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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2019-08-17 16:30:22 +0100 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2019-08-17 18:46:33 +0100 |
| commit | f2cb60e9a3881e679465f84140754bc9d29956ea (patch) | |
| tree | 62b3bc44752ee688d651354aedf6742ffb8b51e0 /drivers/dma-buf | |
| parent | 0fc89b6802ba1fcc561b0c906e0cefd384e3b2e5 (diff) | |
| download | lwn-f2cb60e9a3881e679465f84140754bc9d29956ea.tar.gz lwn-f2cb60e9a3881e679465f84140754bc9d29956ea.zip | |
dma-fence: Store the timestamp in the same union as the cb_list
The timestamp and the cb_list are mutually exclusive, the cb_list can
only be added to prior to being signaled (and once signaled we drain),
while the timestamp is only valid upon being signaled. Both the
timestamp and the cb_list are only valid while the fence is alive, and
as soon as no references are held can be replaced by the rcu_head.
By reusing the union for the timestamp, we squeeze the base dma_fence
struct to 64 bytes on x86-64.
v2: Sort the union chronologically
Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christian König <christian.koenig@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>.
Link: https://patchwork.freedesktop.org/patch/msgid/20190817153022.5749-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/dma-buf')
| -rw-r--r-- | drivers/dma-buf/dma-fence.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 8a6d0250285d..2c136aee3e79 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -129,6 +129,7 @@ EXPORT_SYMBOL(dma_fence_context_alloc); int dma_fence_signal_locked(struct dma_fence *fence) { struct dma_fence_cb *cur, *tmp; + struct list_head cb_list; lockdep_assert_held(fence->lock); @@ -136,16 +137,16 @@ int dma_fence_signal_locked(struct dma_fence *fence) &fence->flags))) return -EINVAL; + /* Stash the cb_list before replacing it with the timestamp */ + list_replace(&fence->cb_list, &cb_list); + fence->timestamp = ktime_get(); set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags); trace_dma_fence_signaled(fence); - if (!list_empty(&fence->cb_list)) { - list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) { - INIT_LIST_HEAD(&cur->node); - cur->func(fence, cur); - } - INIT_LIST_HEAD(&fence->cb_list); + list_for_each_entry_safe(cur, tmp, &cb_list, node) { + INIT_LIST_HEAD(&cur->node); + cur->func(fence, cur); } return 0; @@ -231,7 +232,8 @@ void dma_fence_release(struct kref *kref) trace_dma_fence_destroy(fence); - if (WARN(!list_empty(&fence->cb_list), + if (WARN(!list_empty(&fence->cb_list) && + !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags), "Fence %s:%s:%llx:%llx released with pending signals!\n", fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), |