The patch titled
Subject: mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling-v2
has been removed from the -mm tree. Its filename was
mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling-v2.patch
This patch was dropped because it was folded into mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling.patch
------------------------------------------------------
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Subject: mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling-v2
ChangeLog v1->v2:
- fix function's comment to kernel-doc format
- remove 'inline' directive in get_hwpoison_page() definition
- separate if blocks instead of using else blocks
- add comment about thp refcounting
- add put_page(hpage) in failure path
- clear PageHWPoison if failed to handle thp
- revert the change removing VM_BUG_ON_PAGE() in put_refcounted_compound_pa=
ge()
- revert the change allowing unpoison_memory() to handle thp
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 53 ++++++++++++++++++++++++++++++------------
mm/swap.c | 2 +
2 files changed, 41 insertions(+), 14 deletions(-)
diff -puN mm/memory-failure.c~mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling-v2 mm/memory-failure.c
--- a/mm/memory-failure.c~mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling-v2
+++ a/mm/memory-failure.c
@@ -915,17 +915,26 @@ static int page_action(struct page_state
return (result == RECOVERED || result == DELAYED) ? 0 : -EBUSY;
}
-/*
- * Get refcount for memory error handling:
- * - @page: raw page
+/**
+ * get_hwpoison_page() - Get refcount for memory error handling:
+ * @page: raw error page (hit by memory error)
+ *
+ * Return: return 0 if failed to grab the refcount, otherwise true (some
+ * non-zero value.)
*/
-inline int get_hwpoison_page(struct page *page)
+int get_hwpoison_page(struct page *page)
{
struct page *head = compound_head(page);
if (PageHuge(head))
return get_page_unless_zero(head);
- else if (PageTransHuge(head))
+
+ /*
+ * Thp tail page has special refcounting rule (refcount of tail pages
+ * is stored in ->_mapcount,) so we can't call get_page_unless_zero()
+ * directly for tail pages.
+ */
+ if (PageTransHuge(head)) {
if (get_page_unless_zero(head)) {
if (PageTail(page))
get_page(page);
@@ -933,8 +942,9 @@ inline int get_hwpoison_page(struct page
} else {
return 0;
}
- else
- return get_page_unless_zero(page);
+ }
+
+ return get_page_unless_zero(page);
}
/*
@@ -1151,12 +1161,20 @@ int memory_failure(unsigned long pfn, in
if (!PageHuge(p) && PageTransHuge(hpage)) {
if (!PageAnon(hpage)) {
pr_err("MCE: %#lx: non anonymous thp\n", pfn);
+ if (TestClearPageHWPoison(p))
+ atomic_long_sub(nr_pages, &num_poisoned_pages);
put_page(p);
+ if (p != hpage)
+ put_page(hpage);
return -EBUSY;
}
if (unlikely(split_huge_page(hpage))) {
pr_err("MCE: %#lx: thp split failed\n", pfn);
+ if (TestClearPageHWPoison(p))
+ atomic_long_sub(nr_pages, &num_poisoned_pages);
put_page(p);
+ if (p != hpage)
+ put_page(hpage);
return -EBUSY;
}
VM_BUG_ON_PAGE(!page_count(p), p);
@@ -1427,10 +1445,17 @@ int unpoison_memory(unsigned long pfn)
return 0;
}
- if (PageHuge(page))
- nr_pages = 1 << compound_order(page);
- else
- nr_pages = 1;
+ /*
+ * unpoison_memory() can encounter thp only when the thp is being
+ * worked by memory_failure() and the page lock is not held yet.
+ * In such case, we yield to memory_failure() and make unpoison fail.
+ */
+ if (!PageHuge(page) && PageTransHuge(page)) {
+ pr_info("MCE: Memory failure is now running on %#lx\n", pfn);
+ return 0;
+ }
+
+ nr_pages = 1 << compound_order(page);
if (!get_hwpoison_page(p)) {
/*
@@ -1456,7 +1481,7 @@ int unpoison_memory(unsigned long pfn)
* the PG_hwpoison page will be caught and isolated on the entrance to
* the free buddy page pool.
*/
- if (TestClearPageHWPoison(p)) {
+ if (TestClearPageHWPoison(page)) {
pr_info("MCE: Software-unpoisoned page %#lx\n", pfn);
atomic_long_sub(nr_pages, &num_poisoned_pages);
freeit = 1;
@@ -1465,9 +1490,9 @@ int unpoison_memory(unsigned long pfn)
}
unlock_page(page);
- put_page(p);
+ put_page(page);
if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1))
- put_page(p);
+ put_page(page);
return 0;
}
diff -puN mm/swap.c~mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling-v2 mm/swap.c
--- a/mm/swap.c~mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling-v2
+++ a/mm/swap.c
@@ -209,6 +209,8 @@ out_put_single:
*/
if (put_page_testzero(page_head))
VM_BUG_ON_PAGE(1, page_head);
+ /* __split_huge_page_refcount will wait now */
+ VM_BUG_ON_PAGE(page_mapcount(page) <= 0, page);
atomic_dec(&page->_mapcount);
VM_BUG_ON_PAGE(atomic_read(&page_head->_count) <= 0, page_head);
VM_BUG_ON_PAGE(atomic_read(&page->_count) != 0, page);
_
Patches currently in -mm which might be from n-horiguchi@xxxxxxxxxxxxx are
mm-hwpoison-add-comment-describing-when-to-add-new-cases.patch
mm-hwpoison-remove-obsolete-notebook-todo-list.patch
mm-memory-failure-split-thp-earlier-in-memory-error-handling.patch
mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling.patch
mm-memory-failure-introduce-get_hwpoison_page-for-consistent-refcount-handling-fix.patch
mm-soft-offline-dont-free-target-page-in-successful-page-migration.patch
mm-memory-failure-me_huge_page-does-nothing-for-thp.patch
mm-hugetlb-introduce-minimum-hugepage-order.patch
hugetlb-do-not-account-hugetlb-pages-as-nr_file_pages.patch
memory-failure-export-page_type-and-action-result.patch
memory-failure-change-type-of-action_results-param-3-to-enum.patch
tracing-add-trace-event-for-memory-failure.patch
tracing-add-trace-event-for-memory-failure-fix.patch
mm-hugetlb-document-the-reserve-map-region-tracking-routines.patch
mm-hugetlb-compute-return-the-number-of-regions-added-by-region_add.patch
mm-hugetlb-handle-races-in-alloc_huge_page-and-hugetlb_reserve_pages.patch
mm-hugetlb-handle-races-in-alloc_huge_page-and-hugetlb_reserve_pages-v4.patch
mm-memory-hotplug-print-the-last-vmemmap-region-at-the-end-of-hot-add-memory.patch
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