We want to restrict waitboosting to known process contexts, where we can
track which clients are receiving waitboosts and prevent excessive power
wasting. For fence_wait() we do not have any client tracking and so that
leaves it open to abuse.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_request.c | 7 ++++---
drivers/gpu/drm/i915/i915_gem_request.h | 1 +
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 987a43f1aac8..ba745f0740d0 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -74,7 +74,7 @@ static signed long i915_fence_wait(struct fence *fence,
ret = __i915_wait_request(to_i915_request(fence),
interruptible, timeout,
- NULL);
+ NO_WAITBOOST);
if (ret == -ETIME)
return 0;
@@ -634,7 +634,7 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
* forcing the clocks too high for the whole system, we only allow
* each client to waitboost once in a busy period.
*/
- if (INTEL_INFO(req->i915)->gen >= 6)
+ if (!IS_ERR(rps) && INTEL_INFO(req->i915)->gen >= 6)
gen6_rps_boost(req->i915, rps, req->emitted_jiffies);
/* Optimistic spin for the next ~jiffie before touching IRQs */
@@ -707,7 +707,8 @@ complete:
*timeout = 0;
}
- if (rps && req->fence.seqno == req->engine->last_submitted_seqno) {
+ if (!IS_ERR_OR_NULL(rps) &&
+ req->fence.seqno == req->engine->last_submitted_seqno) {
/* The GPU is now idle and this client has stalled.
* Since no other client has submitted a request in the
* meantime, assume that this client is the only one
diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h
index b1bc96c9e31d..a3cac13ab9af 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.h
+++ b/drivers/gpu/drm/i915/i915_gem_request.h
@@ -205,6 +205,7 @@ void __i915_add_request(struct drm_i915_gem_request *req,
__i915_add_request(req, NULL, false)
struct intel_rps_client;
+#define NO_WAITBOOST ERR_PTR(-1)
int __i915_wait_request(struct drm_i915_gem_request *req,
bool interruptible,
--
2.8.1
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