ia64/linux-2.6.18-xen.hg

view scripts/kconfig/zconf.gperf @ 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 %language=ANSI-C
2 %define hash-function-name kconf_id_hash
3 %define lookup-function-name kconf_id_lookup
4 %define string-pool-name kconf_id_strings
5 %compare-strncmp
6 %enum
7 %pic
8 %struct-type
10 struct kconf_id;
12 %%
13 mainmenu, T_MAINMENU, TF_COMMAND
14 menu, T_MENU, TF_COMMAND
15 endmenu, T_ENDMENU, TF_COMMAND
16 source, T_SOURCE, TF_COMMAND
17 choice, T_CHOICE, TF_COMMAND
18 endchoice, T_ENDCHOICE, TF_COMMAND
19 comment, T_COMMENT, TF_COMMAND
20 config, T_CONFIG, TF_COMMAND
21 menuconfig, T_MENUCONFIG, TF_COMMAND
22 help, T_HELP, TF_COMMAND
23 if, T_IF, TF_COMMAND|TF_PARAM
24 endif, T_ENDIF, TF_COMMAND
25 depends, T_DEPENDS, TF_COMMAND
26 requires, T_REQUIRES, TF_COMMAND
27 optional, T_OPTIONAL, TF_COMMAND
28 default, T_DEFAULT, TF_COMMAND, S_UNKNOWN
29 prompt, T_PROMPT, TF_COMMAND
30 tristate, T_TYPE, TF_COMMAND, S_TRISTATE
31 def_tristate, T_DEFAULT, TF_COMMAND, S_TRISTATE
32 bool, T_TYPE, TF_COMMAND, S_BOOLEAN
33 boolean, T_TYPE, TF_COMMAND, S_BOOLEAN
34 def_bool, T_DEFAULT, TF_COMMAND, S_BOOLEAN
35 def_boolean, T_DEFAULT, TF_COMMAND, S_BOOLEAN
36 int, T_TYPE, TF_COMMAND, S_INT
37 hex, T_TYPE, TF_COMMAND, S_HEX
38 string, T_TYPE, TF_COMMAND, S_STRING
39 select, T_SELECT, TF_COMMAND
40 enable, T_SELECT, TF_COMMAND
41 range, T_RANGE, TF_COMMAND
42 option, T_OPTION, TF_COMMAND
43 on, T_ON, TF_PARAM
44 modules, T_OPT_MODULES, TF_OPTION
45 defconfig_list, T_OPT_DEFCONFIG_LIST,TF_OPTION
46 %%