linux-kernel - [PATCH 5.19 023/365] drm/i915/gt: Ignore TLB invalidations on idle engines

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Date:   Tue, 23 Aug 2022 09:58:44 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chris Wilson <chris.p.wilson@...el.com>,
        Fei Yang <fei.yang@...el.com>,
        Andi Shyti <andi.shyti@...ux.intel.com>,
        Thomas Hellström 
        <thomas.hellstrom@...ux.intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...el.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>
Subject: [PATCH 5.19 023/365] drm/i915/gt: Ignore TLB invalidations on idle engines

From: Chris Wilson <chris.p.wilson@...el.com>

commit db100e28fdf026a1fc10657c5170bb1e65663805 upstream.

Check if the device is powered down prior to any engine activity,
as, on such cases, all the TLBs were already invalidated, so an
explicit TLB invalidation is not needed, thus reducing the
performance regression impact due to it.

This becomes more significant with GuC, as it can only do so when
the connection to the GuC is awake.

Cc: stable@...r.kernel.org
Fixes: 7938d61591d3 ("drm/i915: Flush TLBs before releasing backing store")
Signed-off-by: Chris Wilson <chris.p.wilson@...el.com>
Cc: Fei Yang <fei.yang@...el.com>
Reviewed-by: Andi Shyti <andi.shyti@...ux.intel.com>
Acked-by: Thomas Hellström <thomas.hellstrom@...ux.intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@...el.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>
Signed-off-by: Andi Shyti <andi.shyti@...ux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/278a57a672edac75683f0818b292e95da583a5fe.1658924372.git.mchehab@kernel.org
(cherry picked from commit 4bedceaed1ae1172cfe72d3ff752b3a1d32fe4d9)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/gpu/drm/i915/gem/i915_gem_pages.c |   10 ++++++----
 drivers/gpu/drm/i915/gt/intel_gt.c        |   17 ++++++++++-------
 drivers/gpu/drm/i915/gt/intel_gt_pm.h     |    3 +++
 3 files changed, 19 insertions(+), 11 deletions(-)

--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -6,14 +6,15 @@
 
 #include <drm/drm_cache.h>
 
+#include "gt/intel_gt.h"
+#include "gt/intel_gt_pm.h"
+
 #include "i915_drv.h"
 #include "i915_gem_object.h"
 #include "i915_scatterlist.h"
 #include "i915_gem_lmem.h"
 #include "i915_gem_mman.h"
 
-#include "gt/intel_gt.h"
-
 void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 				 struct sg_table *pages,
 				 unsigned int sg_page_sizes)
@@ -217,10 +218,11 @@ __i915_gem_object_unset_pages(struct drm
 
 	if (test_and_clear_bit(I915_BO_WAS_BOUND_BIT, &obj->flags)) {
 		struct drm_i915_private *i915 = to_i915(obj->base.dev);
+		struct intel_gt *gt = to_gt(i915);
 		intel_wakeref_t wakeref;
 
-		with_intel_runtime_pm_if_active(&i915->runtime_pm, wakeref)
-			intel_gt_invalidate_tlbs(to_gt(i915));
+		with_intel_gt_pm_if_awake(gt, wakeref)
+			intel_gt_invalidate_tlbs(gt);
 	}
 
 	return pages;
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -11,6 +11,7 @@
 
 #include "i915_drv.h"
 #include "intel_context.h"
+#include "intel_engine_pm.h"
 #include "intel_engine_regs.h"
 #include "intel_gt.h"
 #include "intel_gt_buffer_pool.h"
@@ -1181,6 +1182,7 @@ void intel_gt_invalidate_tlbs(struct int
 	struct drm_i915_private *i915 = gt->i915;
 	struct intel_uncore *uncore = gt->uncore;
 	struct intel_engine_cs *engine;
+	intel_engine_mask_t awake, tmp;
 	enum intel_engine_id id;
 	const i915_reg_t *regs;
 	unsigned int num = 0;
@@ -1204,26 +1206,31 @@ void intel_gt_invalidate_tlbs(struct int
 
 	GEM_TRACE("\n");
 
-	assert_rpm_wakelock_held(&i915->runtime_pm);
-
 	mutex_lock(&gt->tlb_invalidate_lock);
 	intel_uncore_forcewake_get(uncore, FORCEWAKE_ALL);
 
 	spin_lock_irq(&uncore->lock); /* serialise invalidate with GT reset */
 
+	awake = 0;
 	for_each_engine(engine, gt, id) {
 		struct reg_and_bit rb;
 
+		if (!intel_engine_pm_is_awake(engine))
+			continue;
+
 		rb = get_reg_and_bit(engine, regs == gen8_regs, regs, num);
 		if (!i915_mmio_reg_offset(rb.reg))
 			continue;
 
 		intel_uncore_write_fw(uncore, rb.reg, rb.bit);
+		awake |= engine->mask;
 	}
 
 	spin_unlock_irq(&uncore->lock);
 
-	for_each_engine(engine, gt, id) {
+	for_each_engine_masked(engine, gt, awake, tmp) {
+		struct reg_and_bit rb;
+
 		/*
 		 * HW architecture suggest typical invalidation time at 40us,
 		 * with pessimistic cases up to 100us and a recommendation to
@@ -1231,12 +1238,8 @@ void intel_gt_invalidate_tlbs(struct int
 		 */
 		const unsigned int timeout_us = 100;
 		const unsigned int timeout_ms = 4;
-		struct reg_and_bit rb;
 
 		rb = get_reg_and_bit(engine, regs == gen8_regs, regs, num);
-		if (!i915_mmio_reg_offset(rb.reg))
-			continue;
-
 		if (__intel_wait_for_register_fw(uncore,
 						 rb.reg, rb.bit, 0,
 						 timeout_us, timeout_ms,
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
@@ -55,6 +55,9 @@ static inline void intel_gt_pm_might_put
 	for (tmp = 1, intel_gt_pm_get(gt); tmp; \
 	     intel_gt_pm_put(gt), tmp = 0)
 
+#define with_intel_gt_pm_if_awake(gt, wf) \
+	for (wf = intel_gt_pm_get_if_awake(gt); wf; intel_gt_pm_put_async(gt), wf = 0)
+
 static inline int intel_gt_pm_wait_for_idle(struct intel_gt *gt)
 {
 	return intel_wakeref_wait_for_idle(&gt->wakeref);