From: "John Daley (johndale)" <johndale@cisco.com>
To: Olivier Matz <olivier.matz@6wind.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: "bruce.richardson@intel.com" <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH] net/enic: decrement Tx mbuf reference count before recycling
Date: Mon, 11 Jul 2016 19:41:02 +0000 [thread overview]
Message-ID: <eb3d65106f0c4da1b5b5c3679757d427@XCH-RCD-007.cisco.com> (raw)
In-Reply-To: <1ca338a4-a8fe-8149-2373-d02fee3199cb@6wind.com>
> -----Original Message-----
> From: Olivier Matz [mailto:olivier.matz@6wind.com]
> Sent: Monday, July 11, 2016 3:04 AM
> To: John Daley (johndale) <johndale@cisco.com>; dev@dpdk.org
> Cc: bruce.richardson@intel.com
> Subject: Re: [dpdk-dev] [PATCH] net/enic: decrement Tx mbuf reference
> count before recycling
>
> Hi John,
>
> On 07/09/2016 12:22 AM, John Daley wrote:
> > In the Tx cleanup function, the reference count in mbufs to be
> > returned to the pool should to be decremented before they are
> > returned. Decrementing is not done by rte_mempool_put_bulk() so it
> > must be done separately using __rte_pktmbuf_prefree_seg().
> > If decrementing does not result in a 0 reference count the mbuf is not
> > returned to the pool and whatever has the last reference is
> > responsible for freeing.
> >
> > Fixes: 36935afbc53c ("net/enic: refactor Tx mbuf recycling")
> > Reviewed-by: Nelson Escobar <neescoba@cisco.com>
> > Signed-off-by: John Daley <johndale@cisco.com>
> > ---
> > Since reference counts are set to 0 when mbufs are reallocated from
> > the pool, and sending packets with reference count not equal to 1 is
> > probably an application error, this patch may not be critical. But a
> > debug ASSERT caught it and it would be nice to have it fixed in 16.07.
>
> Sending a packet with refcnt != 1 is not an error. It can happen when using
> mbuf clones. So indeed it would be better to have in 16.07.
>
> For the same reason, I also wonder if enic_free_wq_buf() should also be
> updated with:
>
> - rte_mempool_put(mbuf->pool, mbuf);
> + rte_pktmbuf_free(mbuf);
That is a very good point, thank you. I'll use rte_pktmubf_free_seg(mbuf) though, since we are walking an array of all mbuf segments. V2 coming momentarily.
-john
>
>
> Regards,
> Olivier
next prev parent reply other threads:[~2016-07-11 19:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-08 22:22 John Daley
2016-07-08 22:22 ` [dpdk-dev] [PATCH] net/enic: increment filter failure counter John Daley
2016-07-15 21:26 ` Thomas Monjalon
2016-07-11 10:04 ` [dpdk-dev] [PATCH] net/enic: decrement Tx mbuf reference count before recycling Olivier Matz
2016-07-11 19:41 ` John Daley (johndale) [this message]
2016-07-11 19:45 ` [dpdk-dev] [PATCH v2] " John Daley
2016-07-15 21:27 ` Thomas Monjalon
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