[PATCH 00/13] pwrite/pread rework

Daniel Vetter
2011-11-06T19:13:47Z

Hi all,

I've finally managed to clean up my pwrite/pread rework. Major changes since the
first submission:
- fixed a bunch of bugs, some of them discovered by the intel-gpu-tools gem test
suite
- extracted the clflush helper into common drm code as suggested by Chris
Wilson.
- extended the prefault helpers in pagemap.h instead of rolling our own. Also
add a patch to not prefault for writes (which change the userspace memory)
before we're committed to the write. Both address issues raised by Keith
Packard.

Why this is cool stuff:
- fixes the spurious -EFAULTS when handing in a pointer to a gem gtt mappings.
See https://bugs.freedesktop.org/show_bug.cgi?id=38115
- Kills a bunch of code by dropping the practically useless ranged cpu read
domain tracking and integrating the slow paths into the fast paths.
- Fixes pwrite/pread to use snooped cpu access on llc machines, hereby decently
speeding up microbenchmarks.
- Paves the way for further clever tricks to reduce pressure on the mappable gtt
area.

Reviews and comments highly welcome.

Yours, Daniel

Daniel Vetter (13):
drm/i915: fall through pwrite_gtt_slow to the shmem slow path
drm/i915: rewrite shmem_pwrite_slow to use copy_from_user
drm/i915: rewrite shmem_pread_slow to use copy_to_user
drm/i915: merge shmem_pwrite slow&fast-path
drm/i915: merge shmem_pread slow&fast-path
drm: add helper to clflush a virtual address range
drm/i915: move clflushing into shmem_pread
drm/i915: kill ranged cpu read domain support
drm/i915: don't use gtt_pwrite on LLC cached objects
drm/i915: don't call shmem_read_mapping unnecessarily
mm: extend prefault helpers to fault in more than PAGE_SIZE
drm/i915: drop gtt slowpath
drm/i915: don't clobber userspace memory before commiting to the
pread

drivers/gpu/drm/drm_cache.c | 23 ++
drivers/gpu/drm/i915/i915_drv.h | 7 -
drivers/gpu/drm/i915/i915_gem.c | 824 +++++++++++----------------------------
include/drm/drmP.h | 1 +
include/linux/pagemap.h | 28 +-
5 files changed, 273 insertions(+), 610 deletions(-)

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