mm,hwpoison: unify THP handling for hard and soft offline

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: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200922135650.1634-8-osalvador@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 4a9f8dc..2ff4ba7 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1102,6 +1102,25 @@ 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);
@@ -1324,21 +1343,8 @@ 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);
        }
 
@@ -1855,19 +1861,9 @@ static int soft_offline_in_use_page(struct page *page, int flags)
        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