[Intel-gfx] [PATCH 0/3] Introduce a new create ioctl for user specified

[sourab.gupta at intel.com]

From: Sourab Gupta <sourab.gupta at intel.com>

This patch series introduces a new gem create ioctl for user specified
placement.

Despite being a unified memory architecture (UMA) some bits of memory
are more equal than others. In particular we have the thorny issue of
stolen memory, memory stolen from the system by the BIOS and reserved
for igfx use. Stolen memory is required for some functions of the GPU
and display engine, but in general it goes wasted. Whilst we cannot
return it back to the system, we need to find some other method for
utilising it. As we do not support direct access to the physical address
in the stolen region, it behaves like a different class of memory,
closer in kin to local GPU memory. This strongly suggests that we need a
placement model like TTM if we are to fully utilize these discrete
chunks of differing memory.
    
This new create ioctl therefore exists to allow the user to create these
second class buffer objects from stolen memory. At the moment direct
access by the CPU through mmaps and pread/pwrite are verboten on the
objects, and so the user must be aware of the limitations of the objects
created. Yet, those limitations rarely reduce the desired functionality
in many use cases and so the user should be able to easily fill the
stolen memory and so help to reduce overall memory pressure.
    
The most obvious use case for stolen memory is for the creation of objects
for the display engine which already have very similar restrictions on
access. However, we want a reasonably general ioctl in order to cater
for diverse scenarios beyond the author's imagination.

Chris Wilson (3):
  drm/i915: Clearing buffer objects via blitter engine
  drm/i915: Introduce a new create ioctl for user specified placement
  drm/i915: Add support for stealing purgable stolen pages

 drivers/gpu/drm/i915/Makefile          |   1 +
 drivers/gpu/drm/i915/i915_dma.c        |  11 +-
 drivers/gpu/drm/i915/i915_drv.h        |  18 ++-
 drivers/gpu/drm/i915/i915_gem.c        | 208 ++++++++++++++++++++++++++++++---
 drivers/gpu/drm/i915/i915_gem_exec.c   | 120 +++++++++++++++++++
 drivers/gpu/drm/i915/i915_gem_stolen.c | 121 +++++++++++++++++--
 drivers/gpu/drm/i915/i915_gem_tiling.c | 106 +++++++++--------
 include/uapi/drm/i915_drm.h            | 107 +++++++++++++++++
 8 files changed, 607 insertions(+), 85 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/i915_gem_exec.c

-- 
1.8.5.1