From 1ab22356b37ab08a391d6f007fda4c822bef9fb5 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 7 Nov 2017 22:06:56 +0000 Subject: [PATCH] drm/i915: Prune the reservation shared fence array The shared fence array is not autopruning and may continue to grow as an object is shared between new timelines. Take the opportunity when we think the object is idle (we have to confirm that any external fence is also signaled) to decouple all the fences. We apply a similar trick after waiting on an object, see commit e54ca9774777 ("drm/i915: Remove completed fences after a wait") v2: No longer need to handle the batch pool as a special case. v3: Need to trylock from within i915_vma_retire as this may be called form the shrinker - and we may later try to allocate underneath the reservation lock, so a deadlock is possible. References: https://bugs.freedesktop.org/show_bug.cgi?id=102936 Fixes: d07f0e59b2c7 ("drm/i915: Move GEM activity tracking into a common struct reservation_object") Fixes: 80b204bce8f2 ("drm/i915: Enable multiple timelines") Signed-off-by: Chris Wilson Cc: Joonas Lahtinen Link: https://patchwork.freedesktop.org/patch/msgid/20171107220656.5020-1-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen --- drivers/gpu/drm/i915/i915_vma.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 7cdf34800549..b7ac84db1d2e 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -54,6 +54,13 @@ i915_vma_retire(struct i915_gem_active *active, if (--obj->active_count) return; + /* Prune the shared fence arrays iff completely idle (inc. external) */ + if (reservation_object_trylock(obj->resv)) { + if (reservation_object_test_signaled_rcu(obj->resv, true)) + reservation_object_add_excl_fence(obj->resv, NULL); + reservation_object_unlock(obj->resv); + } + /* Bump our place on the bound list to keep it roughly in LRU order * so that we don't steal from recently used but inactive objects * (unless we are forced to ofc!)