From: Naoya Horiguchi on

This is the 2nd version of "hugepage migration" patchset.

There were two points of issue.

* Dividing hugepage migration functions from original migration code.
This is to avoid complexity.
In present version, some high level migration routines are defined to handle
hugepage, but some low level routines (such as migrate_copy_page() etc.)
are shared with original migration code in order not to increase duplication.

* Locking problem between direct I/O and hugepage migration
As a result of digging the race between hugepage I/O and hugepage migration,
(where hugepage I/O can be seen only in direct I/O,)
I noticed that without additional locking we can avoid this race condition
because in direct I/O we can get whether some subpages are under I/O or not
from reference count of the head page and hugepage migration safely fails
if some references remain. So no data lost should occurs on the migration
concurrent with direct I/O.

This patchset is based on the following commit:

commit 1c9bc0d7945bbbcdae99f197535588e5ad24bc1c
"hugetlb: add missing unlock in avoidcopy path in hugetlb_cow()"

on "hwpoison" branch in Andi's tree.;a=summary


[PATCH 1/9] HWPOISON, hugetlb: move PG_HWPoison bit check
[PATCH 2/9] hugetlb: add allocate function for hugepage migration
[PATCH 3/9] hugetlb: rename hugepage allocation functions
[PATCH 4/9] hugetlb: redefine hugepage copy functions
[PATCH 5/9] hugetlb: hugepage migration core
[PATCH 6/9] HWPOISON, hugetlb: soft offlining for hugepage
[PATCH 7/9] HWPOISON, hugetlb: fix unpoison for hugepage
[PATCH 8/9] page-types.c: fix name of unpoison interface
[PATCH 9/9] hugetlb: add corrupted hugepage counter

Documentation/vm/page-types.c | 2 +-
fs/hugetlbfs/inode.c | 15 +++
include/linux/hugetlb.h | 12 ++
include/linux/migrate.h | 12 ++
mm/hugetlb.c | 248 +++++++++++++++++++++++++++++++++--------
mm/memory-failure.c | 88 ++++++++++++---
mm/migrate.c | 196 +++++++++++++++++++++++++++++----
7 files changed, 487 insertions(+), 86 deletions(-)

Naoya Horiguchi
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