On Mon, Jan 9, 2023 at 5:13 AM Christian König
<ckoenig.leichtzumerken@xxxxxxxxx> wrote:
>
> Am 07.01.23 um 16:15 schrieb Arunpravin Paneer Selvam:
> > As we are observing low numbers in viewperf graphics benchmark, we
> > are strictly not allowing the top down flag enabled allocations
> > to steal the memory space from cpu visible region.
> >
> > The approach is, we are sorting each order list entries in
> > ascending order and compare the last entry of each order
> > list in the freelist and return the max block.
> >
> > This patch improves the viewperf 3D benchmark scores.
> >
> > Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@xxxxxxx>
>
> Acked-by: Christian König <christian.koenig@xxxxxxx>, but somebody with more insight of the drm buddy allocator should take a closer look at this.
I'm not a drm_buddy expert either, but this patch fixes a lot of
issues on both dGPUs and APUs:
Acked-by: Alex Deucher <alexander.deucher@xxxxxxx>
>
>
> > ---
> > drivers/gpu/drm/drm_buddy.c | 81 ++++++++++++++++++++++++-------------
> > 1 file changed, 54 insertions(+), 27 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
> > index 11bb59399471..50916b2f2fc5 100644
> > --- a/drivers/gpu/drm/drm_buddy.c
> > +++ b/drivers/gpu/drm/drm_buddy.c
> > @@ -38,6 +38,25 @@ static void drm_block_free(struct drm_buddy *mm,
> > kmem_cache_free(slab_blocks, block);
> > }
> >
> > +static void list_insert_sorted(struct drm_buddy *mm,
> > + struct drm_buddy_block *block)
> > +{
> > + struct drm_buddy_block *node;
> > + struct list_head *head;
> > +
> > + head = &mm->free_list[drm_buddy_block_order(block)];
> > + if (list_empty(head)) {
> > + list_add(&block->link, head);
> > + return;
> > + }
> > +
> > + list_for_each_entry(node, head, link)
> > + if (drm_buddy_block_offset(block) < drm_buddy_block_offset(node))
> > + break;
> > +
> > + __list_add(&block->link, node->link.prev, &node->link);
> > +}
> > +
> > static void mark_allocated(struct drm_buddy_block *block)
> > {
> > block->header &= ~DRM_BUDDY_HEADER_STATE;
> > @@ -52,8 +71,7 @@ static void mark_free(struct drm_buddy *mm,
> > block->header &= ~DRM_BUDDY_HEADER_STATE;
> > block->header |= DRM_BUDDY_FREE;
> >
> > - list_add(&block->link,
> > - &mm->free_list[drm_buddy_block_order(block)]);
> > + list_insert_sorted(mm, block);
> > }
> >
> > static void mark_split(struct drm_buddy_block *block)
> > @@ -387,20 +405,26 @@ alloc_range_bias(struct drm_buddy *mm,
> > }
> >
> > static struct drm_buddy_block *
> > -get_maxblock(struct list_head *head)
> > +get_maxblock(struct drm_buddy *mm, unsigned int order)
> > {
> > struct drm_buddy_block *max_block = NULL, *node;
> > + unsigned int i;
> >
> > - max_block = list_first_entry_or_null(head,
> > - struct drm_buddy_block,
> > - link);
> > - if (!max_block)
> > - return NULL;
> > + for (i = order; i <= mm->max_order; ++i) {
> > + if (!list_empty(&mm->free_list[i])) {
> > + node = list_last_entry(&mm->free_list[i],
> > + struct drm_buddy_block,
> > + link);
> > + if (!max_block) {
> > + max_block = node;
> > + continue;
> > + }
> >
> > - list_for_each_entry(node, head, link) {
> > - if (drm_buddy_block_offset(node) >
> > - drm_buddy_block_offset(max_block))
> > - max_block = node;
> > + if (drm_buddy_block_offset(node) >
> > + drm_buddy_block_offset(max_block)) {
> > + max_block = node;
> > + }
> > + }
> > }
> >
> > return max_block;
> > @@ -412,20 +436,23 @@ alloc_from_freelist(struct drm_buddy *mm,
> > unsigned long flags)
> > {
> > struct drm_buddy_block *block = NULL;
> > - unsigned int i;
> > + unsigned int tmp;
> > int err;
> >
> > - for (i = order; i <= mm->max_order; ++i) {
> > - if (flags & DRM_BUDDY_TOPDOWN_ALLOCATION) {
> > - block = get_maxblock(&mm->free_list[i]);
> > - if (block)
> > - break;
> > - } else {
> > - block = list_first_entry_or_null(&mm->free_list[i],
> > - struct drm_buddy_block,
> > - link);
> > - if (block)
> > - break;
> > + if (flags & DRM_BUDDY_TOPDOWN_ALLOCATION) {
> > + block = get_maxblock(mm, order);
> > + if (block)
> > + /* Store the obtained block order */
> > + tmp = drm_buddy_block_order(block);
> > + } else {
> > + for (tmp = order; tmp <= mm->max_order; ++tmp) {
> > + if (!list_empty(&mm->free_list[tmp])) {
> > + block = list_last_entry(&mm->free_list[tmp],
> > + struct drm_buddy_block,
> > + link);
> > + if (block)
> > + break;
> > + }
> > }
> > }
> >
> > @@ -434,18 +461,18 @@ alloc_from_freelist(struct drm_buddy *mm,
> >
> > BUG_ON(!drm_buddy_block_is_free(block));
> >
> > - while (i != order) {
> > + while (tmp != order) {
> > err = split_block(mm, block);
> > if (unlikely(err))
> > goto err_undo;
> >
> > block = block->right;
> > - i--;
> > + tmp--;
> > }
> > return block;
> >
> > err_undo:
> > - if (i != order)
> > + if (tmp != order)
> > __drm_buddy_free(mm, block);
> > return ERR_PTR(err);
> > }
>
