[Intel-xe] [PATCH 2/2] drm/xe: Drop coalescing of GGTT invalidations

[Niranjana Vishwanathapura]

On Thu, Apr 06, 2023 at 03:44:33AM +0000, Matthew Brost wrote:
>On Wed, Apr 05, 2023 at 08:42:36PM -0700, Niranjana Vishwanathapura wrote:
>> On Wed, Apr 05, 2023 at 04:34:03PM -0700, Matthew Brost wrote:
>> > Causing a bunch of hangs driver load and in user space. Benefit is
>> > rather small too, so just drop this for to stablize the stack.
>> >
>>
>> Looks like this should instead be revert of following patches?
>>
>> drm/xe: Coalesce GGTT invalidations
>> drm/xe: Pad GGTT mapping with an extra page pointing to scratch
>>
>
>git revert conflicts...
>

Looks like a minor conflict.
I am seeing reverting above patches brings back some XE_BUG_ON()
checks and a xe_ggtt_invalidate() in __xe_ggtt_insert_bo_at().
Wondering if we need them as well.

Niranjana

>Matt
>
>> Niranjana
>>
>> > Signed-off-by: Matthew Brost <matthew.brost at intel.com>
>> > ---
>> > drivers/gpu/drm/xe/xe_bo.c         |  1 -
>> > drivers/gpu/drm/xe/xe_bo_types.h   |  2 --
>> > drivers/gpu/drm/xe/xe_ggtt.c       | 25 +------------------------
>> > drivers/gpu/drm/xe/xe_ggtt_types.h |  2 --
>> > 4 files changed, 1 insertion(+), 29 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
>> > index 5460e6fe3c1f..c7f175a149be 100644
>> > --- a/drivers/gpu/drm/xe/xe_bo.c
>> > +++ b/drivers/gpu/drm/xe/xe_bo.c
>> > @@ -975,7 +975,6 @@ struct xe_bo *__xe_bo_create_locked(struct xe_device *xe, struct xe_bo *bo,
>> > 			return bo;
>> > 	}
>> >
>> > -	bo->requested_size = size;
>> > 	if (flags & (XE_BO_CREATE_VRAM_MASK | XE_BO_CREATE_STOLEN_BIT) &&
>> > 	    !(flags & XE_BO_CREATE_IGNORE_MIN_PAGE_SIZE_BIT) &&
>> > 	    xe->info.vram_flags & XE_VRAM_FLAGS_NEED64K) {
>> > diff --git a/drivers/gpu/drm/xe/xe_bo_types.h b/drivers/gpu/drm/xe/xe_bo_types.h
>> > index db217500a970..6071611a2b29 100644
>> > --- a/drivers/gpu/drm/xe/xe_bo_types.h
>> > +++ b/drivers/gpu/drm/xe/xe_bo_types.h
>> > @@ -23,8 +23,6 @@ struct xe_vm;
>> > struct xe_bo {
>> > 	/** @ttm: TTM base buffer object */
>> > 	struct ttm_buffer_object ttm;
>> > -	/** @requested_size: Requested size of this buffer object */
>> > -	size_t requested_size;
>> > 	/** @size: Size of this buffer object after alignment adjusting */
>> > 	size_t size;
>> > 	/** @flags: flags for this buffer object */
>> > diff --git a/drivers/gpu/drm/xe/xe_ggtt.c b/drivers/gpu/drm/xe/xe_ggtt.c
>> > index a430d1568890..93f78aba2c8e 100644
>> > --- a/drivers/gpu/drm/xe/xe_ggtt.c
>> > +++ b/drivers/gpu/drm/xe/xe_ggtt.c
>> > @@ -273,15 +273,7 @@ void xe_ggtt_map_bo(struct xe_ggtt *ggtt, struct xe_bo *bo)
>> > 		xe_ggtt_set_pte(ggtt, start + offset, pte);
>> > 	}
>> >
>> > -	if (bo->size == bo->requested_size) {
>> > -		pte = xe_ggtt_pte_encode(ggtt->scratch ?: bo, 0);
>> > -		xe_ggtt_set_pte(ggtt, start + bo->size, pte);
>> > -	}
>> > -
>> > -	if (ggtt->invalidate) {
>> > -		xe_ggtt_invalidate(ggtt->gt);
>> > -		ggtt->invalidate = false;
>> > -	}
>> > +	xe_ggtt_invalidate(ggtt->gt);
>> > }
>> >
>> > static int __xe_ggtt_insert_bo_at(struct xe_ggtt *ggtt, struct xe_bo *bo,
>> > @@ -302,19 +294,6 @@ static int __xe_ggtt_insert_bo_at(struct xe_ggtt *ggtt, struct xe_bo *bo,
>> > 	if (err)
>> > 		return err;
>> >
>> > -	/*
>> > -	 * We add an extra page when mapping a BO in the GGTT so we can coalesce
>> > -	 * GGTT invalidations. Without this extra page GGTT prefetches can leave
>> > -	 * entries in the TLB pointing to an invalidation GGTT entry when in
>> > -	 * fact we have programmed this GGTT entry to a valid entry. BO aligned
>> > -	 * to 64k already have padding so no need to add an extra page.
>> > -	 */
>> > -	if (bo->size == bo->requested_size) {
>> > -		size += SZ_4K;
>> > -		if (end != U64_MAX)
>> > -			end += SZ_4K;
>> > -	}
>> > -
>> > 	mutex_lock(&ggtt->lock);
>> > 	err = drm_mm_insert_node_in_range(&ggtt->mm, &bo->ggtt_node, size,
>> > 					  alignment, 0, start, end, 0);
>> > @@ -344,8 +323,6 @@ void xe_ggtt_remove_node(struct xe_ggtt *ggtt, struct drm_mm_node *node)
>> > 	drm_mm_remove_node(node);
>> > 	node->size = 0;
>> >
>> > -	ggtt->invalidate = true;
>> > -
>> > 	mutex_unlock(&ggtt->lock);
>> > }
>> >
>> > diff --git a/drivers/gpu/drm/xe/xe_ggtt_types.h b/drivers/gpu/drm/xe/xe_ggtt_types.h
>> > index 8198aa784654..ea70aaef4b31 100644
>> > --- a/drivers/gpu/drm/xe/xe_ggtt_types.h
>> > +++ b/drivers/gpu/drm/xe/xe_ggtt_types.h
>> > @@ -26,8 +26,6 @@ struct xe_ggtt {
>> > 	u64 __iomem *gsm;
>> >
>> > 	struct drm_mm mm;
>> > -
>> > -	bool invalidate;
>> > };
>> >
>> > #endif
>> > --
>> > 2.34.1
>> >