view drivers/telephony/Kconfig @ 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 #
2 # Telephony device configuration
3 #
5 menu "Telephony Support"
7 config PHONE
8 tristate "Linux telephony support"
9 ---help---
10 Say Y here if you have a telephony card, which for example allows
11 you to use a regular phone for voice-over-IP applications.
13 Note: this has nothing to do with modems. You do not need to say Y
14 here in order to be able to use a modem under Linux.
16 To compile this driver as a module, choose M here: the
17 module will be called phonedev.
19 config PHONE_IXJ
20 tristate "QuickNet Internet LineJack/PhoneJack support"
21 depends on PHONE
22 ---help---
23 Say M if you have a telephony card manufactured by Quicknet
24 Technologies, Inc. These include the Internet PhoneJACK and
25 Internet LineJACK Telephony Cards. You will get a module called
26 ixj.
28 For the ISA versions of these products, you can configure the
29 cards using the isapnp tools (pnpdump/isapnp) or you can use the
30 isapnp support. Please read <file:Documentation/telephony/ixj.txt>.
32 For more information on these cards, see Quicknet's web site at:
33 <http://www.quicknet.net/>.
35 If you do not have any Quicknet telephony cards, you can safely
36 say N here.
39 tristate "QuickNet Internet LineJack/PhoneJack PCMCIA support"
40 depends on PHONE_IXJ && PCMCIA
41 help
42 Say Y here to configure in PCMCIA service support for the Quicknet
43 cards manufactured by Quicknet Technologies, Inc. This changes the
44 card initialization code to work with the card manager daemon.
46 endmenu