[PATCH 0/2] gpu/buddy: Per-order free and used block scoreboards

[Francois Dugast <francois.dugast@intel.com>]

drm_buddy_print() currently reports per-order free block counts by
walking all rbtrees, which is O(n) in the total number of free blocks
and holds the allocator lock for the duration. On large VRAM heaps with
many small fragments this becomes expensive.

This series replaces the rbtree walk with two lightweight scoreboard
arrays — free_scoreboard and used_scoreboard — indexed by order and
maintained incrementally at the points where block state transitions
occur. The print functions become simple array lookups, and drivers
reading debugfs (/sys/kernel/debug/dri/0/tile0/vram_mm) now get both
free and used counts per order at O(1) cost.

Francois Dugast (2):
  gpu/buddy: Track per-order free blocks with a scoreboard
  gpu/buddy: Track per-order used blocks with a scoreboard

 drivers/gpu/buddy.c         | 60 +++++++++++++++++++++++++------------
 drivers/gpu/drm/drm_buddy.c | 20 ++++---------
 include/linux/gpu_buddy.h   | 15 ++++++++++
 3 files changed, 61 insertions(+), 34 deletions(-)

-- 
2.43.0