From 42df271439f77a06f4f0034d819fbb6f9c36f834 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 20 Jul 2016 09:21:12 +0100 Subject: [PATCH] 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 Reviewed-by: Mika Kuoppala Link: http://patchwork.freedesktop.org/patch/msgid/1469002875-2335-5-git-send-email-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem_request.c | 7 ++++--- drivers/gpu/drm/i915/i915_gem_request.h | 3 +++ 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c index 6528536878f2..f483e605a715 100644 --- a/drivers/gpu/drm/i915/i915_gem_request.c +++ b/drivers/gpu/drm/i915/i915_gem_request.c @@ -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 @@ complete: *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 diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h index 6f2c820785f3..0a01d01cac51 100644 --- a/drivers/gpu/drm/i915/i915_gem_request.h +++ b/drivers/gpu/drm/i915/i915_gem_request.h @@ -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, -- 2.20.1