On 03/15/2017 04:18 AM, Jan Blunck wrote:
On Tue, Mar 14, 2017 at 5:38 PM, Charles (Chas) Williams
<ciwil...@brocade.com> wrote:


On 03/14/2017 12:11 PM, Jan Blunck wrote:

On Mon, Mar 13, 2017 at 11:41 PM, Charles (Chas) Williams
<ciwil...@brocade.com> wrote:

If the user reconfigures the queues size, then the previosly allocated
memzone may potentially be too small.  Instead, always free the old
memzone and allocate a new one.

Fixes: dfaff37fc46d ("vmxnet3: import new vmxnet3 poll mode driver
implementation")

Signed-off-by: Chas Williams <ciwil...@brocade.com>
---
 drivers/net/vmxnet3/vmxnet3_rxtx.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_rxtx.c
b/drivers/net/vmxnet3/vmxnet3_rxtx.c
index 6649c3f..104e040 100644
--- a/drivers/net/vmxnet3/vmxnet3_rxtx.c
+++ b/drivers/net/vmxnet3/vmxnet3_rxtx.c
@@ -893,8 +893,8 @@ vmxnet3_recv_pkts(void *rx_queue, struct rte_mbuf
**rx_pkts, uint16_t nb_pkts)

 /*
  * Create memzone for device rings. malloc can't be used as the physical
address is
- * needed. If the memzone is already created, then this function returns
a ptr
- * to the old one.
+ * needed. If the memzone already exists, we free it since it may have
been created
+ * with a different size.
  */
 static const struct rte_memzone *
 ring_dma_zone_reserve(struct rte_eth_dev *dev, const char *ring_name,
@@ -909,7 +909,7 @@ ring_dma_zone_reserve(struct rte_eth_dev *dev, const
char *ring_name,

        mz = rte_memzone_lookup(z_name);
        if (mz)
-               return mz;
+               rte_memzone_free(mz);

        return rte_memzone_reserve_aligned(z_name, ring_size,
                                           socket_id, 0,
VMXNET3_RING_BA_ALIGN);


Chas,

Thanks for hunting this one down. Wouldn't the rte_memzone_free()
better fit into vmxnet3_cmd_ring_release() ?


I don't care which way it goes.  I just did what is basically done in
gpa_zone_reserve() to match the "style".  Tracking the current ring size
and avoiding reallocating a potentially large chunk of memory seems like
a better idea.

Also the ring_dma_zone_reserve() could get replaced by
rte_eth_dma_zone_reserve() (see also


Yes, it probably should get changed to that along with tracking the size.

Why don't we always allocate VMXNET3_RX_RING_MAX_SIZE entries? That
way we don't need to reallocate on a later queue setup change?

That's using more memory than it needs to use.  It might break someone's 
application
that already runs in some tightly constrained machine.  Failing to shrink the 
memzone
isn't likely to break anything since they have (apparently) already dealt with 
having
less memory available before switching to a smaller queue size.

Still, it can be a matter for another day.


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