From c21be1c9c1ab42fe285a74f184e1acbc37ee084b Mon Sep 17 00:00:00 2001 From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Date: Wed, 11 Oct 2006 01:21:42 -0700 Subject: [PATCH] [PATCH] uml: allow finer tuning for host VMSPLIT setting Now that various memory splits are enabled, add a config option allowing the user to compile UML for its need - HOST_2G_2G allowed to choose either 3G/1G or 2G/2G, and enabling it reduced the usable virtual memory. Detecting this at run time should be implemented in the future, but we must make the stop-gap measure work well enough (this is valid in _many_ cases). Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> --- arch/um/Kconfig.i386 | 49 ++++++++++++++++++++++++++++++-------------- 1 file changed, 34 insertions(+), 15 deletions(-) diff --git a/arch/um/Kconfig.i386 b/arch/um/Kconfig.i386 index f6eb72d117b9e..f191a550a079c 100644 --- a/arch/um/Kconfig.i386 +++ b/arch/um/Kconfig.i386 @@ -16,23 +16,42 @@ config SEMAPHORE_SLEEPERS bool default y -config HOST_2G_2G - bool "2G/2G host address space split" - default n - help - This is needed when the host on which you run has a 2G/2G memory - split, instead of the customary 3G/1G. - - Note that to enable such a host - configuration, which makes sense only in some cases, you need special - host patches. - - So, if you do not know what to do here, say 'N'. +choice + prompt "Host memory split" + default HOST_VMSPLIT_3G + ---help--- + This is needed when the host kernel on which you run has a non-default + (like 2G/2G) memory split, instead of the customary 3G/1G. If you did + not recompile your own kernel but use the default distro's one, you can + safely accept the "Default split" option. + + It can be enabled on recent (>=2.6.16-rc2) vanilla kernels via + CONFIG_VM_SPLIT_*, or on previous kernels with special patches (-ck + patchset by Con Kolivas, or other ones) - option names match closely the + host CONFIG_VM_SPLIT_* ones. + + A lower setting (where 1G/3G is lowest and 3G/1G is higher) will + tolerate even more "normal" host kernels, but an higher setting will be + stricter. + + So, if you do not know what to do here, say 'Default split'. + + config HOST_VMSPLIT_3G + bool "Default split (3G/1G user/kernel host split)" + config HOST_VMSPLIT_3G_OPT + bool "3G/1G user/kernel host split (for full 1G low memory)" + config HOST_VMSPLIT_2G + bool "2G/2G user/kernel host split" + config HOST_VMSPLIT_1G + bool "1G/3G user/kernel host split" +endchoice config TOP_ADDR - hex - default 0xc0000000 if !HOST_2G_2G - default 0x80000000 if HOST_2G_2G + hex + default 0xB0000000 if HOST_VMSPLIT_3G_OPT + default 0x78000000 if HOST_VMSPLIT_2G + default 0x40000000 if HOST_VMSPLIT_1G + default 0xC0000000 config 3_LEVEL_PGTABLES bool "Three-level pagetables (EXPERIMENTAL)" -- GitLab