From 13f8458f9a4522bcb7d1856dd8b329ff5d90f887 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 27 Jun 2017 18:37:31 +0100
Subject: [PATCH] drm/i915: Drop flushing of the object free list/worker from i915_gem_suspend
Git-commit: 13f8458f9a4522bcb7d1856dd8b329ff5d90f887
Patch-mainline: v4.14-rc1
References: FATE#322643 bsc#1055900
i915_gem_suspend() is called from all of our finalization paths
(suspend, hibernate, unload). i915_gem_drain_freed_objects() adds an
arbitrary delay as it uses an rcu_barrier() to ensure that there are no
more freed objects in flight, and this delay causes a large amount of
variability in suspend timings. For S3 suspend, we do not need to free
pages as doing so does not impact at all upon the system in its
suspended state, unlike S4 hibernation where we do want the hibernation
image to be as small as possible. Therefore we can forgo waiting inside
i915_gem_suspend(), so long as we ensure that we do cleanup before
unload (see i915_gem_load_cleanup()) and prefer to reap our objects
prior to hibernation (see i915_gem_freeze()).
Removing the rcu_barrier() from i915_gem_suspend() improves S3 latency
by about 30ms on Skylake (ymmv).
Reported-by: David Weinehall <david.weinehall@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Weinehall <david.weinehall@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170627173731.11566-1-chris@chris-wilson.co.uk
Tested-by: David Weinehall <david.weinehall@linux.intel.com>
Reviewed-by: David Weinehall <david.weinehall@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/i915_gem.c | 2 --
1 file changed, 2 deletions(-)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4598,8 +4598,6 @@ int i915_gem_suspend(struct drm_i915_pri
while (flush_delayed_work(&dev_priv->gt.idle_work))
;
- i915_gem_drain_freed_objects(dev_priv);
-
/* Assert that we sucessfully flushed all the work and
* reset the GPU back to its idle, low power state.
*/