[PATCH v3 10/15] mm,hwpoison: Unify THP handling for hard and soft offline

nao.horiguchi
2020-06-24T15:02:19Z

From: Oscar Salvador <osalvador@suse.de>

Place the THP's page handling in a helper and use it
from both hard and soft-offline machinery, so we get rid
of some duplicated code.

Signed-off-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
---
mm/memory-failure.c | 48 +++++++++++++++++++++------------------------
1 file changed, 22 insertions(+), 26 deletions(-)

diff --git v5.8-rc1-mmots-2020-06-20-21-44/mm/memory-failure.c v5.8-rc1-mmots-2020-06-20-21-44_patched/mm/memory-failure.c
index 03d3aae77f89..2e244d5b83e0 100644
--- v5.8-rc1-mmots-2020-06-20-21-44/mm/memory-failure.c
+++ v5.8-rc1-mmots-2020-06-20-21-44_patched/mm/memory-failure.c
@@ -1103,6 +1103,25 @@ static int identify_page_state(unsigned long pfn, struct page *p,
return page_action(ps, p, pfn);
}

+static int try_to_split_thp_page(struct page *page, const char *msg)
+{
+ lock_page(page);
+ if (!PageAnon(page) || unlikely(split_huge_page(page))) {
+ unsigned long pfn = page_to_pfn(page);
+
+ unlock_page(page);
+ if (!PageAnon(page))
+ pr_info("%s: %#lx: non anonymous thp\n", msg, pfn);
+ else
+ pr_info("%s: %#lx: thp split failed\n", msg, pfn);
+ put_page(page);
+ return -EBUSY;
+ }
+ unlock_page(page);
+
+ return 0;
+}
+
static int memory_failure_hugetlb(unsigned long pfn, int flags)
{
struct page *p = pfn_to_page(pfn);
@@ -1325,21 +1344,8 @@ int memory_failure(unsigned long pfn, int flags)
}

if (PageTransHuge(hpage)) {
- lock_page(p);
- if (!PageAnon(p) || unlikely(split_huge_page(p))) {
- unlock_page(p);
- if (!PageAnon(p))
- pr_err("Memory failure: %#lx: non anonymous thp\n",
- pfn);
- else
- pr_err("Memory failure: %#lx: thp split failed\n",
- pfn);
- if (TestClearPageHWPoison(p))
- num_poisoned_pages_dec();
- put_page(p);
+ if (try_to_split_thp_page(p, "Memory Failure") < 0)
return -EBUSY;
- }
- unlock_page(p);
VM_BUG_ON_PAGE(!page_count(p), p);
}

@@ -1847,19 +1853,9 @@ static int soft_offline_in_use_page(struct page *page)
int mt;
struct page *hpage = compound_head(page);

- if (!PageHuge(page) && PageTransHuge(hpage)) {
- lock_page(page);
- if (!PageAnon(page) || unlikely(split_huge_page(page))) {
- unlock_page(page);
- if (!PageAnon(page))
- pr_info("soft offline: %#lx: non anonymous thp\n", page_to_pfn(page));
- else
- pr_info("soft offline: %#lx: thp split failed\n", page_to_pfn(page));
- put_page(page);
+ if (!PageHuge(page) && PageTransHuge(hpage))
+ if (try_to_split_thp_page(page, "soft offline") < 0)
return -EBUSY;
- }
- unlock_page(page);
- }

/*
* Setting MIGRATE_ISOLATE here ensures that the page will be linked
--
2.17.1