On 03.07.2025 15:28, Caterina Shablia wrote:
> From: Boris Brezillon <boris.brezil...@collabora.com>
>
> We are going to add flags/properties that will impact the VA merging
> ability. Instead of sprinkling tests all over the place in
> __drm_gpuvm_sm_map(), let's add a helper aggregating all these checks
> can call it for every existing VA we walk through in the
> __drm_gpuvm_sm_map() loop.
>
> Signed-off-by: Boris Brezillon <boris.brezil...@collabora.com>
> Signed-off-by: Caterina Shablia <caterina.shab...@collabora.com>
> ---
> drivers/gpu/drm/drm_gpuvm.c | 47 +++++++++++++++++++++++++++++--------
> 1 file changed, 37 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c
> index ae201d45e6b8..2df04dfcb6ef 100644
> --- a/drivers/gpu/drm/drm_gpuvm.c
> +++ b/drivers/gpu/drm/drm_gpuvm.c
> @@ -2098,12 +2098,48 @@ op_unmap_cb(const struct drm_gpuvm_ops *fn, void
> *priv,
> return fn->sm_step_unmap(&op, priv);
> }
>
> +static bool can_merge(struct drm_gpuvm *gpuvm, const struct drm_gpuva *a,
> + const struct drm_gpuva *b)
> +{
> + /* Only GEM-based mappings can be merged, and they must point to
> + * the same GEM object.
> + */
> + if (a->gem.obj != b->gem.obj || !a->gem.obj)
> + return false;
> +
> + /* Let's keep things simple for now and force all flags to match. */
> + if (a->flags != b->flags)
> + return false;
> +
> + /* Order VAs for the rest of the checks. */
> + if (a->va.addr > b->va.addr)
> + swap(a, b);
> +
> + /* We assume the caller already checked that VAs overlap or are
> + * contiguous.
> + */
> + if (drm_WARN_ON(gpuvm->drm, b->va.addr > a->va.addr + a->va.range))
> + return false;
> +
> + /* We intentionally ignore u64 underflows because all we care about
> + * here is whether the VA diff matches the GEM offset diff.
> + */
> + return b->va.addr - a->va.addr == b->gem.offset - a->gem.offset;
> +}
> +
> static int
> __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
> const struct drm_gpuvm_ops *ops, void *priv,
> const struct drm_gpuvm_map_req *req)
> {
> struct drm_gpuva *va, *next;
> + struct drm_gpuva reqva = {
> + .va.addr = req->va.addr,
> + .va.range = req->va.range,
> + .gem.offset = req->gem.offset,
> + .gem.obj = req->gem.obj,
> + .flags = req->flags,
struct drm_gpuvm_map_req::flags is not added until the next commit in the series
("drm/gpuvm: Add a flags field to drm_gpuva_op_map") so maybe you could reorder
the series and have Lina's commits come earlier than this one. Otherwise this is
going to break the build and make the series unbisectable.
> + };
> u64 req_end = req->va.addr + req->va.range;
> int ret;
>
> @@ -2116,12 +2152,9 @@ __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
> u64 addr = va->va.addr;
> u64 range = va->va.range;
> u64 end = addr + range;
> - bool merge = !!va->gem.obj;
> + bool merge = can_merge(gpuvm, va, &reqva);
>
> if (addr == req->va.addr) {
> - merge &= obj == req->gem.obj &&
> - offset == req->gem.offset;
> -
> if (end == req_end) {
> ret = op_unmap_cb(ops, priv, va, merge);
> if (ret)
> @@ -2163,8 +2196,6 @@ __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
> };
> struct drm_gpuva_op_unmap u = { .va = va };
>
> - merge &= obj == req->gem.obj &&
> - offset + ls_range == req->gem.offset;
> u.keep = merge;
>
> if (end == req_end) {
> @@ -2196,10 +2227,6 @@ __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
> break;
> }
> } else if (addr > req->va.addr) {
> - merge &= obj == req->gem.obj &&
> - offset == req->gem.offset +
> - (addr - req->va.addr);
> -
> if (end == req_end) {
> ret = op_unmap_cb(ops, priv, va, merge);
> if (ret)
> --
> 2.47.2
Adrian Larumbe
