view Documentation/networking/dmfe.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
line source
1 Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver for Linux.
3 This program is free software; you can redistribute it and/or
4 modify it under the terms of the GNU General Public License
5 as published by the Free Software Foundation; either version 2
6 of the License, or (at your option) any later version.
8 This program is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 GNU General Public License for more details.
14 This driver provides kernel support for Davicom DM9102(A)/DM9132/DM9801 ethernet cards ( CNET
15 10/100 ethernet cards uses Davicom chipset too, so this driver supports CNET cards too ).If you
16 didn't compile this driver as a module, it will automatically load itself on boot and print a
17 line similar to :
19 dmfe: Davicom DM9xxx net driver, version 1.36.4 (2002-01-17)
21 If you compiled this driver as a module, you have to load it on boot.You can load it with command :
23 insmod dmfe
25 This way it will autodetect the device mode.This is the suggested way to load the module.Or you can pass
26 a mode= setting to module while loading, like :
28 insmod dmfe mode=0 # Force 10M Half Duplex
29 insmod dmfe mode=1 # Force 100M Half Duplex
30 insmod dmfe mode=4 # Force 10M Full Duplex
31 insmod dmfe mode=5 # Force 100M Full Duplex
33 Next you should configure your network interface with a command similar to :
35 ifconfig eth0
36 ^^^^^^^^^^^
37 Your IP Adress
39 Then you may have to modify the default routing table with command :
41 route add default eth0
44 Now your ethernet card should be up and running.
47 TODO:
49 Implement pci_driver::suspend() and pci_driver::resume() power management methods.
50 Check on 64 bit boxes.
51 Check and fix on big endian boxes.
52 Test and make sure PCI latency is now correct for all cases.
55 Authors:
57 Sten Wang <sten_wang@davicom.com.tw > : Original Author
58 Tobias Ringstrom <tori@unhappy.mine.nu> : Current Maintainer
60 Contributors:
62 Marcelo Tosatti <marcelo@conectiva.com.br>
63 Alan Cox <alan@redhat.com>
64 Jeff Garzik <jgarzik@pobox.com>
65 Vojtech Pavlik <vojtech@suse.cz>