From 2947e4080f22b63b46dbbb95e838396b58a9914b Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Sun, 18 Dec 2016 15:37:23 +0000
Subject: [PATCH] drm/i915/execlists: Request the kernel context be pinned high

PIN_HIGH is an expensive operation (in comparison to allocating from the
hole stack) unsuitable for frequent use (such as switching between
contexts). However, the kernel context should be pinned just once for
the lifetime of the driver, and here it is appropriate to keep it out of
the mappable range (in order to maximise mappable space for users).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161218153724.8439-6-chris@chris-wilson.co.uk
---
 drivers/gpu/drm/i915/intel_lrc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 599afedc44941..1f8f35a94157e 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -767,6 +767,7 @@ static int execlists_context_pin(struct intel_engine_cs *engine,
 				 struct i915_gem_context *ctx)
 {
 	struct intel_context *ce = &ctx->engine[engine->id];
+	unsigned int flags;
 	void *vaddr;
 	int ret;
 
@@ -781,8 +782,11 @@ static int execlists_context_pin(struct intel_engine_cs *engine,
 			goto err;
 	}
 
-	ret = i915_vma_pin(ce->state, 0, GEN8_LR_CONTEXT_ALIGN,
-			   PIN_OFFSET_BIAS | GUC_WOPCM_TOP | PIN_GLOBAL);
+	flags = PIN_OFFSET_BIAS | GUC_WOPCM_TOP | PIN_GLOBAL;
+	if (ctx == ctx->i915->kernel_context)
+		flags |= PIN_HIGH;
+
+	ret = i915_vma_pin(ce->state, 0, GEN8_LR_CONTEXT_ALIGN, flags);
 	if (ret)
 		goto err;