From: "Hsu, Chiahao" <andyhsu@amazon.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 1/2] xen-netback: add module parameter to disable ctrl-ring
Date: Tue, 9 Mar 2021 14:10:12 +0000 [thread overview]
Message-ID: <CEC939E8-3F18-46A0-B7B6-ECBE97678DAC@amazon.com> (raw)
In-Reply-To: <20210225122940.9310-1-andyhsu@amazon.com>
On 25.02.21, 13:29, "Hsu, Chiahao" <andyhsu@amazon.com> wrote:
In order to support live migration of guests between kernels
that do and do not support 'feature-ctrl-ring', we add a
module parameter that allows the feature to be disabled
at run time, instead of using hardcode value.
The default value is enable.
Signed-off-by: ChiaHao Hsu <andyhsu@amazon.com>
---
drivers/net/xen-netback/common.h | 2 ++
drivers/net/xen-netback/netback.c | 6 ++++++
drivers/net/xen-netback/xenbus.c | 13 ++++++++-----
3 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 4a16d6e33c09..bfb7a3054917 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -276,6 +276,7 @@ struct backend_info {
u8 have_hotplug_status_watch:1;
const char *hotplug_script;
+ bool ctrl_ring_enabled;
};
struct xenvif {
@@ -413,6 +414,7 @@ static inline pending_ring_idx_t nr_pending_reqs(struct xenvif_queue *queue)
irqreturn_t xenvif_interrupt(int irq, void *dev_id);
+extern bool control_ring;
extern bool separate_tx_rx_irq;
extern bool provides_xdp_headroom;
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index e5c73f819662..20d858f0456a 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -48,6 +48,12 @@
#include <asm/xen/hypercall.h>
+/* Provide an option to disable control ring which is used to pass
+ * large quantities of data from frontend to backend.
+ */
+bool control_ring = true;
+module_param(control_ring, bool, 0644);
+
/* Provide an option to disable split event channels at load time as
* event channels are limited resource. Split event channels are
* enabled by default.
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index a5439c130130..8a9169cff9c5 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -1123,11 +1123,14 @@ static int netback_probe(struct xenbus_device *dev,
if (err)
pr_debug("Error writing multi-queue-max-queues\n");
- err = xenbus_printf(XBT_NIL, dev->nodename,
- "feature-ctrl-ring",
- "%u", true);
- if (err)
- pr_debug("Error writing feature-ctrl-ring\n");
+ be->ctrl_ring_enabled = READ_ONCE(control_ring);
+ if (be->ctrl_ring_enabled) {
+ err = xenbus_printf(XBT_NIL, dev->nodename,
+ "feature-ctrl-ring",
+ "%u", true);
+ if (err)
+ pr_debug("Error writing feature-ctrl-ring\n");
+ }
backend_switch_state(be, XenbusStateInitWait);
--
2.23.3
Gentle ping.
next prev parent reply other threads:[~2021-03-09 14:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 12:29 [PATCH 1/2] xen-netback: add module parameter to disable ctrl-ring ChiaHao Hsu
2021-03-09 14:10 ` Hsu, Chiahao [this message]
2021-03-09 14:34 ` Paul Durrant
2021-03-09 19:21 ` Wei Liu
2021-03-09 19:23 ` Wei Liu
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=CEC939E8-3F18-46A0-B7B6-ECBE97678DAC@amazon.com \
--to=andyhsu@amazon.com \
--cc=xen-devel@lists.xenproject.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).