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2020-10-16mm/doc: fix a literal block markupMauro Carvalho Chehab
Literal blocks with :: markup should be indented, as otherwise Sphinx complains: Documentation/vm/hmm.rst:363: WARNING: Literal block expected; none found. Fixes: f7ebd9ed7767 ("mm/doc: add usage description for migrate_vma_*()") Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-09-16mm/doc: add usage description for migrate_vma_*()Ralph Campbell
The migrate_vma_setup(), migrate_vma_pages(), and migrate_vma_finalize() API usage by device drivers is not well documented. Add a description for how device drivers are expected to use it. Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Link: https://lore.kernel.org/r/20200909212956.20104-1-rcampbell@nvidia.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-09-09mm/doc: editorial pass on page migrationRalph Campbell
Add Sphinx reference links to HMM and CPUSETS, and numerous small editorial changes to make the page_migration.rst document more readable. Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20200902225247.15213-1-rcampbell@nvidia.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-06-09mmap locking API: convert mmap_sem API commentsMichel Lespinasse
Convert comments that reference old mmap_sem APIs to reference corresponding new mmap locking APIs instead. Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-12-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-11mm/hmm: remove the customizable pfn format from hmm_range_faultJason Gunthorpe
Presumably the intent here was that hmm_range_fault() could put the data into some HW specific format and thus avoid some work. However, nothing actually does that, and it isn't clear how anything actually could do that as hmm_range_fault() provides CPU addresses which must be DMA mapped. Perhaps there is some special HW that does not need DMA mapping, but we don't have any examples of this, and the theoretical performance win of avoiding an extra scan over the pfns array doesn't seem worth the complexity. Plus pfns needs to be scanned anyhow to sort out any DEVICE_PRIVATE pages. This version replaces the uint64_t with an usigned long containing a pfn and fixed flags. On input flags is filled with the HMM_PFN_REQ_* values, on successful output it is filled with HMM_PFN_* values, describing the state of the pages. amdgpu is simple to convert, it doesn't use snapshot and doesn't use per-page flags. nouveau uses only 16 hmm_pte entries at most (ie fits in a few cache lines), and it sweeps over its pfns array a couple of times anyhow. It also has a nasty call chain before it reaches the dma map and hardware suggesting performance isn't important: nouveau_svm_fault(): args.i.m.method = NVIF_VMM_V0_PFNMAP nouveau_range_fault() nvif_object_ioctl() client->driver->ioctl() struct nvif_driver nvif_driver_nvkm: .ioctl = nvkm_client_ioctl nvkm_ioctl() nvkm_ioctl_path() nvkm_ioctl_v0[type].func(..) nvkm_ioctl_mthd() nvkm_object_mthd() struct nvkm_object_func nvkm_uvmm: .mthd = nvkm_uvmm_mthd nvkm_uvmm_mthd() nvkm_uvmm_mthd_pfnmap() nvkm_vmm_pfn_map() nvkm_vmm_ptes_get_map() func == gp100_vmm_pgt_pfn struct nvkm_vmm_desc_func gp100_vmm_desc_spt: .pfn = gp100_vmm_pgt_pfn nvkm_vmm_iter() REF_PTES == func == gp100_vmm_pgt_pfn() dma_map_page() Link: https://lore.kernel.org/r/5-v2-b4e84f444c7d+24f57-hmm_no_flags_jgg@mellanox.com Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> Tested-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2020-05-11mm/hmm: make hmm_range_fault return 0 or -1Jason Gunthorpe
hmm_vma_walk->last is supposed to be updated after every write to the pfns, so that it can be returned by hmm_range_fault(). However, this is not done consistently. Fortunately nothing checks the return code of hmm_range_fault() for anything other than error. More importantly last must be set before returning -EBUSY as it is used to prevent reading an output pfn as an input flags when the loop restarts. For clarity and simplicity make hmm_range_fault() return 0 or -ERRNO. Only set last when returning -EBUSY. Link: https://lore.kernel.org/r/2-v2-b4e84f444c7d+24f57-hmm_no_flags_jgg@mellanox.com Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> Tested-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2020-03-27mm/hmm: remove HMM_FAULT_SNAPSHOTJason Gunthorpe
Now that flags are handled on a fine-grained per-page basis this global flag is redundant and has a confusing overlap with the pfn_flags_mask and default_flags. Normalize the HMM_FAULT_SNAPSHOT behavior into one place. Callers needing the SNAPSHOT behavior should set a pfn_flags_mask and default_flags that always results in a cleared HMM_PFN_VALID. Then no pages will be faulted, and HMM_FAULT_SNAPSHOT is not a special flow that overrides the masking mechanism. As this is the last flag, also remove the flags argument. If future flags are needed they can be part of the struct hmm_range function arguments. Link: https://lore.kernel.org/r/20200327200021.29372-5-jgg@ziepe.ca Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2020-01-14mm/mmu_notifiers: Use 'interval_sub' as the variable for mmu_interval_notifierJason Gunthorpe
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 <jgg@mellanox.com>
2019-11-23mm/hmm: remove hmm_mirror and relatedJason Gunthorpe
The only two users of this are now converted to use mmu_interval_notifier, delete all the code and update hmm.rst. Link: https://lore.kernel.org/r/20191112202231.3856-14-jgg@ziepe.ca Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Tested-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-20mm: turn migrate_vma upside downChristoph Hellwig
There isn't any good reason to pass callbacks to migrate_vma. Instead we can just export the three steps done by this function to drivers and let them sequence the operation without callbacks. This removes a lot of boilerplate code as-is, and will allow the drivers to drastically improve code flow and error handling further on. Link: https://lore.kernel.org/r/20190814075928.23766-2-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Tested-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-07mm/hmm: remove superfluous arguments from hmm_range_registerChristoph Hellwig
The start, end and page_shift values are all saved in the range structure, so we might as well use that for argument passing. Link: https://lore.kernel.org/r/20190806160554.14046-7-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-26mm/hmm: merge hmm_range_snapshot into hmm_range_faultChristoph Hellwig
Add a HMM_FAULT_SNAPSHOT flag so that hmm_range_snapshot can be merged into the almost identical hmm_range_fault function. Link: https://lore.kernel.org/r/20190726005650.2566-5-rcampbell@nvidia.com Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-25mm/hmm: always return EBUSY for invalid ranges in hmm_range_{fault,snapshot}Christoph Hellwig
We should not have two different error codes for the same condition. EAGAIN must be reserved for the FAULT_FLAG_ALLOW_RETRY retry case and signals to the caller that the mmap_sem has been unlocked. Use EBUSY for the !valid case so that callers can get the locking right. Link: https://lore.kernel.org/r/20190724065258.16603-2-hch@lst.de Tested-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com> [jgg: elaborated commit message] Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02Merge branch 'hmm-devmem-cleanup.4' into rdma.git hmmJason Gunthorpe
Christoph Hellwig says: ==================== Below is a series that cleans up the dev_pagemap interface so that it is more easily usable, which removes the need to wrap it in hmm and thus allowing to kill a lot of code Changes since v3: - pull in "mm/swap: Fix release_pages() when releasing devmap pages" and rebase the other patches on top of that - fold the hmm_devmem_add_resource into the DEVICE_PUBLIC memory removal patch - remove _vm_normal_page as it isn't needed without DEVICE_PUBLIC memory - pick up various ACKs Changes since v2: - fix nvdimm kunit build - add a new memory type for device dax - fix a few issues in intermediate patches that didn't show up in the end result - incorporate feedback from Michal Hocko, including killing of the DEVICE_PUBLIC memory type entirely Changes since v1: - rebase - also switch p2pdma to the internal refcount - add type checking for pgmap->type - rename the migrate method to migrate_to_ram - cleanup the altmap_valid flag - various tidbits from the reviews ==================== Conflicts resolved by: - Keeping Ira's version of the code in swap.c - Using the delete for the section in hmm.rst - Using the delete for the devmap code in hmm.c and .h * branch 'hmm-devmem-cleanup.4': (24 commits) mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR mm: remove the HMM config option mm: sort out the DEVICE_PRIVATE Kconfig mess mm: simplify ZONE_DEVICE page private data mm: remove hmm_devmem_add mm: remove hmm_vma_alloc_locked_page nouveau: use devm_memremap_pages directly nouveau: use alloc_page_vma directly PCI/P2PDMA: use the dev_pagemap internal refcount device-dax: use the dev_pagemap internal refcount memremap: provide an optional internal refcount in struct dev_pagemap memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag memremap: remove the data field in struct dev_pagemap memremap: add a migrate_to_ram method to struct dev_pagemap_ops memremap: lift the devmap_enable manipulation into devm_memremap_pages memremap: pass a struct dev_pagemap to ->kill and ->cleanup memremap: move dev_pagemap callbacks into a separate structure memremap: validate the pagemap type passed to devm_memremap_pages mm: factor out a devm_request_free_mem_region helper mm: export alloc_pages_vma ... Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02mm: remove hmm_devmem_addChristoph Hellwig
There isn't really much value add in the hmm_devmem_add wrapper and more, as using devm_memremap_pages directly now is just as simple. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-06-06mm/hmm: update HMM documentationRalph Campbell
Update the HMM documentation to reflect the latest API and make a few minor wording changes. Cc: John Hubbard <jhubbard@nvidia.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-06-01mm: fix Documentation/vm/hmm.rst Sphinx warningsRandy Dunlap
Fix Sphinx warnings in Documentation/vm/hmm.rst by using "::" notation and inserting a blank line. Also add a missing ';'. Documentation/vm/hmm.rst:292: WARNING: Unexpected indentation. Documentation/vm/hmm.rst:300: WARNING: Unexpected indentation. Link: http://lkml.kernel.org/r/c5995359-7c82-4e47-c7be-b58a4dda0953@infradead.org Fixes: 023a019a9b4e ("mm/hmm: add default fault flags to avoid the need to pre-fill pfns arrays") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/hmm: add default fault flags to avoid the need to pre-fill pfns arraysJérôme Glisse
The HMM mirror API can be use in two fashions. The first one where the HMM user coalesce multiple page faults into one request and set flags per pfns for of those faults. The second one where the HMM user want to pre-fault a range with specific flags. For the latter one it is a waste to have the user pre-fill the pfn arrays with a default flags value. This patch adds a default flags value allowing user to set them for a range without having to pre-fill the pfn array. Link: http://lkml.kernel.org/r/20190403193318.16478-8-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/hmm: improve driver API to work and wait over a rangeJérôme Glisse
A common use case for HMM mirror is user trying to mirror a range and before they could program the hardware it get invalidated by some core mm event. Instead of having user re-try right away to mirror the range provide a completion mechanism for them to wait for any active invalidation affecting the range. This also changes how hmm_range_snapshot() and hmm_range_fault() works by not relying on vma so that we can drop the mmap_sem when waiting and lookup the vma again on retry. Link: http://lkml.kernel.org/r/20190403193318.16478-7-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/hmm: improve and rename hmm_vma_fault() to hmm_range_fault()Jérôme Glisse
Minor optimization around hmm_pte_need_fault(). Rename for consistency between code, comments and documentation. Also improves the comments on all the possible returns values. Improve the function by returning the number of populated entries in pfns array. Link: http://lkml.kernel.org/r/20190403193318.16478-6-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/hmm: improve and rename hmm_vma_get_pfns() to hmm_range_snapshot()Jérôme Glisse
Rename for consistency between code, comments and documentation. Also improves the comments on all the possible returns values. Improve the function by returning the number of populated entries in pfns array. Link: http://lkml.kernel.org/r/20190403193318.16478-5-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-31docs/vm/hmm.rst: Add missed spaceBaoquan He
This space missing caused the colour scheme in vim editor messy after that line. Add it to fix. Signed-off-by: Baoquan He <bhe@redhat.com> [ jc: fixed alignment after the changed line ] Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-04-16Merge branch 'mm-rst' into docs-nextJonathan Corbet
Mike Rapoport says: These patches convert files in Documentation/vm to ReST format, add an initial index and link it to the top level documentation. There are no contents changes in the documentation, except few spelling fixes. The relatively large diffstat stems from the indentation and paragraph wrapping changes. I've tried to keep the formatting as consistent as possible, but I could miss some places that needed markup and add some markup where it was not necessary. [jc: significant conflicts in vm/hmm.rst]
2018-04-16docs/vm: rename documentation files to .rstMike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>