drm/i915: Call cond_resched() before repeating i915_gem_evict_something()

Insert a breakpoint, a chance to escape back to the scheduler and run
something else for a bit, if we find that the GGTT is full and needs to
be idled in order to make some room. In practice, this should only be an
issue in stress tests as the wait itself will normally give the chance
for the scheduler to intervene and make progress.

References: https://bugs.freedesktop.org/show_bug.cgi?id=103438
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171024205053.7845-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index 8daa8a78cdc06897ab3b75d1b582dd886231c17c..a6b769994d8df6cbdc834a608162fe320c7dd830 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -216,6 +216,7 @@ i915_gem_evict_something(struct i915_address_space *vm,
                if (ret)
                        return ret;
 
+               cond_resched();
                goto search_again;
        }