Prev: [PATCH 1/9] HWPOISON, hugetlb: move PG_HWPoison bit check
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From: Naoya Horiguchi on 10 Aug 2010 05:40
This patch extends soft offlining framework to support hugepage.
When memory corrected errors occur repeatedly on a hugepage,
we can choose to stop using it by migrating data onto another hugepage
and disabling the original (maybe half-broken) one.

ChangeLog since v1:
- add double check in isolating hwpoisoned hugepage
- define free/non-free checker for hugepage
- postpone calling put_page() for hugepage in soft_offline_page()

Signed-off-by: Naoya Horiguchi <n-horiguchi(a)ah.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura(a)ce.jp.nec.com>
---
include/linux/hugetlb.h | 2 +
mm/hugetlb.c | 26 +++++++++++++++++
mm/memory-failure.c | 70 ++++++++++++++++++++++++++++++++++++-----------
3 files changed, 82 insertions(+), 16 deletions(-)

diff --git linux-mce-hwpoison/include/linux/hugetlb.h linux-mce-hwpoison/include/linux/hugetlb.h
index f77d2ba..2b7de04 100644
--- linux-mce-hwpoison/include/linux/hugetlb.h
+++ linux-mce-hwpoison/include/linux/hugetlb.h
@@ -44,6 +44,7 @@ int hugetlb_reserve_pages(struct inode *inode, long from, long to,
int acctflags);
void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed);
void __isolate_hwpoisoned_huge_page(struct page *page);
+void isolate_hwpoisoned_huge_page(struct page *page);
void copy_huge_page(struct page *dst, struct page *src);

extern unsigned long hugepages_treat_as_movable;
@@ -103,6 +104,7 @@ static inline void hugetlb_report_meminfo(struct seq_file *m)
#define hugetlb_fault(mm, vma, addr, flags) ({ BUG(); 0; })
#define huge_pte_offset(mm, address) 0
#define __isolate_hwpoisoned_huge_page(page) 0
+#define isolate_hwpoisoned_huge_page(page) 0
#define copy_huge_page(dst, src) NULL

#define hugetlb_change_protection(vma, address, end, newprot)
diff --git linux-mce-hwpoison/mm/hugetlb.c linux-mce-hwpoison/mm/hugetlb.c
index 0805524..2a61a8f 100644
--- linux-mce-hwpoison/mm/hugetlb.c
+++ linux-mce-hwpoison/mm/hugetlb.c
@@ -2995,3 +2995,29 @@ void __isolate_hwpoisoned_huge_page(struct page *hpage)
h->free_huge_pages_node[nid]--;
spin_unlock(&hugetlb_lock);
}
+
+static int is_hugepage_on_freelist(struct page *hpage)
+{
+ struct page *page;
+ struct page *tmp;
+ struct hstate *h = page_hstate(hpage);
+ int nid = page_to_nid(hpage);
+
+ spin_lock(&hugetlb_lock);
+ list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) {
+ if (page == hpage) {
+ spin_unlock(&hugetlb_lock);
+ return 1;
+ }
+ }
+ spin_unlock(&hugetlb_lock);
+ return 0;
+}
+
+void isolate_hwpoisoned_huge_page(struct page *hpage)
+{
+ lock_page(hpage);
+ if (is_hugepage_on_freelist(hpage))
+ __isolate_hwpoisoned_huge_page(hpage);
+ unlock_page(hpage);
+}
diff --git linux-mce-hwpoison/mm/memory-failure.c linux-mce-hwpoison/mm/memory-failure.c
index d0b420a..0bfe5b3 100644
--- linux-mce-hwpoison/mm/memory-failure.c
+++ linux-mce-hwpoison/mm/memory-failure.c
@@ -1186,7 +1186,11 @@ EXPORT_SYMBOL(unpoison_memory);
static struct page *new_page(struct page *p, unsigned long private, int **x)
{
int nid = page_to_nid(p);
- return alloc_pages_exact_node(nid, GFP_HIGHUSER_MOVABLE, 0);
+ if (PageHuge(p))
+ return alloc_huge_page_node(page_hstate(compound_head(p)),
+ nid);
+ else
+ return alloc_pages_exact_node(nid, GFP_HIGHUSER_MOVABLE, 0);
}

/*
@@ -1214,8 +1218,16 @@ static int get_any_page(struct page *p, unsigned long pfn, int flags)
* was free.
*/
set_migratetype_isolate(p);
+ /*
+ * When the target page is a free hugepage, just remove it
+ * from free hugepage list.
+ */
if (!get_page_unless_zero(compound_head(p))) {
- if (is_free_buddy_page(p)) {
+ if (PageHuge(p)) {
+ pr_debug("get_any_page: %#lx free huge page\n", pfn);
+ ret = 0;
+ SetPageHWPoison(compound_head(p));
+ } else if (is_free_buddy_page(p)) {
pr_debug("get_any_page: %#lx free buddy page\n", pfn);
/* Set hwpoison bit while page is still isolated */
SetPageHWPoison(p);
@@ -1260,6 +1272,7 @@ int soft_offline_page(struct page *page, int flags)
{
int ret;
unsigned long pfn = page_to_pfn(page);
+ struct page *hpage = compound_head(page);

ret = get_any_page(page, pfn, flags);
if (ret < 0)
@@ -1270,7 +1283,7 @@ int soft_offline_page(struct page *page, int flags)
/*
* Page cache page we can handle?
*/
- if (!PageLRU(page)) {
+ if (!PageLRU(page) && !PageHuge(page)) {
/*
* Try to free it.
*/
@@ -1286,21 +1299,21 @@ int soft_offline_page(struct page *page, int flags)
if (ret == 0)
goto done;
}
- if (!PageLRU(page)) {
+ if (!PageLRU(page) && !PageHuge(page)) {
pr_debug("soft_offline: %#lx: unknown non LRU page type %lx\n",
pfn, page->flags);
return -EIO;
}

- lock_page(page);
- wait_on_page_writeback(page);
+ lock_page(hpage);
+ wait_on_page_writeback(hpage);

/*
* Synchronized using the page lock with memory_failure()
*/
- if (PageHWPoison(page)) {
- unlock_page(page);
- put_page(page);
+ if (PageHWPoison(hpage)) {
+ unlock_page(hpage);
+ put_page(hpage);
pr_debug("soft offline: %#lx page already poisoned\n", pfn);
return -EBUSY;
}
@@ -1310,7 +1323,7 @@ int soft_offline_page(struct page *page, int flags)
* non dirty unmapped page cache pages.
*/
ret = invalidate_inode_page(page);
- unlock_page(page);
+ unlock_page(hpage);

/*
* Drop count because page migration doesn't like raised
@@ -1318,8 +1331,13 @@ int soft_offline_page(struct page *page, int flags)
* LRU the isolation will just fail.
* RED-PEN would be better to keep it isolated here, but we
* would need to fix isolation locking first.
+ *
+ * Postpone dropping count for hugepage until migration completes,
+ * because otherwise old hugepage will be freed before copying.
*/
- put_page(page);
+ if (!PageHuge(hpage))
+ put_page(hpage);
+
if (ret == 1) {
ret = 0;
pr_debug("soft_offline: %#lx: invalidated\n", pfn);
@@ -1330,19 +1348,33 @@ int soft_offline_page(struct page *page, int flags)
* Simple invalidation didn't work.
* Try to migrate to a new page instead. migrate.c
* handles a large number of cases for us.
+ *
+ * Hugepage has no link to LRU list, so just skip this.
*/
- ret = isolate_lru_page(page);
+ if (PageHuge(page))
+ ret = 0;
+ else
+ ret = isolate_lru_page(page);
+
if (!ret) {
LIST_HEAD(pagelist);

- list_add(&page->lru, &pagelist);
+ list_add(&hpage->lru, &pagelist);
ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL, 0);
if (ret) {
pr_debug("soft offline: %#lx: migration failed %d, type %lx\n",
pfn, ret, page->flags);
if (ret > 0)
ret = -EIO;
+ /*
+ * When hugepage migration succeeded, the old hugepage
+ * should already be freed, so we put it only
+ * in the failure path.
+ */
+ if (PageHuge(hpage))
+ put_page(hpage);
}
+
} else {
pr_debug("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n",
pfn, ret, page_count(page), page->flags);
@@ -1351,8 +1383,14 @@ int soft_offline_page(struct page *page, int flags)
return ret;

done:
- atomic_long_add(1, &mce_bad_pages);
- SetPageHWPoison(page);
- /* keep elevated page count for bad page */
+ if (!PageHWPoison(hpage))
+ atomic_long_add(1 << compound_order(hpage), &mce_bad_pages);
+ if (PageHuge(hpage)) {
+ set_page_hwpoison_huge_page(hpage);
+ isolate_hwpoisoned_huge_page(hpage);
+ } else {
+ SetPageHWPoison(page);
+ /* keep elevated page count for bad page */
+ }
return ret;
}
--
1.7.2.1

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Next: [PATCH 4/9] hugetlb: redefine hugepage copy functions