This patchset fix checking unmapped holes for mbind().
First patch makes sure the vma been correctly tracked in .test_walk(),
so each time when .test_walk() is called, the neighborhood of two vma
is correct.
Current problem is that the !vma_migratable() check could
cause return immediately without update tracking to vma.
Second patch fix the inconsistent report of EFAULT when mbind() is
called for MPOL_DEFAULT and non MPOL_DEFAULT cases, so application do
not need to have workaround code to handle this special behavior.
Currently there are two problems, one is that the .test_walk() can not
know there is hole at tail side of range, because .test_walk() only
call for vma not for hole. The other one is that mbind_range() checks
for hole at head side of range but do not consider the
MPOL_MF_DISCONTIG_OK flag as done in .test_walk().
Changes v3->v4:
- Split to two patch;
- Illustrates the application visible behaviors in changelog;
- Hole at tail side of range is checked in .test_walk(), not after
walk page. Only the case for whole range in hole is checked after
walk page, because our .test_walk() function would not be called at
all in this case.
Changes v2->v3:
- Add more details in change log;
- Check holes in .test_walk() and after call walk_page_range();
Li Xinhai (2):
mm: Check range first in queue_pages_test_walk
mm: Fix checking unmapped holes for mbind
mm/mempolicy.c | 47 +++++++++++++++++++++++++++++++----------------
1 file changed, 31 insertions(+), 16 deletions(-)
--
1.8.3.1
