Commit 7baac8b9 authored May 13, 2008 by Alexander van Heukelum Committed by Thomas Gleixner May 23, 2008

cpumask: make for_each_cpu_mask a bit smaller



The for_each_cpu_mask loop is used quite often in the kernel. It
makes use of two functions: first_cpu and next_cpu. This patch
changes for_each_cpu_mask to use only the latter. Because next_cpu
finds the next eligible cpu _after_ the given one, the iteration
variable has to be initialized to -1 and next_cpu has to be
called with this value before the first iteration. An x86_64
defconfig kernel (from sched/latest) is about 2500 bytes smaller
with this patch applied:

   text	   data	    bss	    dec	    hex	filename
6222517	 917952	 749932	7890401	 7865e1	vmlinux.orig
6219922	 917952	 749932	7887806	 785bbe	vmlinux

The same size reduction is seen for defconfig+MAXSMP

   text	   data	    bss	    dec	    hex	filename
6241772	2563968	1492716	10298456	 9d2458	vmlinux.orig
6239211	2563968	1492716	10295895	 9d1a57	vmlinux

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent 3f9b48a7

include/linux/cpumask.h

+8 −8

Original line number	Diff line number	Diff line
		@@ -371,9 +371,9 @@ int __any_online_cpu(const cpumask_t *mask);
		#define next_cpu(n, src) __next_cpu((n), &(src))
		#define any_online_cpu(mask) __any_online_cpu(&(mask))
		#define for_each_cpu_mask(cpu, mask) \
		for ((cpu) = first_cpu(mask); \
		(cpu) < NR_CPUS; \
		(cpu) = next_cpu((cpu), (mask)))
		for ((cpu) = -1; \
		(cpu) = next_cpu((cpu), (mask)), \
		(cpu) < NR_CPUS; )
		#endif

		#if NR_CPUS <= 64
		@@ -388,9 +388,9 @@ int __next_cpu_nr(int n, const cpumask_t *srcp);
		#define next_cpu_nr(n, src) __next_cpu_nr((n), &(src))
		#define cpus_weight_nr(cpumask) __cpus_weight(&(cpumask), nr_cpu_ids)
		#define for_each_cpu_mask_nr(cpu, mask) \
		for ((cpu) = first_cpu(mask); \
		(cpu) < nr_cpu_ids; \
		(cpu) = next_cpu_nr((cpu), (mask)))
		for ((cpu) = -1; \
		(cpu) = next_cpu_nr((cpu), (mask)), \
		(cpu) < nr_cpu_ids; )

		#endif /* NR_CPUS > 64 */

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