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* [PATCH 1/3] drm/vmwgfx: Don't use memory accounting for kernel-side fence objects
@ 2014-12-02 11:59 Thomas Hellstrom
  2014-12-02 11:59 ` [PATCH 2/3] drm/vmwgfx: Fix fence event code Thomas Hellstrom
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Thomas Hellstrom @ 2014-12-02 11:59 UTC (permalink / raw)
  To: dri-devel; +Cc: Thomas Hellstrom, stable

Kernel side fence objects are used when unbinding resources and may thus be
created as part of a memory reclaim operation. This might trigger recursive
memory reclaims and result in the kernel running out of stack space.

So a simple way out is to avoid accounting of these fence objects.
In principle this is OK since while user-space can trigger the creation of
such objects, it can't really hold on to them. However, their lifetime is
quite long, so some form of accounting should perhaps be implemented in the
future.

Fixes kernel crashes when running, for example viewperf11 ensight-04 test 3
with low system memory settings.

Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 22 ++--------------------
 1 file changed, 2 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
index 197164f..6773938 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
@@ -545,35 +545,19 @@ void vmw_fence_obj_flush(struct vmw_fence_obj *fence)
 
 static void vmw_fence_destroy(struct vmw_fence_obj *fence)
 {
-	struct vmw_fence_manager *fman = fman_from_fence(fence);
-
 	fence_free(&fence->base);
-
-	/*
-	 * Free kernel space accounting.
-	 */
-	ttm_mem_global_free(vmw_mem_glob(fman->dev_priv),
-			    fman->fence_size);
 }
 
 int vmw_fence_create(struct vmw_fence_manager *fman,
 		     uint32_t seqno,
 		     struct vmw_fence_obj **p_fence)
 {
-	struct ttm_mem_global *mem_glob = vmw_mem_glob(fman->dev_priv);
 	struct vmw_fence_obj *fence;
 	int ret;
 
-	ret = ttm_mem_global_alloc(mem_glob, fman->fence_size,
-				   false, false);
-	if (unlikely(ret != 0))
-		return ret;
-
 	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
-	if (unlikely(fence == NULL)) {
-		ret = -ENOMEM;
-		goto out_no_object;
-	}
+	if (unlikely(fence == NULL))
+		return -ENOMEM;
 
 	ret = vmw_fence_obj_init(fman, fence, seqno,
 				 vmw_fence_destroy);
@@ -585,8 +569,6 @@ int vmw_fence_create(struct vmw_fence_manager *fman,
 
 out_err_init:
 	kfree(fence);
-out_no_object:
-	ttm_mem_global_free(mem_glob, fman->fence_size);
 	return ret;
 }
 
-- 
2.1.0

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^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2014-12-03  6:31 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-12-02 11:59 [PATCH 1/3] drm/vmwgfx: Don't use memory accounting for kernel-side fence objects Thomas Hellstrom
2014-12-02 11:59 ` [PATCH 2/3] drm/vmwgfx: Fix fence event code Thomas Hellstrom
2014-12-02 11:59 ` [PATCH 3/3] drm/vmwgfx: (Re)bind shaders to MOBs with the correct offset Thomas Hellstrom
2014-12-03  1:06 ` [PATCH 1/3] drm/vmwgfx: Don't use memory accounting for kernel-side fence objects Dave Airlie
2014-12-03  6:30   ` Thomas Hellstrom

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