[PATCH v7 1/2] drm/buddy: Add start address support to trim function
Matthew Auld
matthew.auld at intel.com
Wed Jul 24 09:37:54 UTC 2024
On 24/07/2024 02:35, Marek Olšák wrote:
> The reason is that our DCC requires 768K alignment in some cases. I
> haven't read this patch series, but one way to do that is to align to
> 256K, overallocate by 512K, and then not use either 0, 256K, or 512K at
> the beginning to get to 768K alignment.
Ah, so we need a non power-of-two alignment. That makes sense, thanks.
>
> Marek
>
> On Tue, Jul 23, 2024, 11:04 Matthew Auld <matthew.auld at intel.com
> <mailto:matthew.auld at intel.com>> wrote:
>
> On 23/07/2024 14:43, Paneer Selvam, Arunpravin wrote:
> > Hi Matthew,
> >
> > Can we push this version for now as we need to mainline the DCC
> changes
> > ASAP,
> > while we continue our discussion and proceed to implement the
> permanent
> > solution
> > for address alignment?
>
> Yeah, we can always merge now and circle back around later, if this for
> sure helps your usecase and is needed asap. I just didn't fully get the
> idea for needing this interface, but likely I am missing something.
>
> >
> > Thanks,
> > Arun.
> >
> > On 7/23/2024 6:55 PM, Arunpravin Paneer Selvam wrote:
> >> - Add a new start parameter in trim function to specify exact
> >> address from where to start the trimming. This would help us
> >> in situations like if drivers would like to do address alignment
> >> for specific requirements.
> >>
> >> - Add a new flag DRM_BUDDY_TRIM_DISABLE. Drivers can use this
> >> flag to disable the allocator trimming part. This patch enables
> >> the drivers control trimming and they can do it themselves
> >> based on the application requirements.
> >>
> >> v1:(Matthew)
> >> - check new_start alignment with min chunk_size
> >> - use range_overflows()
> >>
> >> Signed-off-by: Arunpravin Paneer Selvam
> <Arunpravin.PaneerSelvam at amd.com
> <mailto:Arunpravin.PaneerSelvam at amd.com>>
> >> Acked-by: Alex Deucher <alexander.deucher at amd.com
> <mailto:alexander.deucher at amd.com>>
> >> Acked-by: Christian König <christian.koenig at amd.com
> <mailto:christian.koenig at amd.com>>
> >> ---
> >> drivers/gpu/drm/drm_buddy.c | 25
> +++++++++++++++++++++++--
> >> drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 2 +-
> >> include/drm/drm_buddy.h | 2 ++
> >> 3 files changed, 26 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/drm_buddy.c
> b/drivers/gpu/drm/drm_buddy.c
> >> index 6a8e45e9d0ec..103c185bb1c8 100644
> >> --- a/drivers/gpu/drm/drm_buddy.c
> >> +++ b/drivers/gpu/drm/drm_buddy.c
> >> @@ -851,6 +851,7 @@ static int __alloc_contig_try_harder(struct
> >> drm_buddy *mm,
> >> * drm_buddy_block_trim - free unused pages
> >> *
> >> * @mm: DRM buddy manager
> >> + * @start: start address to begin the trimming.
> >> * @new_size: original size requested
> >> * @blocks: Input and output list of allocated blocks.
> >> * MUST contain single block as input to be trimmed.
> >> @@ -866,11 +867,13 @@ static int __alloc_contig_try_harder(struct
> >> drm_buddy *mm,
> >> * 0 on success, error code on failure.
> >> */
> >> int drm_buddy_block_trim(struct drm_buddy *mm,
> >> + u64 *start,
> >> u64 new_size,
> >> struct list_head *blocks)
> >> {
> >> struct drm_buddy_block *parent;
> >> struct drm_buddy_block *block;
> >> + u64 block_start, block_end;
> >> LIST_HEAD(dfs);
> >> u64 new_start;
> >> int err;
> >> @@ -882,6 +885,9 @@ int drm_buddy_block_trim(struct drm_buddy *mm,
> >> struct drm_buddy_block,
> >> link);
> >> + block_start = drm_buddy_block_offset(block);
> >> + block_end = block_start + drm_buddy_block_size(mm, block);
> >> +
> >> if (WARN_ON(!drm_buddy_block_is_allocated(block)))
> >> return -EINVAL;
> >> @@ -894,6 +900,20 @@ int drm_buddy_block_trim(struct drm_buddy *mm,
> >> if (new_size == drm_buddy_block_size(mm, block))
> >> return 0;
> >> + new_start = block_start;
> >> + if (start) {
> >> + new_start = *start;
> >> +
> >> + if (new_start < block_start)
> >> + return -EINVAL;
> >> +
> >> + if (!IS_ALIGNED(new_start, mm->chunk_size))
> >> + return -EINVAL;
> >> +
> >> + if (range_overflows(new_start, new_size, block_end))
> >> + return -EINVAL;
> >> + }
> >> +
> >> list_del(&block->link);
> >> mark_free(mm, block);
> >> mm->avail += drm_buddy_block_size(mm, block);
> >> @@ -904,7 +924,6 @@ int drm_buddy_block_trim(struct drm_buddy *mm,
> >> parent = block->parent;
> >> block->parent = NULL;
> >> - new_start = drm_buddy_block_offset(block);
> >> list_add(&block->tmp_link, &dfs);
> >> err = __alloc_range(mm, &dfs, new_start, new_size,
> blocks, NULL);
> >> if (err) {
> >> @@ -1066,7 +1085,8 @@ int drm_buddy_alloc_blocks(struct
> drm_buddy *mm,
> >> } while (1);
> >> /* Trim the allocated block to the required size */
> >> - if (original_size != size) {
> >> + if (!(flags & DRM_BUDDY_TRIM_DISABLE) &&
> >> + original_size != size) {
> >> struct list_head *trim_list;
> >> LIST_HEAD(temp);
> >> u64 trim_size;
> >> @@ -1083,6 +1103,7 @@ int drm_buddy_alloc_blocks(struct
> drm_buddy *mm,
> >> }
> >> drm_buddy_block_trim(mm,
> >> + NULL,
> >> trim_size,
> >> trim_list);
> >> diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> >> b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> >> index fe3779fdba2c..423b261ea743 100644
> >> --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> >> +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> >> @@ -150,7 +150,7 @@ static int xe_ttm_vram_mgr_new(struct
> >> ttm_resource_manager *man,
> >> } while (remaining_size);
> >> if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
> >> - if (!drm_buddy_block_trim(mm, vres->base.size,
> &vres->blocks))
> >> + if (!drm_buddy_block_trim(mm, NULL, vres->base.size,
> >> &vres->blocks))
> >> size = vres->base.size;
> >> }
> >> diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
> >> index 2a74fa9d0ce5..9689a7c5dd36 100644
> >> --- a/include/drm/drm_buddy.h
> >> +++ b/include/drm/drm_buddy.h
> >> @@ -27,6 +27,7 @@
> >> #define DRM_BUDDY_CONTIGUOUS_ALLOCATION BIT(2)
> >> #define DRM_BUDDY_CLEAR_ALLOCATION BIT(3)
> >> #define DRM_BUDDY_CLEARED BIT(4)
> >> +#define DRM_BUDDY_TRIM_DISABLE BIT(5)
> >> struct drm_buddy_block {
> >> #define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
> >> @@ -155,6 +156,7 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm,
> >> unsigned long flags);
> >> int drm_buddy_block_trim(struct drm_buddy *mm,
> >> + u64 *start,
> >> u64 new_size,
> >> struct list_head *blocks);
> >>
> >> base-commit: b27d70e1042bf6a31ba7e5acf58b61c9cd28f95b
> >
>
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