| Message ID | 20161212115350.780-31-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On ma, 2016-12-12 at 11:53 +0000, Chris Wilson wrote: > For power-of-two alignments, we can avoid the 64bit divide and do a > simple bitwise add instead. > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > --- > 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 eec0a46f5b38..7245483f1111 100644 > --- a/drivers/gpu/drm/drm_mm.c > +++ b/drivers/gpu/drm/drm_mm.c > @@ -741,8 +741,12 @@ 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->alignment_mask = is_power_of_2(alignment) ? alignment - 1 : 0; One would assume alignment_mask to be the bit-opposite, really. reminder_mask should describe it better. And sprinkle a likely() for the POT case, because I think that's something to expect. With above comments; Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Regards, Joonas
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index eec0a46f5b38..7245483f1111 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -741,8 +741,12 @@ 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->alignment_mask = is_power_of_2(alignment) ? alignment - 1 : 0; scan->size = size; scan->flags = flags; @@ -810,7 +814,10 @@ 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 (scan->alignment_mask) + rem = adj_start & scan->alignment_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 5e8350b91fcf..90d607e31301 100644 --- a/include/drm/drm_mm.h +++ b/include/drm/drm_mm.h @@ -109,6 +109,7 @@ struct drm_mm_scan { u64 size; u64 alignment; + u64 alignment_mask; u64 range_start; u64 range_end;
For power-of-two alignments, we can avoid the 64bit divide and do a simple bitwise add instead. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> --- drivers/gpu/drm/drm_mm.c | 9 ++++++++- include/drm/drm_mm.h | 1 + 2 files changed, 9 insertions(+), 1 deletion(-)