user/sven/linux.git/include/linux/mmu_notifier.h, branch v5.15.197

mm: fix spelling mistakes in header files

2021-07-08T18:48:21Z

Fix some spelling mistakes in comments: successfull ==> successful potentialy ==> potentially alloced ==> allocated indicies ==> indices wont ==> won't resposible ==> responsible dirtyness ==> dirtiness droppped ==> dropped alread ==> already occured ==> occurred interupts ==> interrupts extention ==> extension slighly ==> slightly Dont't ==> Don't Link: https://lkml.kernel.org/r/20210531034849.9549-2-thunder.leizhen@huawei.com Signed-off-by: Zhen Lei Cc: Jerome Glisse Cc: Mike Kravetz Cc: Dennis Zhou Cc: Tejun Heo Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: device exclusive memory access

2021-07-01T18:06:03Z

Some devices require exclusive write access to shared virtual memory (SVM) ranges to perform atomic operations on that memory. This requires CPU page tables to be updated to deny access whilst atomic operations are occurring. In order to do this introduce a new swap entry type (SWP_DEVICE_EXCLUSIVE). When a SVM range needs to be marked for exclusive access by a device all page table mappings for the particular range are replaced with device exclusive swap entries. This causes any CPU access to the page to result in a fault. Faults are resovled by replacing the faulting entry with the original mapping. This results in MMU notifiers being called which a driver uses to update access permissions such as revoking atomic access. After notifiers have been called the device will no longer have exclusive access to the region. Walking of the page tables to find the target pages is handled by get_user_pages() rather than a direct page table walk. A direct page table walk similar to what migrate_vma_collect()/unmap() does could also have been utilised. However this resulted in more code similar in functionality to what get_user_pages() provides as page faulting is required to make the PTEs present and to break COW. [dan.carpenter@oracle.com: fix signedness bug in make_device_exclusive_range()] Link: https://lkml.kernel.org/r/YNIz5NVnZ5GiZ3u1@mwanda Link: https://lkml.kernel.org/r/20210616105937.23201-8-apopple@nvidia.com Signed-off-by: Alistair Popple Signed-off-by: Dan Carpenter Reviewed-by: Christoph Hellwig Cc: Ben Skeggs Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: John Hubbard Cc: "Matthew Wilcox (Oracle)" Cc: Peter Xu Cc: Ralph Campbell Cc: Shakeel Butt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: rename migrate_pgmap_owner

2021-07-01T18:06:03Z

MMU notifier ranges have a migrate_pgmap_owner field which is used by drivers to store a pointer. This is subsequently used by the driver callback to filter MMU_NOTIFY_MIGRATE events. Other notifier event types can also benefit from this filtering, so rename the 'migrate_pgmap_owner' field to 'owner' and create a new notifier initialisation function to initialise this field. Link: https://lkml.kernel.org/r/20210616105937.23201-6-apopple@nvidia.com Signed-off-by: Alistair Popple Suggested-by: Peter Xu Reviewed-by: Peter Xu Cc: Ben Skeggs Cc: Christoph Hellwig Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: John Hubbard Cc: "Matthew Wilcox (Oracle)" Cc: Ralph Campbell Cc: Shakeel Butt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/mmu_notifiers: ensure range_end() is paired with range_start()

2021-03-25T16:22:55Z

If one or more notifiers fails .invalidate_range_start(), invoke .invalidate_range_end() for "all" notifiers. If there are multiple notifiers, those that did not fail are expecting _start() and _end() to be paired, e.g. KVM's mmu_notifier_count would become imbalanced. Disallow notifiers that can fail _start() from implementing _end() so that it's unnecessary to either track which notifiers rejected _start(), or had already succeeded prior to a failed _start(). Note, the existing behavior of calling _start() on all notifiers even after a previous notifier failed _start() was an unintented "feature". Make it canon now that the behavior is depended on for correctness. As of today, the bug is likely benign: 1. The only caller of the non-blocking notifier is OOM kill. 2. The only notifiers that can fail _start() are the i915 and Nouveau drivers. 3. The only notifiers that utilize _end() are the SGI UV GRU driver and KVM. 4. The GRU driver will never coincide with the i195/Nouveau drivers. 5. An imbalanced kvm->mmu_notifier_count only causes soft lockup in the _guest_, and the guest is already doomed due to being an OOM victim. Fix the bug now to play nice with future usage, e.g. KVM has a potential use case for blocking memslot updates in KVM while an invalidation is in-progress, and failure to unblock would result in said updates being blocked indefinitely and hanging. Found by inspection. Verified by adding a second notifier in KVM that periodically returns -EAGAIN on non-blockable ranges, triggering OOM, and observing that KVM exits with an elevated notifier count. Link: https://lkml.kernel.org/r/20210311180057.1582638-1-seanjc@google.com Fixes: 93065ac753e4 ("mm, oom: distinguish blockable mode for mmu notifiers") Signed-off-by: Sean Christopherson Suggested-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe Cc: David Rientjes Cc: Ben Gardon Cc: Michal Hocko Cc: "Jérôme Glisse" Cc: Andrea Arcangeli Cc: Johannes Weiner Cc: Dimitri Sivanich Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/migrate: fix migrate_pgmap_owner w/o CONFIG_MMU_NOTIFIER

2020-08-07T18:33:21Z

On x86_64, when CONFIG_MMU_NOTIFIER is not set/enabled, there is a compiler error: mm/migrate.c: In function 'migrate_vma_collect': mm/migrate.c:2481:7: error: 'struct mmu_notifier_range' has no member named 'migrate_pgmap_owner' range.migrate_pgmap_owner = migrate->pgmap_owner; ^ Fixes: 998427b3ad2c ("mm/notifier: add migration invalidation type") Reported-by: Randy Dunlap Signed-off-by: Ralph Campbell Signed-off-by: Andrew Morton Tested-by: Randy Dunlap Acked-by: Randy Dunlap Cc: Jerome Glisse Cc: John Hubbard Cc: Christoph Hellwig Cc: "Jason Gunthorpe" Link: http://lkml.kernel.org/r/20200806193353.7124-1-rcampbell@nvidia.com Signed-off-by: Linus Torvalds

mm/notifier: add migration invalidation type

2020-07-28T19:20:33Z

Currently migrate_vma_setup() calls mmu_notifier_invalidate_range_start() which flushes all device private page mappings whether or not a page is being migrated to/from device private memory. In order to not disrupt device mappings that are not being migrated, shift the responsibility for clearing device private mappings to the device driver and leave CPU page table unmapping handled by migrate_vma_setup(). To support this, the caller of migrate_vma_setup() should always set struct migrate_vma::pgmap_owner to a non NULL value that matches the device private page->pgmap->owner. This value is then passed to the struct mmu_notifier_range with a new event type which the driver's invalidation function can use to avoid device MMU invalidations. Link: https://lore.kernel.org/r/20200723223004.9586-4-rcampbell@nvidia.com Signed-off-by: Ralph Campbell Signed-off-by: Jason Gunthorpe

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14Z

Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Daniel Jordan Cc: Davidlohr Bueso Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds

MMU notifier: use the new mmap locking API

2020-06-09T16:39:14Z

This use is converted manually ahead of the next patch in the series, as it requires including a new header which the automated conversion would miss. Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Daniel Jordan Reviewed-by: Davidlohr Bueso Reviewed-by: Laurent Dufour Reviewed-by: Vlastimil Babka Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-3-walken@google.com Signed-off-by: Linus Torvalds

mm/mmu_notifiers: Use 'interval_sub' as the variable for mmu_interval_notifier

2020-01-14T15:54:47Z

The 'interval_sub' is placed on the 'notifier_subscriptions' interval tree. This eliminates the poor name 'mni' for this variable. Signed-off-by: Jason Gunthorpe

mm/mmu_notifiers: Use 'subscription' as the variable name for mmu_notifier

2020-01-14T15:54:47Z

The 'subscription' is placed on the 'notifier_subscriptions' list. This eliminates the poor name 'mn' for this variable. Signed-off-by: Jason Gunthorpe