From e54ca97747770a6b08413ae9afa776c0d8c4f6c3 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri, 17 Feb 2017 15:13:04 +0000
Subject: [PATCH] drm/i915: Remove completed fences after a wait
If we wait upon the full (i.e. all shared fences, or upon an exclusive
fence) reservation object successfully, we know that all fences beneath
it have been signaled, so long as no new fences were added whilst we
slept. If the reservation_object remains the same, as detected by its
seqcount, we can then reap all the fences upon completion.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170217151304.16665-6-chris@chris-wilson.co.uk
---
drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 5f7b8c88eb7e..d93032875f28 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -427,7 +427,9 @@ i915_gem_object_wait_reservation(struct reservation_object *resv,
long timeout,
struct intel_rps_client *rps)
{
+ unsigned int seq = __read_seqcount_begin(&resv->seq);
struct dma_fence *excl;
+ bool prune_fences = false;
if (flags & I915_WAIT_ALL) {
struct dma_fence **shared;
@@ -452,15 +454,26 @@ i915_gem_object_wait_reservation(struct reservation_object *resv,
for (; i < count; i++)
dma_fence_put(shared[i]);
kfree(shared);
+
+ prune_fences = count && timeout >= 0;
} else {
excl = reservation_object_get_excl_rcu(resv);
}
- if (excl && timeout >= 0)
+ if (excl && timeout >= 0) {
timeout = i915_gem_object_wait_fence(excl, flags, timeout, rps);
+ prune_fences = timeout >= 0;
+ }
dma_fence_put(excl);
+ if (prune_fences && !__read_seqcount_retry(&resv->seq, seq)) {
+ reservation_object_lock(resv, NULL);
+ if (!__read_seqcount_retry(&resv->seq, seq))
+ reservation_object_add_excl_fence(resv, NULL);
+ reservation_object_unlock(resv);
+ }
+
return timeout;
}
--
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