On 04.09.21 11:20, Miaohe Lin wrote:
In start_isolate_page_range() undo path, pfn_to_online_page() just checks
the first pfn in a pageblock while __first_valid_page() will traverse the
pageblock until the first online pfn is found. So we may miss the call to
unset_migratetype_isolate() in undo path and pages will remain isolated
unexpectedly. Fix this by calling undo_isolate_page_range() and this will
also help to remove some duplicated codes.
Fixes: 2ce13640b3f4 ("mm: __first_valid_page skip over offline pages")
While that is true, we shouldn't ever trigger, neither via cma,
virtio-mem nor memory offlining, because essentially all operate on
MAX_ORDER -1 -aligned ranges without memory holes.
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
mm/page_isolation.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 471e3a13b541..9bb562d5d194 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -202,14 +202,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
}
return 0;
undo:
- for (pfn = start_pfn;
- pfn < undo_pfn;
- pfn += pageblock_nr_pages) {
- struct page *page = pfn_to_online_page(pfn);
- if (!page)
- continue;
- unset_migratetype_isolate(page, migratetype);
- }
+ undo_isolate_page_range(start_pfn, undo_pfn, migratetype);
It'd be even cleaner to drop the label completely and call it from the
single callsite. We can even avoid undo_pfn ...
if (page && set_migratetype_isolate(page, migratetype, flags)) {
undo_isolate_page_range(start_pfn, pfn, migratetype);
return -EBUSY;
}
If pfn == start_pfn, undo_isolate_page_range() will simply do nothing.
return -EBUSY;
}
--
Thanks,
David / dhildenb
