drm/i915: Avoid evicting user fault mappable vma for pread/pwrite

Both pread/pwrite GTT paths provide a fast fallback in case we cannot
map the whole object at a time. Currently, we use the fallback for very
large objects and for active objects that would require remapping, but
we can also add active fault mappable objects to the list that we want
to avoid evicting. The rationale is that such fault mappable objects are
in active use and to evict requires tearing down the CPU PTE and forcing
a page fault on the next access; more costly, and intefers with other
processes, than our per-page GTT fallback.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171009084401.29090-6-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
This commit is contained in:
Chris Wilson 2017-10-09 09:44:00 +01:00
parent 3c755c5b56
commit a3259ca9f8

View file

@ -1055,7 +1055,9 @@ i915_gem_gtt_pread(struct drm_i915_gem_object *obj,
intel_runtime_pm_get(i915);
vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,
PIN_MAPPABLE | PIN_NONBLOCK);
PIN_MAPPABLE |
PIN_NONFAULT |
PIN_NONBLOCK);
if (!IS_ERR(vma)) {
node.start = i915_ggtt_offset(vma);
node.allocated = false;
@ -1239,7 +1241,9 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj,
intel_runtime_pm_get(i915);
vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,
PIN_MAPPABLE | PIN_NONBLOCK);
PIN_MAPPABLE |
PIN_NONFAULT |
PIN_NONBLOCK);
if (!IS_ERR(vma)) {
node.start = i915_ggtt_offset(vma);
node.allocated = false;