kernel/linux.git/mm/zsmalloc.c, branch v6.19.11

mm: remove unused zpool layer

2025-09-21T21:21:59+00:00

With zswap using zsmalloc directly, there are no more in-tree users of this code. Remove it. With zpool gone, zsmalloc is now always a simple dependency and no longer something the user needs to configure. Hide CONFIG_ZSMALLOC from the user and have zswap and zram pull it in as needed. Link: https://lkml.kernel.org/r/20250829162212.208258-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Acked-by: SeongJae Park Acked-by: Yosry Ahmed Cc: Chengming Zhou Cc: Nhat Pham Cc: Vitaly Wool Signed-off-by: Andrew Morton

treewide: remove MIGRATEPAGE_SUCCESS

2025-09-13T23:54:50+00:00

At this point MIGRATEPAGE_SUCCESS is misnamed for all folio users, and now that we remove MIGRATEPAGE_UNMAP, it's really the only "success" return value that the code uses and expects. Let's just get rid of MIGRATEPAGE_SUCCESS completely and just use "0" for success. Link: https://lkml.kernel.org/r/20250811143949.1117439-3-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Zi Yan [mm] Acked-by: Dave Kleikamp [jfs] Acked-by: David Sterba [btrfs] Acked-by: Greg Kroah-Hartman Reviewed-by: Byungchul Park Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Benjamin LaHaise Cc: Chris Mason Cc: Christian Brauner Cc: Christophe Leroy Cc: Dave Kleikamp Cc: Eugenio Pé rez Cc: Gregory Price Cc: "Huang, Ying" Cc: Jan Kara Cc: Jason Wang Cc: Jerrin Shaji George Cc: Josef Bacik Cc: Joshua Hahn Cc: Madhavan Srinivasan Cc: Mathew Brost Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Minchan Kim Cc: Muchun Song Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Rakie Kim Cc: Sergey Senozhatsky Cc: Xuan Zhuo Cc: Lance Yang Signed-off-by: Andrew Morton

mm/migrate: fix NULL movable_ops if CONFIG_ZSMALLOC=m

2025-08-19T23:35:57+00:00

After commit 84caf98838a3e5f4bdb34 ("mm: stop storing migration_ops in page->mapping") we get such an error message if CONFIG_ZSMALLOC=m: WARNING: CPU: 3 PID: 42 at mm/migrate.c:142 isolate_movable_ops_page+0xa8/0x1c0 CPU: 3 UID: 0 PID: 42 Comm: kcompactd0 Not tainted 6.16.0-rc5+ #2133 PREEMPT pc 9000000000540bd8 ra 9000000000540b84 tp 9000000100420000 sp 9000000100423a60 a0 9000000100193a80 a1 000000000000000c a2 000000000000001b a3 ffffffffffffffff a4 ffffffffffffffff a5 0000000000000267 a6 0000000000000000 a7 9000000100423ae0 t0 00000000000000f1 t1 00000000000000f6 t2 0000000000000000 t3 0000000000000001 t4 ffffff00010eb834 t5 0000000000000040 t6 900000010c89d380 t7 90000000023fcc70 t8 0000000000000018 u0 0000000000000000 s9 ffffff00010eb800 s0 ffffff00010eb800 s1 000000000000000c s2 0000000000043ae0 s3 0000800000000000 s4 900000000219cc40 s5 0000000000000000 s6 ffffff00010eb800 s7 0000000000000001 s8 90000000025b4000 ra: 9000000000540b84 isolate_movable_ops_page+0x54/0x1c0 ERA: 9000000000540bd8 isolate_movable_ops_page+0xa8/0x1c0 CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE) PRMD: 00000004 (PPLV0 +PIE -PWE) EUEN: 00000000 (-FPE -SXE -ASXE -BTE) ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7) ESTAT: 000c0000 [BRK] (IS= ECode=12 EsubCode=0) PRID: 0014c010 (Loongson-64bit, Loongson-3A5000) CPU: 3 UID: 0 PID: 42 Comm: kcompactd0 Not tainted 6.16.0-rc5+ #2133 PREEMPT Stack : 90000000021fd000 0000000000000000 9000000000247720 9000000100420000 90000001004236a0 90000001004236a8 0000000000000000 90000001004237e8 90000001004237e0 90000001004237e0 9000000100423550 0000000000000001 0000000000000001 90000001004236a8 725a84864a19e2d9 90000000023fcc58 9000000100420000 90000000024c6848 9000000002416848 0000000000000001 0000000000000000 000000000000000a 0000000007fe0000 ffffff00010eb800 0000000000000000 90000000021fd000 0000000000000000 900000000205cf30 000000000000008e 0000000000000009 ffffff00010eb800 0000000000000001 90000000025b4000 0000000000000000 900000000024773c 00007ffff103d748 00000000000000b0 0000000000000004 0000000000000000 0000000000071c1d ... Call Trace: [<900000000024773c>] show_stack+0x5c/0x190 [<90000000002415e0>] dump_stack_lvl+0x70/0x9c [<90000000004abe6c>] isolate_migratepages_block+0x3bc/0x16e0 [<90000000004af408>] compact_zone+0x558/0x1000 [<90000000004b0068>] compact_node+0xa8/0x1e0 [<90000000004b0aa4>] kcompactd+0x394/0x410 [<90000000002b3c98>] kthread+0x128/0x140 [<9000000001779148>] ret_from_kernel_thread+0x28/0xc0 [<9000000000245528>] ret_from_kernel_thread_asm+0x10/0x88 The reason is that defined(CONFIG_ZSMALLOC) evaluates to 1 only when CONFIG_ZSMALLOC=y, we should use IS_ENABLED(CONFIG_ZSMALLOC) instead. But when I use IS_ENABLED(CONFIG_ZSMALLOC), page_movable_ops() cannot access zsmalloc_mops because zsmalloc_mops is in a module. To solve this problem, we define a set_movable_ops() interface to register and unregister offline_movable_ops / zsmalloc_movable_ops in mm/migrate.c, and call them at mm/balloon_compaction.c & mm/zsmalloc.c. Since offline_movable_ops / zsmalloc_movable_ops are always accessible, all #ifdef / #endif are removed in page_movable_ops(). Link: https://lkml.kernel.org/r/20250817151759.2525174-1-chenhuacai@loongson.cn Fixes: 84caf98838a3 ("mm: stop storing migration_ops in page->mapping") Signed-off-by: Huacai Chen Acked-by: Zi Yan Acked-by: David Hildenbrand Cc: Huacai Chen Cc: Huacai Chen Cc: Lorenzo Stoakes Cc: "Michael S. Tsirkin" Cc: Minchan Kim Cc: Sergey Senozhatsky Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-07-31T21:57:54+00:00

Pull MM updates from Andrew Morton: "As usual, many cleanups. The below blurbiage describes 42 patchsets. 21 of those are partially or fully cleanup work. "cleans up", "cleanup", "maintainability", "rationalizes", etc. I never knew the MM code was so dirty. "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes) addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly mapped VMAs were not eligible for merging with existing adjacent VMAs. "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park) adds a new kernel module which simplifies the setup and usage of DAMON in production environments. "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig) is a cleanup to the writeback code which removes a couple of pointers from struct writeback_control. "drivers/base/node.c: optimization and cleanups" (Donet Tom) contains largely uncorrelated cleanups to the NUMA node setup and management code. "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman) does some maintenance work on the userfaultfd code. "Readahead tweaks for larger folios" (Ryan Roberts) implements some tuneups for pagecache readahead when it is reading into order>0 folios. "selftests/mm: Tweaks to the cow test" (Mark Brown) provides some cleanups and consistency improvements to the selftests code. "Optimize mremap() for large folios" (Dev Jain) does that. A 37% reduction in execution time was measured in a memset+mremap+munmap microbenchmark. "Remove zero_user()" (Matthew Wilcox) expunges zero_user() in favor of the more modern memzero_page(). "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand) addresses some warts which David noticed in the huge page code. These were not known to be causing any issues at this time. "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park) provides some cleanup and consolidation work in DAMON. "use vm_flags_t consistently" (Lorenzo Stoakes) uses vm_flags_t in places where we were inappropriately using other types. "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy) increases the reliability of large page allocation in the memfd code. "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple) removes several now-unneeded PFN_* flags. "mm/damon: decouple sysfs from core" (SeongJae Park) implememnts some cleanup and maintainability work in the DAMON sysfs layer. "madvise cleanup" (Lorenzo Stoakes) does quite a lot of cleanup/maintenance work in the madvise() code. "madvise anon_name cleanups" (Vlastimil Babka) provides additional cleanups on top or Lorenzo's effort. "Implement numa node notifier" (Oscar Salvador) creates a standalone notifier for NUMA node memory state changes. Previously these were lumped under the more general memory on/offline notifier. "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan) cleans up the pageblock isolation code and fixes a potential issue which doesn't seem to cause any problems in practice. "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park) adds additional drgn- and python-based DAMON selftests which are more comprehensive than the existing selftest suite. "Misc rework on hugetlb faulting path" (Oscar Salvador) fixes a rather obscure deadlock in the hugetlb fault code and follows that fix with a series of cleanups. "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport) rationalizes and cleans up the highmem-specific code in the CMA allocator. "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand) provides cleanups and future-preparedness to the migration code. "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park) adds some tracepoints to some DAMON auto-tuning code. "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park) does that. "mm/damon: misc cleanups" (SeongJae Park) also does what it claims. "mm: folio_pte_batch() improvements" (David Hildenbrand) cleans up the large folio PTE batching code. "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park) facilitates dynamic alteration of DAMON's inter-node allocation policy. "Remove unmap_and_put_page()" (Vishal Moola) provides a couple of page->folio conversions. "mm: per-node proactive reclaim" (Davidlohr Bueso) implements a per-node control of proactive reclaim - beyond the current memcg-based implementation. "mm/damon: remove damon_callback" (SeongJae Park) replaces the damon_callback interface with a more general and powerful damon_call()+damos_walk() interface. "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes) implements a number of mremap cleanups (of course) in preparation for adding new mremap() functionality: newly permit the remapping of multiple VMAs when the user is specifying MREMAP_FIXED. It still excludes some specialized situations where this cannot be performed reliably. "drop hugetlb_free_pgd_range()" (Anthony Yznaga) switches some sparc hugetlb code over to the generic version and removes the thus-unneeded hugetlb_free_pgd_range(). "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park) augments the present userspace-requested update of DAMON sysfs monitoring files. Automatic update is now provided, along with a tunable to control the update interval. "Some randome fixes and cleanups to swapfile" (Kemeng Shi) does what is claims. "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand) provides (and uses) a means by which debug-style functions can grab a copy of a pageframe and inspect it locklessly without tripping over the races inherent in operating on the live pageframe directly. "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan) addresses the large contention issues which can be triggered by reads from that procfs file. Latencies are reduced by more than half in some situations. The series also introduces several new selftests for the /proc/pid/maps interface. "__folio_split() clean up" (Zi Yan) cleans up __folio_split()! "Optimize mprotect() for large folios" (Dev Jain) provides some quite large (>3x) speedups to mprotect() when dealing with large folios. "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian) does some cleanup work in the selftests code. "tools/testing: expand mremap testing" (Lorenzo Stoakes) extends the mremap() selftest in several ways, including adding more checking of Lorenzo's recently added "permit mremap() move of multiple VMAs" feature. "selftests/damon/sysfs.py: test all parameters" (SeongJae Park) extends the DAMON sysfs interface selftest so that it tests all possible user-requested parameters. Rather than the present minimal subset" * tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits) MAINTAINERS: add missing headers to mempory policy & migration section MAINTAINERS: add missing file to cgroup section MAINTAINERS: add MM MISC section, add missing files to MISC and CORE MAINTAINERS: add missing zsmalloc file MAINTAINERS: add missing files to page alloc section MAINTAINERS: add missing shrinker files MAINTAINERS: move memremap.[ch] to hotplug section MAINTAINERS: add missing mm_slot.h file THP section MAINTAINERS: add missing interval_tree.c to memory mapping section MAINTAINERS: add missing percpu-internal.h file to per-cpu section mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info() selftests/damon: introduce _common.sh to host shared function selftests/damon/sysfs.py: test runtime reduction of DAMON parameters selftests/damon/sysfs.py: test non-default parameters runtime commit selftests/damon/sysfs.py: generalize DAMON context commit assertion selftests/damon/sysfs.py: generalize monitoring attributes commit assertion selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion selftests/damon/sysfs.py: test DAMOS filters commitment selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion selftests/damon/sysfs.py: test DAMOS destinations commitment ...

mm/zsmalloc: do not pass __GFP_MOVABLE if CONFIG_COMPACTION=n

2025-07-20T02:26:15+00:00

Commit 48b4800a1c6a ("zsmalloc: page migration support") added support for migrating zsmalloc pages using the movable_operations migration framework. However, the commit did not take into account that zsmalloc supports migration only when CONFIG_COMPACTION is enabled. Tracing shows that zsmalloc was still passing the __GFP_MOVABLE flag even when compaction is not supported. This can result in unmovable pages being allocated from movable page blocks (even without stealing page blocks), ZONE_MOVABLE and CMA area. Possible user visible effects: - Some ZONE_MOVABLE memory can be not actually movable - CMA allocation can fail because of this - Increased memory fragmentation due to ignoring the page mobility grouping feature I'm not really sure who uses kernels without compaction support, though :( To fix this, clear the __GFP_MOVABLE flag when !IS_ENABLED(CONFIG_COMPACTION). Link: https://lkml.kernel.org/r/20250704103053.6913-1-harry.yoo@oracle.com Fixes: 48b4800a1c6a ("zsmalloc: page migration support") Signed-off-by: Harry Yoo Acked-by: David Hildenbrand Reviewed-by: Sergey Senozhatsky Cc: Minchan Kim Cc: Signed-off-by: Andrew Morton

mm: stop storing migration_ops in page->mapping

2025-07-13T23:38:29+00:00

... instead, look them up statically based on the page type. Maybe in the future we want a registration interface? At least for now, it can be easily handled using the two page types that actually support page migration. The remaining usage of page->mapping is to flag such pages as actually being movable (having movable_ops), which we will change next. Link: https://lkml.kernel.org/r/20250704102524.326966-20-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Zi Yan Reviewed-by: Lorenzo Stoakes Reviewed-by: Harry Yoo Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Brendan Jackman Cc: Byungchul Park Cc: Chengming Zhou Cc: Christian Brauner Cc: Christophe Leroy Cc: Eugenio Pé rez Cc: Greg Kroah-Hartman Cc: Gregory Price Cc: "Huang, Ying" Cc: Jan Kara Cc: Jason Gunthorpe Cc: Jason Wang Cc: Jerrin Shaji George Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joshua Hahn Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Michal Hocko Cc: Mike Rapoport Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Cc: Qi Zheng Cc: Rakie Kim Cc: Rik van Riel Cc: Sergey Senozhatsky Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: xu xin Signed-off-by: Andrew Morton

mm/zsmalloc: stop using __ClearPageMovable()

2025-07-13T23:38:28+00:00

Instead, let's check in the callbacks if the page was already destroyed, which can be checked by looking at zpdesc->zspage (see reset_zpdesc()). If we detect that the page was destroyed: (1) Fail isolation, just like the migration core would (2) Fake migration success just like the migration core would In the putback case there is nothing to do, as we don't do anything just like the migration core would do. In the future, we should look into not letting these pages get destroyed while they are isolated -- and instead delaying that to the putback/migration call. Add a TODO for that. Link: https://lkml.kernel.org/r/20250704102524.326966-13-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Harry Yoo Reviewed-by: Lorenzo Stoakes Reviewed-by: Sergey Senozhatsky Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Brendan Jackman Cc: Byungchul Park Cc: Chengming Zhou Cc: Christian Brauner Cc: Christophe Leroy Cc: Eugenio Pé rez Cc: Greg Kroah-Hartman Cc: Gregory Price Cc: "Huang, Ying" Cc: Jan Kara Cc: Jason Gunthorpe Cc: Jason Wang Cc: Jerrin Shaji George Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joshua Hahn Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Michal Hocko Cc: Mike Rapoport Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Cc: Qi Zheng Cc: Rakie Kim Cc: Rik van Riel Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: xu xin Cc: Zi Yan Signed-off-by: Andrew Morton

mm/zsmalloc: make PageZsmalloc() sticky until the page is freed

2025-07-13T23:38:26+00:00

Let the page freeing code handle clearing the page type. Being able to identify balloon pages until actually freed is a requirement for upcoming movable_ops migration changes. Link: https://lkml.kernel.org/r/20250704102524.326966-7-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Zi Yan Reviewed-by: Sergey Senozhatsky Acked-by: Harry Yoo Reviewed-by: Lorenzo Stoakes Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Brendan Jackman Cc: Byungchul Park Cc: Chengming Zhou Cc: Christian Brauner Cc: Christophe Leroy Cc: Eugenio Pé rez Cc: Greg Kroah-Hartman Cc: Gregory Price Cc: "Huang, Ying" Cc: Jan Kara Cc: Jason Gunthorpe Cc: Jason Wang Cc: Jerrin Shaji George Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joshua Hahn Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Michal Hocko Cc: Mike Rapoport Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Cc: Qi Zheng Cc: Rakie Kim Cc: Rik van Riel Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: xu xin Signed-off-by: Andrew Morton

mm/zsmalloc: drop PageIsolated() related VM_BUG_ONs

2025-07-13T23:38:25+00:00

Let's drop these checks; these are conditions the core migration code must make sure will hold either way, no need to double check. Link: https://lkml.kernel.org/r/20250704102524.326966-4-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Zi Yan Reviewed-by: Sergey Senozhatsky Acked-by: Harry Yoo Reviewed-by: Lorenzo Stoakes Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Brendan Jackman Cc: Byungchul Park Cc: Chengming Zhou Cc: Christian Brauner Cc: Christophe Leroy Cc: Eugenio Pé rez Cc: Greg Kroah-Hartman Cc: Gregory Price Cc: "Huang, Ying" Cc: Jan Kara Cc: Jason Gunthorpe Cc: Jason Wang Cc: Jerrin Shaji George Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joshua Hahn Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Michal Hocko Cc: Mike Rapoport Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Cc: Qi Zheng Cc: Rakie Kim Cc: Rik van Riel Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: xu xin Signed-off-by: Andrew Morton

zsmalloc: cleanup headers includes

2025-05-12T00:48:16+00:00

Remove unused headers includes from zsmalloc and move pagemap.h and migrate.h includes into zpdesc header. Link: https://lkml.kernel.org/r/20250325080427.3449359-1-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky Cc: Minchan Kim Signed-off-by: Andrew Morton