1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
From 88337ce8246a453cd3c6e60e96aead43549a5e1d Mon Sep 17 00:00:00 2001
From: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Date: Thu, 9 May 2019 16:26:53 -0700
Subject: [PATCH] Add flow control to prevent buffer over run
This service uses direct frame update with bypassing image
compression and invalidating logic in libvncserver to achieve
better performance by using of H/W compressed JPEG frames as those
come from the video engine driver.
This behavior helps quick frame update using very small amount of
CPU resources but it causes a side effect which crashes bmcweb
by OOM killer due to a buffer over run issue. Usually, this issue
happens often in a slow speed connection because this service
keeps sending all frames without any handshaking with clients so
a session buffer in the bmcweb gets bigger and bigger since the
low speed connection can't send all stream data on time.
To fix this issue, this commit adds flow control logic to make
frame updating handshakes with client so that it'll send frames
only when it recieved client frame update messages. All other
frames when the client doesn't request will be dropped out to
prevent the buffer over run issue.
Tested:
bmcweb didn't keep increasing its KVM session buffer.
KVM worked well with showing good refresh speed.
resolves https://github.com/openbmc/bmcweb/issues/80
Change-Id: I6b09a711137d15a38fce59adada9bf3d00afde86
Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
---
ikvm_server.cpp | 20 ++++++++++++++++++++
ikvm_server.hpp | 11 +++++++++++
2 files changed, 31 insertions(+)
diff --git a/ikvm_server.cpp b/ikvm_server.cpp
index 35310da292be..dfafe3a82e64 100644
--- a/ikvm_server.cpp
+++ b/ikvm_server.cpp
@@ -119,6 +119,12 @@ void Server::sendFrame()
continue;
}
+ if (!cd->needUpdate)
+ {
+ continue;
+ }
+ cd->needUpdate = false;
+
if (cl->enableLastRectEncoding)
{
fu->nRects = 0xFFFF;
@@ -149,6 +155,19 @@ void Server::sendFrame()
rfbReleaseClientIterator(it);
}
+void Server::clientFramebufferUpdateRequest(
+ rfbClientPtr cl, rfbFramebufferUpdateRequestMsg *furMsg)
+{
+ ClientData *cd = (ClientData *)cl->clientData;
+
+ if (!cd)
+ return;
+
+ // Ignore the furMsg info. This service uses full frame update always.
+
+ cd->needUpdate = true;
+}
+
void Server::clientGone(rfbClientPtr cl)
{
Server* server = (Server*)cl->screen->screenData;
@@ -170,6 +189,7 @@ enum rfbNewClientAction Server::newClient(rfbClientPtr cl)
cl->clientData =
new ClientData(server->video.getFrameRate(), &server->input);
cl->clientGoneHook = clientGone;
+ cl->clientFramebufferUpdateRequestHook = clientFramebufferUpdateRequest;
if (!server->numClients++)
{
server->pendingResize = false;
diff --git a/ikvm_server.hpp b/ikvm_server.hpp
index b8062017b8ca..ebe4ad2b287e 100644
--- a/ikvm_server.hpp
+++ b/ikvm_server.hpp
@@ -32,6 +32,7 @@ class Server
*/
ClientData(int s, Input* i) : skipFrame(s), input(i)
{
+ needUpdate = false;
}
~ClientData() = default;
ClientData(const ClientData&) = default;
@@ -41,6 +42,7 @@ class Server
int skipFrame;
Input* input;
+ bool needUpdate;
};
/*
@@ -85,6 +87,15 @@ class Server
private:
/*
+ * @brief Handler for a client frame update message
+ *
+ * @param[in] cl - Handle to the client object
+ * @param[in] furMsg - Pointer of the FUR message
+ */
+ static void
+ clientFramebufferUpdateRequest(rfbClientPtr cl,
+ rfbFramebufferUpdateRequestMsg *furMsg);
+ /*
* @brief Handler for a client disconnecting
*
* @param[in] cl - Handle to the client object
--
2.7.4
|
