diff options
| author | Dave Hansen <dave.hansen@linux.intel.com> | 2013-11-21 14:31:58 -0800 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-04-09 13:13:54 +0200 |
| commit | 1ef840f5d8195897c80d40eb9f822ee6e91f9f4a (patch) | |
| tree | ae50ac20d7b2d499ef0ee7d326b8ce57106b7cf4 /include/linux | |
| parent | 04240adfe44b8a38c21ca0972ef620254b931e25 (diff) | |
mm: thp: give transparent hugepage code a separate copy_page
commit 30b0a105d9f7141e4cbf72ae5511832457d89788 upstream.
Right now, the migration code in migrate_page_copy() uses copy_huge_page()
for hugetlbfs and thp pages:
if (PageHuge(page) || PageTransHuge(page))
copy_huge_page(newpage, page);
So, yay for code reuse. But:
void copy_huge_page(struct page *dst, struct page *src)
{
struct hstate *h = page_hstate(src);
and a non-hugetlbfs page has no page_hstate(). This works 99% of the
time because page_hstate() determines the hstate from the page order
alone. Since the page order of a THP page matches the default hugetlbfs
page order, it works.
But, if you change the default huge page size on the boot command-line
(say default_hugepagesz=1G), then we might not even *have* a 2MB hstate
so page_hstate() returns null and copy_huge_page() oopses pretty fast
since copy_huge_page() dereferences the hstate:
void copy_huge_page(struct page *dst, struct page *src)
{
struct hstate *h = page_hstate(src);
if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
...
Mel noticed that the migration code is really the only user of these
functions. This moves all the copy code over to migrate.c and makes
copy_huge_page() work for THP by checking for it explicitly.
I believe the bug was introduced in commit b32967ff101a ("mm: numa: Add
THP migration for the NUMA working set scanning fault case")
[akpm@linux-foundation.org: fix coding-style and comment text, per Naoya Horiguchi]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/hugetlb.h | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 2a943a396d20..1eaf61dde2c3 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -70,7 +70,6 @@ int dequeue_hwpoisoned_huge_page(struct page *page); bool isolate_huge_page(struct page *page, struct list_head *list); void putback_active_hugepage(struct page *page); bool is_hugepage_active(struct page *page); -void copy_huge_page(struct page *dst, struct page *src); #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud); @@ -149,9 +148,6 @@ static inline bool isolate_huge_page(struct page *page, struct list_head *list) } #define putback_active_hugepage(p) do {} while (0) #define is_hugepage_active(x) false -static inline void copy_huge_page(struct page *dst, struct page *src) -{ -} static inline unsigned long hugetlb_change_protection(struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot) |