| Message ID | 20220126152155.3070602-3-matthew.auld@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Initial support for small BAR recovery | expand |
On 26/01/2022 15:21, Matthew Auld wrote: > From: Arunpravin <Arunpravin.PaneerSelvam@amd.com> > > Implemented a function which walk through the order list, > compares the offset and returns the maximum offset block, > this method is unpredictable in obtaining the high range > address blocks which depends on allocation and deallocation. > for instance, if driver requests address at a low specific > range, allocator traverses from the root block and splits > the larger blocks until it reaches the specific block and > in the process of splitting, lower orders in the freelist > are occupied with low range address blocks and for the > subsequent TOPDOWN memory request we may return the low > range blocks.To overcome this issue, we may go with the > below approach. > > The other approach, sorting each order list entries in > ascending order and compares the last entry of each > order list in the freelist and return the max block. > This creates sorting overhead on every drm_buddy_free() > request and split up of larger blocks for a single page > request. ooc, why did you choose to implement this as an alloc flag? Seems to me like it would be a good candidate for a new memory region. That way allocation algorithms wouldn't need exta logic and ttm can already handle migrations. > > v2: > - Fix alignment issues(Matthew Auld) > - Remove unnecessary list_empty check(Matthew Auld) > - merged the below patch to see the feature in action > - add top-down alloc support to i915 driver > > Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@amd.com> > --- > drivers/gpu/drm/drm_buddy.c | 36 ++++++++++++++++--- > drivers/gpu/drm/i915/i915_ttm_buddy_manager.c | 3 ++ > include/drm/drm_buddy.h | 1 + > 3 files changed, 35 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c > index 954e31962c74..6aa5c1ce25bf 100644 > --- a/drivers/gpu/drm/drm_buddy.c > +++ b/drivers/gpu/drm/drm_buddy.c > @@ -371,6 +371,26 @@ alloc_range_bias(struct drm_buddy *mm, > return ERR_PTR(err); > } > > +static struct drm_buddy_block * > +get_maxblock(struct list_head *head) > +{ > + struct drm_buddy_block *max_block = NULL, *node; > + > + max_block = list_first_entry_or_null(head, > + struct drm_buddy_block, > + link); > + if (!max_block) > + return NULL; > + > + list_for_each_entry(node, head, link) { > + if (drm_buddy_block_offset(node) > > + drm_buddy_block_offset(max_block)) > + max_block = node; > + } > + > + return max_block; > +} > + > static struct drm_buddy_block * > alloc_from_freelist(struct drm_buddy *mm, > unsigned int order, > @@ -381,11 +401,17 @@ alloc_from_freelist(struct drm_buddy *mm, > int err; > > for (i = order; i <= mm->max_order; ++i) { > - 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->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 (!block) > diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c > index 1411f4cf1f21..3662434b64bb 100644 > --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c > +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c > @@ -53,6 +53,9 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man, > INIT_LIST_HEAD(&bman_res->blocks); > bman_res->mm = mm; > > + if (place->flags & TTM_PL_FLAG_TOPDOWN) > + bman_res->flags |= DRM_BUDDY_TOPDOWN_ALLOCATION; > + > if (place->fpfn || lpfn != man->size) > bman_res->flags |= DRM_BUDDY_RANGE_ALLOCATION; > > diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h > index 865664b90a8a..424fc443115e 100644 > --- a/include/drm/drm_buddy.h > +++ b/include/drm/drm_buddy.h > @@ -28,6 +28,7 @@ > }) > > #define DRM_BUDDY_RANGE_ALLOCATION (1 << 0) > +#define DRM_BUDDY_TOPDOWN_ALLOCATION (1 << 1) > > struct drm_buddy_block { > #define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c index 954e31962c74..6aa5c1ce25bf 100644 --- a/drivers/gpu/drm/drm_buddy.c +++ b/drivers/gpu/drm/drm_buddy.c @@ -371,6 +371,26 @@ alloc_range_bias(struct drm_buddy *mm, return ERR_PTR(err); } +static struct drm_buddy_block * +get_maxblock(struct list_head *head) +{ + struct drm_buddy_block *max_block = NULL, *node; + + max_block = list_first_entry_or_null(head, + struct drm_buddy_block, + link); + if (!max_block) + return NULL; + + list_for_each_entry(node, head, link) { + if (drm_buddy_block_offset(node) > + drm_buddy_block_offset(max_block)) + max_block = node; + } + + return max_block; +} + static struct drm_buddy_block * alloc_from_freelist(struct drm_buddy *mm, unsigned int order, @@ -381,11 +401,17 @@ alloc_from_freelist(struct drm_buddy *mm, int err; for (i = order; i <= mm->max_order; ++i) { - 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->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 (!block) diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c index 1411f4cf1f21..3662434b64bb 100644 --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c @@ -53,6 +53,9 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man, INIT_LIST_HEAD(&bman_res->blocks); bman_res->mm = mm; + if (place->flags & TTM_PL_FLAG_TOPDOWN) + bman_res->flags |= DRM_BUDDY_TOPDOWN_ALLOCATION; + if (place->fpfn || lpfn != man->size) bman_res->flags |= DRM_BUDDY_RANGE_ALLOCATION; diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h index 865664b90a8a..424fc443115e 100644 --- a/include/drm/drm_buddy.h +++ b/include/drm/drm_buddy.h @@ -28,6 +28,7 @@ }) #define DRM_BUDDY_RANGE_ALLOCATION (1 << 0) +#define DRM_BUDDY_TOPDOWN_ALLOCATION (1 << 1) struct drm_buddy_block { #define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)