drm: Improve drm_mm search (and fix topdown allocation) with rbtrees

The drm_mm range manager claimed to support top-down insertion, but it
was neither searching for the top-most hole that could fit the
allocation request nor fitting the request to the hole correctly.

In order to search the range efficiently, we create a secondary index
for the holes using either their size or their address. This index
allows us to find the smallest hole or the hole at the bottom or top of
the range efficiently, whilst keeping the hole stack to rapidly service
evictions.

v2: Search for holes both high and low. Rename flags to mode.
v3: Discover rb_entry_safe() and use it!
v4: Kerneldoc for enum drm_mm_insert_mode.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Sinclair Yeh <syeh@vmware.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com> # vmwgfx
Reviewed-by: Lucas Stach <l.stach@pengutronix.de> #etnaviv
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170202210438.28702-1-chris@chris-wilson.co.uk

3 files changed, 5 insertions, 6 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index 63239b5b5092..a0cd4ea15f07 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -593,7 +593,7 @@ static int vc4_crtc_atomic_check(struct drm_crtc *crtc,
 
 	spin_lock_irqsave(&vc4->hvs->mm_lock, flags);
 	ret = drm_mm_insert_node(&vc4->hvs->dlist_mm, &vc4_state->mm,
-				 dlist_count, 1, 0);
+				 dlist_count);
 	spin_unlock_irqrestore(&vc4->hvs->mm_lock, flags);
 	if (ret)
 		return ret;
diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
index fc68b1b4da52..f7f7677f6d8d 100644
--- a/drivers/gpu/drm/vc4/vc4_hvs.c
+++ b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -141,8 +141,7 @@ static int vc4_hvs_upload_linear_kernel(struct vc4_hvs *hvs,
 	int ret, i;
 	u32 __iomem *dst_kernel;
 
-	ret = drm_mm_insert_node(&hvs->dlist_mm, space, VC4_KERNEL_DWORDS, 1,
-				 0);
+	ret = drm_mm_insert_node(&hvs->dlist_mm, space, VC4_KERNEL_DWORDS);
 	if (ret) {
 		DRM_ERROR("Failed to allocate space for filter kernel: %d\n",
 			  ret);
diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
index 110d1518f5d5..c1f06897136b 100644
--- a/drivers/gpu/drm/vc4/vc4_plane.c
+++ b/drivers/gpu/drm/vc4/vc4_plane.c
@@ -514,9 +514,9 @@ static int vc4_plane_mode_set(struct drm_plane *plane,
 	if (lbm_size) {
 		if (!vc4_state->lbm.allocated) {
 			spin_lock_irqsave(&vc4->hvs->mm_lock, irqflags);
-			ret = drm_mm_insert_node(&vc4->hvs->lbm_mm,
-						 &vc4_state->lbm,
-						 lbm_size, 32, 0);
+			ret = drm_mm_insert_node_generic(&vc4->hvs->lbm_mm,
+							 &vc4_state->lbm,
+							 lbm_size, 32, 0, 0);
 			spin_unlock_irqrestore(&vc4->hvs->mm_lock, irqflags);
 		} else {
 			WARN_ON_ONCE(lbm_size != vc4_state->lbm.size);