cpumask: make cpumask_next() out-of-line

Every for_each_XXX_cpu() invocation calls cpumask_next() which is an
inline function:

	static inline unsigned int cpumask_next(int n, const struct cpumask *srcp)
	{
	        /* -1 is a legal arg here. */
	        if (n != -1)
	                cpumask_check(n);
	        return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1);
	}

However!

find_next_bit() is regular out-of-line function which means "nr_cpu_ids"
load and increment happen at the caller resulting in a lot of bloat

x86_64 defconfig:
	add/remove: 3/0 grow/shrink: 8/373 up/down: 155/-5668 (-5513)
x86_64 allyesconfig-ish:
	add/remove: 3/1 grow/shrink: 57/634 up/down: 3515/-28177 (-24662) !!!

Some archs redefine find_next_bit() but it is OK:

	m68k		inline but SMP is not supported
	arm		out-of-line
	unicore32	out-of-line

Function call will happen anyway, so move load and increment into callee.

Link: http://lkml.kernel.org/r/20170824230010.GA1593@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 14 deletions

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 68c5a8290275..cd415b733c2a 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -178,20 +178,7 @@ static inline unsigned int cpumask_first(const struct cpumask *srcp)
         return find_first_bit(cpumask_bits(srcp), nr_cpumask_bits);
 }
 
-/**
- * cpumask_next - get the next cpu in a cpumask
- * @n: the cpu prior to the place to search (ie. return will be > @n)
- * @srcp: the cpumask pointer
- *
- * Returns >= nr_cpu_ids if no further cpus set.
- */
-static inline unsigned int cpumask_next(int n, const struct cpumask *srcp)
-{
-        /* -1 is a legal arg here. */
-        if (n != -1)
-                cpumask_check(n);
-        return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1);
-}
+unsigned int cpumask_next(int n, const struct cpumask *srcp);
 
 /**
  * cpumask_next_zero - get the next unset cpu in a cpumask