+

Pasting original message at bottom.


On 30/11/2018 08:42, Christoph Hellwig wrote:

On Thu, Nov 29, 2018 at 10:54:56PM -0500, Qian Cai wrote:

quoted

 /* allow architectures to override this if absolutely required */
 #ifndef PREALLOC_DMA_DEBUG_ENTRIES
+/* amount of DMA mappings on this driver is huge. */
+#ifdef	HNS_ENET
+#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 17)
+#else
 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 #endif
+#endif

How would this be defined in a header that leaks into this file?

I think we need to turn PREALLOC_DMA_DEBUG_ENTRIES into a user
selectable config options, as I really don't want to collect hacks like
this.
_______________________________________________
iommu mailing list
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

The amount of DMA mappings from Hisilicon HNS ethernet devices is huge,
so it could trigger "DMA-API: debugging out of memory - disabling".

hnae_get_handle [1]
   hnae_init_queue
     hnae_init_ring
       hnae_alloc_buffers [2]
         debug_dma_map_page
           dma_entry_alloc

[1] for (i = 0; i < handle->q_num; i++)
[2] for (i = 0; i < ring->desc_num; i++)

On this Huawei TaiShan 2280 aarch64 server, it has reached the limit
already,

4 (ports) x 16 (handles) x 1024 (rings) = 65536

Signed-off-by: Qian Cai <cai-0UDz38MK/Mo@public.gmane.org>
---
  kernel/dma/debug.c | 5 +++++
  1 file changed, 5 insertions(+)

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 231ca4628062..ae91689cc9ad 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c

@@ -43,8 +43,13 @@

  /* allow architectures to override this if absolutely required */
  #ifndef PREALLOC_DMA_DEBUG_ENTRIES
+/* amount of DMA mappings on this driver is huge. */
+#ifdef	HNS_ENET
+#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 17)
+#else
  #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
  #endif
+#endif

  enum {
  	dma_debug_single,