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drm/i915: Disable waitboosting for fence_wait() 

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.

v2: Hide the IS_ERR_OR_NULL testing for special clients

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469002875-2335-5-git-send-email-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2016-07-20 09:21:12 +01:00
parent 04769652c8
commit 42df271439
2 changed files with 7 additions and 3 deletions
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7
drivers/gpu/drm/i915/i915_gem_request.c
View File

@ -70,7 +70,7 @@ static signed long i915_fence_wait(struct fence *fence,
ret = __i915_wait_request(to_request(fence),
interruptible, timeout,
NULL);
NO_WAITBOOST);
if (ret == -ETIME)
return 0;
@ -642,7 +642,7 @@ 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_GEN(req->i915) >= 6)
if (IS_RPS_CLIENT(rps) && INTEL_GEN(req->i915) >= 6)
gen6_rps_boost(req->i915, rps, req->emitted_jiffies);
/* Optimistic spin for the next ~jiffie before touching IRQs */
@ -713,7 +713,8 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
*timeout = 0;
}
if (rps && req->fence.seqno == req->engine->last_submitted_seqno) {
if (IS_RPS_USER(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

3
drivers/gpu/drm/i915/i915_gem_request.h
View File

@ -206,6 +206,9 @@ 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)
#define IS_RPS_CLIENT(p) (!IS_ERR(p))
#define IS_RPS_USER(p) (!IS_ERR_OR_NULL(p))
int __i915_wait_request(struct drm_i915_gem_request *req,
bool interruptible,