Re: [PATCH drm-next 03/14] drm: manager to keep track of GPUs VA mappings

From: Bagas Sanjaya
Date: Wed Jan 18 2023 - 23:47:14 EST


On Wed, Jan 18, 2023 at 07:12:45AM +0100, Danilo Krummrich wrote:
> This adds the infrastructure for a manager implementation to keep track
> of GPU virtual address (VA) mappings.

"Add infrastructure for ..."

> + * Analogue to drm_gpuva_sm_map_ops_create() drm_gpuva_sm_unmap_ops_create()
> + * provides drivers a the list of operations to be executed in order to unmap
> + * a range of GPU VA space. The logic behind this functions is way simpler
> + * though: For all existent mappings enclosed by the given range unmap
> + * operations are created. For mappings which are only partically located within
> + * the given range, remap operations are created such that those mappings are
> + * split up and re-mapped partically.

"Analogous to ..."

> + *
> + * The following paragraph depicts the basic constellations of existent GPU VA
> + * mappings, a newly requested mapping and the resulting mappings as implemented
> + * by drm_gpuva_sm_map_ops_create() - it doesn't cover arbitrary combinations
> + * of those constellations.
> + *
> + * ::
> + *
> + * 1) Existent mapping is kept.
> + * ----------------------------
> + *
> + * 0 a 1
> + * old: |-----------| (bo_offset=n)
> + *
> + * 0 a 1
> + * req: |-----------| (bo_offset=n)
> + *
> + * 0 a 1
> + * new: |-----------| (bo_offset=n)
> + *
> + *
> + * 2) Existent mapping is replaced.
> + * --------------------------------
> + *
> + * 0 a 1
> + * old: |-----------| (bo_offset=n)
> + *
> + * 0 a 1
> + * req: |-----------| (bo_offset=m)
> + *
> + * 0 a 1
> + * new: |-----------| (bo_offset=m)
> + *
> + *
> + * 3) Existent mapping is replaced.
> + * --------------------------------
> + *
> + * 0 a 1
> + * old: |-----------| (bo_offset=n)
> + *
> + * 0 b 1
> + * req: |-----------| (bo_offset=n)
> + *
> + * 0 b 1
> + * new: |-----------| (bo_offset=n)
> + *
> + *
> + * 4) Existent mapping is replaced.
> + * --------------------------------
> + *
> + * 0 a 1
> + * old: |-----| (bo_offset=n)
> + *
> + * 0 a 2
> + * req: |-----------| (bo_offset=n)
> + *
> + * 0 a 2
> + * new: |-----------| (bo_offset=n)
> + *
> + * Note: We expect to see the same result for a request with a different bo
> + * and/or bo_offset.
> + *
> + *
> + * 5) Existent mapping is split.
> + * -----------------------------
> + *
> + * 0 a 2
> + * old: |-----------| (bo_offset=n)
> + *
> + * 0 b 1
> + * req: |-----| (bo_offset=n)
> + *
> + * 0 b 1 a' 2
> + * new: |-----|-----| (b.bo_offset=n, a.bo_offset=n+1)
> + *
> + * Note: We expect to see the same result for a request with a different bo
> + * and/or non-contiguous bo_offset.
> + *
> + *
> + * 6) Existent mapping is kept.
> + * ----------------------------
> + *
> + * 0 a 2
> + * old: |-----------| (bo_offset=n)
> + *
> + * 0 a 1
> + * req: |-----| (bo_offset=n)
> + *
> + * 0 a 2
> + * new: |-----------| (bo_offset=n)
> + *
> + *
> + * 7) Existent mapping is split.
> + * -----------------------------
> + *
> + * 0 a 2
> + * old: |-----------| (bo_offset=n)
> + *
> + * 1 b 2
> + * req: |-----| (bo_offset=m)
> + *
> + * 0 a 1 b 2
> + * new: |-----|-----| (a.bo_offset=n,b.bo_offset=m)
> + *
> + *
> + * 8) Existent mapping is kept.
> + * ----------------------------
> + *
> + * 0 a 2
> + * old: |-----------| (bo_offset=n)
> + *
> + * 1 a 2
> + * req: |-----| (bo_offset=n+1)
> + *
> + * 0 a 2
> + * new: |-----------| (bo_offset=n)
> + *
> + *
> + * 9) Existent mapping is split.
> + * -----------------------------
> + *
> + * 0 a 2
> + * old: |-----------| (bo_offset=n)
> + *
> + * 1 b 3
> + * req: |-----------| (bo_offset=m)
> + *
> + * 0 a 1 b 3
> + * new: |-----|-----------| (a.bo_offset=n,b.bo_offset=m)
> + *
> + *
> + * 10) Existent mapping is merged.
> + * -------------------------------
> + *
> + * 0 a 2
> + * old: |-----------| (bo_offset=n)
> + *
> + * 1 a 3
> + * req: |-----------| (bo_offset=n+1)
> + *
> + * 0 a 3
> + * new: |-----------------| (bo_offset=n)
> + *
> + *
> + * 11) Existent mapping is split.
> + * ------------------------------
> + *
> + * 0 a 3
> + * old: |-----------------| (bo_offset=n)
> + *
> + * 1 b 2
> + * req: |-----| (bo_offset=m)
> + *
> + * 0 a 1 b 2 a' 3
> + * new: |-----|-----|-----| (a.bo_offset=n,b.bo_offset=m,a'.bo_offset=n+2)
> + *
> + *
> + * 12) Existent mapping is kept.
> + * -----------------------------
> + *
> + * 0 a 3
> + * old: |-----------------| (bo_offset=n)
> + *
> + * 1 a 2
> + * req: |-----| (bo_offset=n+1)
> + *
> + * 0 a 3
> + * old: |-----------------| (bo_offset=n)
> + *
> + *
> + * 13) Existent mapping is replaced.
> + * ---------------------------------
> + *
> + * 1 a 2
> + * old: |-----| (bo_offset=n)
> + *
> + * 0 a 2
> + * req: |-----------| (bo_offset=n)
> + *
> + * 0 a 2
> + * new: |-----------| (bo_offset=n)
> + *
> + * Note: We expect to see the same result for a request with a different bo
> + * and/or non-contiguous bo_offset.
> + *
> + *
> + * 14) Existent mapping is replaced.
> + * ---------------------------------
> + *
> + * 1 a 2
> + * old: |-----| (bo_offset=n)
> + *
> + * 0 a 3
> + * req: |----------------| (bo_offset=n)
> + *
> + * 0 a 3
> + * new: |----------------| (bo_offset=n)
> + *
> + * Note: We expect to see the same result for a request with a different bo
> + * and/or non-contiguous bo_offset.
> + *
> + *
> + * 15) Existent mapping is split.
> + * ------------------------------
> + *
> + * 1 a 3
> + * old: |-----------| (bo_offset=n)
> + *
> + * 0 b 2
> + * req: |-----------| (bo_offset=m)
> + *
> + * 0 b 2 a' 3
> + * new: |-----------|-----| (b.bo_offset=m,a.bo_offset=n+2)
> + *
> + *
> + * 16) Existent mappings are merged.
> + * ---------------------------------
> + *
> + * 0 a 1
> + * old: |-----------| (bo_offset=n)
> + *
> + * 2 a 3
> + * old': |-----------| (bo_offset=n+2)
> + *
> + * 1 a 2
> + * req: |-----------| (bo_offset=n+1)
> + *
> + * a
> + * new: |----------------------------------| (bo_offset=n)
> + */

Factor out lists from the big code block above:

---- >8 ----

diff --git a/drivers/gpu/drm/drm_gpuva_mgr.c b/drivers/gpu/drm/drm_gpuva_mgr.c
index e665f642689d03..411c0aa80bfa1f 100644
--- a/drivers/gpu/drm/drm_gpuva_mgr.c
+++ b/drivers/gpu/drm/drm_gpuva_mgr.c
@@ -129,15 +129,14 @@
* the given range, remap operations are created such that those mappings are
* split up and re-mapped partically.
*
- * The following paragraph depicts the basic constellations of existent GPU VA
+ * The following diagram depicts the basic relationships of existent GPU VA
* mappings, a newly requested mapping and the resulting mappings as implemented
- * by drm_gpuva_sm_map_ops_create() - it doesn't cover arbitrary combinations
- * of those constellations.
+ * by drm_gpuva_sm_map_ops_create() - it doesn't cover any arbitrary
+ * combinations of these.
*
- * ::
- *
- * 1) Existent mapping is kept.
- * ----------------------------
+ * 1) Existent mapping is kept.
+ *
+ * ::
*
* 0 a 1
* old: |-----------| (bo_offset=n)
@@ -149,8 +148,9 @@
* new: |-----------| (bo_offset=n)
*
*
- * 2) Existent mapping is replaced.
- * --------------------------------
+ * 2) Existent mapping is replaced.
+ *
+ * ::
*
* 0 a 1
* old: |-----------| (bo_offset=n)
@@ -162,8 +162,9 @@
* new: |-----------| (bo_offset=m)
*
*
- * 3) Existent mapping is replaced.
- * --------------------------------
+ * 3) Existent mapping is replaced.
+ *
+ * ::
*
* 0 a 1
* old: |-----------| (bo_offset=n)
@@ -175,8 +176,9 @@
* new: |-----------| (bo_offset=n)
*
*
- * 4) Existent mapping is replaced.
- * --------------------------------
+ * 4) Existent mapping is replaced.
+ *
+ * ::
*
* 0 a 1
* old: |-----| (bo_offset=n)
@@ -187,12 +189,14 @@
* 0 a 2
* new: |-----------| (bo_offset=n)
*
- * Note: We expect to see the same result for a request with a different bo
- * and/or bo_offset.
+ * .. note::
+ * We expect to see the same result for a request with a different bo
+ * and/or bo_offset.
*
*
- * 5) Existent mapping is split.
- * -----------------------------
+ * 5) Existent mapping is split.
+ *
+ * ::
*
* 0 a 2
* old: |-----------| (bo_offset=n)
@@ -203,12 +207,14 @@
* 0 b 1 a' 2
* new: |-----|-----| (b.bo_offset=n, a.bo_offset=n+1)
*
- * Note: We expect to see the same result for a request with a different bo
- * and/or non-contiguous bo_offset.
+ * .. note::
+ * We expect to see the same result for a request with a different bo
+ * and/or non-contiguous bo_offset.
*
*
- * 6) Existent mapping is kept.
- * ----------------------------
+ * 6) Existent mapping is kept.
+ *
+ * ::
*
* 0 a 2
* old: |-----------| (bo_offset=n)
@@ -220,8 +226,9 @@
* new: |-----------| (bo_offset=n)
*
*
- * 7) Existent mapping is split.
- * -----------------------------
+ * 7) Existent mapping is split.
+ *
+ * ::
*
* 0 a 2
* old: |-----------| (bo_offset=n)
@@ -233,8 +240,9 @@
* new: |-----|-----| (a.bo_offset=n,b.bo_offset=m)
*
*
- * 8) Existent mapping is kept.
- * ----------------------------
+ * 8) Existent mapping is kept.
+ *
+ * ::
*
* 0 a 2
* old: |-----------| (bo_offset=n)
@@ -246,8 +254,9 @@
* new: |-----------| (bo_offset=n)
*
*
- * 9) Existent mapping is split.
- * -----------------------------
+ * 9) Existent mapping is split.
+ *
+ * ::
*
* 0 a 2
* old: |-----------| (bo_offset=n)
@@ -259,104 +268,113 @@
* new: |-----|-----------| (a.bo_offset=n,b.bo_offset=m)
*
*
- * 10) Existent mapping is merged.
- * -------------------------------
+ * 10) Existent mapping is merged.
*
- * 0 a 2
- * old: |-----------| (bo_offset=n)
+ * ::
*
- * 1 a 3
- * req: |-----------| (bo_offset=n+1)
+ * 0 a 2
+ * old: |-----------| (bo_offset=n)
*
- * 0 a 3
- * new: |-----------------| (bo_offset=n)
+ * 1 a 3
+ * req: |-----------| (bo_offset=n+1)
+ *
+ * 0 a 3
+ * new: |-----------------| (bo_offset=n)
*
*
- * 11) Existent mapping is split.
- * ------------------------------
+ * 11) Existent mapping is split.
*
- * 0 a 3
- * old: |-----------------| (bo_offset=n)
+ * ::
*
- * 1 b 2
- * req: |-----| (bo_offset=m)
+ * 0 a 3
+ * old: |-----------------| (bo_offset=n)
*
- * 0 a 1 b 2 a' 3
- * new: |-----|-----|-----| (a.bo_offset=n,b.bo_offset=m,a'.bo_offset=n+2)
+ * 1 b 2
+ * req: |-----| (bo_offset=m)
+ *
+ * 0 a 1 b 2 a' 3
+ * new: |-----|-----|-----| (a.bo_offset=n,b.bo_offset=m,a'.bo_offset=n+2)
*
*
- * 12) Existent mapping is kept.
- * -----------------------------
+ * 12) Existent mapping is kept.
*
- * 0 a 3
- * old: |-----------------| (bo_offset=n)
+ * ::
*
- * 1 a 2
- * req: |-----| (bo_offset=n+1)
+ * 0 a 3
+ * old: |-----------------| (bo_offset=n)
*
- * 0 a 3
- * old: |-----------------| (bo_offset=n)
+ * 1 a 2
+ * req: |-----| (bo_offset=n+1)
+ *
+ * 0 a 3
+ * old: |-----------------| (bo_offset=n)
*
*
- * 13) Existent mapping is replaced.
- * ---------------------------------
+ * 13) Existent mapping is replaced.
*
- * 1 a 2
- * old: |-----| (bo_offset=n)
+ * ::
*
- * 0 a 2
- * req: |-----------| (bo_offset=n)
+ * 1 a 2
+ * old: |-----| (bo_offset=n)
*
- * 0 a 2
- * new: |-----------| (bo_offset=n)
+ * 0 a 2
+ * req: |-----------| (bo_offset=n)
*
- * Note: We expect to see the same result for a request with a different bo
- * and/or non-contiguous bo_offset.
+ * 0 a 2
+ * new: |-----------| (bo_offset=n)
+ *
+ * .. note::
+ * We expect to see the same result for a request with a different bo
+ * and/or non-contiguous bo_offset.
*
*
- * 14) Existent mapping is replaced.
- * ---------------------------------
+ * 14) Existent mapping is replaced.
*
- * 1 a 2
- * old: |-----| (bo_offset=n)
+ * ::
*
- * 0 a 3
- * req: |----------------| (bo_offset=n)
+ * 1 a 2
+ * old: |-----| (bo_offset=n)
*
- * 0 a 3
- * new: |----------------| (bo_offset=n)
+ * 0 a 3
+ * req: |----------------| (bo_offset=n)
*
- * Note: We expect to see the same result for a request with a different bo
- * and/or non-contiguous bo_offset.
+ * 0 a 3
+ * new: |----------------| (bo_offset=n)
+ *
+ * .. note::
+ * We expect to see the same result for a request with a different bo
+ * and/or non-contiguous bo_offset.
*
*
- * 15) Existent mapping is split.
- * ------------------------------
+ * 15) Existent mapping is split.
*
- * 1 a 3
- * old: |-----------| (bo_offset=n)
+ * ::
*
- * 0 b 2
- * req: |-----------| (bo_offset=m)
+ * 1 a 3
+ * old: |-----------| (bo_offset=n)
*
- * 0 b 2 a' 3
- * new: |-----------|-----| (b.bo_offset=m,a.bo_offset=n+2)
+ * 0 b 2
+ * req: |-----------| (bo_offset=m)
+ *
+ * 0 b 2 a' 3
+ * new: |-----------|-----| (b.bo_offset=m,a.bo_offset=n+2)
*
*
- * 16) Existent mappings are merged.
- * ---------------------------------
+ * 16) Existent mappings are merged.
*
- * 0 a 1
- * old: |-----------| (bo_offset=n)
+ * ::
*
- * 2 a 3
- * old': |-----------| (bo_offset=n+2)
+ * 0 a 1
+ * old: |-----------| (bo_offset=n)
*
- * 1 a 2
- * req: |-----------| (bo_offset=n+1)
+ * 2 a 3
+ * old': |-----------| (bo_offset=n+2)
*
- * a
- * new: |----------------------------------| (bo_offset=n)
+ * 1 a 2
+ * req: |-----------| (bo_offset=n+1)
+ *
+ * a
+ * new: |----------------------------------| (bo_offset=n)
*/

/**

However, the relationship scenario descriptions are too generic (different
diagrams are described by the same text). Please rewrite them, taking into
account bo_offset values in each scenario.

Thanks.

--
An old man doll... just what I always wanted! - Clara

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