hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

x86/Kconfig: Further simplify the NR_CPUS config 

Clean up various aspects of the x86 CONFIG_NR_CPUS configuration switches:

- Rename the three CONFIG_NR_CPUS related variables to create a common
  namespace for them:

    RANGE_BEGIN_CPUS => NR_CPUS_RANGE_BEGIN
    RANGE_END_CPUS   => NR_CPUS_RANGE_END
    DEF_CONFIG_CPUS  => NR_CPUS_DEFAULT

- Align them vertically, such as:

    config NR_CPUS_RANGE_END
            int
            depends on X86_64
            default 8192 if  SMP && ( MAXSMP ||  CPUMASK_OFFSTACK)
            default  512 if  SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
            default    1 if !SMP

- Update help text, add more comments.

Test results:

 # i386 allnoconfig:
 CONFIG_NR_CPUS_RANGE_BEGIN=1
 CONFIG_NR_CPUS_RANGE_END=1
 CONFIG_NR_CPUS_DEFAULT=1
 CONFIG_NR_CPUS=1

 # i386 defconfig:
 CONFIG_NR_CPUS_RANGE_BEGIN=2
 CONFIG_NR_CPUS_RANGE_END=8
 CONFIG_NR_CPUS_DEFAULT=8
 CONFIG_NR_CPUS=8

 # i386 allyesconfig:
 CONFIG_NR_CPUS_RANGE_BEGIN=2
 CONFIG_NR_CPUS_RANGE_END=64
 CONFIG_NR_CPUS_DEFAULT=32
 CONFIG_NR_CPUS=32

 # x86_64 allnoconfig:
 CONFIG_NR_CPUS_RANGE_BEGIN=1
 CONFIG_NR_CPUS_RANGE_END=1
 CONFIG_NR_CPUS_DEFAULT=1
 CONFIG_NR_CPUS=1

 # x86_64 defconfig:
 CONFIG_NR_CPUS_RANGE_BEGIN=2
 CONFIG_NR_CPUS_RANGE_END=512
 CONFIG_NR_CPUS_DEFAULT=64
 CONFIG_NR_CPUS=64

 # x86_64 allyesconfig:
 CONFIG_NR_CPUS_RANGE_BEGIN=8192
 CONFIG_NR_CPUS_RANGE_END=8192
 CONFIG_NR_CPUS_DEFAULT=8192
 CONFIG_NR_CPUS=8192

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180210113629.jcv6su3r4suuno63@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2018-02-10 12:36:29 +01:00
parent a0d0bb4deb
commit aec6487e99
1 changed files with 40 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
arch/x86/Kconfig
View File

@ -949,52 +949,66 @@ config MAXSMP
Enable maximum number of CPUS and NUMA Nodes for this architecture. Enable maximum number of CPUS and NUMA Nodes for this architecture.
If unsure, say N. If unsure, say N.
config RANGE_END_CPUS #
# The maximum number of CPUs supported:
#
# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
# and which can be configured interactively in the
# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
#
# The ranges are different on 32-bit and 64-bit kernels, depending on
# hardware capabilities and scalability features of the kernel.
#
# ( If MAXSMP is enabled we just use the highest possible value and disable
# interactive configuration. )
#
config NR_CPUS_RANGE_BEGIN
int
default NR_CPUS_RANGE_END if MAXSMP
default 1 if !SMP
default 2
config NR_CPUS_RANGE_END
int int
depends on X86_32 depends on X86_32
default 8 if SMP && !X86_BIGSMP default 64 if SMP && X86_BIGSMP
default 64 if SMP && X86_BIGSMP default 8 if SMP && !X86_BIGSMP
default 1 if !SMP default 1 if !SMP
config RANGE_END_CPUS config NR_CPUS_RANGE_END
int int
depends on X86_64 depends on X86_64
default 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK default 8192 if SMP && ( MAXSMP || CPUMASK_OFFSTACK)
default 8192 if SMP && (MAXSMP || CPUMASK_OFFSTACK) default 512 if SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
default 1 if !SMP default 1 if !SMP
config RANGE_BEGIN_CPUS config NR_CPUS_DEFAULT
int
default 1 if !SMP
default RANGE_END_CPUS if MAXSMP
default 2
config DEF_CONFIG_CPUS
int int
depends on X86_32 depends on X86_32
default 1 if !SMP default 32 if X86_BIGSMP
default 32 if X86_BIGSMP default 8 if SMP
default 8 if SMP default 1 if !SMP
config DEF_CONFIG_CPUS config NR_CPUS_DEFAULT
int int
depends on X86_64 depends on X86_64
default 1 if !SMP default 8192 if MAXSMP
default 8192 if MAXSMP default 64 if SMP
default 64 if SMP default 1 if !SMP
config NR_CPUS config NR_CPUS
int "Maximum number of CPUs" if SMP && !MAXSMP int "Maximum number of CPUs" if SMP && !MAXSMP
range RANGE_BEGIN_CPUS RANGE_END_CPUS range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
default DEF_CONFIG_CPUS default NR_CPUS_DEFAULT
---help--- ---help---
This allows you to specify the maximum number of CPUs which this This allows you to specify the maximum number of CPUs which this
kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
supported value is 8192, otherwise the maximum value is 512. The supported value is 8192, otherwise the maximum value is 512. The
minimum value which makes sense is 2. minimum value which makes sense is 2.
This is purely to save memory - each supported CPU adds This is purely to save memory: each supported CPU adds about 8KB
approximately eight kilobytes to the kernel image. to the kernel image.
config SCHED_SMT config SCHED_SMT
bool "SMT (Hyperthreading) scheduler support" bool "SMT (Hyperthreading) scheduler support"