For power-of-two alignments, we can avoid the 64bit divide and do a simple bitwise add instead.
v2: s/alignment_mask/remainder_mask/
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen joonas.lahtinen@linux.intel.com --- drivers/gpu/drm/drm_mm.c | 9 ++++++++- include/drm/drm_mm.h | 1 + 2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index 189ab84c5a59..0441d84fba74 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -742,8 +742,12 @@ void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
scan->mm = mm;
+ if (alignment <= 1) + alignment = 0; + scan->color = color; scan->alignment = alignment; + scan->remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0; scan->size = size; scan->flags = flags;
@@ -811,7 +815,10 @@ bool drm_mm_scan_add_block(struct drm_mm_scan *scan, if (scan->alignment) { u64 rem;
- div64_u64_rem(adj_start, scan->alignment, &rem); + if (likely(scan->remainder_mask)) + rem = adj_start & scan->remainder_mask; + else + div64_u64_rem(adj_start, scan->alignment, &rem); if (rem) { adj_start -= rem; if (scan->flags != DRM_MM_CREATE_TOP) diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h index 606336fc229a..d6701d56ea74 100644 --- a/include/drm/drm_mm.h +++ b/include/drm/drm_mm.h @@ -110,6 +110,7 @@ struct drm_mm_scan {
u64 size; u64 alignment; + u64 remainder_mask;
u64 range_start; u64 range_end;