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: [dpdk-dev] [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 John Daley
2018-08-02 8:26 ` Thomas Monjalon [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1580713.dMrMSxmPF2@xps \
--to=thomas@monjalon.net \
--cc=dev@dpdk.org \
--cc=ferruh.yigit@intel.com \
--cc=hyonkim@cisco.com \
--cc=johndale@cisco.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).