From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Stefan Puiu <stefan.puiu@gmail.com>, dev@dpdk.org
Cc: yongwang@vmware.com, mac_leehk@yahoo.com.hk,
dpdk stable <stable@dpdk.org>
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH v4] vmxnet3: fix Rx deadlock
Date: Mon, 19 Dec 2016 12:26:21 +0000 [thread overview]
Message-ID: <006e2ee9-f586-8b40-a06c-d386833dee10@intel.com> (raw)
In-Reply-To: <8e9b361a-566c-2c25-5497-da0ee0e7c818@intel.com>
On 12/19/2016 10:41 AM, Ferruh Yigit wrote:
> On 12/19/2016 9:40 AM, Stefan Puiu wrote:
>> Our use case is that we have an app that needs to keep mbufs around
>> for a while. We've seen cases when calling vmxnet3_post_rx_bufs() from
>> vmxet3_recv_pkts(), it might not succeed to add any mbufs to any RX
>> descriptors (where it returns -err). Since there are no mbufs that the
>> virtual hardware can use, no packets will be received after this; the
>> driver won't refill the mbuf after this so it gets stuck in this
>> state. I call this a deadlock for lack of a better term - the virtual
>> HW waits for free mbufs, while the app waits for the hardware to
>> notify it for data (by flipping the generation bit on the used Rx
>> descriptors). Note that after this, the app can't recover.
>>
>> This fix is a rework of this patch by Marco Lee:
>> http://dpdk.org/dev/patchwork/patch/6575/. I had to forward port
>> it, address review comments and also reverted the allocation
>> failure handling to the first version of the patch
>> (http://dpdk.org/ml/archives/dev/2015-July/022079.html), since
>> that's the only approach that seems to work, and seems to be what
>> other drivers are doing (I checked ixgbe and em). Reusing the mbuf
>> that's getting passed to the application doesn't seem to make
>> sense, and it was causing weird issues in our app. Also, reusing
>> rxm without checking if it's NULL could cause the code to crash.
>>
>> Signed-off-by: Stefan Puiu <stefan.puiu@gmail.com>
>
> Applied to dpdk-next-net/master, thanks.
>
CC:stable@dpdk.org
parent reply other threads:[~2016-12-19 12:26 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <8e9b361a-566c-2c25-5497-da0ee0e7c818@intel.com>]
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=006e2ee9-f586-8b40-a06c-d386833dee10@intel.com \
--to=ferruh.yigit@intel.com \
--cc=dev@dpdk.org \
--cc=mac_leehk@yahoo.com.hk \
--cc=stable@dpdk.org \
--cc=stefan.puiu@gmail.com \
--cc=yongwang@vmware.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).