Re: [dpdk-dev] [PATCH 1/2] ixgbe: remove static qualifier for thread safety

[Masaru Oki <m-oki@stratosphere.co.jp>]

Oh, sorry, you are right.  I had missed first * for copy.
thank you.

2014-10-24 19:34 GMT+09:00 Bruce Richardson <bruce.richardson@intel.com>:
> On Thu, Oct 23, 2014 at 08:43:39AM +0900, Masaru Oki wrote:
>> Hi,
>>
>> in this code, pointer of local variable (mb_def) is returned by your changes.
>> mb_def should be static for each thread.
>
> Actually, no. A copy is made of 8 bytes of the mb_def variable and stored as
> an mbuf initializer inside the rxq structure. No use of the memory occupied
> by mb_def is made outside of the function, so the value does not need to be
> static.
>
> /Bruce
>>
>> 2014-10-22 19:55 GMT+09:00 Bruce Richardson <bruce.richardson@intel.com>:
>> > Remove the "static" prefix to the template mbuf variable in
>> > ixgbe_rxq_vec_setup function. This will then allow different
>> > threads to initialize different RX queues at the same time,
>> > without one overwriting the other's data.
>> >
>> > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
>> > ---
>> >  lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
>> > index a0d3d78..e813e43 100644
>> > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
>> > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
>> > @@ -730,7 +730,7 @@ static struct ixgbe_txq_ops vec_txq_ops = {
>> >  int
>> >  ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq)
>> >  {
>> > -       static struct rte_mbuf mb_def = {
>> > +       struct rte_mbuf mb_def = {
>> >                 .nb_segs = 1,
>> >                 .data_off = RTE_PKTMBUF_HEADROOM,
>> >  #ifdef RTE_MBUF_REFCNT
>> > --
>> > 1.9.3
>> >