From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: David Marchand <david.marchand@redhat.com>
Cc: dev@dpdk.org, chenbox@nvidia.com, bnemeth@redhat.com,
echaudro@redhat.com, stable@dpdk.org
Subject: Re: [PATCH v2 1/2] vhost: fix memory leak in Virtio Tx split path
Date: Tue, 6 Feb 2024 14:57:27 +0100 [thread overview]
Message-ID: <7927f9fb-9438-4cfd-918a-2242f83e785f@redhat.com> (raw)
In-Reply-To: <CAJFAV8y5YHwNZF196ibew6QO61eTo_jzPpo7xd0_FmBecg2kRQ@mail.gmail.com>
On 2/6/24 11:29, David Marchand wrote:
> On Wed, Jan 31, 2024 at 8:53 PM Maxime Coquelin
> <maxime.coquelin@redhat.com> wrote:
>>
>> When vIOMMU is enabled and Virtio device is bound to kernel
>> driver in guest, rte_vhost_dequeue_burst() will often return
>> early because of IOTLB misses.
>
> In theory, we can hit this issue with a dpdk pmd too, as long as the
> vIOMMU is in use.
> But the consequence would be a "really small" leak which does not have
> the same impact as what was seen with the kernel driver which
> maps/unmaps pages associated with virtio-net skb way more often :-).
> So maybe rephrase this part emphasizing on the kernel case like:
>
> """
> When vIOMMU is enabled, rte_vhost_dequeue_burst() can return early
> because of IOTLB misses.
> Such IOTLB misses are especially frequent when a Virtio device is
> bound to a kernel driver in guest.
> """
Thanks, I agree with your suggestion, Virtio PMD is indeed also
impacted.
>>
>> This patch fixes a mbuf leak occurring in this case.
>>
>> Fixes: 242695f6122a ("vhost: allocate and free packets in bulk in Tx split")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Signed-off-by: David Marchand <david.marchand@redhat.com>
>
> Reviewed-by: David Marchand <david.marchand@redhat.com>
>
>
next prev parent reply other threads:[~2024-02-06 13:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-31 19:53 Maxime Coquelin
2024-02-06 10:29 ` David Marchand
2024-02-06 13:57 ` Maxime Coquelin [this message]
2024-02-06 14:59 ` Maxime Coquelin
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=7927f9fb-9438-4cfd-918a-2242f83e785f@redhat.com \
--to=maxime.coquelin@redhat.com \
--cc=bnemeth@redhat.com \
--cc=chenbox@nvidia.com \
--cc=david.marchand@redhat.com \
--cc=dev@dpdk.org \
--cc=echaudro@redhat.com \
--cc=stable@dpdk.org \
/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).