ia64/linux-2.6.18-xen.hg

view Documentation/stallion.txt @ 897:329ea0ccb344

balloon: try harder to balloon up under memory pressure.

Currently if the balloon driver is unable to increase the guest's
reservation it assumes the failure was due to reaching its full
allocation, gives up on the ballooning operation and records the limit
it reached as the "hard limit". The driver will not try again until
the target is set again (even to the same value).

However it is possible that ballooning has in fact failed due to
memory pressure in the host and therefore it is desirable to keep
attempting to reach the target in case memory becomes available. The
most likely scenario is that some guests are ballooning down while
others are ballooning up and therefore there is temporary memory
pressure while things stabilise. You would not expect a well behaved
toolstack to ask a domain to balloon to more than its allocation nor
would you expect it to deliberately over-commit memory by setting
balloon targets which exceed the total host memory.

This patch drops the concept of a hard limit and causes the balloon
driver to retry increasing the reservation on a timer in the same
manner as when decreasing the reservation.

Also if we partially succeed in increasing the reservation
(i.e. receive less pages than we asked for) then we may as well keep
those pages rather than returning them to Xen.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Fri Jun 05 14:01:20 2009 +0100 (2009-06-05)
parents 831230e53067
children
line source
1 * NOTE - This is an unmaintained driver. Lantronix, which bought Stallion
2 technologies, is not active in driver maintenance, and they have no information
3 on when or if they will have a 2.6 driver.
5 James Nelson <james4765@gmail.com> - 12-12-2004
7 Stallion Multiport Serial Driver Readme
8 ---------------------------------------
10 Copyright (C) 1994-1999, Stallion Technologies.
12 Version: 5.5.1
13 Date: 28MAR99
17 1. INTRODUCTION
19 There are two drivers that work with the different families of Stallion
20 multiport serial boards. One is for the Stallion smart boards - that is
21 EasyIO, EasyConnection 8/32 and EasyConnection 8/64-PCI, the other for
22 the true Stallion intelligent multiport boards - EasyConnection 8/64
23 (ISA, EISA, MCA), EasyConnection/RA-PCI, ONboard and Brumby.
25 If you are using any of the Stallion intelligent multiport boards (Brumby,
26 ONboard, EasyConnection 8/64 (ISA, EISA, MCA), EasyConnection/RA-PCI) with
27 Linux you will need to get the driver utility package. This contains a
28 firmware loader and the firmware images necessary to make the devices operate.
30 The Stallion Technologies ftp site, ftp.stallion.com, will always have
31 the latest version of the driver utility package.
33 ftp://ftp.stallion.com/drivers/ata5/Linux/ata-linux-550.tar.gz
35 As of the printing of this document the latest version of the driver
36 utility package is 5.5.0. If a later version is now available then you
37 should use the latest version.
39 If you are using the EasyIO, EasyConnection 8/32 or EasyConnection 8/64-PCI
40 boards then you don't need this package, although it does have a serial stats
41 display program.
43 If you require DIP switch settings, EISA or MCA configuration files, or any
44 other information related to Stallion boards then have a look at Stallion's
45 web pages at http://www.stallion.com.
49 2. INSTALLATION
51 The drivers can be used as loadable modules or compiled into the kernel.
52 You can choose which when doing a "config" on the kernel.
54 All ISA, EISA and MCA boards that you want to use need to be configured into
55 the driver(s). All PCI boards will be automatically detected when you load
56 the driver - so they do not need to be entered into the driver(s)
57 configuration structure. Note that kernel PCI support is required to use PCI
58 boards.
60 There are two methods of configuring ISA, EISA and MCA boards into the drivers.
61 If using the driver as a loadable module then the simplest method is to pass
62 the driver configuration as module arguments. The other method is to modify
63 the driver source to add configuration lines for each board in use.
65 If you have pre-built Stallion driver modules then the module argument
66 configuration method should be used. A lot of Linux distributions come with
67 pre-built driver modules in /lib/modules/X.Y.Z/misc for the kernel in use.
68 That makes things pretty simple to get going.
71 2.1 MODULE DRIVER CONFIGURATION:
73 The simplest configuration for modules is to use the module load arguments
74 to configure any ISA, EISA or MCA boards. PCI boards are automatically
75 detected, so do not need any additional configuration at all.
77 If using EasyIO, EasyConnection 8/32 ISA or MCA, or EasyConnection 8/63-PCI
78 boards then use the "stallion" driver module, Otherwise if you are using
79 an EasyConnection 8/64 ISA, EISA or MCA, EasyConnection/RA-PCI, ONboard,
80 Brumby or original Stallion board then use the "istallion" driver module.
82 Typically to load up the smart board driver use:
84 modprobe stallion
86 This will load the EasyIO and EasyConnection 8/32 driver. It will output a
87 message to say that it loaded and print the driver version number. It will
88 also print out whether it found the configured boards or not. These messages
89 may not appear on the console, but typically are always logged to
90 /var/adm/messages or /var/log/syslog files - depending on how the klogd and
91 syslogd daemons are setup on your system.
93 To load the intelligent board driver use:
95 modprobe istallion
97 It will output similar messages to the smart board driver.
99 If not using an auto-detectable board type (that is a PCI board) then you
100 will also need to supply command line arguments to the modprobe command
101 when loading the driver. The general form of the configuration argument is
103 board?=<name>[,<ioaddr>[,<addr>][,<irq>]]
105 where:
107 board? -- specifies the arbitrary board number of this board,
108 can be in the range 0 to 3.
110 name -- textual name of this board. The board name is the common
111 board name, or any "shortened" version of that. The board
112 type number may also be used here.
114 ioaddr -- specifies the I/O address of this board. This argument is
115 optional, but should generally be specified.
117 addr -- optional second address argument. Some board types require
118 a second I/O address, some require a memory address. The
119 exact meaning of this argument depends on the board type.
121 irq -- optional IRQ line used by this board.
123 Up to 4 board configuration arguments can be specified on the load line.
124 Here is some examples:
126 modprobe stallion board0=easyio,0x2a0,5
128 This configures an EasyIO board as board 0 at I/O address 0x2a0 and IRQ 5.
130 modprobe istallion board3=ec8/64,0x2c0,0xcc000
132 This configures an EasyConnection 8/64 ISA as board 3 at I/O address 0x2c0 at
133 memory address 0xcc000.
135 modprobe stallion board1=ec8/32-at,0x2a0,0x280,10
137 This configures an EasyConnection 8/32 ISA board at primary I/O address 0x2a0,
138 secondary address 0x280 and IRQ 10.
140 You will probably want to enter this module load and configuration information
141 into your system startup scripts so that the drivers are loaded and configured
142 on each system boot. Typically the start up script would be something like
143 /etc/modprobe.conf.
146 2.2 STATIC DRIVER CONFIGURATION:
148 For static driver configuration you need to modify the driver source code.
149 Entering ISA, EISA and MCA boards into the driver(s) configuration structure
150 involves editing the driver(s) source file. It's pretty easy if you follow
151 the instructions below. Both drivers can support up to 4 boards. The smart
152 card driver (the stallion.c driver) supports any combination of EasyIO and
153 EasyConnection 8/32 boards (up to a total of 4). The intelligent driver
154 supports any combination of ONboards, Brumbys, Stallions and EasyConnection
155 8/64 (ISA and EISA) boards (up to a total of 4).
157 To set up the driver(s) for the boards that you want to use you need to
158 edit the appropriate driver file and add configuration entries.
160 If using EasyIO or EasyConnection 8/32 ISA or MCA boards,
161 In drivers/char/stallion.c:
162 - find the definition of the stl_brdconf array (of structures)
163 near the top of the file
164 - modify this to match the boards you are going to install
165 (the comments before this structure should help)
166 - save and exit
168 If using ONboard, Brumby, Stallion or EasyConnection 8/64 (ISA or EISA)
169 boards,
170 In drivers/char/istallion.c:
171 - find the definition of the stli_brdconf array (of structures)
172 near the top of the file
173 - modify this to match the boards you are going to install
174 (the comments before this structure should help)
175 - save and exit
177 Once you have set up the board configurations then you are ready to build
178 the kernel or modules.
180 When the new kernel is booted, or the loadable module loaded then the
181 driver will emit some kernel trace messages about whether the configured
182 boards were detected or not. Depending on how your system logger is set
183 up these may come out on the console, or just be logged to
184 /var/adm/messages or /var/log/syslog. You should check the messages to
185 confirm that all is well.
188 2.3 SHARING INTERRUPTS
190 It is possible to share interrupts between multiple EasyIO and
191 EasyConnection 8/32 boards in an EISA system. To do this you must be using
192 static driver configuration, modifying the driver source code to add driver
193 configuration. Then a couple of extra things are required:
195 1. When entering the board resources into the stallion.c file you need to
196 mark the boards as using level triggered interrupts. Do this by replacing
197 the "0" entry at field position 6 (the last field) in the board
198 configuration structure with a "1". (This is the structure that defines
199 the board type, I/O locations, etc. for each board). All boards that are
200 sharing an interrupt must be set this way, and each board should have the
201 same interrupt number specified here as well. Now build the module or
202 kernel as you would normally.
204 2. When physically installing the boards into the system you must enter
205 the system EISA configuration utility. You will need to install the EISA
206 configuration files for *all* the EasyIO and EasyConnection 8/32 boards
207 that are sharing interrupts. The Stallion EasyIO and EasyConnection 8/32
208 EISA configuration files required are supplied by Stallion Technologies
209 on the EASY Utilities floppy diskette (usually supplied in the box with
210 the board when purchased. If not, you can pick it up from Stallion's FTP
211 site, ftp.stallion.com). You will need to edit the board resources to
212 choose level triggered interrupts, and make sure to set each board's
213 interrupt to the same IRQ number.
215 You must complete both the above steps for this to work. When you reboot
216 or load the driver your EasyIO and EasyConnection 8/32 boards will be
217 sharing interrupts.
220 2.4 USING HIGH SHARED MEMORY
222 The EasyConnection 8/64-EI, ONboard and Stallion boards are capable of
223 using shared memory addresses above the usual 640K - 1Mb range. The ONboard
224 ISA and the Stallion boards can be programmed to use memory addresses up to
225 16Mb (the ISA bus addressing limit), and the EasyConnection 8/64-EI and
226 ONboard/E can be programmed for memory addresses up to 4Gb (the EISA bus
227 addressing limit).
229 The higher than 1Mb memory addresses are fully supported by this driver.
230 Just enter the address as you normally would for a lower than 1Mb address
231 (in the driver's board configuration structure).
235 2.5 TROUBLE SHOOTING
237 If a board is not found by the driver but is actually in the system then the
238 most likely problem is that the I/O address is wrong. Change the module load
239 argument for the loadable module form. Or change it in the driver stallion.c
240 or istallion.c configuration structure and rebuild the kernel or modules, or
241 change it on the board.
243 On EasyIO and EasyConnection 8/32 boards the IRQ is software programmable, so
244 if there is a conflict you may need to change the IRQ used for a board. There
245 are no interrupts to worry about for ONboard, Brumby or EasyConnection 8/64
246 (ISA, EISA and MCA) boards. The memory region on EasyConnection 8/64 and
247 ONboard boards is software programmable, but not on the Brumby boards.
251 3. USING THE DRIVERS
253 3.1 INTELLIGENT DRIVER OPERATION
255 The intelligent boards also need to have their "firmware" code downloaded
256 to them. This is done via a user level application supplied in the driver
257 utility package called "stlload". Compile this program wherever you dropped
258 the package files, by typing "make". In its simplest form you can then type
260 ./stlload -i cdk.sys
262 in this directory and that will download board 0 (assuming board 0 is an
263 EasyConnection 8/64 or EasyConnection/RA board). To download to an
264 ONboard, Brumby or Stallion do:
266 ./stlload -i 2681.sys
268 Normally you would want all boards to be downloaded as part of the standard
269 system startup. To achieve this, add one of the lines above into the
270 /etc/rc.d/rc.S or /etc/rc.d/rc.serial file. To download each board just add
271 the "-b <brd-number>" option to the line. You will need to download code for
272 every board. You should probably move the stlload program into a system
273 directory, such as /usr/sbin. Also, the default location of the cdk.sys image
274 file in the stlload down-loader is /usr/lib/stallion. Create that directory
275 and put the cdk.sys and 2681.sys files in it. (It's a convenient place to put
276 them anyway). As an example your /etc/rc.d/rc.S file might have the
277 following lines added to it (if you had 3 boards):
279 /usr/sbin/stlload -b 0 -i /usr/lib/stallion/cdk.sys
280 /usr/sbin/stlload -b 1 -i /usr/lib/stallion/2681.sys
281 /usr/sbin/stlload -b 2 -i /usr/lib/stallion/2681.sys
283 The image files cdk.sys and 2681.sys are specific to the board types. The
284 cdk.sys will only function correctly on an EasyConnection 8/64 board. Similarly
285 the 2681.sys image fill only operate on ONboard, Brumby and Stallion boards.
286 If you load the wrong image file into a board it will fail to start up, and
287 of course the ports will not be operational!
289 If you are using the modularized version of the driver you might want to put
290 the modprobe calls in the startup script as well (before the download lines
291 obviously).
294 3.2 USING THE SERIAL PORTS
296 Once the driver is installed you will need to setup some device nodes to
297 access the serial ports. The simplest method is to use the /dev/MAKEDEV program.
298 It will automatically create device entries for Stallion boards. This will
299 create the normal serial port devices as /dev/ttyE# where# is the port number
300 starting from 0. A bank of 64 minor device numbers is allocated to each board,
301 so the first port on the second board is port 64,etc. A set of callout type
302 devices may also be created. They are created as the devices /dev/cue# where #
303 is the same as for the ttyE devices.
305 For the most part the Stallion driver tries to emulate the standard PC system
306 COM ports and the standard Linux serial driver. The idea is that you should
307 be able to use Stallion board ports and COM ports interchangeably without
308 modifying anything but the device name. Anything that doesn't work like that
309 should be considered a bug in this driver!
311 If you look at the driver code you will notice that it is fairly closely
312 based on the Linux serial driver (linux/drivers/char/serial.c). This is
313 intentional, obviously this is the easiest way to emulate its behavior!
315 Since this driver tries to emulate the standard serial ports as much as
316 possible, most system utilities should work as they do for the standard
317 COM ports. Most importantly "stty" works as expected and "setserial" can
318 also be used (excepting the ability to auto-configure the I/O and IRQ
319 addresses of boards). Higher baud rates are supported in the usual fashion
320 through setserial or using the CBAUDEX extensions. Note that the EasyIO and
321 EasyConnection (all types) support at least 57600 and 115200 baud. The newer
322 EasyConnection XP modules and new EasyIO boards support 230400 and 460800
323 baud as well. The older boards including ONboard and Brumby support a
324 maximum baud rate of 38400.
326 If you are unfamiliar with how to use serial ports, then get the Serial-HOWTO
327 by Greg Hankins. It will explain everything you need to know!
331 4. NOTES
333 You can use both drivers at once if you have a mix of board types installed
334 in a system. However to do this you will need to change the major numbers
335 used by one of the drivers. Currently both drivers use major numbers 24, 25
336 and 28 for their devices. Change one driver to use some other major numbers,
337 and then modify the mkdevnods script to make device nodes based on those new
338 major numbers. For example, you could change the istallion.c driver to use
339 major numbers 60, 61 and 62. You will also need to create device nodes with
340 different names for the ports, for example ttyF# and cuf#.
342 The original Stallion board is no longer supported by Stallion Technologies.
343 Although it is known to work with the istallion driver.
345 Finding a free physical memory address range can be a problem. The older
346 boards like the Stallion and ONboard need large areas (64K or even 128K), so
347 they can be very difficult to get into a system. If you have 16 Mb of RAM
348 then you have no choice but to put them somewhere in the 640K -> 1Mb range.
349 ONboards require 64K, so typically 0xd0000 is good, or 0xe0000 on some
350 systems. If you have an original Stallion board, "V4.0" or Rev.O, then you
351 need a 64K memory address space, so again 0xd0000 and 0xe0000 are good.
352 Older Stallion boards are a much bigger problem. They need 128K of address
353 space and must be on a 128K boundary. If you don't have a VGA card then
354 0xc0000 might be usable - there is really no other place you can put them
355 below 1Mb.
357 Both the ONboard and old Stallion boards can use higher memory addresses as
358 well, but you must have less than 16Mb of RAM to be able to use them. Usual
359 high memory addresses used include 0xec0000 and 0xf00000.
361 The Brumby boards only require 16Kb of address space, so you can usually
362 squeeze them in somewhere. Common addresses are 0xc8000, 0xcc000, or in
363 the 0xd0000 range. EasyConnection 8/64 boards are even better, they only
364 require 4Kb of address space, again usually 0xc8000, 0xcc000 or 0xd0000
365 are good.
367 If you are using an EasyConnection 8/64-EI or ONboard/E then usually the
368 0xd0000 or 0xe0000 ranges are the best options below 1Mb. If neither of
369 them can be used then the high memory support to use the really high address
370 ranges is the best option. Typically the 2Gb range is convenient for them,
371 and gets them well out of the way.
373 The ports of the EasyIO-8M board do not have DCD or DTR signals. So these
374 ports cannot be used as real modem devices. Generally, when using these
375 ports you should only use the cueX devices.
377 The driver utility package contains a couple of very useful programs. One
378 is a serial port statistics collection and display program - very handy
379 for solving serial port problems. The other is an extended option setting
380 program that works with the intelligent boards.
384 5. DISCLAIMER
386 The information contained in this document is believed to be accurate and
387 reliable. However, no responsibility is assumed by Stallion Technologies
388 Pty. Ltd. for its use, nor any infringements of patents or other rights
389 of third parties resulting from its use. Stallion Technologies reserves
390 the right to modify the design of its products and will endeavour to change
391 the information in manuals and accompanying documentation accordingly.