[PATCH v6 0/8] drm/xe: Prioritize BO eviction based on VM exec queue priority

This series ties a BO's TTM LRU priority (i.e. how likely it is to be
picked for eviction/shrinking under memory pressure) to how userspace
is actually using the VM and BOs it belongs to, instead of treating
every BO the same.

The reasoning behind the heuristic:

 - Kernel BOs, and any BO not private to a single VM (no vm_id, e.g.
   shared/exported buffers), are given the highest priority so they
   are the least likely to be evicted -- these are foundational or
   shared resources.
 - BOs private to a VM are then prioritized based on the highest
   priority band userspace has assigned to any exec queue attached to
   that VM: a VM with a HIGH priority exec queue keeps its BOs at the
   highest priority (matching kernel/shared BOs), a VM with only
   NORMAL priority queues (or none yet) gets the next priority band
   down, and a VM with only LOW priority queues gets the band below
   that.
 - The lowest priority band is reserved exclusively for BOs (private
   or shared) that have no VMA mappings left anywhere. This lets
   userspace use an unbind as a signal of "drop this from my working
   set, but keep the backing store around in case I need it again" --
   the BO is retained, just made a preferred candidate for
   eviction/shrinking until it is rebound.

v3:
 - Rebase for CI
v4:
 - Fix issues raised by Sashiko
v5:
 - Fix more issues raised by Sashiko
v6:
 - Move DONTNEED to lowest priorty + continue purge scan across entire band
 - Create sub-bands favoring WB over WC/UC for shrinking

Matt

Matthew Brost (8):
  drm/xe: Track exec queue priority band counts for user VMs
  drm/xe: Re-prioritize VM's private BOs when adding an exec queue
  drm/xe: Lower BO TTM priority to lowest when fully unmapped from VM
  drm/xe: Fix up BO TTM priority for late VM binds
  drm/xe: Adjust BO TTM priority on DONTNEED/WILLNEED madvise
    transitions
  drm/xe: Limit purge shrinker pass to the lowest TTM priority band
  drm/ttm: Increase maximum TTM priorities to 8
  drm/xe: Favor evicting WB-cached BOs within each priority band

 drivers/gpu/drm/xe/xe_bo.c        |  35 ++++-
 drivers/gpu/drm/xe/xe_bo.h        |  37 ++++-
 drivers/gpu/drm/xe/xe_bo_types.h  |  17 ++-
 drivers/gpu/drm/xe/xe_dma_buf.c   |   2 +-
 drivers/gpu/drm/xe/xe_pagefault.c |   2 +
 drivers/gpu/drm/xe/xe_shrinker.c  |  15 ++
 drivers/gpu/drm/xe/xe_vm.c        | 246 ++++++++++++++++++++++++++++--
 drivers/gpu/drm/xe/xe_vm.h        |   4 +
 drivers/gpu/drm/xe/xe_vm_types.h  |  13 ++
 include/drm/ttm/ttm_resource.h    |   2 +-
 10 files changed, 350 insertions(+), 23 deletions(-)

-- 
2.34.1