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Message-Id: <20221019052200.1604488-1-yury.norov@gmail.com>
Date: Tue, 18 Oct 2022 22:22:00 -0700
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Andrew Morton <akpm@...ux-foundation.org>,
Stephen Rothwell <sfr@...b.auug.org.au>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>,
"Paul E . McKenney" <paulmck@...nel.org>,
Vlastimil Babka <vbabka@...e.cz>,
Dmitry Vyukov <dvyukov@...gle.com>,
Valentin Schneider <vschneid@...hat.com>,
Sander Vanheule <sander@...nheule.net>,
Alexey Klimov <klimov.linux@...il.com>,
Eric Biggers <ebiggers@...gle.com>
Cc: Yury Norov <yury.norov@...il.com>
Subject: [PATCH] cpumask: limit visibility of FORCE_NR_CPUS
In current form, FORCE_NR_CPUS is visible to all users building their
kernels, even not experts. It is also set in allmodconfig or allyesconfig,
which is not a correct behavior.
Suggested-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Yury Norov <yury.norov@...il.com>
---
lib/Kconfig | 31 ++++++++++++++++++++++++-------
1 file changed, 24 insertions(+), 7 deletions(-)
diff --git a/lib/Kconfig b/lib/Kconfig
index 9bbf8a4b2108..1ada12f5dda6 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -528,14 +528,31 @@ config CPUMASK_OFFSTACK
them on the stack. This is a bit more expensive, but avoids
stack overflow.
+choice
+ prompt "Number of CPUs detection method"
+ default UNFORCE_NR_CPUS
+ depends on SMP && EXPERT
+ help
+ Select between boot-time and compile-time detection of number
+ of CPUs. If it's possible to provide exact number of CPUs at
+ compile-time, kernel code may be optimized better.
+ For general-purpose kernel, choose "boot time" option.
+
+config UNFORCE_NR_CPUS
+ bool "Set number of CPUs at boot time"
+ help
+ Choose it if you build general-purpose kernel and want to rely
+ on kernel to detect actual number of CPUs.
+
config FORCE_NR_CPUS
- bool "NR_CPUS is set to an actual number of CPUs"
- depends on SMP
- help
- Say Yes if you have NR_CPUS set to an actual number of possible
- CPUs in your system, not to a default value. This forces the core
- code to rely on compile-time value and optimize kernel routines
- better.
+ bool "Set number of CPUs at compile time"
+ help
+ Choose it if NR_CPUS corresponds to an actual number of
+ possible CPUs in your system. This forces the core code
+ to rely on compile-time value and optimize kernel routines
+ better.
+
+endchoice
config CPU_RMAP
bool
--
2.34.1
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