Re: [PATCH RFC] Simplify the Linux kernel by reducing its state space
From: Paul E. McKenney <hidden>
Date: 2012-03-31 16:54:57
Also in:
linux-alpha, linux-arm-kernel, linux-mips, linux-sh, lkml, sparclinux
On Sat, Mar 31, 2012 at 06:40:30PM +0200, Geert Uytterhoeven wrote:
Hi Paul, On Sat, Mar 31, 2012 at 18:33, Paul E. McKenney [off-list ref] wrote:quoted
Although there have been numerous complaints about the complexity of parallel programming (especially over the past 5-10 years), the plain truth is that the incremental complexity of parallel programming over that of sequential programming is not as large as is commonly believed. Despite that you might have heard, the mind-numbing complexity of modern computer systems is not due so much to there being multiple CPUs, but rather to there being any CPUs at all. In short, for the ultimate in computer-system simplicity, the optimal choice is NR_CPUS=0. This commit therefore limits kernel builds to zero CPUs. This change has the beneficial side effect of rendering all kernel bugs harmless. Furthermore, this commit enables additional beneficial changes, for example, the removal of those parts of the kernel that are not needed when there are zero CPUs. Signed-off-by: Paul E. McKenney <redacted> Reviewed-by: Thomas Gleixner <redacted> --- alpha/Kconfig | 11 ++++++----- arm/Kconfig | 6 +++--- blackfin/Kconfig | 3 ++- hexagon/Kconfig | 9 +++++---- ia64/Kconfig | 9 +++++---- m32r/Kconfig | 10 ++++++---- mips/Kconfig | 21 +++++++++++---------- mn10300/Kconfig | 3 ++- parisc/Kconfig | 6 +++--- powerpc/platforms/Kconfig.cputype | 8 ++++---- s390/Kconfig | 12 +++++++----- sh/Kconfig | 11 ++++++----- sparc/Kconfig | 8 ++++---- tile/Kconfig | 9 +++++---- x86/Kconfig | 16 +++++++++------- 15 files changed, 78 insertions(+), 64 deletions(-)You forgot to fix half of the architectures, a.o. m68k?
I must confess that I fixed only the SMP-capable architectures. I of course would welcome additions for UP-only architectures. Thanx, Paul