We're going to use migration entries instead of compound_lock() to
stabilize page refcounts. Setup and remove migration entries require
page to be locked.
Some of split_huge_page() callers already have the page locked. Let's
require everybody to lock the page before calling split_huge_page().
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Tested-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
mm/memory-failure.c | 12 +++++++++---
mm/migrate.c | 8 ++++++--
2 files changed, 15 insertions(+), 5 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 441eff52d099..d9b06727e480 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -996,7 +996,10 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
* enough * to be safe.
*/
if (!PageHuge(hpage) && PageAnon(hpage)) {
- if (unlikely(split_huge_page(hpage))) {
+ lock_page(hpage);
+ ret = split_huge_page(hpage);
+ unlock_page(hpage);
+ if (unlikely(ret)) {
/*
* FIXME: if splitting THP is failed, it is
* better to stop the following operation rather
@@ -1750,10 +1753,13 @@ int soft_offline_page(struct page *page, int flags)
return -EBUSY;
}
if (!PageHuge(page) && PageTransHuge(hpage)) {
- if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
+ lock_page(page);
+ ret = split_huge_page(hpage);
+ unlock_page(page);
+ if (unlikely(ret)) {
pr_info("soft offline: %#lx: failed to split THP\n",
pfn);
- return -EBUSY;
+ return ret;
}
}
diff --git a/mm/migrate.c b/mm/migrate.c
index b51e88c9dba2..03b9c4ba56dc 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -932,9 +932,13 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
goto out;
}
- if (unlikely(PageTransHuge(page)))
- if (unlikely(split_huge_page(page)))
+ if (unlikely(PageTransHuge(page))) {
+ lock_page(page);
+ rc = split_huge_page(page);
+ unlock_page(page);
+ if (rc)
goto out;
+ }
rc = __unmap_and_move(page, newpage, force, mode);
--
2.1.4
--
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