drm/xe/madvise: Implement purgeable buffer object support

Browse source

This allows userspace applications to provide memory usage hints to
the kernel for better memory management under pressure:

Add the core implementation for purgeable buffer objects, enabling
memory reclamation of user-designated DONTNEED buffers during eviction.

This patch implements the purge operation and state machine transitions:

Purgeable States (from xe_madv_purgeable_state):
 - WILLNEED (0): BO should be retained, actively used
 - DONTNEED (1): BO eligible for purging, not currently needed
 - PURGED (2): BO backing store reclaimed, permanently invalid

Design Rationale:
  - Async TLB invalidation via trigger_rebind (no blocking
    xe_vm_invalidate_vma)
  - i915 compatibility: retained field, "once purged always purged"
    semantics
  - Shared BO protection prevents multi-process memory corruption
  - Scratch PTE reuse avoids new infrastructure, safe for fault mode

Note: The madvise_purgeable() function is implemented but not hooked
into the IOCTL handler (madvise_funcs[] entry is NULL) to maintain
bisectability. The feature will be enabled in the final patch when all
supporting infrastructure (shrinker, per-VMA tracking) is complete.

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Arvind Yadav <arvind.yadav@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260326130843.3545241-4-arvind.yadav@intel.com

...

This commit is contained in:

Arvind Yadav 2026-03-26 18:38:29 +05:30 • committed by Matthew Brost

parent b67427f939

commit ad9843aac9

6 changed files with 298 additions and 22 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

107

drivers/gpu/drm/xe/xe_bo.c

View file

2

drivers/gpu/drm/xe/xe_bo.h

View file

15

drivers/gpu/drm/xe/xe_pagefault.c

View file

40

drivers/gpu/drm/xe/xe_pt.c

View file

20

drivers/gpu/drm/xe/xe_vm.c

View file

136

drivers/gpu/drm/xe/xe_vm_madvise.c

View file