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authorLinus Torvalds <torvalds@linux-foundation.org>2022-10-10 12:49:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-10-10 12:49:34 -0700
commitd4013bc4d49f6da8178a340348369bb9920225c9 (patch)
tree3e7ad8a2b2d726179aca30d04d52c2fabef97e7c /kernel/smp.c
parentcdf072acb5baa18e5b05bdf3f13d6481f62396fc (diff)
parent585463f0d58aa4d29b744c7c53b222b8028de87f (diff)
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Merge tag 'bitmap-6.1-rc1' of https://github.com/norov/linux
Pull bitmap updates from Yury Norov: - Fix unsigned comparison to -1 in CPUMAP_FILE_MAX_BYTES (Phil Auld) - cleanup nr_cpu_ids vs nr_cpumask_bits mess (me) This series cleans that mess and adds new config FORCE_NR_CPUS that allows to optimize cpumask subsystem if the number of CPUs is known at compile-time. - optimize find_bit() functions (me) Reworks find_bit() functions based on new FIND_{FIRST,NEXT}_BIT() macros. - add find_nth_bit() (me) Adds find_nth_bit(), which is ~70 times faster than bitcounting with for_each() loop: for_each_set_bit(bit, mask, size) if (n-- == 0) return bit; Also adds bitmap_weight_and() to let people replace this pattern: tmp = bitmap_alloc(nbits); bitmap_and(tmp, map1, map2, nbits); weight = bitmap_weight(tmp, nbits); bitmap_free(tmp); with a single bitmap_weight_and() call. - repair cpumask_check() (me) After switching cpumask to use nr_cpu_ids, cpumask_check() started generating many false-positive warnings. This series fixes it. - Add for_each_cpu_andnot() and for_each_cpu_andnot() (Valentin Schneider) Extends the API with one more function and applies it in sched/core. * tag 'bitmap-6.1-rc1' of https://github.com/norov/linux: (28 commits) sched/core: Merge cpumask_andnot()+for_each_cpu() into for_each_cpu_andnot() lib/test_cpumask: Add for_each_cpu_and(not) tests cpumask: Introduce for_each_cpu_andnot() lib/find_bit: Introduce find_next_andnot_bit() cpumask: fix checking valid cpu range lib/bitmap: add tests for for_each() loops lib/find: optimize for_each() macros lib/bitmap: introduce for_each_set_bit_wrap() macro lib/find_bit: add find_next{,_and}_bit_wrap cpumask: switch for_each_cpu{,_not} to use for_each_bit() net: fix cpu_max_bits_warn() usage in netif_attrmask_next{,_and} cpumask: add cpumask_nth_{,and,andnot} lib/bitmap: remove bitmap_ord_to_pos lib/bitmap: add tests for find_nth_bit() lib: add find_nth{,_and,_andnot}_bit() lib/bitmap: add bitmap_weight_and() lib/bitmap: don't call __bitmap_weight() in kernel code tools: sync find_bit() implementation lib/find_bit: optimize find_next_bit() functions lib/find_bit: create find_first_zero_bit_le() ...
Diffstat (limited to 'kernel/smp.c')
-rw-r--r--kernel/smp.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/smp.c b/kernel/smp.c
index e8cdc025a046..06a413987a14 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -1069,7 +1069,7 @@ static int __init nrcpus(char *str)
int nr_cpus;
if (get_option(&str, &nr_cpus) && nr_cpus > 0 && nr_cpus < nr_cpu_ids)
- nr_cpu_ids = nr_cpus;
+ set_nr_cpu_ids(nr_cpus);
return 0;
}
@@ -1087,14 +1087,16 @@ static int __init maxcpus(char *str)
early_param("maxcpus", maxcpus);
+#if (NR_CPUS > 1) && !defined(CONFIG_FORCE_NR_CPUS)
/* Setup number of possible processor ids */
unsigned int nr_cpu_ids __read_mostly = NR_CPUS;
EXPORT_SYMBOL(nr_cpu_ids);
+#endif
/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
void __init setup_nr_cpu_ids(void)
{
- nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
+ set_nr_cpu_ids(find_last_bit(cpumask_bits(cpu_possible_mask), NR_CPUS) + 1);
}
/* Called by boot processor to activate the rest. */