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authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>2013-06-12 14:05:04 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-06-20 11:28:20 -0700
commit79848ba66d91e0c171ff203363e0c96629279c15 (patch)
tree6573331e1bfb895058433d0faa8a6bee4d70e552 /include
parent78ef884ebb6c02d45abefc95350f428be7390a26 (diff)
mm: migration: add migrate_entry_wait_huge()
commit 30dad30922ccc733cfdbfe232090cf674dc374dc upstream. When we have a page fault for the address which is backed by a hugepage under migration, the kernel can't wait correctly and do busy looping on hugepage fault until the migration finishes. As a result, users who try to kick hugepage migration (via soft offlining, for example) occasionally experience long delay or soft lockup. This is because pte_offset_map_lock() can't get a correct migration entry or a correct page table lock for hugepage. This patch introduces migration_entry_wait_huge() to solve this. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Andi Kleen <andi@firstfloor.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/swapops.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index cd42e30b7c6e..96c7110986ca 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -113,6 +113,7 @@ static inline void make_migration_entry_read(swp_entry_t *entry)
extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
unsigned long address);
+extern void migration_entry_wait_huge(struct mm_struct *mm, pte_t *pte);
#else
#define make_migration_entry(page, write) swp_entry(0, 0)
@@ -124,6 +125,8 @@ static inline int is_migration_entry(swp_entry_t swp)
static inline void make_migration_entry_read(swp_entry_t *entryp) { }
static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
unsigned long address) { }
+static inline void migration_entry_wait_huge(struct mm_struct *mm,
+ pte_t *pte) { }
static inline int is_write_migration_entry(swp_entry_t entry)
{
return 0;