* folio_migrate_mapping(), except that here we allow migration of a
* ZONE_DEVICE page.
*/
-static bool migrate_vma_check_page(struct page *page)
+static bool migrate_vma_check_page(struct page *page, struct page *fault_page)
{
/*
* One extra ref because caller holds an extra reference, either from
* isolate_lru_page() for a regular page, or migrate_vma_collect() for
* a device page.
*/
- int extra = 1;
+ int extra = 1 + (page == fault_page);
/*
* FIXME support THP (transparent huge page), it is bit more complex to
}
/*
- * migrate_vma_unmap() - replace page mapping with special migration pte entry
- * @migrate: migrate struct containing all migration information
- *
- * Isolate pages from the LRU and replace mappings (CPU page table pte) with a
- * special migration pte entry and check if it has been pinned. Pinned pages are
- * restored because we cannot migrate them.
- *
- * This is the last step before we call the device driver callback to allocate
- * destination memory and copy contents of original page over to new page.
+ * Unmaps pages for migration. Returns number of unmapped pages.
*/
-static void migrate_vma_unmap(struct migrate_vma *migrate)
+static unsigned long migrate_device_unmap(unsigned long *src_pfns,
+ unsigned long npages,
+ struct page *fault_page)
{
- const unsigned long npages = migrate->npages;
unsigned long i, restore = 0;
bool allow_drain = true;
+ unsigned long unmapped = 0;
lru_add_drain();
for (i = 0; i < npages; i++) {
- struct page *page = migrate_pfn_to_page(migrate->src[i]);
+ struct page *page = migrate_pfn_to_page(src_pfns[i]);
struct folio *folio;
if (!page)
}
if (isolate_lru_page(page)) {
- migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
- migrate->cpages--;
+ src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
restore++;
continue;
}
if (folio_mapped(folio))
try_to_migrate(folio, 0);
- if (page_mapped(page) || !migrate_vma_check_page(page)) {
+ if (page_mapped(page) ||
+ !migrate_vma_check_page(page, fault_page)) {
if (!is_zone_device_page(page)) {
get_page(page);
putback_lru_page(page);
}
- migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
- migrate->cpages--;
+ src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
restore++;
continue;
}
+
+ unmapped++;
}
for (i = 0; i < npages && restore; i++) {
- struct page *page = migrate_pfn_to_page(migrate->src[i]);
+ struct page *page = migrate_pfn_to_page(src_pfns[i]);
struct folio *folio;
- if (!page || (migrate->src[i] & MIGRATE_PFN_MIGRATE))
+ if (!page || (src_pfns[i] & MIGRATE_PFN_MIGRATE))
continue;
folio = page_folio(page);
remove_migration_ptes(folio, folio, false);
- migrate->src[i] = 0;
+ src_pfns[i] = 0;
folio_unlock(folio);
folio_put(folio);
restore--;
}
+
+ return unmapped;
+}
+
+/*
+ * migrate_vma_unmap() - replace page mapping with special migration pte entry
+ * @migrate: migrate struct containing all migration information
+ *
+ * Isolate pages from the LRU and replace mappings (CPU page table pte) with a
+ * special migration pte entry and check if it has been pinned. Pinned pages are
+ * restored because we cannot migrate them.
+ *
+ * This is the last step before we call the device driver callback to allocate
+ * destination memory and copy contents of original page over to new page.
+ */
+static void migrate_vma_unmap(struct migrate_vma *migrate)
+{
+ migrate->cpages = migrate_device_unmap(migrate->src, migrate->npages,
+ migrate->fault_page);
}
/**
return -EINVAL;
if (!args->src || !args->dst)
return -EINVAL;
+ if (args->fault_page && !is_device_private_page(args->fault_page))
+ return -EINVAL;
memset(args->src, 0, sizeof(*args->src) * nr_pages);
args->cpages = 0;
*src &= ~MIGRATE_PFN_MIGRATE;
}
-/**
- * migrate_vma_pages() - migrate meta-data from src page to dst page
- * @migrate: migrate struct containing all migration information
- *
- * This migrates struct page meta-data from source struct page to destination
- * struct page. This effectively finishes the migration from source page to the
- * destination page.
- */
-void migrate_vma_pages(struct migrate_vma *migrate)
+static void __migrate_device_pages(unsigned long *src_pfns,
+ unsigned long *dst_pfns, unsigned long npages,
+ struct migrate_vma *migrate)
{
- const unsigned long npages = migrate->npages;
- const unsigned long start = migrate->start;
struct mmu_notifier_range range;
- unsigned long addr, i;
+ unsigned long i;
bool notified = false;
- for (i = 0, addr = start; i < npages; addr += PAGE_SIZE, i++) {
- struct page *newpage = migrate_pfn_to_page(migrate->dst[i]);
- struct page *page = migrate_pfn_to_page(migrate->src[i]);
+ for (i = 0; i < npages; i++) {
+ struct page *newpage = migrate_pfn_to_page(dst_pfns[i]);
+ struct page *page = migrate_pfn_to_page(src_pfns[i]);
struct address_space *mapping;
int r;
if (!newpage) {
- migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
+ src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
continue;
}
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
* called if the page could not be unmapped.
*/
- VM_BUG_ON(!migrate->vma);
- if (!(migrate->src[i] & MIGRATE_PFN_MIGRATE))
- continue;
+ VM_BUG_ON(!migrate);
+ addr = migrate->start + i*PAGE_SIZE;
if (!notified) {
notified = true;
mmu_notifier_invalidate_range_start(&range);
}
migrate_vma_insert_page(migrate, addr, newpage,
- &migrate->src[i]);
+ &src_pfns[i]);
continue;
}
* device private or coherent memory.
*/
if (mapping) {
- migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
+ src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
continue;
}
} else if (is_zone_device_page(newpage)) {
/*
* Other types of ZONE_DEVICE page are not supported.
*/
- migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
+ src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
continue;
}
- r = migrate_folio(mapping, page_folio(newpage),
- page_folio(page), MIGRATE_SYNC_NO_COPY);
+ if (migrate && migrate->fault_page == page)
+ r = migrate_folio_extra(mapping, page_folio(newpage),
+ page_folio(page),
+ MIGRATE_SYNC_NO_COPY, 1);
+ else
+ r = migrate_folio(mapping, page_folio(newpage),
+ page_folio(page), MIGRATE_SYNC_NO_COPY);
if (r != MIGRATEPAGE_SUCCESS)
- migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
+ src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
}
/*
if (notified)
mmu_notifier_invalidate_range_only_end(&range);
}
-EXPORT_SYMBOL(migrate_vma_pages);
/**
- * migrate_vma_finalize() - restore CPU page table entry
+ * 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
*
- * This replaces the special migration pte entry with either a mapping to the
- * new page if migration was successful for that page, or to the original page
- * otherwise.
+ * This migrates struct page meta-data from source struct page to destination
+ * struct page. This effectively finishes the migration from source page to the
+ * destination page.
+ */
+void migrate_vma_pages(struct migrate_vma *migrate)
+{
+ __migrate_device_pages(migrate->src, migrate->dst, migrate->npages, migrate);
+}
+EXPORT_SYMBOL(migrate_vma_pages);
+
+/*
+ * 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
*
- * This also unlocks the pages and puts them back on the lru, or drops the extra
- * refcount, for device pages.
+ * 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_vma_finalize(struct migrate_vma *migrate)
+void migrate_device_finalize(unsigned long *src_pfns,
+ unsigned long *dst_pfns, unsigned long npages)
{
- const unsigned long npages = migrate->npages;
unsigned long i;
for (i = 0; i < npages; i++) {
struct folio *dst, *src;
- struct page *newpage = migrate_pfn_to_page(migrate->dst[i]);
- struct page *page = migrate_pfn_to_page(migrate->src[i]);
+ struct page *newpage = migrate_pfn_to_page(dst_pfns[i]);
+ struct page *page = migrate_pfn_to_page(src_pfns[i]);
if (!page) {
if (newpage) {
continue;
}
- if (!(migrate->src[i] & MIGRATE_PFN_MIGRATE) || !newpage) {
+ if (!(src_pfns[i] & MIGRATE_PFN_MIGRATE) || !newpage) {
if (newpage) {
unlock_page(newpage);
put_page(newpage);
}
}
}
+EXPORT_SYMBOL(migrate_device_finalize);
+
+/**
+ * migrate_vma_finalize() - restore CPU page table entry
+ * @migrate: migrate struct containing all migration information
+ *
+ * This replaces the special migration pte entry with either a mapping to the
+ * new page if migration was successful for that page, or to the original page
+ * otherwise.
+ *
+ * This also unlocks the pages and puts them back on the lru, or drops the extra
+ * refcount, for device pages.
+ */
+void migrate_vma_finalize(struct migrate_vma *migrate)
+{
+ migrate_device_finalize(migrate->src, migrate->dst, migrate->npages);
+}
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
int migrate_device_coherent_page(struct page *page)
{
unsigned long src_pfn, dst_pfn = 0;
- struct migrate_vma args;
struct page *dpage;
WARN_ON_ONCE(PageCompound(page));
lock_page(page);
src_pfn = migrate_pfn(page_to_pfn(page)) | MIGRATE_PFN_MIGRATE;
- args.src = &src_pfn;
- args.dst = &dst_pfn;
- args.cpages = 1;
- args.npages = 1;
- args.vma = NULL;
/*
* We don't have a VMA and don't need to walk the page tables to find
* the source page. So call migrate_vma_unmap() directly to unmap the
* page as migrate_vma_setup() will fail if args.vma == NULL.
*/
- migrate_vma_unmap(&args);
+ migrate_device_unmap(&src_pfn, 1, NULL);
if (!(src_pfn & MIGRATE_PFN_MIGRATE))
return -EBUSY;
dst_pfn = migrate_pfn(page_to_pfn(dpage));
}
- migrate_vma_pages(&args);
+ migrate_device_pages(&src_pfn, &dst_pfn, 1);
if (src_pfn & MIGRATE_PFN_MIGRATE)
copy_highpage(dpage, page);
- migrate_vma_finalize(&args);
+ migrate_device_finalize(&src_pfn, &dst_pfn, 1);
if (src_pfn & MIGRATE_PFN_MIGRATE)
return 0;
projects / platform / kernel / linux-starfive.git / blobdiff