[PATCH v2 00/17] Dynamic drm_pagemaps and Initial multi-device SVM

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

This series aims at providing an initial implementation of multi-device
SVM, where communitcation with peers (migration and direct execution out
of peer memory) uses some form of fast interconnect. In this series
we're using pcie p2p.

In a multi-device environment, the struct pages for device-private memory
(the dev_pagemap) may take up a significant amount of system memory. We
therefore want to provide a means of revoking / removing the dev_pagemaps
not in use. In particular when a device is offlined, we want to block
migrating *to* the device memory and migrate data already existing in the
devices memory to system. The dev_pagemap then becomes unused and can be
removed.

Removing and setting up a large dev_pagemap is also quite time-consuming,
so removal of unused dev_pagemaps only happens on system memory pressure
using a shrinker.

Patch 1 is a small debug printout fix.
Patches 2-7 deals with dynamic drm_pagemaps as described above.
Patches 8-12 adds infrastructure to handle remote drm_pagemaps with
fast interconnects.
Patch 13 extends the xe madvise() UAPI to handle remote drm_pagemaps.
Patch 14 adds a pcie-p2p dma SVM interconnect to the xe driver.
Patch 15 adds some SVM-related debug printouts for xe.
Patch 16 adds direct interconnect migration.
Patch 17 adds some documentation.

What's still missing is implementation of migration policies.
That will be implemented in follow-up series. 

v2:
- Address review comments from Matt Brost.
- Fix compilation issues reported by automated testing
- Add patch 1, 17.
- What's now patch 16 was extended to support p2p migration.

Thomas Hellström (17):
  drm/xe/svm: Fix a debug printout
  drm/pagemap, drm/xe: Add refcounting to struct drm_pagemap
  drm/pagemap: Add a refcounted drm_pagemap backpointer to struct
    drm_pagemap_zdd
  drm/pagemap, drm/xe: Manage drm_pagemap provider lifetimes
  drm/pagemap: Add a drm_pagemap cache and shrinker
  drm/xe: Use the drm_pagemap cache and shrinker
  drm/pagemap: Remove the drm_pagemap_create() interface
  drm/pagemap_util: Add a utility to assign an owner to a set of
    interconnected gpus
  drm/xe: Use the drm_pagemap_util helper to get a svm pagemap owner
  drm/xe: Pass a drm_pagemap pointer around with the memory advise
    attributes
  drm/xe: Use the vma attibute drm_pagemap to select where to migrate
  drm/xe: Simplify madvise_preferred_mem_loc()
  drm/xe/uapi: Extend the madvise functionality to support foreign
    pagemap placement for svm
  drm/xe: Support pcie p2p dma as a fast interconnect
  drm/xe/vm: Add a couple of VM debug printouts
  drm/pagemap, drm/xe: Support migration over interconnect
  drm/xe/svm: Document how xe keeps drm_pagemap references

 drivers/gpu/drm/Makefile             |   3 +-
 drivers/gpu/drm/drm_gpusvm.c         |   4 +-
 drivers/gpu/drm/drm_pagemap.c        | 354 ++++++++++++---
 drivers/gpu/drm/drm_pagemap_util.c   | 568 ++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_device.c       |  20 +
 drivers/gpu/drm/xe/xe_device.h       |   2 +
 drivers/gpu/drm/xe/xe_device_types.h |   5 +
 drivers/gpu/drm/xe/xe_svm.c          | 631 ++++++++++++++++++++++-----
 drivers/gpu/drm/xe/xe_svm.h          |  82 +++-
 drivers/gpu/drm/xe/xe_tile.c         |  34 +-
 drivers/gpu/drm/xe/xe_tile.h         |  21 +
 drivers/gpu/drm/xe/xe_userptr.c      |   2 +-
 drivers/gpu/drm/xe/xe_vm.c           |  65 ++-
 drivers/gpu/drm/xe/xe_vm.h           |   1 +
 drivers/gpu/drm/xe/xe_vm_madvise.c   | 106 ++++-
 drivers/gpu/drm/xe/xe_vm_types.h     |  21 +-
 drivers/gpu/drm/xe/xe_vram_types.h   |  15 +-
 include/drm/drm_pagemap.h            |  91 +++-
 include/drm/drm_pagemap_util.h       |  92 ++++
 include/uapi/drm/xe_drm.h            |  18 +-
 20 files changed, 1898 insertions(+), 237 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_pagemap_util.c
 create mode 100644 include/drm/drm_pagemap_util.h

-- 
2.51.1