Messages in this thread Patch in this message | | | From | Randy Dunlap <> | Subject | [PATCH] x86: try to simplify NR_CPUS config | Date | Fri, 9 Feb 2018 14:01:50 -0800 |
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From: Randy Dunlap <rdunlap@infradead.org>
Clean up and simplify the X86 NR_CPUS Kconfig symbol/option by introducing MIN_CONFIG_CPUS, MAX_CONFIG_CPUS, and DEF_CONFIG_CPUS. Then combine some default values when their conditionals can be reduced.
Also move the X86_BIGSMP kconfig option inside an "if X86_32"/"endif" config block and drop its explicit "depends on X86_32".
This is a rather literal interpretation of Linus's suggestion. It mostly moves the complexity to other kconfig symbols, although a little bit more reduction can be done, especially in RANGE_BEGIN_CPUS, at the sake of understandability, so I chose to leave it more understandable (at least to me).
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Link: lkml.kernel.org/r/CA+55aFzOd3j6ZUSkEwTdk85qtt1JywOtm3ZAb-qAvt8_hJ6D4A@mail.gmail.com Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: x86@kernel.org --- arch/x86/Kconfig | 48 ++++++++++++++++++++++++++++++--------------- 1 file changed, 33 insertions(+), 15 deletions(-)
--- linux-next-20180209.orig/arch/x86/Kconfig +++ linux-next-20180209/arch/x86/Kconfig @@ -423,12 +423,6 @@ config X86_MPPARSE For old smp systems that do not have proper acpi support. Newer systems (esp with 64bit cpus) with acpi support, MADT and DSDT will override it -config X86_BIGSMP - bool "Support for big SMP systems with more than 8 CPUs" - depends on X86_32 && SMP - ---help--- - This option is needed for the systems that have more than 8 CPUs - config GOLDFISH def_bool y depends on X86_GOLDFISH @@ -460,6 +454,12 @@ config INTEL_RDT Say N if unsure. if X86_32 +config X86_BIGSMP + bool "Support for big SMP systems with more than 8 CPUs" + depends on SMP + ---help--- + This option is needed for the systems that have more than 8 CPUs + config X86_EXTENDED_PLATFORM bool "Support for extended (non-PC) x86 platforms" default y @@ -949,17 +949,35 @@ config MAXSMP Enable maximum number of CPUS and NUMA Nodes for this architecture. If unsure, say N. +config RANGE_BEGIN_CPUS + int + default 2 if SMP && X86_32 + default 2 if SMP && !MAXSMP && X86_64 + default 8192 if SMP && MAXSMP && X86_64 + default 1 if !SMP + default 2 + +config RANGE_END_CPUS + int + default 8 if SMP && X86_32 && !X86_BIGSMP + default 64 if SMP && X86_32 && X86_BIGSMP + default 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK && X86_64 + default 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64 + default 8192 if SMP && MAXSMP && X86_64 + default 1 if !SMP + +config DEF_CONFIG_CPUS + int + default 1 if !SMP + default 8192 if MAXSMP + default 32 if SMP && X86_BIGSMP + default 8 if SMP && X86_32 + default 64 if SMP + config NR_CPUS int "Maximum number of CPUs" if SMP && !MAXSMP - range 2 8 if SMP && X86_32 && !X86_BIGSMP - range 2 64 if SMP && X86_32 && X86_BIGSMP - range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK && X86_64 - range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64 - default "1" if !SMP - default "8192" if MAXSMP - default "32" if SMP && X86_BIGSMP - default "8" if SMP && X86_32 - default "64" if SMP + range RANGE_BEGIN_CPUS RANGE_END_CPUS + default DEF_CONFIG_CPUS ---help--- This allows you to specify the maximum number of CPUs which this kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
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