On 04.04.24 09:26, Vivek Kasireddy wrote:
This helper is the folio equivalent of check_and_migrate_movable_pages().
Therefore, all the rules that apply to check_and_migrate_movable_pages()
also apply to this one as well. Currently, this helper is only used by
memfd_pin_folios().
This patch also includes changes to rename and convert the internal
functions collect_longterm_unpinnable_pages() and
migrate_longterm_unpinnable_pages() to work on folios. As a result,
check_and_migrate_movable_pages() is now a wrapper around
check_and_migrate_movable_folios().
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
---
[...]
+/*
+ * Check whether all folios are *allowed* to be pinned indefinitely (longterm).
+ * Rather confusingly, all folios in the range are required to be pinned via
+ * FOLL_PIN, before calling this routine.
+ *
+ * If any folios in the range are not allowed to be pinned, then this routine
+ * will migrate those folios away, unpin all the folios in the range and return
+ * -EAGAIN. The caller should re-pin the entire range with FOLL_PIN and then
+ * call this routine again.
+ *
+ * If an error other than -EAGAIN occurs, this indicates a migration failure.
+ * The caller should give up, and propagate the error back up the call stack.
+ *
+ * If everything is OK and all folios in the range are allowed to be pinned,
+ * then this routine leaves all folios pinned and returns zero for success.
+ */
+static long check_and_migrate_movable_folios(unsigned long nr_folios,
+ struct folio **folios)
+{
+ unsigned long collected;
+ LIST_HEAD(movable_folio_list);
+
+ collected = collect_longterm_unpinnable_folios(&movable_folio_list,
+ nr_folios, folios);
+ if (!collected)
+ return 0;
+
+ return migrate_longterm_unpinnable_folios(&movable_folio_list,
+ nr_folios, folios);
+}
+
/*
* Check whether all pages are *allowed* to be pinned. Rather confusingly, all
* pages in the range are required to be pinned via FOLL_PIN, before calling
Likely we should just drop that comment and refer to
check_and_migrate_movable_folios() instead. No need to duplicate all that.
@@ -2555,16 +2585,20 @@ static int migrate_longterm_unpinnable_pages(
static long check_and_migrate_movable_pages(unsigned long nr_pages,
struct page **pages)
{
- unsigned long collected;
- LIST_HEAD(movable_page_list);
+ struct folio **folios;
+ long i, ret;
- collected = collect_longterm_unpinnable_pages(&movable_page_list,
- nr_pages, pages);
- if (!collected)
- return 0;
+ folios = kmalloc_array(nr_pages, sizeof(*folios), GFP_KERNEL);
+ if (!folios)
+ return -ENOMEM;
- return migrate_longterm_unpinnable_pages(&movable_page_list, nr_pages,
- pages);
+ for (i = 0; i < nr_pages; i++)
+ folios[i] = page_folio(pages[i]);
I wonder if we have to handle pages[i] being NULL. Hopefully not :)
Looks straight forward now:
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
