On Tue, Jun 28, 2022 at 12:31:55PM +0100, Matthew Wilcox wrote:
> On Tue, Jun 28, 2022 at 12:27:40PM +0100, Matthew Wilcox wrote:
> > On Tue, Jun 28, 2022 at 05:31:20PM +1000, Dave Chinner wrote:
> > > So using this technique, I've discovered that there's a dirty page
> > > accounting leak that eventually results in fsx hanging in
> > > balance_dirty_pages().
> >
> > Alas, I think this is only an accounting error, and not related to
> > the problem(s) that Darrick & Zorro are seeing. I think what you're
> > seeing is dirty pages being dropped at truncation without the
> > appropriate accounting. ie this should be the fix:
>
> Argh, try one that actually compiles.
... that one's going to underflow the accounting. Maybe I shouldn't
be writing code at 6am?
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f7248002dad9..4eec6ee83e44 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -18,6 +18,7 @@
#include <linux/shrinker.h>
#include <linux/mm_inline.h>
#include <linux/swapops.h>
+#include <linux/backing-dev.h>
#include <linux/dax.h>
#include <linux/khugepaged.h>
#include <linux/freezer.h>
@@ -2439,11 +2440,15 @@ static void __split_huge_page(struct page *page, struct list_head *list,
__split_huge_page_tail(head, i, lruvec, list);
/* Some pages can be beyond EOF: drop them from page cache */
if (head[i].index >= end) {
- ClearPageDirty(head + i);
- __delete_from_page_cache(head + i, NULL);
+ struct folio *tail = page_folio(head + i);
+
if (shmem_mapping(head->mapping))
shmem_uncharge(head->mapping->host, 1);
- put_page(head + i);
+ else if (folio_test_clear_dirty(tail))
+ folio_account_cleaned(tail,
+ inode_to_wb(folio->mapping->host));
+ __filemap_remove_folio(tail, NULL);
+ folio_put(tail);
} else if (!PageAnon(page)) {
__xa_store(&head->mapping->i_pages, head[i].index,
head + i, 0);
