diff options
| -rw-r--r-- | include/linux/migrate.h | 7 | ||||
| -rw-r--r-- | mm/migrate_device.c | 89 |
2 files changed, 89 insertions, 7 deletions
diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 52090d1f9230..3ef77f52a4f0 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -210,6 +210,13 @@ struct migrate_vma { int migrate_vma_setup(struct migrate_vma *args); void migrate_vma_pages(struct migrate_vma *migrate); void migrate_vma_finalize(struct migrate_vma *migrate); +int migrate_device_range(unsigned long *src_pfns, unsigned long start, + unsigned long npages); +void migrate_device_pages(unsigned long *src_pfns, unsigned long *dst_pfns, + unsigned long npages); +void migrate_device_finalize(unsigned long *src_pfns, + unsigned long *dst_pfns, unsigned long npages); + #endif /* CONFIG_MIGRATION */ #endif /* _LINUX_MIGRATE_H */ diff --git a/mm/migrate_device.c b/mm/migrate_device.c index 7707c1d898f5..6fa682eef7a0 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -693,7 +693,7 @@ abort: *src &= ~MIGRATE_PFN_MIGRATE; } -static void migrate_device_pages(unsigned long *src_pfns, +static void __migrate_device_pages(unsigned long *src_pfns, unsigned long *dst_pfns, unsigned long npages, struct migrate_vma *migrate) { @@ -715,6 +715,9 @@ static void migrate_device_pages(unsigned long *src_pfns, if (!page) { unsigned long addr; + if (!(src_pfns[i] & MIGRATE_PFN_MIGRATE)) + continue; + /* * The only time there is no vma is when called from * migrate_device_coherent_page(). However this isn't @@ -722,8 +725,6 @@ static void migrate_device_pages(unsigned long *src_pfns, */ VM_BUG_ON(!migrate); addr = migrate->start + i*PAGE_SIZE; - if (!(src_pfns[i] & MIGRATE_PFN_MIGRATE)) - continue; if (!notified) { notified = true; @@ -779,6 +780,22 @@ static void migrate_device_pages(unsigned long *src_pfns, } /** + * migrate_device_pages() - migrate meta-data from src page to dst page + * @src_pfns: src_pfns returned from migrate_device_range() + * @dst_pfns: array of pfns allocated by the driver to migrate memory to + * @npages: number of pages in the range + * + * Equivalent to migrate_vma_pages(). This is called to migrate struct page + * meta-data from source struct page to destination. + */ +void migrate_device_pages(unsigned long *src_pfns, unsigned long *dst_pfns, + unsigned long npages) +{ + __migrate_device_pages(src_pfns, dst_pfns, npages, NULL); +} +EXPORT_SYMBOL(migrate_device_pages); + +/** * migrate_vma_pages() - migrate meta-data from src page to dst page * @migrate: migrate struct containing all migration information * @@ -788,12 +805,22 @@ static void migrate_device_pages(unsigned long *src_pfns, */ void migrate_vma_pages(struct migrate_vma *migrate) { - migrate_device_pages(migrate->src, migrate->dst, migrate->npages, migrate); + __migrate_device_pages(migrate->src, migrate->dst, migrate->npages, migrate); } EXPORT_SYMBOL(migrate_vma_pages); -static void migrate_device_finalize(unsigned long *src_pfns, - unsigned long *dst_pfns, unsigned long npages) +/* + * migrate_device_finalize() - complete page migration + * @src_pfns: src_pfns returned from migrate_device_range() + * @dst_pfns: array of pfns allocated by the driver to migrate memory to + * @npages: number of pages in the range + * + * Completes migration of the page by removing special migration entries. + * Drivers must ensure copying of page data is complete and visible to the CPU + * before calling this. + */ +void migrate_device_finalize(unsigned long *src_pfns, + unsigned long *dst_pfns, unsigned long npages) { unsigned long i; @@ -837,6 +864,7 @@ static void migrate_device_finalize(unsigned long *src_pfns, } } } +EXPORT_SYMBOL(migrate_device_finalize); /** * migrate_vma_finalize() - restore CPU page table entry @@ -855,6 +883,53 @@ void migrate_vma_finalize(struct migrate_vma *migrate) } EXPORT_SYMBOL(migrate_vma_finalize); +/** + * migrate_device_range() - migrate device private pfns to normal memory. + * @src_pfns: array large enough to hold migrating source device private pfns. + * @start: starting pfn in the range to migrate. + * @npages: number of pages to migrate. + * + * migrate_vma_setup() is similar in concept to migrate_vma_setup() except that + * instead of looking up pages based on virtual address mappings a range of + * device pfns that should be migrated to system memory is used instead. + * + * This is useful when a driver needs to free device memory but doesn't know the + * virtual mappings of every page that may be in device memory. For example this + * is often the case when a driver is being unloaded or unbound from a device. + * + * Like migrate_vma_setup() this function will take a reference and lock any + * migrating pages that aren't free before unmapping them. Drivers may then + * allocate destination pages and start copying data from the device to CPU + * memory before calling migrate_device_pages(). + */ +int migrate_device_range(unsigned long *src_pfns, unsigned long start, + unsigned long npages) +{ + unsigned long i, pfn; + + for (pfn = start, i = 0; i < npages; pfn++, i++) { + struct page *page = pfn_to_page(pfn); + + if (!get_page_unless_zero(page)) { + src_pfns[i] = 0; + continue; + } + + if (!trylock_page(page)) { + src_pfns[i] = 0; + put_page(page); + continue; + } + + src_pfns[i] = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE; + } + + migrate_device_unmap(src_pfns, npages, NULL); + + return 0; +} +EXPORT_SYMBOL(migrate_device_range); + /* * Migrate a device coherent page back to normal memory. The caller should have * a reference on page which will be copied to the new page if migration is @@ -885,7 +960,7 @@ int migrate_device_coherent_page(struct page *page) dst_pfn = migrate_pfn(page_to_pfn(dpage)); } - migrate_device_pages(&src_pfn, &dst_pfn, 1, NULL); + migrate_device_pages(&src_pfn, &dst_pfn, 1); if (src_pfn & MIGRATE_PFN_MIGRATE) copy_highpage(dpage, page); migrate_device_finalize(&src_pfn, &dst_pfn, 1); |