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| author | Sander Vanheule <sander@svanheule.net> | 2022-08-09 19:36:34 +0200 |
|---|---|---|
| committer | Yury Norov <yury.norov@gmail.com> | 2022-08-15 11:00:44 -0700 |
| commit | 2248ccd80124e61c2c84a22b22409bab452e1f0c (patch) | |
| tree | b6c88a201ab4132acc8f547f2bfdf445abbf0a5c | |
| parent | be599244865cb788abe2c6f59ccb05d7240448e4 (diff) | |
| download | lwn-2248ccd80124e61c2c84a22b22409bab452e1f0c.tar.gz lwn-2248ccd80124e61c2c84a22b22409bab452e1f0c.zip | |
lib/cpumask: add inline cpumask_next_wrap() for UP
In the uniprocessor case, cpumask_next_wrap() can be simplified, as the
number of valid argument combinations is limited:
- 'start' can only be 0
- 'n' can only be -1 or 0
The only valid CPU that can then be returned, if any, will be the first
one set in the provided 'mask'.
For NR_CPUS == 1, include/linux/cpumask.h now provides an inline
definition of cpumask_next_wrap(), which will conflict with the one
provided by lib/cpumask.c. Make building of lib/cpumask.o again depend
on CONFIG_SMP=y (i.e. NR_CPUS > 1) to avoid the re-definition.
Suggested-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
| -rw-r--r-- | include/linux/cpumask.h | 19 | ||||
| -rw-r--r-- | lib/Makefile | 3 |
2 files changed, 21 insertions, 1 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index d8c2a40f8beb..bd047864c7ac 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -262,7 +262,26 @@ unsigned int cpumask_next_and(int n, const struct cpumask *src1p, (cpu) = cpumask_next_zero((cpu), (mask)), \ (cpu) < nr_cpu_ids;) +#if NR_CPUS == 1 +static inline +unsigned int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap) +{ + cpumask_check(start); + if (n != -1) + cpumask_check(n); + + /* + * Return the first available CPU when wrapping, or when starting before cpu0, + * since there is only one valid option. + */ + if (wrap && n >= 0) + return nr_cpumask_bits; + + return cpumask_first(mask); +} +#else unsigned int __pure cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap); +#endif /** * for_each_cpu_wrap - iterate over every cpu in a mask, starting at a specified location diff --git a/lib/Makefile b/lib/Makefile index c95212141928..5927d7fa0806 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -34,9 +34,10 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ is_single_threaded.o plist.o decompress.o kobject_uevent.o \ earlycpio.o seq_buf.o siphash.o dec_and_lock.o \ nmi_backtrace.o win_minmax.o memcat_p.o \ - buildid.o cpumask.o + buildid.o lib-$(CONFIG_PRINTK) += dump_stack.o +lib-$(CONFIG_SMP) += cpumask.o lib-y += kobject.o klist.o obj-y += lockref.o |