ia64/linux-2.6.18-xen.hg

view arch/alpha/Makefile @ 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 #
2 # alpha/Makefile
3 #
4 # This file is subject to the terms and conditions of the GNU General Public
5 # License. See the file "COPYING" in the main directory of this archive
6 # for more details.
7 #
8 # Copyright (C) 1994 by Linus Torvalds
9 #
11 NM := $(NM) -B
13 LDFLAGS_vmlinux := -static -N #-relax
14 CHECKFLAGS += -D__alpha__ -m64
15 cflags-y := -pipe -mno-fp-regs -ffixed-8
17 # Determine if we can use the BWX instructions with GAS.
18 old_gas := $(shell if $(AS) --version 2>&1 | grep 'version 2.7' > /dev/null; then echo y; else echo n; fi)
20 ifeq ($(old_gas),y)
21 $(error The assembler '$(AS)' does not support the BWX instruction)
22 endif
24 # Determine if GCC understands the -mcpu= option.
25 have_mcpu := $(call cc-option-yn, -mcpu=ev5)
26 have_mcpu_pca56 := $(call cc-option-yn, -mcpu=pca56)
27 have_mcpu_ev6 := $(call cc-option-yn, -mcpu=ev6)
28 have_mcpu_ev67 := $(call cc-option-yn, -mcpu=ev67)
29 have_msmall_data := $(call cc-option-yn, -msmall-data)
31 cflags-$(have_msmall_data) += -msmall-data
33 # Turn on the proper cpu optimizations.
34 ifeq ($(have_mcpu),y)
35 mcpu_done := n
36 # If GENERIC, make sure to turn off any instruction set extensions that
37 # the host compiler might have on by default. Given that EV4 and EV5
38 # have the same instruction set, prefer EV5 because an EV5 schedule is
39 # more likely to keep an EV4 processor busy than vice-versa.
40 ifeq ($(CONFIG_ALPHA_GENERIC),y)
41 mcpu := ev5
42 mcpu_done := y
43 endif
44 ifeq ($(mcpu_done)$(CONFIG_ALPHA_SX164)$(have_mcpu_pca56),nyy)
45 mcpu := pca56
46 mcpu_done := y
47 endif
48 ifeq ($(mcpu_done)$(CONFIG_ALPHA_POLARIS)$(have_mcpu_pca56),nyy)
49 mcpu := pca56
50 mcpu_done := y
51 endif
52 ifeq ($(mcpu_done)$(CONFIG_ALPHA_EV4),ny)
53 mcpu := ev4
54 mcpu_done := y
55 endif
56 ifeq ($(mcpu_done)$(CONFIG_ALPHA_EV56),ny)
57 mcpu := ev56
58 mcpu_done := y
59 endif
60 ifeq ($(mcpu_done)$(CONFIG_ALPHA_EV5),ny)
61 mcpu := ev5
62 mcpu_done := y
63 endif
64 ifeq ($(mcpu_done)$(CONFIG_ALPHA_EV67)$(have_mcpu_ev67),nyy)
65 mcpu := ev67
66 mcpu_done := y
67 endif
68 ifeq ($(mcpu_done)$(CONFIG_ALPHA_EV6),ny)
69 ifeq ($(have_mcpu_ev6),y)
70 mcpu := ev6
71 else
72 ifeq ($(have_mcpu_pca56),y)
73 mcpu := pca56
74 else
75 mcpu=ev56
76 endif
77 endif
78 mcpu_done := y
79 endif
80 cflags-$(mcpu_done) += -mcpu=$(mcpu)
81 endif
84 # For TSUNAMI, we must have the assembler not emulate our instructions.
85 # The same is true for IRONGATE, POLARIS, PYXIS.
86 # BWX is most important, but we don't really want any emulation ever.
87 CFLAGS += $(cflags-y) -Wa,-mev6
89 head-y := arch/alpha/kernel/head.o
91 core-y += arch/alpha/kernel/ arch/alpha/mm/
92 core-$(CONFIG_MATHEMU) += arch/alpha/math-emu/
93 drivers-$(CONFIG_OPROFILE) += arch/alpha/oprofile/
94 libs-y += arch/alpha/lib/
96 # export what is needed by arch/alpha/boot/Makefile
97 LIBS_Y := $(patsubst %/, %/lib.a, $(libs-y))
98 export LIBS_Y
100 boot := arch/alpha/boot
102 #Default target when executing make with no arguments
103 all boot: $(boot)/vmlinux.gz
105 $(boot)/vmlinux.gz: vmlinux
106 $(Q)$(MAKE) $(build)=$(boot) $@
108 bootimage bootpfile bootpzfile: vmlinux
109 $(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
111 archclean:
112 $(Q)$(MAKE) $(clean)=$(boot)
114 define archhelp
115 echo '* boot - Compressed kernel image (arch/alpha/boot/vmlinux.gz)'
116 echo ' bootimage - SRM bootable image (arch/alpha/boot/bootimage)'
117 echo ' bootpfile - BOOTP bootable image (arch/alpha/boot/bootpfile)'
118 echo ' bootpzfile - compressed kernel BOOTP image (arch/alpha/boot/bootpzfile)'
119 endef