The patch titled
Subject: mm/swap.c: fix release_pages() when releasing devmap pages
has been removed from the -mm tree. Its filename was
mm-swap-fix-release_pages-when-releasing-devmap-pages.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Ira Weiny <ira.weiny@xxxxxxxxx>
Subject: mm/swap.c: fix release_pages() when releasing devmap pages
release_pages() is an optimized version of a loop around put_page().
Unfortunately for devmap pages the logic is not entirely correct in
release_pages(). This is because device pages can be more than type
MEMORY_DEVICE_PUBLIC. There are in fact 4 types, private, public, FS DAX,
and PCI P2PDMA. Some of these have specific needs to "put" the page while
others do not.
This logic to handle any special needs is contained in
put_devmap_managed_page(). Therefore all devmap pages should be processed
by this function where we can contain the correct logic for a page put.
Handle all device type pages within release_pages() by calling
put_devmap_managed_page() on all devmap pages. If
put_devmap_managed_page() returns true the page has been put and we
continue with the next page. A false return of put_devmap_managed_page()
means the page did not require special processing and should fall to
"normal" processing.
This was found via code inspection while determining if release_pages()
and the new put_user_pages() could be interchangeable.[1]
[1] https://lore.kernel.org/lkml/20190523172852.GA27175@xxxxxxxxxxxxxxxxxxxxxxxxx/
Link: http://lkml.kernel.org/r/20190523223746.4982-1-ira.weiny@xxxxxxxxx
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swap.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
--- a/mm/swap.c~mm-swap-fix-release_pages-when-releasing-devmap-pages
+++ a/mm/swap.c
@@ -740,15 +740,14 @@ void release_pages(struct page **pages,
if (is_huge_zero_page(page))
continue;
- /* Device public page can not be huge page */
- if (is_device_public_page(page)) {
+ if (is_zone_device_page(page)) {
if (locked_pgdat) {
spin_unlock_irqrestore(&locked_pgdat->lru_lock,
flags);
locked_pgdat = NULL;
}
- put_devmap_managed_page(page);
- continue;
+ if (put_devmap_managed_page(page))
+ continue;
}
page = compound_head(page);
_
Patches currently in -mm which might be from ira.weiny@xxxxxxxxx are
