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* [PATCH] drm/i915/wm: reduce stack usage in skl_print_wm_changes()
@ 2025-06-20 11:37 Arnd Bergmann
  2025-06-20 11:43 ` ✗ CI.checkpatch: warning for " Patchwork
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Arnd Bergmann @ 2025-06-20 11:37 UTC (permalink / raw)
  To: Jani Nikula, Rodrigo Vivi, Joonas Lahtinen, Tvrtko Ursulin,
	David Airlie, Simona Vetter
  Cc: Arnd Bergmann, Ville Syrjälä, Vinod Govindapillai,
	Suraj Kandpal, Mitul Golani, Stanislav Lisovskiy, intel-gfx,
	intel-xe, dri-devel, linux-kernel

From: Arnd Bergmann <arnd@arndb.de>

When KMSAN is enabled, this function causes has a rather excessive stack usage:

drivers/gpu/drm/i915/display/skl_watermark.c:2977:1: error: stack frame size (1432) exceeds limit (1408) in 'skl_compute_wm' [-Werror,-Wframe-larger-than]

This is apparently all caused by the varargs calls to drm_dbg_kms(). Inlining
this into skl_compute_wm() means that any function called by skl_compute_wm()
has its own stack on top of that.

Move the worst bit into a separate function marked as noinline_for_stack to
limit that to the one code path that actually needs it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/i915/display/skl_watermark.c | 176 ++++++++++---------
 1 file changed, 92 insertions(+), 84 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c b/drivers/gpu/drm/i915/display/skl_watermark.c
index 2c2371574d6f..b7c92c718c8f 100644
--- a/drivers/gpu/drm/i915/display/skl_watermark.c
+++ b/drivers/gpu/drm/i915/display/skl_watermark.c
@@ -2680,6 +2680,97 @@ static char enast(bool enable)
 	return enable ? '*' : ' ';
 }
 
+static noinline_for_stack void
+skl_print_plane_changes(struct intel_display *display,
+			struct intel_plane *plane,
+			const struct skl_plane_wm *old_wm,
+			const struct skl_plane_wm *new_wm)
+{
+	drm_dbg_kms(display->drm,
+		    "[PLANE:%d:%s]   level %cwm0,%cwm1,%cwm2,%cwm3,%cwm4,%cwm5,%cwm6,%cwm7,%ctwm,%cswm,%cstwm"
+		    " -> %cwm0,%cwm1,%cwm2,%cwm3,%cwm4,%cwm5,%cwm6,%cwm7,%ctwm,%cswm,%cstwm\n",
+		    plane->base.base.id, plane->base.name,
+		    enast(old_wm->wm[0].enable), enast(old_wm->wm[1].enable),
+		    enast(old_wm->wm[2].enable), enast(old_wm->wm[3].enable),
+		    enast(old_wm->wm[4].enable), enast(old_wm->wm[5].enable),
+		    enast(old_wm->wm[6].enable), enast(old_wm->wm[7].enable),
+		    enast(old_wm->trans_wm.enable),
+		    enast(old_wm->sagv.wm0.enable),
+		    enast(old_wm->sagv.trans_wm.enable),
+		    enast(new_wm->wm[0].enable), enast(new_wm->wm[1].enable),
+		    enast(new_wm->wm[2].enable), enast(new_wm->wm[3].enable),
+		    enast(new_wm->wm[4].enable), enast(new_wm->wm[5].enable),
+		    enast(new_wm->wm[6].enable), enast(new_wm->wm[7].enable),
+		    enast(new_wm->trans_wm.enable),
+		    enast(new_wm->sagv.wm0.enable),
+		    enast(new_wm->sagv.trans_wm.enable));
+
+	drm_dbg_kms(display->drm,
+		    "[PLANE:%d:%s]   lines %c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%4d"
+		      " -> %c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%4d\n",
+		    plane->base.base.id, plane->base.name,
+		    enast(old_wm->wm[0].ignore_lines), old_wm->wm[0].lines,
+		    enast(old_wm->wm[1].ignore_lines), old_wm->wm[1].lines,
+		    enast(old_wm->wm[2].ignore_lines), old_wm->wm[2].lines,
+		    enast(old_wm->wm[3].ignore_lines), old_wm->wm[3].lines,
+		    enast(old_wm->wm[4].ignore_lines), old_wm->wm[4].lines,
+		    enast(old_wm->wm[5].ignore_lines), old_wm->wm[5].lines,
+		    enast(old_wm->wm[6].ignore_lines), old_wm->wm[6].lines,
+		    enast(old_wm->wm[7].ignore_lines), old_wm->wm[7].lines,
+		    enast(old_wm->trans_wm.ignore_lines), old_wm->trans_wm.lines,
+		    enast(old_wm->sagv.wm0.ignore_lines), old_wm->sagv.wm0.lines,
+		    enast(old_wm->sagv.trans_wm.ignore_lines), old_wm->sagv.trans_wm.lines,
+		    enast(new_wm->wm[0].ignore_lines), new_wm->wm[0].lines,
+		    enast(new_wm->wm[1].ignore_lines), new_wm->wm[1].lines,
+		    enast(new_wm->wm[2].ignore_lines), new_wm->wm[2].lines,
+		    enast(new_wm->wm[3].ignore_lines), new_wm->wm[3].lines,
+		    enast(new_wm->wm[4].ignore_lines), new_wm->wm[4].lines,
+		    enast(new_wm->wm[5].ignore_lines), new_wm->wm[5].lines,
+		    enast(new_wm->wm[6].ignore_lines), new_wm->wm[6].lines,
+		    enast(new_wm->wm[7].ignore_lines), new_wm->wm[7].lines,
+		    enast(new_wm->trans_wm.ignore_lines), new_wm->trans_wm.lines,
+		    enast(new_wm->sagv.wm0.ignore_lines), new_wm->sagv.wm0.lines,
+		    enast(new_wm->sagv.trans_wm.ignore_lines), new_wm->sagv.trans_wm.lines);
+
+	drm_dbg_kms(display->drm,
+		    "[PLANE:%d:%s]  blocks %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%5d"
+		    " -> %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%5d\n",
+		    plane->base.base.id, plane->base.name,
+		    old_wm->wm[0].blocks, old_wm->wm[1].blocks,
+		    old_wm->wm[2].blocks, old_wm->wm[3].blocks,
+		    old_wm->wm[4].blocks, old_wm->wm[5].blocks,
+		    old_wm->wm[6].blocks, old_wm->wm[7].blocks,
+		    old_wm->trans_wm.blocks,
+		    old_wm->sagv.wm0.blocks,
+		    old_wm->sagv.trans_wm.blocks,
+		    new_wm->wm[0].blocks, new_wm->wm[1].blocks,
+		    new_wm->wm[2].blocks, new_wm->wm[3].blocks,
+		    new_wm->wm[4].blocks, new_wm->wm[5].blocks,
+		    new_wm->wm[6].blocks, new_wm->wm[7].blocks,
+		    new_wm->trans_wm.blocks,
+		    new_wm->sagv.wm0.blocks,
+		    new_wm->sagv.trans_wm.blocks);
+
+	drm_dbg_kms(display->drm,
+		    "[PLANE:%d:%s] min_ddb %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%5d"
+		    " -> %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%5d\n",
+		    plane->base.base.id, plane->base.name,
+		    old_wm->wm[0].min_ddb_alloc, old_wm->wm[1].min_ddb_alloc,
+		    old_wm->wm[2].min_ddb_alloc, old_wm->wm[3].min_ddb_alloc,
+		    old_wm->wm[4].min_ddb_alloc, old_wm->wm[5].min_ddb_alloc,
+		    old_wm->wm[6].min_ddb_alloc, old_wm->wm[7].min_ddb_alloc,
+		    old_wm->trans_wm.min_ddb_alloc,
+		    old_wm->sagv.wm0.min_ddb_alloc,
+		    old_wm->sagv.trans_wm.min_ddb_alloc,
+		    new_wm->wm[0].min_ddb_alloc, new_wm->wm[1].min_ddb_alloc,
+		    new_wm->wm[2].min_ddb_alloc, new_wm->wm[3].min_ddb_alloc,
+		    new_wm->wm[4].min_ddb_alloc, new_wm->wm[5].min_ddb_alloc,
+		    new_wm->wm[6].min_ddb_alloc, new_wm->wm[7].min_ddb_alloc,
+		    new_wm->trans_wm.min_ddb_alloc,
+		    new_wm->sagv.wm0.min_ddb_alloc,
+		    new_wm->sagv.trans_wm.min_ddb_alloc);
+}
+
 static void
 skl_print_wm_changes(struct intel_atomic_state *state)
 {
@@ -2709,7 +2800,6 @@ skl_print_wm_changes(struct intel_atomic_state *state)
 
 			if (skl_ddb_entry_equal(old, new))
 				continue;
-
 			drm_dbg_kms(display->drm,
 				    "[PLANE:%d:%s] ddb (%4d - %4d) -> (%4d - %4d), size %4d -> %4d\n",
 				    plane->base.base.id, plane->base.name,
@@ -2727,89 +2817,7 @@ skl_print_wm_changes(struct intel_atomic_state *state)
 			if (skl_plane_wm_equals(display, old_wm, new_wm))
 				continue;
 
-			drm_dbg_kms(display->drm,
-				    "[PLANE:%d:%s]   level %cwm0,%cwm1,%cwm2,%cwm3,%cwm4,%cwm5,%cwm6,%cwm7,%ctwm,%cswm,%cstwm"
-				    " -> %cwm0,%cwm1,%cwm2,%cwm3,%cwm4,%cwm5,%cwm6,%cwm7,%ctwm,%cswm,%cstwm\n",
-				    plane->base.base.id, plane->base.name,
-				    enast(old_wm->wm[0].enable), enast(old_wm->wm[1].enable),
-				    enast(old_wm->wm[2].enable), enast(old_wm->wm[3].enable),
-				    enast(old_wm->wm[4].enable), enast(old_wm->wm[5].enable),
-				    enast(old_wm->wm[6].enable), enast(old_wm->wm[7].enable),
-				    enast(old_wm->trans_wm.enable),
-				    enast(old_wm->sagv.wm0.enable),
-				    enast(old_wm->sagv.trans_wm.enable),
-				    enast(new_wm->wm[0].enable), enast(new_wm->wm[1].enable),
-				    enast(new_wm->wm[2].enable), enast(new_wm->wm[3].enable),
-				    enast(new_wm->wm[4].enable), enast(new_wm->wm[5].enable),
-				    enast(new_wm->wm[6].enable), enast(new_wm->wm[7].enable),
-				    enast(new_wm->trans_wm.enable),
-				    enast(new_wm->sagv.wm0.enable),
-				    enast(new_wm->sagv.trans_wm.enable));
-
-			drm_dbg_kms(display->drm,
-				    "[PLANE:%d:%s]   lines %c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%4d"
-				      " -> %c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%3d,%c%4d\n",
-				    plane->base.base.id, plane->base.name,
-				    enast(old_wm->wm[0].ignore_lines), old_wm->wm[0].lines,
-				    enast(old_wm->wm[1].ignore_lines), old_wm->wm[1].lines,
-				    enast(old_wm->wm[2].ignore_lines), old_wm->wm[2].lines,
-				    enast(old_wm->wm[3].ignore_lines), old_wm->wm[3].lines,
-				    enast(old_wm->wm[4].ignore_lines), old_wm->wm[4].lines,
-				    enast(old_wm->wm[5].ignore_lines), old_wm->wm[5].lines,
-				    enast(old_wm->wm[6].ignore_lines), old_wm->wm[6].lines,
-				    enast(old_wm->wm[7].ignore_lines), old_wm->wm[7].lines,
-				    enast(old_wm->trans_wm.ignore_lines), old_wm->trans_wm.lines,
-				    enast(old_wm->sagv.wm0.ignore_lines), old_wm->sagv.wm0.lines,
-				    enast(old_wm->sagv.trans_wm.ignore_lines), old_wm->sagv.trans_wm.lines,
-				    enast(new_wm->wm[0].ignore_lines), new_wm->wm[0].lines,
-				    enast(new_wm->wm[1].ignore_lines), new_wm->wm[1].lines,
-				    enast(new_wm->wm[2].ignore_lines), new_wm->wm[2].lines,
-				    enast(new_wm->wm[3].ignore_lines), new_wm->wm[3].lines,
-				    enast(new_wm->wm[4].ignore_lines), new_wm->wm[4].lines,
-				    enast(new_wm->wm[5].ignore_lines), new_wm->wm[5].lines,
-				    enast(new_wm->wm[6].ignore_lines), new_wm->wm[6].lines,
-				    enast(new_wm->wm[7].ignore_lines), new_wm->wm[7].lines,
-				    enast(new_wm->trans_wm.ignore_lines), new_wm->trans_wm.lines,
-				    enast(new_wm->sagv.wm0.ignore_lines), new_wm->sagv.wm0.lines,
-				    enast(new_wm->sagv.trans_wm.ignore_lines), new_wm->sagv.trans_wm.lines);
-
-			drm_dbg_kms(display->drm,
-				    "[PLANE:%d:%s]  blocks %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%5d"
-				    " -> %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%5d\n",
-				    plane->base.base.id, plane->base.name,
-				    old_wm->wm[0].blocks, old_wm->wm[1].blocks,
-				    old_wm->wm[2].blocks, old_wm->wm[3].blocks,
-				    old_wm->wm[4].blocks, old_wm->wm[5].blocks,
-				    old_wm->wm[6].blocks, old_wm->wm[7].blocks,
-				    old_wm->trans_wm.blocks,
-				    old_wm->sagv.wm0.blocks,
-				    old_wm->sagv.trans_wm.blocks,
-				    new_wm->wm[0].blocks, new_wm->wm[1].blocks,
-				    new_wm->wm[2].blocks, new_wm->wm[3].blocks,
-				    new_wm->wm[4].blocks, new_wm->wm[5].blocks,
-				    new_wm->wm[6].blocks, new_wm->wm[7].blocks,
-				    new_wm->trans_wm.blocks,
-				    new_wm->sagv.wm0.blocks,
-				    new_wm->sagv.trans_wm.blocks);
-
-			drm_dbg_kms(display->drm,
-				    "[PLANE:%d:%s] min_ddb %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%5d"
-				    " -> %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%5d\n",
-				    plane->base.base.id, plane->base.name,
-				    old_wm->wm[0].min_ddb_alloc, old_wm->wm[1].min_ddb_alloc,
-				    old_wm->wm[2].min_ddb_alloc, old_wm->wm[3].min_ddb_alloc,
-				    old_wm->wm[4].min_ddb_alloc, old_wm->wm[5].min_ddb_alloc,
-				    old_wm->wm[6].min_ddb_alloc, old_wm->wm[7].min_ddb_alloc,
-				    old_wm->trans_wm.min_ddb_alloc,
-				    old_wm->sagv.wm0.min_ddb_alloc,
-				    old_wm->sagv.trans_wm.min_ddb_alloc,
-				    new_wm->wm[0].min_ddb_alloc, new_wm->wm[1].min_ddb_alloc,
-				    new_wm->wm[2].min_ddb_alloc, new_wm->wm[3].min_ddb_alloc,
-				    new_wm->wm[4].min_ddb_alloc, new_wm->wm[5].min_ddb_alloc,
-				    new_wm->wm[6].min_ddb_alloc, new_wm->wm[7].min_ddb_alloc,
-				    new_wm->trans_wm.min_ddb_alloc,
-				    new_wm->sagv.wm0.min_ddb_alloc,
-				    new_wm->sagv.trans_wm.min_ddb_alloc);
+			skl_print_plane_changes(display, plane, old_wm, new_wm);
 		}
 	}
 }
-- 
2.39.5


^ permalink raw reply related	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2025-06-24 21:17 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-06-20 11:37 [PATCH] drm/i915/wm: reduce stack usage in skl_print_wm_changes() Arnd Bergmann
2025-06-20 11:43 ` ✗ CI.checkpatch: warning for " Patchwork
2025-06-20 11:44 ` ✓ CI.KUnit: success " Patchwork
2025-06-20 21:33 ` ✗ Xe.CI.Full: failure " Patchwork
2025-06-24 21:16 ` [PATCH] " Rodrigo Vivi

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