Avoid the two calls to ktime_get_raw_ns() (at best it reads the TSC) as
we only need to compute the elapsed time for a timed wait.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_gem.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d595d72e53b1..ca327c0e73f1 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1222,7 +1222,6 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
int state = interruptible ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;
struct intel_breadcrumb wait;
unsigned long timeout_remain;
- s64 before, now;
int ret = 0;
might_sleep();
@@ -1241,13 +1240,12 @@ int __i915_wait_request(struct drm_i915_gem_request
*req,
if (*timeout == 0)
return -ETIME;
+ /* Record current time in case interrupted, or wedged */
timeout_remain = nsecs_to_jiffies_timeout(*timeout);
+ *timeout += ktime_get_raw_ns();
}
- /* Record current time in case interrupted by signal, or wedged */
trace_i915_gem_request_wait_begin(req);
- before = ktime_get_raw_ns();
-
if (INTEL_INFO(req->i915)->gen >= 6)
gen6_rps_boost(req->i915, rps, req->emitted_jiffies);
@@ -1324,13 +1322,12 @@ wakeup: set_task_state(wait.task, state);
out:
intel_engine_remove_breadcrumb(req->ring, &wait);
__set_task_state(wait.task, TASK_RUNNING);
- now = ktime_get_raw_ns();
trace_i915_gem_request_wait_end(req);
if (timeout) {
- s64 tres = *timeout - (now - before);
-
- *timeout = tres < 0 ? 0 : tres;
+ *timeout -= ktime_get_raw_ns();
+ if (*timeout < 0)
+ *timeout = 0;
/*
* Apparently ktime isn't accurate enough and occasionally has a
--
2.6.3
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