diff options
| author | Nishanth Aravamudan <nacc@us.ibm.com> | 2006-08-31 21:27:53 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-01 11:39:10 -0700 |
| commit | 3b98b087fc2daab67518d2baa8aef19a6ad82723 (patch) | |
| tree | a7defc8fa53b2023affc072cd20c4f4734e4395d | |
| parent | 1678df37be8abbb381becdc40242ed915e775550 (diff) | |
[PATCH] fix NUMA interleaving for huge pages
Since vma->vm_pgoff is in units of smallpages, VMAs for huge pages have the
lower HPAGE_SHIFT - PAGE_SHIFT bits always cleared, which results in badd
offsets to the interleave functions. Take this difference from small pages
into account when calculating the offset. This does add a 0-bit shift into
the small-page path (via alloc_page_vma()), but I think that is negligible.
Also add a BUG_ON to prevent the offset from growing due to a negative
right-shift, which probably shouldn't be allowed anyways.
Tested on an 8-memory node ppc64 NUMA box and got the interleaving I
expected.
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Acked-by: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | mm/mempolicy.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index e07e27e846a2..a9963ceddd65 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1176,7 +1176,15 @@ static inline unsigned interleave_nid(struct mempolicy *pol, if (vma) { unsigned long off; - off = vma->vm_pgoff; + /* + * for small pages, there is no difference between + * shift and PAGE_SHIFT, so the bit-shift is safe. + * for huge pages, since vm_pgoff is in units of small + * pages, we need to shift off the always 0 bits to get + * a useful offset. + */ + BUG_ON(shift < PAGE_SHIFT); + off = vma->vm_pgoff >> (shift - PAGE_SHIFT); off += (addr - vma->vm_start) >> shift; return offset_il_node(pol, vma, off); } else |