drm/i915; Preallocate the lazy request
It is possible for us to be forced to perform an allocation for the lazy
request whilst running the shrinker. This allocation may fail, leaving
us unable to reclaim any memory leading to premature OOM. A neat
solution to the problem is to preallocate the request at the same time
as acquiring the seqno for the ring transaction. This means that we can
report ENOMEM prior to touching the rings.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 858e788..399e159 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2041,8 +2041,8 @@
if (ret)
return ret;
- request = kmalloc(sizeof(*request), GFP_KERNEL);
- if (request == NULL)
+ request = ring->preallocated_lazy_request;
+ if (WARN_ON(request == NULL))
return -ENOMEM;
/* Record the position of the start of the request so that
@@ -2053,10 +2053,8 @@
request_ring_position = intel_ring_get_tail(ring);
ret = ring->add_request(ring);
- if (ret) {
- kfree(request);
+ if (ret)
return ret;
- }
request->seqno = intel_ring_get_seqno(ring);
request->ring = ring;
@@ -2095,6 +2093,7 @@
trace_i915_gem_request_add(ring, request->seqno);
ring->outstanding_lazy_seqno = 0;
+ ring->preallocated_lazy_request = NULL;
if (!dev_priv->ums.mm_suspended) {
i915_queue_hangcheck(ring->dev);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index a83ff18..284afaf 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1498,6 +1498,16 @@
if (ring->outstanding_lazy_seqno)
return 0;
+ if (ring->preallocated_lazy_request == NULL) {
+ struct drm_i915_gem_request *request;
+
+ request = kmalloc(sizeof(*request), GFP_KERNEL);
+ if (request == NULL)
+ return -ENOMEM;
+
+ ring->preallocated_lazy_request = request;
+ }
+
return i915_gem_get_seqno(ring->dev, &ring->outstanding_lazy_seqno);
}
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index c6aa2b3..ad2dd65 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -140,6 +140,7 @@
/**
* Do we have some not yet emitted requests outstanding?
*/
+ struct drm_i915_gem_request *preallocated_lazy_request;
u32 outstanding_lazy_seqno;
bool gpu_caches_dirty;
bool fbc_dirty;