linux-kernel - [PATCH v2 04/21] drm/i915/gt: Only invalidate TLBs exposed to user manipulation

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Message-Id: <c0ab69f803cfe439f9218d0c0a930eae563dee83.1657800199.git.mchehab@kernel.org>
Date:   Thu, 14 Jul 2022 13:06:09 +0100
From:   Mauro Carvalho Chehab <mchehab@...nel.org>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Chris Wilson <chris.p.wilson@...el.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Dave Airlie <airlied@...hat.com>,
        David Airlie <airlied@...ux.ie>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
        dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Fei Yang <fei.yang@...el.com>,
        Andi Shyti <andi.shyti@...ux.intel.com>,
        Thomas Hellström 
        <thomas.hellstrom@...ux.intel.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
Subject: [PATCH v2 04/21] drm/i915/gt: Only invalidate TLBs exposed to user manipulation

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

Don't flush TLBs when the buffer is only used in the GGTT under full
control of the kernel, as there's no risk of concurrent access
and stale access from prefetch.

We only need to invalidate the TLB if they are accessible by the user.
That helps to reduce the performance regression introduced by TLB
invalidate logic.

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>
Cc: Andi Shyti <andi.shyti@...ux.intel.com>
Acked-by: Thomas Hellström <thomas.hellstrom@...ux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>
---

To avoid mailbombing on a large number of people, only mailing lists were C/C on the cover.
See [PATCH v2 00/21] at: https://lore.kernel.org/all/cover.1657800199.git.mchehab@kernel.org/

 drivers/gpu/drm/i915/i915_vma.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index ef3b04c7e153..646f419b2035 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -538,7 +538,8 @@ int i915_vma_bind(struct i915_vma *vma,
 				   bind_flags);
 	}
 
-	set_bit(I915_BO_WAS_BOUND_BIT, &vma->obj->flags);
+	if (bind_flags & I915_VMA_LOCAL_BIND)
+		set_bit(I915_BO_WAS_BOUND_BIT, &vma->obj->flags);
 
 	atomic_or(bind_flags, &vma->flags);
 	return 0;
-- 
2.36.1