| Message ID | 20190808132243.23632-1-christian.koenig@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dma-buf: make dma_fence structure a bit smaller v2 | expand |
Daniel any more comments on this one? If not I'm going to push it. Christian. Am 08.08.19 um 15:22 schrieb Christian König: > We clear the callback list on kref_put so that by the time we > release the fence it is unused. No one should be adding to the cb_list > that they don't themselves hold a reference for. > > This small change is actually making the structure 16% smaller. > > v2: add the comment to the code as well. > > Signed-off-by: Christian König <christian.koenig@amd.com> > Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> > --- > include/linux/dma-fence.h | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h > index 05d29dbc7e62..bea1d05cf51e 100644 > --- a/include/linux/dma-fence.h > +++ b/include/linux/dma-fence.h > @@ -65,8 +65,14 @@ struct dma_fence_cb; > struct dma_fence { > struct kref refcount; > const struct dma_fence_ops *ops; > - struct rcu_head rcu; > - struct list_head cb_list; > + /* We clear the callback list on kref_put so that by the time we > + * release the fence it is unused. No one should be adding to the cb_list > + * that they don't themselves hold a reference for. > + */ > + union { > + struct rcu_head rcu; > + struct list_head cb_list; > + }; > spinlock_t *lock; > u64 context; > u64 seqno;
On Thu, Aug 08, 2019 at 04:41:39PM +0200, Christian König wrote: > Daniel any more comments on this one? It's not kerneldoc, but then all the dma-* docs need some serious love anyway, so all good with me. -Daniel > > If not I'm going to push it. > > Christian. > > Am 08.08.19 um 15:22 schrieb Christian König: > > We clear the callback list on kref_put so that by the time we > > release the fence it is unused. No one should be adding to the cb_list > > that they don't themselves hold a reference for. > > > > This small change is actually making the structure 16% smaller. > > > > v2: add the comment to the code as well. > > > > Signed-off-by: Christian König <christian.koenig@amd.com> > > Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> > > --- > > include/linux/dma-fence.h | 10 ++++++++-- > > 1 file changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h > > index 05d29dbc7e62..bea1d05cf51e 100644 > > --- a/include/linux/dma-fence.h > > +++ b/include/linux/dma-fence.h > > @@ -65,8 +65,14 @@ struct dma_fence_cb; > > struct dma_fence { > > struct kref refcount; > > const struct dma_fence_ops *ops; > > - struct rcu_head rcu; > > - struct list_head cb_list; > > + /* We clear the callback list on kref_put so that by the time we > > + * release the fence it is unused. No one should be adding to the cb_list > > + * that they don't themselves hold a reference for. > > + */ > > + union { > > + struct rcu_head rcu; > > + struct list_head cb_list; > > + }; > > spinlock_t *lock; > > u64 context; > > u64 seqno; >
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 05d29dbc7e62..bea1d05cf51e 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -65,8 +65,14 @@ struct dma_fence_cb; struct dma_fence { struct kref refcount; const struct dma_fence_ops *ops; - struct rcu_head rcu; - struct list_head cb_list; + /* We clear the callback list on kref_put so that by the time we + * release the fence it is unused. No one should be adding to the cb_list + * that they don't themselves hold a reference for. + */ + union { + struct rcu_head rcu; + struct list_head cb_list; + }; spinlock_t *lock; u64 context; u64 seqno;