[PATCH 08/12] drm/xe: Introduce xe_ggtt_largest_hole

[Lucas De Marchi]

On Fri, Aug 16, 2024 at 11:02:39AM GMT, Rodrigo Vivi wrote:
>Introduce a new xe_ggtt_largest_hole helper that attends the SRIOV
>demand and continue with the goal of limiting drm_mm access to xe_ggtt.
>
>v2: Fix a typo (Michal)
>
>Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
>Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
>---
> drivers/gpu/drm/xe/xe_ggtt.c               | 35 ++++++++++++++++++++++
> drivers/gpu/drm/xe/xe_ggtt.h               |  1 +
> drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c | 23 ++------------
> 3 files changed, 38 insertions(+), 21 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/xe_ggtt.c b/drivers/gpu/drm/xe/xe_ggtt.c
>index 7c8bbaa30fca..2d055f489879 100644
>--- a/drivers/gpu/drm/xe/xe_ggtt.c
>+++ b/drivers/gpu/drm/xe/xe_ggtt.c
>@@ -584,6 +584,41 @@ void xe_ggtt_remove_bo(struct xe_ggtt *ggtt, struct xe_bo *bo)
> 			    bo->flags & XE_BO_FLAG_GGTT_INVALIDATE);
> }
>
>+/**
>+ * xe_ggtt_largest_hole - Largest GGTT hole
>+ * @ggtt: the &xe_ggtt that will be inspected
>+ * @alignment: minimum alignment
>+ * @spare: If not NULL: in: desired memory size to be spared / out: Adjusted possible spare
>+ *
>+ * Return: size of the largest continuous GGTT region
>+ */
>+u64 xe_ggtt_largest_hole(struct xe_ggtt *ggtt, u64 alignment, u64 *spare)
>+{
>+	const struct drm_mm *mm = &ggtt->mm;
>+	const struct drm_mm_node *entry;
>+	u64 hole_min_start = xe_wopcm_size(tile_to_xe(ggtt->tile));
>+	u64 hole_start, hole_end, hole_size;
>+	u64 max_hole = 0;
>+
>+	mutex_lock(&ggtt->lock);
>+
>+	drm_mm_for_each_hole(entry, mm, hole_start, hole_end) {
>+		hole_start = max(hole_start, hole_min_start);
>+		hole_start = ALIGN(hole_start, alignment);
>+		hole_end = ALIGN_DOWN(hole_end, alignment);
>+		if (hole_start >= hole_end)
>+			continue;
>+		hole_size = hole_end - hole_start;
>+		if (spare)
>+			*spare -= min3(*spare, hole_size, max_hole);
>+		max_hole = max(max_hole, hole_size);
>+	}
>+
>+	mutex_unlock(&ggtt->lock);
>+
>+	return max_hole;
>+}
>+
> #ifdef CONFIG_PCI_IOV
> static u64 xe_encode_vfid_pte(u16 vfid)
> {
>diff --git a/drivers/gpu/drm/xe/xe_ggtt.h b/drivers/gpu/drm/xe/xe_ggtt.h
>index f816b3c0732b..31060fe7644b 100644
>--- a/drivers/gpu/drm/xe/xe_ggtt.h
>+++ b/drivers/gpu/drm/xe/xe_ggtt.h
>@@ -29,6 +29,7 @@ int xe_ggtt_insert_bo(struct xe_ggtt *ggtt, struct xe_bo *bo);
> int xe_ggtt_insert_bo_at(struct xe_ggtt *ggtt, struct xe_bo *bo,
> 			 u64 start, u64 end);
> void xe_ggtt_remove_bo(struct xe_ggtt *ggtt, struct xe_bo *bo);
>+u64 xe_ggtt_largest_hole(struct xe_ggtt *ggtt, u64 alignment, u64 *spare);
>
> int xe_ggtt_dump(struct xe_ggtt *ggtt, struct drm_printer *p);
>
>diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
>index 947750d97d7d..1852ff45bea4 100644
>--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
>+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
>@@ -590,30 +590,11 @@ int xe_gt_sriov_pf_config_bulk_set_ggtt(struct xe_gt *gt, unsigned int vfid,
> static u64 pf_get_max_ggtt(struct xe_gt *gt)
> {
> 	struct xe_ggtt *ggtt = gt_to_tile(gt)->mem.ggtt;
>-	const struct drm_mm *mm = &ggtt->mm;
>-	const struct drm_mm_node *entry;
> 	u64 alignment = pf_get_ggtt_alignment(gt);
> 	u64 spare = pf_get_spare_ggtt(gt);
>-	u64 hole_min_start = xe_wopcm_size(gt_to_xe(gt));
>-	u64 hole_start, hole_end, hole_size;
>-	u64 max_hole = 0;
>-
>-	mutex_lock(&ggtt->lock);
>-
>-	drm_mm_for_each_hole(entry, mm, hole_start, hole_end) {
>-		hole_start = max(hole_start, hole_min_start);
>-		hole_start = ALIGN(hole_start, alignment);
>-		hole_end = ALIGN_DOWN(hole_end, alignment);
>-		if (hole_start >= hole_end)
>-			continue;
>-		hole_size = hole_end - hole_start;
>-		xe_gt_sriov_dbg_verbose(gt, "HOLE start %llx size %lluK\n",
>-					hole_start, hole_size / SZ_1K);
>-		spare -= min3(spare, hole_size, max_hole);
>-		max_hole = max(max_hole, hole_size);
>-	}
>+	u64 max_hole;
>
>-	mutex_unlock(&ggtt->lock);
>+	max_hole = xe_ggtt_largest_hole(ggtt, alignment, &spare);

optional: I think this would read better with a single name for the same
thing:

	max_hole = xe_ggtt_max_hole(ggtt, alignment, &spare);

Anyway, checked with git show --color-moved to make sure it retains the
current behavior.


Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>

Lucas De Marchi

>
> 	xe_gt_sriov_dbg_verbose(gt, "HOLE max %lluK reserved %lluK\n",
> 				max_hole / SZ_1K, spare / SZ_1K);
>-- 
>2.46.0
>