memory_failure() is a big function and hard to maintain.
Handling hugetlb- and non-hugetlb- case in a single function is not
good, so this patch separates PageHuge() branch into a new function,
which saves many PageHuge() check.
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
mm/memory-failure.c | 134 ++++++++++++++++++++++++++++++++--------------------
1 file changed, 82 insertions(+), 52 deletions(-)
diff --git v4.12-rc3/mm/memory-failure.c v4.12-rc3_patched/mm/memory-failure.c
index a5f52cc..31b761a 100644
--- v4.12-rc3/mm/memory-failure.c
+++ v4.12-rc3_patched/mm/memory-failure.c
@@ -1009,6 +1009,76 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
return unmap_success;
}
+static int memory_failure_hugetlb(unsigned long pfn, int trapno, int flags)
+{
+ struct page_state *ps;
+ struct page *p = pfn_to_page(pfn);
+ struct page *head = compound_head(p);
+ int res;
+ unsigned long page_flags;
+
+ if (TestSetPageHWPoison(head)) {
+ pr_err("Memory failure: %#lx: already hardware poisoned\n",
+ pfn);
+ return 0;
+ }
+
+ num_poisoned_pages_inc();
+
+ if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) {
+ /*
+ * Check "filter hit" and "race with other subpage."
+ */
+ lock_page(head);
+ if (PageHWPoison(head)) {
+ if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
+ || (p != head && TestSetPageHWPoison(head))) {
+ num_poisoned_pages_dec();
+ unlock_page(head);
+ return 0;
+ }
+ }
+ unlock_page(head);
+ dissolve_free_huge_page(p);
+ action_result(pfn, MF_MSG_FREE_HUGE, MF_DELAYED);
+ return 0;
+ }
+
+ lock_page(head);
+ page_flags = head->flags;
+
+ if (!PageHWPoison(head)) {
+ pr_err("Memory failure: %#lx: just unpoisoned\n", pfn);
+ num_poisoned_pages_dec();
+ unlock_page(head);
+ put_hwpoison_page(head);
+ return 0;
+ }
+
+ if (!hwpoison_user_mappings(p, pfn, trapno, flags, &head)) {
+ action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);
+ res = -EBUSY;
+ goto out;
+ }
+
+ res = -EBUSY;
+
+ for (ps = error_states;; ps++)
+ if ((p->flags & ps->mask) == ps->res)
+ break;
+
+ page_flags |= (p->flags & (1UL << PG_dirty));
+
+ if (!ps->mask)
+ for (ps = error_states;; ps++)
+ if ((page_flags & ps->mask) == ps->res)
+ break;
+ res = page_action(ps, p, pfn);
+out:
+ unlock_page(head);
+ return res;
+}
+
/**
* memory_failure - Handle memory failure of a page.
* @pfn: Page Number of the corrupted page
@@ -1046,33 +1116,22 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
}
p = pfn_to_page(pfn);
- orig_head = hpage = compound_head(p);
-
- /* tmporary check code, to be updated in later patches */
- if (PageHuge(p)) {
- if (TestSetPageHWPoison(hpage)) {
- pr_err("Memory failure: %#lx: already hardware poisoned\n", pfn);
- return 0;
- }
- goto tmp;
- }
+ if (PageHuge(p))
+ return memory_failure_hugetlb(pfn, trapno, flags);
if (TestSetPageHWPoison(p)) {
pr_err("Memory failure: %#lx: already hardware poisoned\n",
pfn);
return 0;
}
-tmp:
+ orig_head = hpage = compound_head(p);
num_poisoned_pages_inc();
/*
* We need/can do nothing about count=0 pages.
* 1) it's a free page, and therefore in safe hand:
* prep_new_page() will be the gate keeper.
- * 2) it's a free hugepage, which is also safe:
- * an affected hugepage will be dequeued from hugepage freelist,
- * so there's no concern about reusing it ever after.
- * 3) it's part of a non-compound high order page.
+ * 2) it's part of a non-compound high order page.
* Implies some kernel user: cannot stop them from
* R/W the page; let's pray that the page has been
* used and will be freed some time later.
@@ -1083,31 +1142,13 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
if (is_free_buddy_page(p)) {
action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
return 0;
- } else if (PageHuge(hpage)) {
- /*
- * Check "filter hit" and "race with other subpage."
- */
- lock_page(hpage);
- if (PageHWPoison(hpage)) {
- if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
- || (p != hpage && TestSetPageHWPoison(hpage))) {
- num_poisoned_pages_dec();
- unlock_page(hpage);
- return 0;
- }
- }
- res = dequeue_hwpoisoned_huge_page(hpage);
- action_result(pfn, MF_MSG_FREE_HUGE,
- res ? MF_IGNORED : MF_DELAYED);
- unlock_page(hpage);
- return res;
} else {
action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);
return -EBUSY;
}
}
- if (!PageHuge(p) && PageTransHuge(hpage)) {
+ if (PageTransHuge(hpage)) {
lock_page(p);
if (!PageAnon(p) || unlikely(split_huge_page(p))) {
unlock_page(p);
@@ -1145,7 +1186,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
return 0;
}
- lock_page(hpage);
+ lock_page(p);
/*
* The page could have changed compound pages during the locking.
@@ -1172,33 +1213,22 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
if (!PageHWPoison(p)) {
pr_err("Memory failure: %#lx: just unpoisoned\n", pfn);
num_poisoned_pages_dec();
- unlock_page(hpage);
- put_hwpoison_page(hpage);
+ unlock_page(p);
+ put_hwpoison_page(p);
return 0;
}
if (hwpoison_filter(p)) {
if (TestClearPageHWPoison(p))
num_poisoned_pages_dec();
- unlock_page(hpage);
- put_hwpoison_page(hpage);
+ unlock_page(p);
+ put_hwpoison_page(p);
return 0;
}
- if (!PageHuge(p) && !PageTransTail(p) && !PageLRU(p))
+ if (!PageTransTail(p) && !PageLRU(p))
goto identify_page_state;
/*
- * For error on the tail page, we should set PG_hwpoison
- * on the head page to show that the hugepage is hwpoisoned
- */
- if (PageHuge(p) && PageTail(p) && TestSetPageHWPoison(hpage)) {
- action_result(pfn, MF_MSG_POISONED_HUGE, MF_IGNORED);
- unlock_page(hpage);
- put_hwpoison_page(hpage);
- return 0;
- }
-
- /*
* It's very difficult to mess with pages currently under IO
* and in many cases impossible, so we just avoid it here.
*/
@@ -1245,7 +1275,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
break;
res = page_action(ps, p, pfn);
out:
- unlock_page(hpage);
+ unlock_page(p);
return res;
}
EXPORT_SYMBOL_GPL(memory_failure);
--
2.7.0
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