diff options
| author | Minchan Kim <minchan@kernel.org> | 2012-10-08 16:33:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 16:22:58 +0900 |
| commit | 082708072a4250f5c4dbc62065e7af93f5e45646 (patch) | |
| tree | fc8cee89404845ea87f7fa203aec4cb612fb6933 | |
| parent | 6bdb913f0a70a4dfb7f066fb15e2d6f960701d00 (diff) | |
| download | linux-082708072a4250f5c4dbc62065e7af93f5e45646.tar.bz2 | |
mm: revert 0def08e3 ("mm/mempolicy.c: check return code of check_range")
Revert commit 0def08e3acc2 because check_range can't fail in
migrate_to_node with considering current usecases.
Quote from Johannes
: I think it makes sense to revert. Not because of the semantics, but I
: just don't see how check_range() could even fail for this callsite:
:
: 1. we pass mm->mmap->vm_start in there, so we should not fail due to
: find_vma()
:
: 2. we pass MPOL_MF_DISCONTIG_OK, so the discontig checks do not apply
: and so can not fail
:
: 3. we pass MPOL_MF_MOVE | MPOL_MF_MOVE_ALL, the page table loops will
: continue until addr == end, so we never fail with -EIO
And I added a new VM_BUG_ON for checking migrate_to_node's future usecase
which might pass to MPOL_MF_STRICT.
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vasiliy Kulikov <segooon@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/mempolicy.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 3d64b369180d..0b78fb9ea65b 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -946,15 +946,18 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest, nodemask_t nmask; LIST_HEAD(pagelist); int err = 0; - struct vm_area_struct *vma; nodes_clear(nmask); node_set(source, nmask); - vma = check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask, + /* + * This does not "check" the range but isolates all pages that + * need migration. Between passing in the full user address + * space range and MPOL_MF_DISCONTIG_OK, this call can not fail. + */ + VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))); + check_range(mm, mm->mmap->vm_start, mm->task_size, &nmask, flags | MPOL_MF_DISCONTIG_OK, &pagelist); - if (IS_ERR(vma)) - return PTR_ERR(vma); if (!list_empty(&pagelist)) { err = migrate_pages(&pagelist, new_node_page, dest, |