andrey Konovalov has sent along the series 'kasan: assorted fixes and improvements' which does those things - Some page allocator maintenance work from Kemeng Shi in the series 'Two minor cleanups to break_down_buddy_pages' - In thes series 'New selftest for mm' Breno Leitao has developed another MM self test which tickles a race we had between madvise() and page faults - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups and an optimization to the core pagecache code - Nhat Pham has added memcg accounting for hugetlb memory in the series 'hugetlb memcg accounting' - Cleanups and rationalizations to the pagemap code from Lorenzo Stoakes, in the series 'Abstract vma_merge() and split_vma()' - Audra Mitchell has fixed issues in the procfs page_owner code's new timestamping feature which was causing some misbehaviours. In the series 'Fix page_owner's use of free timestamps' - Lorenzo Stoakes has fixed the handling of new mappings of sealed files in the series 'permit write-sealed memfd read-only shared mappings' - Mike Kravetz has optimized the hugetlb vmemmap optimization in the series 'Batch hugetlb vmemmap modification operations' - Some buffer_head folio conversions and cleanups from Matthew Wilcox in the series 'Finish the create_empty_buffers() transition' - As a page allocator performance optimization Huang Ying has added automatic tuning to the allocator's per-cpu-pages feature, in the series 'mm: PCP high auto-tuning' - Roman Gushchin has contributed the patchset 'mm: improve performance of accounted kernel memory allocations' which improves their performance by ~30% as measured by a micro-benchmark - folio conversions from Kefeng Wang in the series 'mm: convert page cpupid functions to folios' - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about kmemleak' - Qi Zheng has improved our handling of memoryless nodes by keeping them off the allocation fallback list. This is done in the series 'handle memoryless nodes more appropriately' - khugepaged conversions from Vishal Moola in the series 'Some khugepaged folio conversions'" [ bcachefs conflicts with the dynamically allocated shrinkers have been resolved as per Stephen Rothwell in https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/ with help from Qi Zheng. The clone3 test filtering conflict was half-arsed by yours truly ] * tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits) mm/damon/sysfs: update monitoring target regions for online input commit mm/damon/sysfs: remove requested targets when online-commit inputs selftests: add a sanity check for zswap Documentation: maple_tree: fix word spelling error mm/vmalloc: fix the unchecked dereference warning in vread_iter() zswap: export compression failure stats Documentation: ubsan: drop "the" from article title mempolicy: migration attempt to match interleave nodes mempolicy: mmap_lock is not needed while migrating folios mempolicy: alloc_pages_mpol() for NUMA policy without vma mm: add page_rmappable_folio() wrapper mempolicy: remove confusing MPOL_MF_LAZY dead code mempolicy: mpol_shared_policy_init() without pseudo-vma mempolicy trivia: use pgoff_t in shared mempolicy tree mempolicy trivia: slightly more consistent naming mempolicy trivia: delete those ancient pr_debug()s mempolicy: fix migrate_pages(2) syscall return nr_failed kernfs: drop shared NUMA mempolicy hooks hugetlbfs: drop shared NUMA mempolicy pretence mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets() ...

iomap: fix short copy in iomap_write_iter()

2023-10-19T16:41:36+00:00

Starting with commit 5d8edfb900d5 ("iomap: Copy larger chunks from userspace"), iomap_write_iter() can get into endless loop. This can be reproduced with LTP writev07 which uses partially valid iovecs: struct iovec wr_iovec[] = { { buffer, 64 }, { bad_addr, 64 }, { buffer + 64, 64 }, { buffer + 64 * 2, 64 }, }; commit bc1bb416bbb9 ("generic_perform_write()/iomap_write_actor(): saner logics for short copy") previously introduced the logic, which made short copy retry in next iteration with amount of "bytes" it managed to copy: if (unlikely(status == 0)) { /* * A short copy made iomap_write_end() reject the * thing entirely. Might be memory poisoning * halfway through, might be a race with munmap, * might be severe memory pressure. */ if (copied) bytes = copied; However, since 5d8edfb900d5 "bytes" is no longer carried into next iteration, because it is now always initialized at the beginning of the loop. And for iov_iter_count < PAGE_SIZE, "bytes" ends up with same value as previous iteration, making the loop retry same copy over and over, which leads to writev07 testcase hanging. Make next iteration retry with amount of bytes we managed to copy. Fixes: 5d8edfb900d5 ("iomap: Copy larger chunks from userspace") Signed-off-by: Jan Stancek Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig

iomap: use folio_end_read()

2023-10-18T21:34:16+00:00

Combine the setting of the uptodate flag with the clearing of the locked flag. Link: https://lkml.kernel.org/r/20231004165317.1061855-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Albert Ou Cc: Alexander Gordeev Cc: Andreas Dilger Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Geert Uytterhoeven Cc: Heiko Carstens Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Richard Henderson Cc: Sven Schnelle Cc: "Theodore Ts'o" Cc: Thomas Bogendoerfer Cc: Vasily Gorbik Signed-off-by: Andrew Morton

iomap: protect read_bytes_pending with the state_lock

2023-10-18T21:34:16+00:00

Perform one atomic operation (acquiring the spinlock) instead of two (spinlock & atomic_sub) per read completion. Link: https://lkml.kernel.org/r/20231004165317.1061855-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Albert Ou Cc: Alexander Gordeev Cc: Andreas Dilger Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Geert Uytterhoeven Cc: Heiko Carstens Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Richard Henderson Cc: Sven Schnelle Cc: "Theodore Ts'o" Cc: Thomas Bogendoerfer Cc: Vasily Gorbik Signed-off-by: Andrew Morton

iomap: hold state_lock over call to ifs_set_range_uptodate()

2023-10-18T21:34:16+00:00

Patch series "Add folio_end_read", v2. The core of this patchset is the new folio_end_read() call which filesystems can use when finishing a page cache read instead of separate calls to mark the folio uptodate and unlock it. As an illustration of its use, I converted ext4, iomap & mpage; more can be converted. I think that's useful by itself, but the interesting optimisation is that we can implement that with a single XOR instruction that sets the uptodate bit, clears the lock bit, tests the waiter bit and provides a write memory barrier. That removes one memory barrier and one atomic instruction from each page read, which seems worth doing. That's in patch 15. The last two patches could be a separate series, but basically we can do the same thing with the writeback flag that we do with the unlock flag; clear it and test the waiters bit at the same time. This patch (of 17): This is really preparation for the next patch, but it lets us call folio_mark_uptodate() in just one place instead of two. Link: https://lkml.kernel.org/r/20231004165317.1061855-1-willy@infradead.org Link: https://lkml.kernel.org/r/20231004165317.1061855-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Matthew Wilcox (Oracle) Cc: Nicholas Piggin Cc: "Theodore Ts'o" Cc: Andreas Dilger Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Thomas Bogendoerfer Cc: Michael Ellerman Cc: Christophe Leroy Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Sven Schnelle Cc: Geert Uytterhoeven Signed-off-by: Andrew Morton

iomap: Spelling s/preceeding/preceding/g

2023-09-28T16:26:58+00:00

Fix a misspelling of "preceding". Signed-off-by: Geert Uytterhoeven Reviewed-by: Bill O'Donnell Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

iomap: convert iomap_unshare_iter to use large folios

2023-09-19T16:05:35+00:00

Convert iomap_unshare_iter to create large folios if possible, since the write and zeroing paths already do that. I think this got missed in the conversion of the write paths that landed in 6.6-rc1. Cc: ritesh.list@gmail.com, willy@infradead.org Signed-off-by: Darrick J. Wong Reviewed-by: Ritesh Harjani (IBM)

iomap: don't skip reading in !uptodate folios when unsharing a range

2023-09-18T22:57:39+00:00

Prior to commit a01b8f225248e, we would always read in the contents of a !uptodate folio prior to writing userspace data into the folio, allocated a folio state object, etc. Ritesh introduced an optimization that skips all of that if the write would cover the entire folio. Unfortunately, the optimization misses the unshare case, where we always have to read in the folio contents since there isn't a data buffer supplied by userspace. This can result in stale kernel memory exposure if userspace issues a FALLOC_FL_UNSHARE_RANGE call on part of a shared file that isn't already cached. This was caught by observing fstests regressions in the "unshare around" mechanism that is used for unaligned writes to a reflinked realtime volume when the realtime extent size is larger than 1FSB, though I think it applies to any shared file. Cc: ritesh.list@gmail.com, willy@infradead.org Fixes: a01b8f225248e ("iomap: Allocate ifs in ->write_begin() early") Signed-off-by: Darrick J. Wong Reviewed-by: Ritesh Harjani (IBM)

Merge tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux

2023-08-30T03:21:42+00:00

Pull block updates from Jens Axboe: "Pretty quiet round for this release. This contains: - Add support for zoned storage to ublk (Andreas, Ming) - Series improving performance for drivers that mark themselves as needing a blocking context for issue (Bart) - Cleanup the flush logic (Chengming) - sed opal keyring support (Greg) - Fixes and improvements to the integrity support (Jinyoung) - Add some exports for bcachefs that we can hopefully delete again in the future (Kent) - deadline throttling fix (Zhiguo) - Series allowing building the kernel without buffer_head support (Christoph) - Sanitize the bio page adding flow (Christoph) - Write back cache fixes (Christoph) - MD updates via Song: - Fix perf regression for raid0 large sequential writes (Jan) - Fix split bio iostat for raid0 (David) - Various raid1 fixes (Heinz, Xueshi) - raid6test build fixes (WANG) - Deprecate bitmap file support (Christoph) - Fix deadlock with md sync thread (Yu) - Refactor md io accounting (Yu) - Various non-urgent fixes (Li, Yu, Jack) - Various fixes and cleanups (Arnd, Azeem, Chengming, Damien, Li, Ming, Nitesh, Ruan, Tejun, Thomas, Xu)" * tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux: (113 commits) block: use strscpy() to instead of strncpy() block: sed-opal: keyring support for SED keys block: sed-opal: Implement IOC_OPAL_REVERT_LSP block: sed-opal: Implement IOC_OPAL_DISCOVERY blk-mq: prealloc tags when increase tagset nr_hw_queues blk-mq: delete redundant tagset map update when fallback blk-mq: fix tags leak when shrink nr_hw_queues ublk: zoned: support REQ_OP_ZONE_RESET_ALL md: raid0: account for split bio in iostat accounting md/raid0: Fix performance regression for large sequential writes md/raid0: Factor out helper for mapping and submitting a bio md raid1: allow writebehind to work on any leg device set WriteMostly md/raid1: hold the barrier until handle_read_error() finishes md/raid1: free the r1bio before waiting for blocked rdev md/raid1: call free_r1bio() before allow_barrier() in raid_end_bio_io() blk-cgroup: Fix NULL deref caused by blkg_policy_data being installed before init drivers/rnbd: restore sysfs interface to rnbd-client md/raid5-cache: fix null-ptr-deref for r5l_flush_stripe_to_raid() raid6: test: only check for Altivec if building on powerpc hosts raid6: test: make sure all intermediate and artifact files are .gitignored ...

fs: rename and move block_page_mkwrite_return

2023-08-02T15:13:09+00:00

block_page_mkwrite_return is neither block nor mkwrite specific, and should not be under CONFIG_BLOCK. Move it to mm.h and rename it to vmf_fs_error. Signed-off-by: Christoph Hellwig Reviewed-by: Luis Chamberlain Reviewed-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20230801172201.1923299-3-hch@lst.de Signed-off-by: Jens Axboe