From: Thomas Monjalon <thomas@monjalon.net>
To: John Daley <johndale@cisco.com>, Hyong Youb Kim <hyonkim@cisco.com>
Cc: dev@dpdk.org, ferruh.yigit@intel.com
Subject: Re: [PATCH] net/enic: revert support for mbuf fast free offload
Date: Thu, 02 Aug 2018 10:26:54 +0200 [thread overview]
Message-ID: <1580713.dMrMSxmPF2@xps> (raw)
In-Reply-To: <20180726023028.23394-1-johndale@cisco.com>
26/07/2018 04:30, John Daley:
> From: Hyong Youb Kim <hyonkim@cisco.com>
>
> This reverts the patch that enabled mbuf fast free.
>
> There are two main reasons.
>
> First, enic_fast_free_wq_bufs is broken. When
> DEV_TX_OFFLOAD_MBUF_FAST_FREE is enabled, the driver calls this
> function to free transmitted mbufs. This function currently does not
> reset next and nb_segs. This is simply wrong as the fast-free flag
> does not imply anything about next and nb_segs.
>
> We could fix enic_fast_free_wq_bufs by making it to call
> rte_pktmbuf_prefree_seg to reset the required fields. But, it negates
> most of cycle saving.
>
> Second, there are customer applications that blindly enable all Tx
> offloads supported by the device. Some of these applications do not
> satisfy the requirements of mbuf fast free (i.e. a single pool per
> queue and refcnt = 1), and end up crashing or behaving badly.
>
> Fixes: bcaa54c1a148 ("net/enic: support mbuf fast free offload")
>
> Signed-off-by: Hyong Youb Kim <hyonkim@cisco.com>
> Reviewed-by: John Daley <johndale@cisco.com>
Applied
prev parent reply other threads:[~2018-08-02 8:27 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-26 2:30 [PATCH] net/enic: revert support for mbuf fast free offload John Daley
2018-08-02 8:26 ` Thomas Monjalon [this message]
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