From c32164b1f6a2eafa0658bbf33d02b2da41c72e5a Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 15 Jan 2018 09:06:42 +0000 Subject: [PATCH] drm/i915: Only defer freeing of fence callback when also using the timer Without an accompanying timer (for internal fences), we can free the fence callback immediately as we do not need to employ the RCU barrier to serialise with the timer. By avoiding the RCU delay, we can avoid the extra mempressure under heavy inter-engine request utilisation. Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Joonas Lahtinen Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20180115090643.26696-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_sw_fence.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c index 3669f5eeb91ef..13021326d7775 100644 --- a/drivers/gpu/drm/i915/i915_sw_fence.c +++ b/drivers/gpu/drm/i915/i915_sw_fence.c @@ -398,7 +398,12 @@ static void dma_i915_sw_fence_wake(struct dma_fence *dma, if (fence) i915_sw_fence_complete(fence); - irq_work_queue(&cb->work); + if (cb->dma) { + irq_work_queue(&cb->work); + return; + } + + kfree(cb); } static void irq_i915_sw_fence_work(struct irq_work *wrk) @@ -437,10 +442,12 @@ int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence, i915_sw_fence_await(fence); cb->dma = NULL; - timer_setup(&cb->timer, timer_i915_sw_fence_wake, TIMER_IRQSAFE); - init_irq_work(&cb->work, irq_i915_sw_fence_work); if (timeout) { cb->dma = dma_fence_get(dma); + init_irq_work(&cb->work, irq_i915_sw_fence_work); + + timer_setup(&cb->timer, + timer_i915_sw_fence_wake, TIMER_IRQSAFE); mod_timer(&cb->timer, round_jiffies_up(jiffies + timeout)); } -- 2.30.2