When a large enough area in the iommu bitmap is found but would span a boundary we continue the search starting from the next bit position. For large allocations this can lead to several useless invocations of bitmap_find_next_zero_area() and iommu_is_span_boundary().
Continue the search from the start of the next segment (which is the next bit position such that we'll not cross the same segment boundary again). Signed-off-by: Sebastian Ott <seb...@linux.vnet.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schae...@de.ibm.com> --- lib/iommu-helper.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c index c27e269..a816f3a 100644 --- a/lib/iommu-helper.c +++ b/lib/iommu-helper.c @@ -29,8 +29,7 @@ again: index = bitmap_find_next_zero_area(map, size, start, nr, align_mask); if (index < size) { if (iommu_is_span_boundary(index, nr, shift, boundary_size)) { - /* we could do more effectively */ - start = index + 1; + start = ALIGN(shift + index, boundary_size) - shift; goto again; } bitmap_set(map, index, nr); -- 2.3.0