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* Merge tag 'mm-stable-2024-11-18-19-27' of ↵Linus Torvalds10 days1-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 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: remove redundant condition for THP folioDev Jain2024-11-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | folio_test_pmd_mappable() implies folio_test_large(), therefore, simplify the expression for is_thp. Link: https://lkml.kernel.org/r/20241018094151.3458-1-dev.jain@arm.com Signed-off-by: Dev Jain <dev.jain@arm.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm: migrate LRU_REFS_MASK bits in folio_migrate_flagsZhaoyang Huang2024-11-061-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Bits of LRU_REFS_MASK are not inherited during migration which lead to new folio start from tier0 when MGLRU enabled. Try to bring as much bits of folio->flags as possible since compaction and alloc_contig_range which introduce migration do happen at times. Link: https://lkml.kernel.org/r/20240926050647.5653-1-zhaoyang.huang@unisoc.com Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com> Suggested-by: Yu Zhao <yuzhao@google.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | Merge tag 'vfs-6.13.pagecache' of ↵Linus Torvalds2024-11-181-2/+2
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs pagecache updates from Christian Brauner: "Cleanup filesystem page flag usage: This continues the work to make the mappedtodisk/owner_2 flag available to filesystems which don't use buffer heads. Further patches remove uses of Private2. This brings us very close to being rid of it entirely" * tag 'vfs-6.13.pagecache' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: migrate: Remove references to Private2 ceph: Remove call to PagePrivate2() btrfs: Switch from using the private_2 flag to owner_2 mm: Remove PageMappedToDisk nilfs2: Convert nilfs_copy_buffer() to use folios fs: Move clearing of mappedtodisk to buffer.c
| * migrate: Remove references to Private2Matthew Wilcox (Oracle)2024-10-041-2/+2
| | | | | | | | | | | | | | | | | | These comments are now stale; rewrite them. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Link: https://lore.kernel.org/r/20241002040111.1023018-7-willy@infradead.org Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
* | mm/thp: fix deferred split unqueue naming and lockingHugh Dickins2024-11-061-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recent changes are putting more pressure on THP deferred split queues: under load revealing long-standing races, causing list_del corruptions, "Bad page state"s and worse (I keep BUGs in both of those, so usually don't get to see how badly they end up without). The relevant recent changes being 6.8's mTHP, 6.10's mTHP swapout, and 6.12's mTHP swapin, improved swap allocation, and underused THP splitting. Before fixing locking: rename misleading folio_undo_large_rmappable(), which does not undo large_rmappable, to folio_unqueue_deferred_split(), which is what it does. But that and its out-of-line __callee are mm internals of very limited usability: add comment and WARN_ON_ONCEs to check usage; and return a bool to say if a deferred split was unqueued, which can then be used in WARN_ON_ONCEs around safety checks (sparing callers the arcane conditionals in __folio_unqueue_deferred_split()). Just omit the folio_unqueue_deferred_split() from free_unref_folios(), all of whose callers now call it beforehand (and if any forget then bad_page() will tell) - except for its caller put_pages_list(), which itself no longer has any callers (and will be deleted separately). Swapout: mem_cgroup_swapout() has been resetting folio->memcg_data 0 without checking and unqueueing a THP folio from deferred split list; which is unfortunate, since the split_queue_lock depends on the memcg (when memcg is enabled); so swapout has been unqueueing such THPs later, when freeing the folio, using the pgdat's lock instead: potentially corrupting the memcg's list. __remove_mapping() has frozen refcount to 0 here, so no problem with calling folio_unqueue_deferred_split() before resetting memcg_data. That goes back to 5.4 commit 87eaceb3faa5 ("mm: thp: make deferred split shrinker memcg aware"): which included a check on swapcache before adding to deferred queue, but no check on deferred queue before adding THP to swapcache. That worked fine with the usual sequence of events in reclaim (though there were a couple of rare ways in which a THP on deferred queue could have been swapped out), but 6.12 commit dafff3f4c850 ("mm: split underused THPs") avoids splitting underused THPs in reclaim, which makes swapcache THPs on deferred queue commonplace. Keep the check on swapcache before adding to deferred queue? Yes: it is no longer essential, but preserves the existing behaviour, and is likely to be a worthwhile optimization (vmstat showed much more traffic on the queue under swapping load if the check was removed); update its comment. Memcg-v1 move (deprecated): mem_cgroup_move_account() has been changing folio->memcg_data without checking and unqueueing a THP folio from the deferred list, sometimes corrupting "from" memcg's list, like swapout. Refcount is non-zero here, so folio_unqueue_deferred_split() can only be used in a WARN_ON_ONCE to validate the fix, which must be done earlier: mem_cgroup_move_charge_pte_range() first try to split the THP (splitting of course unqueues), or skip it if that fails. Not ideal, but moving charge has been requested, and khugepaged should repair the THP later: nobody wants new custom unqueueing code just for this deprecated case. The 87eaceb3faa5 commit did have the code to move from one deferred list to another (but was not conscious of its unsafety while refcount non-0); but that was removed by 5.6 commit fac0516b5534 ("mm: thp: don't need care deferred split queue in memcg charge move path"), which argued that the existence of a PMD mapping guarantees that the THP cannot be on a deferred list. As above, false in rare cases, and now commonly false. Backport to 6.11 should be straightforward. Earlier backports must take care that other _deferred_list fixes and dependencies are included. There is not a strong case for backports, but they can fix cornercases. Link: https://lkml.kernel.org/r/8dc111ae-f6db-2da7-b25c-7a20b1effe3b@google.com Fixes: 87eaceb3faa5 ("mm: thp: make deferred split shrinker memcg aware") Fixes: dafff3f4c850 ("mm: split underused THPs") Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | vmscan,migrate: fix page count imbalance on node stats when demoting pagesGregory Price2024-11-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When numa balancing is enabled with demotion, vmscan will call migrate_pages when shrinking LRUs. migrate_pages will decrement the the node's isolated page count, leading to an imbalanced count when invoked from (MG)LRU code. The result is dmesg output like such: $ cat /proc/sys/vm/stat_refresh [77383.088417] vmstat_refresh: nr_isolated_anon -103212 [77383.088417] vmstat_refresh: nr_isolated_file -899642 This negative value may impact compaction and reclaim throttling. The following path produces the decrement: shrink_folio_list demote_folio_list migrate_pages migrate_pages_batch migrate_folio_move migrate_folio_done mod_node_page_state(-ve) <- decrement This path happens for SUCCESSFUL migrations, not failures. Typically callers to migrate_pages are required to handle putback/accounting for failures, but this is already handled in the shrink code. When accounting for migrations, instead do not decrement the count when the migration reason is MR_DEMOTION. As of v6.11, this demotion logic is the only source of MR_DEMOTION. Link: https://lkml.kernel.org/r/20241025141724.17927-1-gourry@gourry.net Fixes: 26aa2d199d6f ("mm/migrate: demote pages during reclaim") Signed-off-by: Gregory Price <gourry@gourry.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Wei Xu <weixugc@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | mm: avoid VM_BUG_ON when try to map an anon large folio to zero page.Zi Yan2024-10-311-1/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | An anonymous large folio can be split into non order-0 folios, try_to_map_unused_to_zeropage() should not VM_BUG_ON compound pages but just return false. This fixes the crash when splitting anonymous large folios to non order-0 folios. Link: https://lkml.kernel.org/r/20241023171236.1122535-1-ziy@nvidia.com Fixes: b1f202060afe ("mm: remap unused subpages to shared zeropage when splitting isolated thp") Signed-off-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Usama Arif <usamaarif642@gmail.com> Cc: Barry Song <baohua@kernel.org> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport (Microsoft) <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: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: migrate: annotate data-race in migrate_folio_unmap()Jeongjun Park2024-09-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I found a report from syzbot [1] This report shows that the value can be changed, but in reality, the value of __folio_set_movable() cannot be changed because it holds the folio refcount. Therefore, it is appropriate to add an annotate to make KCSAN ignore that data-race. [1] ================================================================== BUG: KCSAN: data-race in __filemap_remove_folio / migrate_pages_batch write to 0xffffea0004b81dd8 of 8 bytes by task 6348 on cpu 0: page_cache_delete mm/filemap.c:153 [inline] __filemap_remove_folio+0x1ac/0x2c0 mm/filemap.c:233 filemap_remove_folio+0x6b/0x1f0 mm/filemap.c:265 truncate_inode_folio+0x42/0x50 mm/truncate.c:178 shmem_undo_range+0x25b/0xa70 mm/shmem.c:1028 shmem_truncate_range mm/shmem.c:1144 [inline] shmem_evict_inode+0x14d/0x530 mm/shmem.c:1272 evict+0x2f0/0x580 fs/inode.c:731 iput_final fs/inode.c:1883 [inline] iput+0x42a/0x5b0 fs/inode.c:1909 dentry_unlink_inode+0x24f/0x260 fs/dcache.c:412 __dentry_kill+0x18b/0x4c0 fs/dcache.c:615 dput+0x5c/0xd0 fs/dcache.c:857 __fput+0x3fb/0x6d0 fs/file_table.c:439 ____fput+0x1c/0x30 fs/file_table.c:459 task_work_run+0x13a/0x1a0 kernel/task_work.c:228 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xbe/0x130 kernel/entry/common.c:218 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffea0004b81dd8 of 8 bytes by task 6342 on cpu 1: __folio_test_movable include/linux/page-flags.h:699 [inline] migrate_folio_unmap mm/migrate.c:1199 [inline] migrate_pages_batch+0x24c/0x1940 mm/migrate.c:1797 migrate_pages_sync mm/migrate.c:1963 [inline] migrate_pages+0xff1/0x1820 mm/migrate.c:2072 do_mbind mm/mempolicy.c:1390 [inline] kernel_mbind mm/mempolicy.c:1533 [inline] __do_sys_mbind mm/mempolicy.c:1607 [inline] __se_sys_mbind+0xf76/0x1160 mm/mempolicy.c:1603 __x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1603 x64_sys_call+0x2b4d/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:238 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xffff888127601078 -> 0x0000000000000000 Link: https://lkml.kernel.org/r/20240924130053.107490-1-aha310510@gmail.com Fixes: 7e2a5e5ab217 ("mm: migrate: use __folio_test_movable()") Signed-off-by: Jeongjun Park <aha310510@gmail.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/codetag: add pgalloc_tag_copy()Yu Zhao2024-09-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | Add pgalloc_tag_copy() to transfer the codetag from the old folio to the new one during migration. This makes original allocation sites persist cross migration rather than lump into the get_new_folio callbacks passed into migrate_pages(), e.g., compaction_alloc(): # echo 1 >/proc/sys/vm/compact_memory # grep compaction_alloc /proc/allocinfo Before this patch: 132968448 32463 mm/compaction.c:1880 func:compaction_alloc After this patch: 0 0 mm/compaction.c:1880 func:compaction_alloc Link: https://lkml.kernel.org/r/20240906042108.1150526-3-yuzhao@google.com Fixes: dcfe378c81f7 ("lib: introduce support for page allocation tagging") 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>
* mm: migrate: remove unused includesKefeng Wang2024-09-101-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | random.h is not needed since commit 6c542ab75714 ("mm/demotion: build demotion targets based on explicit memory tiers"), all functions moved into memory-tiers. nsproxy.h is not needed since commit 228ebcbe634a ("Uninline find_task_by_xxx set of functions"), no nsproxy, we only call find_task_by_vpid() now. hugetlb_cgroup.h is not needed since commit ab5ac90aecf5 ("mm, hugetlb: do not rely on overcommit limit during migration"), move_hugetlb_state() is called and it belongs to hugetlb.h, which is already included. balloon_compaction.h, we have more general movable_operations for non-lru movable page migration, so it could be dropped. memremap.h, userfaultfd_k.h and oom.h are introduced for zone device page migration, but all functions are moved into migrate_device.c, so no needed anymore too. Link: https://lkml.kernel.org/r/20240905152432.626877-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: migrate: simplify find_mm_struct()Nanyong Sun2024-09-101-7/+1
| | | | | | | | | | | | | | Use find_get_task_by_vpid() to replace the task_struct find logic in find_mm_struct(), note that this patch move the ptrace_may_access() call out from rcu_read_lock() scope, this is ok because it actually does not need it, find_get_task_by_vpid() already get the pid and task safely, ptrace_may_access() can use the task safely, like what sched_core_share_pid() similarly do. Link: https://lkml.kernel.org/r/20240905153118.1205173-1-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>
* mm: introduce a pageflag for partially mapped foliosUsama Arif2024-09-101-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* mm: remap unused subpages to shared zeropage when splitting isolated thpYu Zhao2024-09-101-9/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* mm: count the number of anonymous THPs per sizeBarry Song2024-09-101-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* mm: migrate: add isolate_folio_to_list()Kefeng Wang2024-09-041-0/+26
| | | | | | | | | | | | | | | | | | | Add isolate_folio_to_list() helper to try to isolate HugeTLB, no-LRU movable and LRU folios to a list, which will be reused by do_migrate_range() from memory hotplug soon, also drop the mf_isolate_folio() since we could directly use new helper in the soft_offline_in_use_page(). Link: https://lkml.kernel.org/r/20240827114728.3212578-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Tested-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: remove PageSwapCacheMatthew Wilcox (Oracle)2024-09-041-1/+2
| | | | | | | | | This flag is now only used on folios, so we can remove all the page accessors and reword the comments that refer to them. Link: https://lkml.kernel.org/r/20240821193445.2294269-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm,memcg: provide per-cgroup counters for NUMA balancing operationsKaiyang Zhao2024-09-041-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ability to observe the demotion and promotion decisions made by the kernel on a per-cgroup basis is important for monitoring and tuning containerized workloads on machines equipped with tiered memory. Different containers in the system may experience drastically different memory tiering actions that cannot be distinguished from the global counters alone. For example, a container running a workload that has a much hotter memory accesses will likely see more promotions and fewer demotions, potentially depriving a colocated container of top tier memory to such an extent that its performance degrades unacceptably. For another example, some containers may exhibit longer periods between data reuse, causing much more numa_hint_faults than numa_pages_migrated. In this case, tuning hot_threshold_ms may be appropriate, but the signal can easily be lost if only global counters are available. In the long term, we hope to introduce per-cgroup control of promotion and demotion actions to implement memory placement policies in tiering. This patch set adds seven counters to memory.stat in a cgroup: numa_pages_migrated, numa_pte_updates, numa_hint_faults, pgdemote_kswapd, pgdemote_khugepaged, pgdemote_direct and pgpromote_success. pgdemote_* and pgpromote_success are also available in memory.numa_stat. count_memcg_events_mm() is added to count multiple event occurrences at once, and get_mem_cgroup_from_folio() is added because we need to get a reference to the memcg of a folio before it's migrated to track numa_pages_migrated. The accounting of PGDEMOTE_* is moved to shrink_inactive_list() before being changed to per-cgroup. [kaiyang2@cs.cmu.edu: add documentation of the memcg counters in cgroup-v2.rst] Link: https://lkml.kernel.org/r/20240814235122.252309-1-kaiyang2@cs.cmu.edu Link: https://lkml.kernel.org/r/20240814174227.30639-1-kaiyang2@cs.cmu.edu Signed-off-by: Kaiyang Zhao <kaiyang2@cs.cmu.edu> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.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> Cc: Wei Xu <weixugc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* fs: remove calls to set and clear the folio error flagMatthew Wilcox (Oracle)2024-09-021-2/+0
| | | | | | | | | | Nobody checks the folio error flag any more, so we can stop setting and clearing it. Also remove the documentation suggesting to not bother setting the error bit. Link: https://lkml.kernel.org/r/20240807193528.1865100-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/migrate: convert add_page_for_migration() from follow_page() to folio_walkDavid Hildenbrand2024-09-021-55/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's use folio_walk instead, so we can avoid taking a folio reference when we won't even be trying to migrate the folio and to get rid of another follow_page()/FOLL_DUMP user. Use FW_ZEROPAGE so we can return "-EFAULT" for it as documented. We now perform the folio_likely_mapped_shared() check under PTL, which is what we want: relying on the mapcount and friends after dropping the PTL does not make too much sense, as the page can get unmapped concurrently from this process. Further, we perform the folio isolation under PTL, similar to how we handle it for MADV_PAGEOUT. The possible return values for follow_page() were confusing, especially with FOLL_DUMP set. We'll handle it like documented in the man page: * -EFAULT: This is a zero page or the memory area is not mapped by the process. * -ENOENT: The page is not present. We'll keep setting -ENOENT for ZONE_DEVICE. Maybe not the right thing to do, but it likely doesn't really matter (just like for weird devmap, whereby we fake "not present"). The other errros are left as is, and match the documentation in the man page. While at it, rename add_page_for_migration() to add_folio_for_migration(). We'll lose the "secretmem" check, but that shouldn't really matter because these folios cannot ever be migrated. Should vma_migratable() refuse these VMAs? Maybe. Link: https://lkml.kernel.org/r/20240802155524.517137-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.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> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/migrate: convert do_pages_stat_array() from follow_page() to folio_walkDavid Hildenbrand2024-09-021-16/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's use folio_walk instead, so we can avoid taking a folio reference just to read the nid and get rid of another follow_page()/FOLL_DUMP user. Use FW_ZEROPAGE so we can return "-EFAULT" for it as documented. The possible return values for follow_page() were confusing, especially with FOLL_DUMP set. We'll handle it like documented in the man page: * -EFAULT: This is a zero page or the memory area is not mapped by the process. * -ENOENT: The page is not present. We'll keep setting -ENOENT for ZONE_DEVICE. Maybe not the right thing to do, but it likely doesn't really matter (just like for weird devmap, whereby we fake "not present"). Note that the other errors (-EACCESS, -EBUSY, -EIO, -EINVAL, -ENOMEM) so far only applied when actually moving pages, not when only querying stats. We'll effectively drop the "secretmem" check we had in follow_page(), but that shouldn't really matter here, we're not accessing folio/page content after all. Link: https://lkml.kernel.org/r/20240802155524.517137-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.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> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: consider CMA pages in watermark check for NUMA balancing target nodeKaiyang Zhao2024-09-021-1/+1
| | | | | | | | | | | | | | | | | | Currently in migrate_balanced_pgdat(), ALLOC_CMA flag is not passed when checking watermark on the migration target node. This does not match the gfp in alloc_misplaced_dst_folio() which allows allocation from CMA. This causes promotion failures when there are a lot of available CMA memory in the system. Therefore, we change the alloc_flags passed to zone_watermark_ok() in migrate_balanced_pgdat(). Link: https://lkml.kernel.org/r/20240801180456.25927-1-kaiyang2@cs.cmu.edu Signed-off-by: Kaiyang Zhao <kaiyang2@cs.cmu.edu> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* memory tiering: count PGPROMOTE_SUCCESS when mem tiering is enabled.Zi Yan2024-09-021-1/+3
| | | | | | | | | | | | | | | | | | | memory tiering can be enabled/disabled at runtime and sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING is used to check it. In migrate_misplaced_folio(), the check is missing when PGPROMOTE_SUCCESS is incremented. Add the missing check. Link: https://lkml.kernel.org/r/20240724130115.793641-4-ziy@nvidia.com Fixes: 33024536bafd ("memory tiering: hot page selection with hint page fault latency") Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com> Closes: https://lore.kernel.org/linux-mm/f4ae2c9c-fe40-4807-bdb2-64cf2d716c1a@huawei.com/ Signed-off-by: Zi Yan <ziy@nvidia.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: "Huang, Ying" <ying.huang@intel.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/migrate: fix deadlock in migrate_pages_batch() on large foliosGao Xiang2024-08-161-5/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, migrate_pages_batch() can lock multiple locked folios with an arbitrary order. Although folio_trylock() is used to avoid deadlock as commit 2ef7dbb26990 ("migrate_pages: try migrate in batch asynchronously firstly") mentioned, it seems try_split_folio() is still missing. It was found by compaction stress test when I explicitly enable EROFS compressed files to use large folios, which case I cannot reproduce with the same workload if large folio support is off (current mainline). Typically, filesystem reads (with locked file-backed folios) could use another bdev/meta inode to load some other I/Os (e.g. inode extent metadata or caching compressed data), so the locking order will be: file-backed folios (A) bdev/meta folios (B) The following calltrace shows the deadlock: Thread 1 takes (B) lock and tries to take folio (A) lock Thread 2 takes (A) lock and tries to take folio (B) lock [Thread 1] INFO: task stress:1824 blocked for more than 30 seconds. Tainted: G OE 6.10.0-rc7+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:stress state:D stack:0 pid:1824 tgid:1824 ppid:1822 flags:0x0000000c Call trace: __switch_to+0xec/0x138 __schedule+0x43c/0xcb0 schedule+0x54/0x198 io_schedule+0x44/0x70 folio_wait_bit_common+0x184/0x3f8 <-- folio mapping ffff00036d69cb18 index 996 (**) __folio_lock+0x24/0x38 migrate_pages_batch+0x77c/0xea0 // try_split_folio (mm/migrate.c:1486:2) // migrate_pages_batch (mm/migrate.c:1734:16) <--- LIST_HEAD(unmap_folios) has .. folio mapping 0xffff0000d184f1d8 index 1711; (*) folio mapping 0xffff0000d184f1d8 index 1712; .. migrate_pages+0xb28/0xe90 compact_zone+0xa08/0x10f0 compact_node+0x9c/0x180 sysctl_compaction_handler+0x8c/0x118 proc_sys_call_handler+0x1a8/0x280 proc_sys_write+0x1c/0x30 vfs_write+0x240/0x380 ksys_write+0x78/0x118 __arm64_sys_write+0x24/0x38 invoke_syscall+0x78/0x108 el0_svc_common.constprop.0+0x48/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x148 el0t_64_sync_handler+0x100/0x130 el0t_64_sync+0x190/0x198 [Thread 2] INFO: task stress:1825 blocked for more than 30 seconds. Tainted: G OE 6.10.0-rc7+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:stress state:D stack:0 pid:1825 tgid:1825 ppid:1822 flags:0x0000000c Call trace: __switch_to+0xec/0x138 __schedule+0x43c/0xcb0 schedule+0x54/0x198 io_schedule+0x44/0x70 folio_wait_bit_common+0x184/0x3f8 <-- folio = 0xfffffdffc6b503c0 (mapping == 0xffff0000d184f1d8 index == 1711) (*) __folio_lock+0x24/0x38 z_erofs_runqueue+0x384/0x9c0 [erofs] z_erofs_readahead+0x21c/0x350 [erofs] <-- folio mapping 0xffff00036d69cb18 range from [992, 1024] (**) read_pages+0x74/0x328 page_cache_ra_order+0x26c/0x348 ondemand_readahead+0x1c0/0x3a0 page_cache_sync_ra+0x9c/0xc0 filemap_get_pages+0xc4/0x708 filemap_read+0x104/0x3a8 generic_file_read_iter+0x4c/0x150 vfs_read+0x27c/0x330 ksys_pread64+0x84/0xd0 __arm64_sys_pread64+0x28/0x40 invoke_syscall+0x78/0x108 el0_svc_common.constprop.0+0x48/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x148 el0t_64_sync_handler+0x100/0x130 el0t_64_sync+0x190/0x198 Link: https://lkml.kernel.org/r/20240729021306.398286-1-hsiangkao@linux.alibaba.com Fixes: 5dfab109d519 ("migrate_pages: batch _unmap and _move") Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* Merge tag 'mm-stable-2024-07-21-14-50' of ↵Linus Torvalds2024-07-221-119/+94
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - In the series "mm: Avoid possible overflows in dirty throttling" Jan Kara addresses a couple of issues in the writeback throttling code. These fixes are also targetted at -stable kernels. - Ryusuke Konishi's series "nilfs2: fix potential issues related to reserved inodes" does that. This should actually be in the mm-nonmm-stable tree, along with the many other nilfs2 patches. My bad. - More folio conversions from Kefeng Wang in the series "mm: convert to folio_alloc_mpol()" - Kemeng Shi has sent some cleanups to the writeback code in the series "Add helper functions to remove repeated code and improve readability of cgroup writeback" - Kairui Song has made the swap code a little smaller and a little faster in the series "mm/swap: clean up and optimize swap cache index". - In the series "mm/memory: cleanly support zeropage in vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David Hildenbrand has reworked the rather sketchy handling of the use of the zeropage in MAP_SHARED mappings. I don't see any runtime effects here - more a cleanup/understandability/maintainablity thing. - Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling of higher addresses, for aarch64. The (poorly named) series is "Restructure va_high_addr_switch". - The core TLB handling code gets some cleanups and possible slight optimizations in Bang Li's series "Add update_mmu_tlb_range() to simplify code". - Jane Chu has improved the handling of our fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in the series "Enhance soft hwpoison handling and injection". - Jeff Johnson has sent a billion patches everywhere to add MODULE_DESCRIPTION() to everything. Some landed in this pull. - In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang has simplified migration's use of hardware-offload memory copying. - Yosry Ahmed performs more folio API conversions in his series "mm: zswap: trivial folio conversions". - In the series "large folios swap-in: handle refault cases first", Chuanhua Han inches us forward in the handling of large pages in the swap code. This is a cleanup and optimization, working toward the end objective of full support of large folio swapin/out. - In the series "mm,swap: cleanup VMA based swap readahead window calculation", Huang Ying has contributed some cleanups and a possible fixlet to his VMA based swap readahead code. - In the series "add mTHP support for anonymous shmem" Baolin Wang has taught anonymous shmem mappings to use multisize THP. By default this is a no-op - users must opt in vis sysfs controls. Dramatic improvements in pagefault latency are realized. - David Hildenbrand has some cleanups to our remaining use of page_mapcount() in the series "fs/proc: move page_mapcount() to fs/proc/internal.h". - David also has some highmem accounting cleanups in the series "mm/highmem: don't track highmem pages manually". - Build-time fixes and cleanups from John Hubbard in the series "cleanups, fixes, and progress towards avoiding "make headers"". - Cleanups and consolidation of the core pagemap handling from Barry Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers and utilize them". - Lance Yang's series "Reclaim lazyfree THP without splitting" has reduced the latency of the reclaim of pmd-mapped THPs under fairly common circumstances. A 10x speedup is seen in a microbenchmark. It does this by punting to aother CPU but I guess that's a win unless all CPUs are pegged. - hugetlb_cgroup cleanups from Xiu Jianfeng in the series "mm/hugetlb_cgroup: rework on cftypes". - Miaohe Lin's series "Some cleanups for memory-failure" does just that thing. - Someone other than SeongJae has developed a DAMON feature in Honggyu Kim's series "DAMON based tiered memory management for CXL memory". This adds DAMON features which may be used to help determine the efficiency of our placement of CXL/PCIe attached DRAM. - DAMON user API centralization and simplificatio work in SeongJae Park's series "mm/damon: introduce DAMON parameters online commit function". - In the series "mm: page_type, zsmalloc and page_mapcount_reset()" David Hildenbrand does some maintenance work on zsmalloc - partially modernizing its use of pageframe fields. - Kefeng Wang provides more folio conversions in the series "mm: remove page_maybe_dma_pinned() and page_mkclean()". - More cleanup from David Hildenbrand, this time in the series "mm/memory_hotplug: use PageOffline() instead of PageReserved() for !ZONE_DEVICE". It "enlightens memory hotplug more about PageOffline() pages" and permits the removal of some virtio-mem hacks. - Barry Song's series "mm: clarify folio_add_new_anon_rmap() and __folio_add_anon_rmap()" is a cleanup to the anon folio handling in preparation for mTHP (multisize THP) swapin. - Kefeng Wang's series "mm: improve clear and copy user folio" implements more folio conversions, this time in the area of large folio userspace copying. - The series "Docs/mm/damon/maintaier-profile: document a mailing tool and community meetup series" tells people how to get better involved with other DAMON developers. From SeongJae Park. - A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does that. - David Hildenbrand sends along more cleanups, this time against the migration code. The series is "mm/migrate: move NUMA hinting fault folio isolation + checks under PTL". - Jan Kara has found quite a lot of strangenesses and minor errors in the readahead code. He addresses this in the series "mm: Fix various readahead quirks". - SeongJae Park's series "selftests/damon: test DAMOS tried regions and {min,max}_nr_regions" adds features and addresses errors in DAMON's self testing code. - Gavin Shan has found a userspace-triggerable WARN in the pagecache code. The series "mm/filemap: Limit page cache size to that supported by xarray" addresses this. The series is marked cc:stable. - Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations and cleanup" cleans up and slightly optimizes KSM. - Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of code motion. The series (which also makes the memcg-v1 code Kconfigurable) are "mm: memcg: separate legacy cgroup v1 code and put under config option" and "mm: memcg: put cgroup v1-specific memcg data under CONFIG_MEMCG_V1" - Dan Schatzberg's series "Add swappiness argument to memory.reclaim" adds an additional feature to this cgroup-v2 control file. - The series "Userspace controls soft-offline pages" from Jiaqi Yan permits userspace to stop the kernel's automatic treatment of excessive correctable memory errors. In order to permit userspace to monitor and handle this situation. - Kefeng Wang's series "mm: migrate: support poison recover from migrate folio" teaches the kernel to appropriately handle migration from poisoned source folios rather than simply panicing. - SeongJae Park's series "Docs/damon: minor fixups and improvements" does those things. - In the series "mm/zsmalloc: change back to per-size_class lock" Chengming Zhou improves zsmalloc's scalability and memory utilization. - Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for pinning memfd folios" makes the GUP code use FOLL_PIN rather than bare refcount increments. So these paes can first be moved aside if they reside in the movable zone or a CMA block. - Andrii Nakryiko has added a binary ioctl()-based API to /proc/pid/maps for much faster reading of vma information. The series is "query VMAs from /proc/<pid>/maps". - In the series "mm: introduce per-order mTHP split counters" Lance Yang improves the kernel's presentation of developer information related to multisize THP splitting. - Michael Ellerman has developed the series "Reimplement huge pages without hugepd on powerpc (8xx, e500, book3s/64)". This permits userspace to use all available huge page sizes. - In the series "revert unconditional slab and page allocator fault injection calls" Vlastimil Babka removes a performance-affecting and not very useful feature from slab fault injection. * tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (411 commits) mm/mglru: fix ineffective protection calculation mm/zswap: fix a white space issue mm/hugetlb: fix kernel NULL pointer dereference when migrating hugetlb folio mm/hugetlb: fix possible recursive locking detected warning mm/gup: clear the LRU flag of a page before adding to LRU batch mm/numa_balancing: teach mpol_to_str about the balancing mode mm: memcg1: convert charge move flags to unsigned long long alloc_tag: fix page_ext_get/page_ext_put sequence during page splitting lib: reuse page_ext_data() to obtain codetag_ref lib: add missing newline character in the warning message mm/mglru: fix overshooting shrinker memory mm/mglru: fix div-by-zero in vmpressure_calc_level() mm/kmemleak: replace strncpy() with strscpy() mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB mm: ignore data-race in __swap_writepage hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr mm: shmem: rename mTHP shmem counters mm: swap_state: use folio_alloc_mpol() in __read_swap_cache_async() mm/migrate: putback split folios when numa hint migration fails ...
| * mm/migrate: putback split folios when numa hint migration failsPeter Xu2024-07-131-9/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This issue is not from any report yet, but by code observation only. This is yet another fix besides Hugh's patch [1] but on relevant code path, where eager split of folio can happen if the folio is already on deferred list during a folio migration. Here the issue is NUMA path (migrate_misplaced_folio()) may start to encounter such folio split now even with MR_NUMA_MISPLACED hint applied. Then when migrate_pages() didn't migrate all the folios, it's possible the split small folios be put onto the list instead of the original folio. Then putting back only the head page won't be enough. Fix it by putting back all the folios on the list. [1] https://lore.kernel.org/all/46c948b4-4dd8-6e03-4c7b-ce4e81cfa536@google.com/ [akpm@linux-foundation.org: remove now unused local `nr_pages'] Link: https://lkml.kernel.org/r/20240708215537.2630610-1-peterx@redhat.com Fixes: 7262f208ca68 ("mm/migrate: split source folio if it is on deferred split list") Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Huang Ying <ying.huang@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm: simplify folio_migrate_mapping()Hugh Dickins2024-07-131-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that folio_undo_large_rmappable() is an inline function checking order and large_rmappable for itself (and __folio_undo_large_rmappable() is now declared even when CONFIG_TRANASPARENT_HUGEPAGE is off) there is no need for folio_migrate_mapping() to check large and large_rmappable first (in the mapping case when it has had to freeze anyway). Link: https://lkml.kernel.org/r/68feee73-050e-8e98-7a3a-abf78738d92c@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm: provide mm_struct and address to huge_ptep_get()Christophe Leroy2024-07-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On powerpc 8xx huge_ptep_get() will need to know whether the given ptep is a PTE entry or a PMD entry. This cannot be known with the PMD entry itself because there is no easy way to know it from the content of the entry. So huge_ptep_get() will need to know either the size of the page or get the pmd. In order to be consistent with huge_ptep_get_and_clear(), give mm and address to huge_ptep_get(). Link: https://lkml.kernel.org/r/cc00c70dd384298796a4e1b25d6c4eb306d3af85.1719928057.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm: migrate: remove folio_migrate_copy()Kefeng Wang2024-07-061-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The folio_migrate_copy() is just a wrapper of folio_copy() and folio_migrate_flags(), it is simple and only aio use it for now, unfold it and remove folio_migrate_copy(). Link: https://lkml.kernel.org/r/20240626085328.608006-7-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * fs: hugetlbfs: support poisoned recover from hugetlbfs_migrate_folio()Kefeng Wang2024-07-061-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is similar to __migrate_folio(), use folio_mc_copy() in HugeTLB folio migration to avoid panic when copy from poisoned folio. Link: https://lkml.kernel.org/r/20240626085328.608006-6-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm: migrate: support poisoned recover from migrate folioKefeng Wang2024-07-061-3/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The folio migration is widely used in kernel, memory compaction, memory hotplug, soft offline page, numa balance, memory demote/promotion, etc, but once access a poisoned source folio when migrating, the kerenl will panic. There is a mechanism in the kernel to recover from uncorrectable memory errors, ARCH_HAS_COPY_MC, which is already used in other core-mm paths, eg, CoW, khugepaged, coredump, ksm copy, see copy_mc_to_{user,kernel}, copy_mc_{user_}highpage callers. In order to support poisoned folio copy recover from migrate folio, we chose to make folio migration tolerant of memory failures and return error for folio migration, because folio migration is no guarantee of success, this could avoid the similar panic shown below. CPU: 1 PID: 88343 Comm: test_softofflin Kdump: loaded Not tainted 6.6.0 pc : copy_page+0x10/0xc0 lr : copy_highpage+0x38/0x50 ... Call trace: copy_page+0x10/0xc0 folio_copy+0x78/0x90 migrate_folio_extra+0x54/0xa0 move_to_new_folio+0xd8/0x1f0 migrate_folio_move+0xb8/0x300 migrate_pages_batch+0x528/0x788 migrate_pages_sync+0x8c/0x258 migrate_pages+0x440/0x528 soft_offline_in_use_page+0x2ec/0x3c0 soft_offline_page+0x238/0x310 soft_offline_page_store+0x6c/0xc0 dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x130/0x1c8 new_sync_write+0xa4/0x138 vfs_write+0x238/0x2d8 ksys_write+0x74/0x110 Note, folio copy is moved in the begin of the __migrate_folio(), which could simplify the error handling since there is no turning back if folio_migrate_mapping() return success, the downside is the folio copied even though folio_migrate_mapping() return fail, an optimization is to check whether source folio does not have extra refs before we do folio copy. Link: https://lkml.kernel.org/r/20240626085328.608006-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * mm: migrate: split folio_migrate_mapping()Kefeng Wang2024-07-061-16/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The folio refcount check is moved out for both !mapping and mapping folio, also update comment from page to folio for folio_migrate_mapping(). No functional change intended. Link: https://lkml.kernel.org/r/20240626085328.608006-4-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * Merge branch 'mm-hotfixes-stable' into mm-stable to pick up "mm: fixAndrew Morton2024-07-061-0/+13
| |\ | | | | | | | | | | | | crashes from deferred split racing folio migration", needed by "mm: migrate: split folio_migrate_mapping()".
| * | mm/migrate: move NUMA hinting fault folio isolation + checks under PTLDavid Hildenbrand2024-07-041-44/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | mm/migrate: make migrate_misplaced_folio() return 0 on successDavid Hildenbrand2024-07-041-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | mm: remove MIGRATE_SYNC_NO_COPY modeKefeng Wang2024-07-041-7/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 2916ecc0f9d4 ("mm/migrate: new migrate mode MIGRATE_SYNC_NO_COPY") introduce a new MIGRATE_SYNC_NO_COPY mode to allow to offload the copy to a device DMA engine, which is only used __migrate_device_pages() to decide whether or not copy the old page, and the MIGRATE_SYNC_NO_COPY mode only set in hmm, as the MIGRATE_SYNC_NO_COPY set is removed by previous cleanup, it seems that we could remove the unnecessary MIGRATE_SYNC_NO_COPY. Link: https://lkml.kernel.org/r/20240524052843.182275-6-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | mm: migrate: remove migrate_folio_extra()Kefeng Wang2024-07-041-22/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | migrate_folio_extra() is only called in migrate.c now, convert it a static function and take a new src_private argument which could be shared by migrate_folio() and filemap_migrate_folio() to simplify code a bit. Link: https://lkml.kernel.org/r/20240524052843.182275-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | mm: migrate: simplify __buffer_migrate_folio()Kefeng Wang2024-07-041-9/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm: cleanup MIGRATE_SYNC_NO_COPY mode". Commit 2916ecc0f9d4 ("mm/migrate: new migrate mode MIGRATE_SYNC_NO_COPY") introduce a new MIGRATE_SYNC_NO_COPY mode to allow to offload the copy to a device DMA engine, which is only used __migrate_device_pages() to decide whether or not copy the old page, and the MIGRATE_SYNC_NO_COPY mode only used in hmm, a easy way is just to call the folio_migrate_mapping() and folio_migrate_flags(), which help to remove the MIGRATE_SYNC_NO_COPY mode. This patch (of 5): Use filemap_migrate_folio() helper to simplify __buffer_migrate_folio(). Link: https://lkml.kernel.org/r/20240524052843.182275-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20240524052843.182275-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | | Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2024-07-201-1/+1
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull kvm updates from Paolo Bonzini: "ARM: - Initial infrastructure for shadow stage-2 MMUs, as part of nested virtualization enablement - Support for userspace changes to the guest CTR_EL0 value, enabling (in part) migration of VMs between heterogenous hardware - Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1 of the protocol - FPSIMD/SVE support for nested, including merged trap configuration and exception routing - New command-line parameter to control the WFx trap behavior under KVM - Introduce kCFI hardening in the EL2 hypervisor - Fixes + cleanups for handling presence/absence of FEAT_TCRX - Miscellaneous fixes + documentation updates LoongArch: - Add paravirt steal time support - Add support for KVM_DIRTY_LOG_INITIALLY_SET - Add perf kvm-stat support for loongarch RISC-V: - Redirect AMO load/store access fault traps to guest - perf kvm stat support - Use guest files for IMSIC virtualization, when available s390: - Assortment of tiny fixes which are not time critical x86: - Fixes for Xen emulation - Add a global struct to consolidate tracking of host values, e.g. EFER - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC bus frequency, because TDX - Print the name of the APICv/AVIC inhibits in the relevant tracepoint - Clean up KVM's handling of vendor specific emulation to consistently act on "compatible with Intel/AMD", versus checking for a specific vendor - Drop MTRR virtualization, and instead always honor guest PAT on CPUs that support self-snoop - Update to the newfangled Intel CPU FMS infrastructure - Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as it reads '0' and writes from userspace are ignored - Misc cleanups x86 - MMU: - Small cleanups, renames and refactoring extracted from the upcoming Intel TDX support - Don't allocate kvm_mmu_page.shadowed_translation for shadow pages that can't hold leafs SPTEs - Unconditionally drop mmu_lock when allocating TDP MMU page tables for eager page splitting, to avoid stalling vCPUs when splitting huge pages - Bug the VM instead of simply warning if KVM tries to split a SPTE that is non-present or not-huge. KVM is guaranteed to end up in a broken state because the callers fully expect a valid SPTE, it's all but dangerous to let more MMU changes happen afterwards x86 - AMD: - Make per-CPU save_area allocations NUMA-aware - Force sev_es_host_save_area() to be inlined to avoid calling into an instrumentable function from noinstr code - Base support for running SEV-SNP guests. API-wise, this includes a new KVM_X86_SNP_VM type, encrypting/measure the initial image into guest memory, and finalizing it before launching it. Internally, there are some gmem/mmu hooks needed to prepare gmem-allocated pages before mapping them into guest private memory ranges This includes basic support for attestation guest requests, enough to say that KVM supports the GHCB 2.0 specification There is no support yet for loading into the firmware those signing keys to be used for attestation requests, and therefore no need yet for the host to provide certificate data for those keys. To support fetching certificate data from userspace, a new KVM exit type will be needed to handle fetching the certificate from userspace. An attempt to define a new KVM_EXIT_COCO / KVM_EXIT_COCO_REQ_CERTS exit type to handle this was introduced in v1 of this patchset, but is still being discussed by community, so for now this patchset only implements a stub version of SNP Extended Guest Requests that does not provide certificate data x86 - Intel: - Remove an unnecessary EPT TLB flush when enabling hardware - Fix a series of bugs that cause KVM to fail to detect nested pending posted interrupts as valid wake eents for a vCPU executing HLT in L2 (with HLT-exiting disable by L1) - KVM: x86: Suppress MMIO that is triggered during task switch emulation Explicitly suppress userspace emulated MMIO exits that are triggered when emulating a task switch as KVM doesn't support userspace MMIO during complex (multi-step) emulation Silently ignoring the exit request can result in the WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to userspace for some other reason prior to purging mmio_needed See commit 0dc902267cb3 ("KVM: x86: Suppress pending MMIO write exits if emulator detects exception") for more details on KVM's limitations with respect to emulated MMIO during complex emulator flows Generic: - Rename the AS_UNMOVABLE flag that was introduced for KVM to AS_INACCESSIBLE, because the special casing needed by these pages is not due to just unmovability (and in fact they are only unmovable because the CPU cannot access them) - New ioctl to populate the KVM page tables in advance, which is useful to mitigate KVM page faults during guest boot or after live migration. The code will also be used by TDX, but (probably) not through the ioctl - Enable halt poll shrinking by default, as Intel found it to be a clear win - Setup empty IRQ routing when creating a VM to avoid having to synchronize SRCU when creating a split IRQCHIP on x86 - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag that arch code can use for hooking both sched_in() and sched_out() - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid truncating a bogus value from userspace, e.g. to help userspace detect bugs - Mark a vCPU as preempted if and only if it's scheduled out while in the KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest memory when retrieving guest state during live migration blackout Selftests: - Remove dead code in the memslot modification stress test - Treat "branch instructions retired" as supported on all AMD Family 17h+ CPUs - Print the guest pseudo-RNG seed only when it changes, to avoid spamming the log for tests that create lots of VMs - Make the PMU counters test less flaky when counting LLC cache misses by doing CLFLUSH{OPT} in every loop iteration" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits) crypto: ccp: Add the SNP_VLEK_LOAD command KVM: x86/pmu: Add kvm_pmu_call() to simplify static calls of kvm_pmu_ops KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops KVM: x86: Replace static_call_cond() with static_call() KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event x86/sev: Move sev_guest.h into common SEV header KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event KVM: x86: Suppress MMIO that is triggered during task switch emulation KVM: x86/mmu: Clean up make_huge_page_split_spte() definition and intro KVM: x86/mmu: Bug the VM if KVM tries to split a !hugepage SPTE KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory() KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault" KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory KVM: Document KVM_PRE_FAULT_MEMORY ioctl mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE perf kvm: Add kvm-stat for loongarch64 LoongArch: KVM: Add PV steal time support in guest side ...
| * | Merge tag 'loongarch-kvm-6.11' of ↵Paolo Bonzini2024-07-121-1/+12
| |\| | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD LoongArch KVM changes for v6.11 1. Add ParaVirt steal time support. 2. Add some VM migration enhancement. 3. Add perf kvm-stat support for loongarch.
| * | mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLEPaolo Bonzini2024-07-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The flags AS_UNMOVABLE and AS_INACCESSIBLE were both added just for guest_memfd; AS_UNMOVABLE is already in existing versions of Linux, while AS_INACCESSIBLE was acked for inclusion in 6.11. But really, they are the same thing: only guest_memfd uses them, at least for now, and guest_memfd pages are unmovable because they should not be accessed by the CPU. So merge them into one; use the AS_INACCESSIBLE name which is more comprehensive. At the same time, this fixes an embarrassing bug where AS_INACCESSIBLE was used as a bit mask, despite it being just a bit index. The bug was mostly benign, because AS_INACCESSIBLE's bit representation (1010) corresponded to setting AS_UNEVICTABLE (which is already set) and AS_ENOSPC (except no async writes can happen on the guest_memfd). So the AS_INACCESSIBLE flag simply had no effect. Fixes: 1d23040caa8b ("KVM: guest_memfd: Use AS_INACCESSIBLE when creating guest_memfd inode") Fixes: c72ceafbd12c ("mm: Introduce AS_INACCESSIBLE for encrypted/confidential memory") Cc: linux-mm@kvack.org Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Hildenbrand <david@redhat.com> Tested-by: Michael Roth <michael.roth@amd.com> Reviewed-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | mm: fix crashes from deferred split racing folio migrationHugh Dickins2024-07-061-0/+13
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Even on 6.10-rc6, I've been seeing elusive "Bad page state"s (often on flags when freeing, yet the flags shown are not bad: PG_locked had been set and cleared??), and VM_BUG_ON_PAGE(page_ref_count(page) == 0)s from deferred_split_scan()'s folio_put(), and a variety of other BUG and WARN symptoms implying double free by deferred split and large folio migration. 6.7 commit 9bcef5973e31 ("mm: memcg: fix split queue list crash when large folio migration") was right to fix the memcg-dependent locking broken in 85ce2c517ade ("memcontrol: only transfer the memcg data for migration"), but missed a subtlety of deferred_split_scan(): it moves folios to its own local list to work on them without split_queue_lock, during which time folio->_deferred_list is not empty, but even the "right" lock does nothing to secure the folio and the list it is on. Fortunately, deferred_split_scan() is careful to use folio_try_get(): so folio_migrate_mapping() can avoid the race by folio_undo_large_rmappable() while the old folio's reference count is temporarily frozen to 0 - adding such a freeze in the !mapping case too (originally, folio lock and unmapping and no swap cache left an anon folio unreachable, so no freezing was needed there: but the deferred split queue offers a way to reach it). Link: https://lkml.kernel.org/r/29c83d1a-11ca-b6c9-f92e-6ccb322af510@google.com Fixes: 9bcef5973e31 ("mm: memcg: fix split queue list crash when large folio migration") Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | mm/migrate: make migrate_pages_batch() stats consistentZi Yan2024-06-251-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As Ying pointed out in [1], stats->nr_thp_failed needs to be updated to avoid stats inconsistency between MIGRATE_SYNC and MIGRATE_ASYNC when calling migrate_pages_batch(). Because if not, when migrate_pages_batch() is called via migrate_pages(MIGRATE_ASYNC), nr_thp_failed will not be increased and when migrate_pages_batch() is called via migrate_pages(MIGRATE_SYNC*), nr_thp_failed will be increase in migrate_pages_sync() by stats->nr_thp_failed += astats.nr_thp_split. [1] https://lore.kernel.org/linux-mm/87msnq7key.fsf@yhuang6-desk2.ccr.corp.intel.com/ Link: https://lkml.kernel.org/r/20240620012712.19804-1-zi.yan@sent.com Link: https://lkml.kernel.org/r/20240618134151.29214-1-zi.yan@sent.com Fixes: 7262f208ca68 ("mm/migrate: split source folio if it is on deferred split list") Signed-off-by: Zi Yan <ziy@nvidia.com> Suggested-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | mm/migrate: fix kernel BUG at mm/compaction.c:2761!Hugh Dickins2024-06-151-1/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | I hit the VM_BUG_ON(!list_empty(&cc->migratepages)) in compact_zone(); and if DEBUG_VM were off, then pages would be lost on a local list. Our convention is that if migrate_pages() reports complete success (0), then the migratepages list will be empty; but if it reports an error or some pages remaining, then its caller must putback_movable_pages(). There's a new case in which migrate_pages() has been reporting complete success, but returning with pages left on the migratepages list: when migrate_pages_batch() successfully split a folio on the deferred list, but then the "Failure isn't counted" call does not dispose of them all. Since that block is expecting the large folio to have been counted as 1 failure already, and since the return code is later adjusted to success whenever the returned list is found empty, the simple way to fix this safely is to count splitting the deferred folio as "a failure". Link: https://lkml.kernel.org/r/46c948b4-4dd8-6e03-4c7b-ce4e81cfa536@google.com Fixes: 7262f208ca68 ("mm/migrate: split source folio if it is on deferred split list") Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: convert hugetlb_page_mapping_lock_write to folioMatthew Wilcox (Oracle)2024-05-061-1/+1
| | | | | | | | | | | | | | The page is only used to get the mapping, so the folio will do just as well. Both callers already have a folio available, so this saves a call to compound_head(). Link: https://lkml.kernel.org/r/20240412193510.2356957-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Jane Chu  <jane.chu@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/ksm: convert chain series funcs and replace get_ksm_pageAlex Shi (tencent)2024-05-061-1/+1
| | | | | | | | | | | | | | | | | | In ksm stable tree all page are single, let's convert them to use and folios as well as stable_tree_insert/stable_tree_search funcs. And replace get_ksm_page() by ksm_get_folio() since there is no more needs. It could save a few compound_head calls. Link: https://lkml.kernel.org/r/20240411061713.1847574-9-alexs@kernel.org Signed-off-by: Alex Shi (tencent) <alexs@kernel.org> Cc: Izik Eidus <izik.eidus@ravellosystems.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/migrate: use folio_likely_mapped_shared() in add_page_for_migration()David Hildenbrand2024-05-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We want to limit the use of page_mapcount() to the places where it is absolutely necessary. In add_page_for_migration(), we actually want to check if the folio is mapped shared, to reject such folios. So let's use folio_likely_mapped_shared() instead. For small folios, fully mapped THP, and hugetlb folios, there is no change. For partially mapped, shared THP, we should now do a better job at rejecting such folios. Link: https://lkml.kernel.org/r/20240409192301.907377-12-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Chris Zankel <chris@zankel.net> Cc: Hugh Dickins <hughd@google.com> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Richard Chang <richardycc@google.com> Cc: Rich Felker <dalias@libc.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yin Fengwei <fengwei.yin@intel.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* remove references to page->flags in documentationMatthew Wilcox (Oracle)2024-04-261-1/+1
| | | | | | | | | | Mostly rewording, but remove entirely the copy of page_fixed_fake_head() in the documentation; we can refer people to the actual source if necessary. Link: https://lkml.kernel.org/r/20240326171045.410737-10-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: convert folio_estimated_sharers() to folio_likely_mapped_shared()David Hildenbrand2024-04-261-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Callers of folio_estimated_sharers() only care about "mapped shared vs. mapped exclusively", not the exact estimate of sharers. Let's consolidate and unify the condition users are checking. While at it clarify the semantics and extend the discussion on the fuzziness. Use the "likely mapped shared" terminology to better express what the (adjusted) function actually checks. Whether a partially-mappable folio is more likely to not be partially mapped than partially mapped is debatable. In the future, we might be able to improve our estimate for partially-mappable folios, though. Note that we will now consistently detect "mapped shared" only if the first subpage is actually mapped multiple times. When the first subpage is not mapped, we will consistently detect it as "mapped exclusively". This change should currently only affect the usage in madvise_free_pte_range() and queue_folios_pte_range() for large folios: if the first page was already unmapped, we would have skipped the folio. [david@redhat.com: folio_likely_mapped_shared() kerneldoc fixup] Link: https://lkml.kernel.org/r/dd0ad9f2-2d7a-45f3-9ba3-979488c7dd27@redhat.com Link: https://lkml.kernel.org/r/20240227201548.857831-1-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Acked-by: Barry Song <v-songbaohua@oppo.com> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/migrate: split source folio if it is on deferred split listZi Yan2024-04-261-0/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the source folio is on deferred split list, it is likely some subpages are not used. Split it before migration to avoid migrating unused subpages. Commit 616b8371539a6 ("mm: thp: enable thp migration in generic path") did not check if a THP is on deferred split list before migration, thus, the destination THP is never put on deferred split list even if the source THP might be. The opportunity of reclaiming free pages in a partially mapped THP during deferred list scanning is lost, but no other harmful consequence is present[1]. [1]: https://lore.kernel.org/linux-mm/03CE3A00-917C-48CC-8E1C-6A98713C817C@nvidia.com/ [zi.yan@sent.com: fix an error in migrate_misplaced_folio()] Link: https://lkml.kernel.org/r/20240326150031.569387-1-zi.yan@sent.com Link: https://lkml.kernel.org/r/20240322193304.522496-1-zi.yan@sent.com Fixes: 616b8371539a ("mm: thp: enable thp migration in generic path") Signed-off-by: Zi Yan <ziy@nvidia.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Huang, Ying <ying.huang@intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>