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authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-17 20:32:05 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-17 20:32:05 +0300
commit3cd0462230d806077c709e44af8733795eaa712c (patch)
tree1b9cfe66a3d8adf91d4907b01a0b86807d2d669b /lib
parent16208cd6c36ac558c2c09042feb2b61e1e58f78a (diff)
parent0c09ab96fc820109d63097a2adcbbd20836b655f (diff)
downloadlinux-3cd0462230d806077c709e44af8733795eaa712c.tar.xz
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull CPU hotplug updates from Thomas Gleixner: "A small update for the SMP hotplug code code: - Track "booted once" CPUs in a cpumask so the x86 APIC code has an easy way to decide whether broadcast IPIs are safe to use or not. - Implement a cpumask_or_equal() helper for the IPI broadcast evaluation. The above two changes have been also pulled into the x86/apic branch for implementing the conditional IPI broadcast feature. - Cache the number of online CPUs instead of reevaluating it over and over. num_online_cpus() is an unreliable snapshot anyway except when it is used outside a cpu hotplug locked region. The cached access is not changing this, but it's definitely faster than calculating the bitmap wheight especially in hot paths" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Cache number of online CPUs cpumask: Implement cpumask_or_equal() smp/hotplug: Track booted once CPUs in a cpumask
Diffstat (limited to 'lib')
-rw-r--r--lib/bitmap.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c
index bbe2589e8497..f9e834841e94 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -59,6 +59,26 @@ int __bitmap_equal(const unsigned long *bitmap1,
}
EXPORT_SYMBOL(__bitmap_equal);
+bool __bitmap_or_equal(const unsigned long *bitmap1,
+ const unsigned long *bitmap2,
+ const unsigned long *bitmap3,
+ unsigned int bits)
+{
+ unsigned int k, lim = bits / BITS_PER_LONG;
+ unsigned long tmp;
+
+ for (k = 0; k < lim; ++k) {
+ if ((bitmap1[k] | bitmap2[k]) != bitmap3[k])
+ return false;
+ }
+
+ if (!(bits % BITS_PER_LONG))
+ return true;
+
+ tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k];
+ return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0;
+}
+
void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
{
unsigned int k, lim = BITS_TO_LONGS(bits);