[Intel-gfx] [PATCH 0/3] Reduce the time for which 'struct_mutex' is held

[Daniel Vetter]

On Mon, Aug 24, 2015 at 05:28:13PM +0530, ankitprasad.r.sharma at intel.com wrote:
> From: Ankitprasad Sharma <ankitprasad.r.sharma at intel.com>
> 
> We are trying to reduce the time for which the global 'struct_mutex'
> is locked. Execbuffer ioctl is one place where it is generally held
> for the longest time. And sometimes because of this occasional 
> glitches/flickers are observed in 60 fps playback (due to miss of
> V-blank intervals) as page flip calls gets blocked/delayed because the
> 'struct_mutex' is already locked.
> 
> For this, we have exposed two new flags in GEM_CREATE ioctl, to pre-populate
> the object with system memory pages and also do an immediate clflush for the
> new pages.
> 
> The third patch too tries to reduce the 'struct_mutex' lock time by
> moving only those objects to CPU domain in put_pages(), that can either
> be used in the future or had a CPU mapping.
> 
> This series is based on an earlier series of Stolen Memory patches,
> extending the GEM_CREATE ioctl further
> http://lists.freedesktop.org/archives/intel-gfx/2015-July/072199.html
> 
> Ankitprasad Sharma (2):
>   drm/i915: Support for pre-populating the object with system pages
>   drm/i915: Support for the clflush of pre-populated pages
> 
> Chris Wilson (1):
>   drm/i915: Only move to the CPU write domain if keeping the GTT pages

Usual broken maintainer record: Needs igt and userspace. And for the case
of the put_pages optimization probably really nasty igt.
-Daniel

> 
>  drivers/gpu/drm/i915/i915_dma.c |   2 +-
>  drivers/gpu/drm/i915/i915_drv.h |   5 ++
>  drivers/gpu/drm/i915/i915_gem.c | 116 ++++++++++++++++++++++++++++++----------
>  include/uapi/drm/i915_drm.h     |  12 ++---
>  4 files changed, 101 insertions(+), 34 deletions(-)
> 
> -- 
> 1.9.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch