drm/ttm: Use init_on_free to delay release TTM BOs

Delay release TTM BOs when the kernel default setting is init_on_free.
This offloads the overhead of clearing the system memory to the work
item and potentially a different CPU. This could be very beneficial when
the application does a lot of malloc/free style allocations of system
memory.

Signed-off-by: Rajneesh Bhardwaj <[email protected]>
Reviewed-by: Christian König <[email protected]>.
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Christian König <[email protected]>

Author: rajbhar

drivers/gpu/drm/ttm/ttm_bo.c

@@ -345,6 +345,7 @@ static void ttm_bo_release(struct kref *kref)
 
 		if (!dma_resv_test_signaled(bo->base.resv,
 					    DMA_RESV_USAGE_BOOKKEEP) ||
+		    (want_init_on_free() && (bo->ttm != NULL)) ||
 		    !dma_resv_trylock(bo->base.resv)) {
 			/* The BO is not idle, resurrect it for delayed destroy */
 			ttm_bo_flush_all_fences(bo);