sna: Only shrink a partial buffer if it is no longer used.

The condition on being able to shrink a buffer is more severe than just
whether we are reading from the buffer, but also we cannot swap the
handles if the existing handle remains exposed via a proxy.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 13 insertions, 8 deletions

diff --git a/src/sna/kgem.c b/src/sna/kgem.c
index a9ccb41e..c7ce7779 100644
--- a/src/sna/kgem.c
+++ b/src/sna/kgem.c
@@ -112,7 +112,6 @@ struct kgem_partial_bo {
 	uint32_t used;
 	uint32_t need_io : 1;
 	uint32_t write : 1;
-	uint32_t shrink : 1;
 	uint32_t mmapped : 1;
 };
 
@@ -294,6 +293,8 @@ static void kgem_bo_retire(struct kgem *kgem, struct kgem_bo *bo)
 		kgem_retire(kgem);
 
 	if (bo->exec == NULL) {
+		DBG(("%s: retiring bo handle=%d (needed flush? %d)\n",
+		     __FUNCTION__, bo->handle, bo->needs_flush));
 		bo->rq = NULL;
 		list_del(&bo->request);
 		bo->needs_flush = bo->flush;
@@ -1079,8 +1080,9 @@ static void kgem_commit(struct kgem *kgem)
 	struct kgem_bo *bo, *next;
 
 	list_for_each_entry_safe(bo, next, &rq->buffers, request) {
-		DBG(("%s: release handle=%d (proxy? %d)\n",
-		     __FUNCTION__, bo->handle, bo->proxy != NULL));
+		DBG(("%s: release handle=%d (proxy? %d), dirty? %d flush? %d\n",
+		     __FUNCTION__, bo->handle, bo->proxy != NULL,
+		     bo->dirty, bo->needs_flush));
 
 		assert(!bo->purged);
 		assert(bo->proxy || bo->rq == rq);
@@ -1193,7 +1195,7 @@ static void kgem_finish_partials(struct kgem *kgem)
 		}
 
 		assert(bo->base.rq == kgem->next_request);
-		if (bo->shrink && bo->used < bo->base.size / 2) {
+		if (bo->base.refcnt == 1 && bo->used < bo->base.size / 2) {
 			struct kgem_bo *shrink;
 
 			shrink = search_linear_cache(kgem,
@@ -1227,9 +1229,12 @@ static void kgem_finish_partials(struct kgem *kgem)
 				list_replace(&bo->base.request,
 					     &shrink->request);
 				list_init(&bo->base.request);
+				shrink->needs_flush = bo->base.dirty;
 
 				bo->base.exec = NULL;
 				bo->base.rq = NULL;
+				bo->base.dirty = false;
+				bo->base.needs_flush = false;
 				bo->used = 0;
 
 				bubble_sort_partial(kgem, bo);
@@ -2497,8 +2502,11 @@ uint32_t kgem_add_reloc(struct kgem *kgem,
 		kgem->reloc[index].target_handle = bo->handle;
 		kgem->reloc[index].presumed_offset = bo->presumed_offset;
 
-		if (read_write_domain & 0x7fff)
+		if (read_write_domain & 0x7fff) {
+			DBG(("%s: marking handle=%d dirty\n",
+			     __FUNCTION__, bo->handle));
 			bo->needs_flush = bo->dirty = true;
+		}
 
 		delta += bo->presumed_offset;
 	} else {
@@ -2898,13 +2906,11 @@ struct kgem_bo *kgem_create_buffer(struct kgem *kgem,
 					DBG(("%s: reusing write buffer for read of %d bytes? used=%d, total=%d\n",
 					     __FUNCTION__, size, bo->used, bo->base.size));
 					offset = 0;
-					bo->shrink = 0;
 					goto done;
 				} else if (bo->used + size <= bo->base.size) {
 					DBG(("%s: reusing unfinished write buffer for read of %d bytes? used=%d, total=%d\n",
 					     __FUNCTION__, size, bo->used, bo->base.size));
 					offset = bo->used;
-					bo->shrink = 0;
 					goto done;
 				}
 			}
@@ -3046,7 +3052,6 @@ struct kgem_bo *kgem_create_buffer(struct kgem *kgem,
 
 	bo->used = size;
 	bo->write = write;
-	bo->shrink = bo->need_io;
 	offset = 0;
 
 	list_add(&bo->base.list, &kgem->partial);