From 5e38401c39b1d2cf3ffbc30b7d798c2d9dacd177 Mon Sep 17 00:00:00 2001
From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Date: Mon, 10 Jul 2017 15:47:41 -0700
Subject: [PATCH 3/8] mm: hugetlb: soft-offline: dissolve source hugepage after
successful migration
Patch-mainline: v4.13-rc1
Git-commit: c3114a84f7f96c9d5c73c8bfa7e21ff42fda97e2
References: bsc#1139712
Currently hugepage migrated by soft-offline (i.e. due to correctable
memory errors) is contained as a hugepage, which means many non-error
pages in it are unreusable, i.e. wasted.
This patch solves this issue by dissolving source hugepages into buddy.
As done in previous patch, PageHWPoison is set only on a head page of
the error hugepage. Then in dissoliving we move the PageHWPoison flag
to the raw error page so that all healthy subpages return back to buddy.
[arnd@arndb.de: fix warnings: replace some macros with inline functions]
Link: http://lkml.kernel.org/r/20170609102544.2947326-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/1496305019-5493-5-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
---
include/linux/hugetlb.h | 31 +++++++++++++++++++++++++++----
mm/hugetlb.c | 10 +++++++++-
mm/memory-failure.c | 5 +----
mm/migrate.c | 2 ++
4 files changed, 39 insertions(+), 9 deletions(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index bb1de231f84a..e495fcc1c38a 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -462,6 +462,7 @@ static inline pgoff_t basepage_index(struct page *page)
return __basepage_index(page);
}
+extern int dissolve_free_huge_page(struct page *page);
extern int dissolve_free_huge_pages(unsigned long start_pfn,
unsigned long end_pfn);
static inline bool hugepage_migration_supported(struct hstate *h)
@@ -524,15 +525,37 @@ static inline unsigned int pages_per_huge_page(struct hstate *h)
{
return 1;
}
-#define hstate_index_to_shift(index) 0
-#define hstate_index(h) 0
+
+static inline unsigned hstate_index_to_shift(unsigned index)
+{
+ return 0;
+}
+
+static inline int hstate_index(struct hstate *h)
+{
+ return 0;
+}
static inline pgoff_t basepage_index(struct page *page)
{
return page->index;
}
-#define dissolve_free_huge_pages(s, e) 0
-#define hugepage_migration_supported(h) false
+
+static inline int dissolve_free_huge_page(struct page *page)
+{
+ return 0;
+}
+
+static inline int dissolve_free_huge_pages(unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ return 0;
+}
+
+static inline bool hugepage_migration_supported(struct hstate *h)
+{
+ return false;
+}
static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
struct mm_struct *mm, pte_t *pte)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0f13a44c8ae7..dfebd5a2592d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1445,7 +1445,7 @@ static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
* number of free hugepages would be reduced below the number of reserved
* hugepages.
*/
-static int dissolve_free_huge_page(struct page *page)
+int dissolve_free_huge_page(struct page *page)
{
int rc = 0;
@@ -1458,6 +1458,14 @@ static int dissolve_free_huge_page(struct page *page)
rc = -EBUSY;
goto out;
}
+ /*
+ * Move PageHWPoison flag from head page to the raw error page,
+ * which makes any subpages rather than the error page reusable.
+ */
+ if (PageHWPoison(head) && page != head) {
+ SetPageHWPoison(page);
+ ClearPageHWPoison(head);
+ }
list_del(&head->lru);
h->free_huge_pages--;
h->free_huge_pages_node[nid]--;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index cbf872432bcc..c5f3411f8011 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1570,11 +1570,8 @@ static int soft_offline_huge_page(struct page *page, int flags)
if (ret > 0)
ret = -EIO;
} else {
- /* overcommit hugetlb page will be freed to buddy */
- SetPageHWPoison(page);
if (PageHuge(page))
- dequeue_hwpoisoned_huge_page(hpage);
- num_poisoned_pages_inc();
+ dissolve_free_huge_page(page);
}
return ret;
}
diff --git a/mm/migrate.c b/mm/migrate.c
index 9bb22a4a5132..5ae662112f96 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1252,6 +1252,8 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
out:
if (rc != -EAGAIN)
putback_active_hugepage(hpage);
+ if (reason == MR_MEMORY_FAILURE && !test_set_page_hwpoison(hpage))
+ num_poisoned_pages_inc();
/*
* If migration was not successful and there's a freeing callback, use
--
2.12.3