sched/isolation: Make CONFIG_CPU_ISOLATION=y depend on SMP or COMPILE_TEST

On uniprocessor systems, critical and non-critical tasks cannot be
isolated, as there is only a single CPU core.  Hence enabling CPU
isolation by default on such systems does not make much sense.

Instead of changing the default for !SMP, fix this by making the feature
depend on SMP, with an override for compile-testing.  Note that its sole
selector (NO_HZ_FULL) already depends on SMP.

This decreases kernel size for a default uniprocessor kernel by ca. 1 KiB.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 2c43838c99 ("sched/isolation: Enable CONFIG_CPU_ISOLATION=y by default")
Link: http://lkml.kernel.org/r/1514891590-20782-1-git-send-email-geert@linux-m68k.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Geert Uytterhoeven 2018-01-02 12:13:10 +01:00 committed by Ingo Molnar
parent 7729bebc61
commit 414a2dc138

View File

@ -461,6 +461,7 @@ endmenu # "CPU/Task time and stats accounting"
config CPU_ISOLATION
bool "CPU isolation"
depends on SMP || COMPILE_TEST
default y
help
Make sure that CPUs running critical tasks are not disturbed by