On Sun, Jan 31, 2010 at 04:58:42PM -0500, Michael Breuer wrote:

On 1/31/2010 1:50 PM, Michael Breuer wrote:

quoted

On 1/30/2010 11:55 PM, Michael Breuer wrote:

quoted

On 01/30/2010 07:34 PM, Jarek Poplawski wrote:

quoted

Could you try the patch below to show maybe some other users of
dma-debug entries?

Jarek P.
---

With the default # entries & dma_debug_driver=sky2:

6:00 is eth0 & 4:00 is eth1.

Jan 30 23:53:14 mail kernel: DMA-API: 0000:06:00.0: entries: 31961
...

I put a printk as a third else case in sky2_tx_unmap. Looks like
the issue is that a large number (perhaps all) calls to
sky2_tx_unmap have re->flags set to neither TX_MAP_SINGLE or
TX_MAP_PAGE. Thus the elements are never being unmapped.

I suspect that the system collapses when using DMAR sooner than if
not using DMAR. Probably some hardware limitation on the number of
mapped elements that is less than the software limitation. I don't
see at present how a ring element can ever get to this code
without re->flags being set to one or the other.

Put some more debugging code in... re->flags is always NULL upon
entry to sky2_tx_unmap.

Yes, good point! Could you try if this patch can fix it. (not compiled)

Thanks,
Jarek P.
---

 drivers/net/sky2.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index d760650..3437917 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c

@@ -1025,9 +1025,10 @@ static void sky2_prefetch_init(struct sky2_hw *hw, u32 qaddr,
 static inline struct sky2_tx_le *get_tx_le(struct sky2_port *sky2, u16 *slot)
 {
 	struct sky2_tx_le *le = sky2->tx_le + *slot;
-	struct tx_ring_info *re = sky2->tx_ring + *slot;
+	struct tx_ring_info *re;
 
 	*slot = RING_NEXT(*slot, sky2->tx_ring_size);
+	re = sky2->tx_ring + *slot;
 	re->flags = 0;
 	re->skb = NULL;
 	le->ctrl = 0;

@@ -1036,13 +1037,16 @@ static inline struct sky2_tx_le *get_tx_le(struct sky2_port *sky2, u16 *slot)
 
 static void tx_init(struct sky2_port *sky2)
 {
-	struct sky2_tx_le *le;
+	struct sky2_tx_le *le = sky2->tx_le;
+	struct tx_ring_info *re = sky2->tx_ring;
 
 	sky2->tx_prod = sky2->tx_cons = 0;
 	sky2->tx_tcpsum = 0;
 	sky2->tx_last_mss = 0;
 
-	le = get_tx_le(sky2, &sky2->tx_prod);
+	re->flags = 0;
+	re->skb = NULL;
+	le->ctrl = 0;
 	le->addr = 0;
 	le->opcode = OP_ADDR64 | HW_OWNER;
 	sky2->tx_last_upper = 0;