On Fri, Feb 07, 2025 at 03:45:51PM +0100, Thomas Hellström wrote:
> On Wed, 2025-01-29 at 11:52 -0800, Matthew Brost wrote:
> > Wire xe_bo_move to GPU SVM migration via new helper xe_svm_bo_evict.
> >
> > v2:
> > - Use xe_svm_bo_evict
> > - Drop bo->range
> > v3:
> > - Kernel doc (Thomas)
> > v4:
> > - Add missing xe_bo.c code
> >
> > Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
>
> I think in the long run, we'd want to do the svm eviction / unbind in
> move_notify(), since that's where we're supposed to unbind other
> subsystems. And then just purge the bo using a NULL placement, but
> since this is equivalent let's postpone that to a more general
> xe_bo_move() cleanup. It's getting pretty hard to follow.
>
Agree xe_bo_move() could use some cleanup.
Matt
> Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
>
>
> > ---
> > drivers/gpu/drm/xe/xe_bo.c | 19 +++++++++++++++++++
> > drivers/gpu/drm/xe/xe_svm.c | 15 ++++++++++++++-
> > drivers/gpu/drm/xe/xe_svm.h | 3 +++
> > 3 files changed, 36 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> > index 20c96709e267..657687ee70d0 100644
> > --- a/drivers/gpu/drm/xe/xe_bo.c
> > +++ b/drivers/gpu/drm/xe/xe_bo.c
> > @@ -255,6 +255,8 @@ int xe_bo_placement_for_flags(struct xe_device
> > *xe, struct xe_bo *bo,
> > static void xe_evict_flags(struct ttm_buffer_object *tbo,
> > struct ttm_placement *placement)
> > {
> > + struct xe_bo *bo;
> > +
> > if (!xe_bo_is_xe_bo(tbo)) {
> > /* Don't handle scatter gather BOs */
> > if (tbo->type == ttm_bo_type_sg) {
> > @@ -266,6 +268,12 @@ static void xe_evict_flags(struct
> > ttm_buffer_object *tbo,
> > return;
> > }
> >
> > + bo = ttm_to_xe_bo(tbo);
> > + if (bo->flags & XE_BO_FLAG_CPU_ADDR_MIRROR) {
> > + *placement = sys_placement;
> > + return;
> > + }
> > +
> > /*
> > * For xe, sg bos that are evicted to system just triggers a
> > * rebind of the sg list upon subsequent validation to
> > XE_PL_TT.
> > @@ -710,6 +718,17 @@ static int xe_bo_move(struct ttm_buffer_object
> > *ttm_bo, bool evict,
> > goto out;
> > }
> >
> > + if (!move_lacks_source && (bo->flags &
> > XE_BO_FLAG_CPU_ADDR_MIRROR) &&
> > + new_mem->mem_type == XE_PL_SYSTEM) {
> > + ret = xe_svm_bo_evict(bo);
> > + if (!ret) {
> > + drm_dbg(&xe->drm, "Evict system allocator BO
> > success\n");
> > + ttm_bo_move_null(ttm_bo, new_mem);
> > + }
> > +
> > + goto out;
> > + }
> > +
> > if (old_mem_type == XE_PL_SYSTEM && new_mem->mem_type ==
> > XE_PL_TT && !handle_system_ccs) {
> > ttm_bo_move_null(ttm_bo, new_mem);
> > goto out;
> > diff --git a/drivers/gpu/drm/xe/xe_svm.c
> > b/drivers/gpu/drm/xe/xe_svm.c
> > index fc030855d078..dafc5061eb42 100644
> > --- a/drivers/gpu/drm/xe/xe_svm.c
> > +++ b/drivers/gpu/drm/xe/xe_svm.c
> > @@ -768,6 +768,20 @@ bool xe_svm_has_mapping(struct xe_vm *vm, u64
> > start, u64 end)
> > return drm_gpusvm_has_mapping(&vm->svm.gpusvm, start, end);
> > }
> >
> > +/**
> > + * xe_svm_bo_evict() - SVM evict BO to system memory
> > + * @bo: BO to evict
> > + *
> > + * SVM evict BO to system memory. GPU SVM layer ensures all device
> > pages
> > + * are evicted before returning.
> > + *
> > + * Return: 0 on success standard error code otherwise
> > + */
> > +int xe_svm_bo_evict(struct xe_bo *bo)
> > +{
> > + return drm_gpusvm_evict_to_ram(&bo->devmem_allocation);
> > +}
> > +
> > #if IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR)
> > static struct drm_pagemap_dma_addr
> > xe_drm_pagemap_map_dma(struct drm_pagemap *dpagemap,
> > @@ -795,7 +809,6 @@ static const struct drm_pagemap_ops
> > xe_drm_pagemap_ops = {
> > .map_dma = xe_drm_pagemap_map_dma,
> > };
> >
> > ->>>>>>> 133db8ade5f0 (drm/xe: Add drm_pagemap ops to SVM)
> > /**
> > * xe_devm_add: Remap and provide memmap backing for device memory
> > * @tile: tile that the memory region belongs to
> > diff --git a/drivers/gpu/drm/xe/xe_svm.h
> > b/drivers/gpu/drm/xe/xe_svm.h
> > index 4c2576162c39..77dec5aae0ee 100644
> > --- a/drivers/gpu/drm/xe/xe_svm.h
> > +++ b/drivers/gpu/drm/xe/xe_svm.h
> > @@ -11,6 +11,7 @@
> >
> > #define XE_INTERCONNECT_VRAM DRM_INTERCONNECT_DRIVER
> >
> > +struct xe_bo;
> > struct xe_mem_region;
> > struct xe_tile;
> > struct xe_vm;
> > @@ -56,6 +57,8 @@ int xe_svm_handle_pagefault(struct xe_vm *vm,
> > struct xe_vma *vma,
> >
> > bool xe_svm_has_mapping(struct xe_vm *vm, u64 start, u64 end);
> >
> > +int xe_svm_bo_evict(struct xe_bo *bo);
> > +
> > static inline bool xe_svm_range_pages_valid(struct xe_svm_range
> > *range)
> > {
> > return drm_gpusvm_range_pages_valid(range->base.gpusvm,
> > &range->base);
>
