diff options
| author | Shrikanth Hegde <sshegde@linux.ibm.com> | 2026-09-28 11:07:17 +0530 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-09-28 08:44:40 +0200 |
| commit | cfb463b7172dca2f29b2221b71b54890f268e3fb (patch) | |
| tree | fad688fd210e231fc9d322b5ac56f787e7639ffa /lib | |
| parent | a8d0854a76a876ea474e17322acb680716a09da2 (diff) | |
cpumask: Introduce cpumask_intersects_and
Introduce bitmap_intersects_and() to determine whether the intersection
of three bitmaps is non-empty. Unlike cpumask_first_and_and(), this
returns immediately when an intersecting word is found and does not
calculate the first matching bit.
Add cpumask_intersects_and() as the corresponding cpumask wrapper.
A subsequent patch uses the helper to determine whether a task
has a CPU that is present in its affinity mask, the preferred CPU mask,
and task possible CPU mask.
Suggested-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Reviwed-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Link: https://patch.msgid.link/20260928053728.797539-3-sshegde@linux.ibm.com
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/bitmap.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index ed685127a107..d1cb8a507c60 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -308,6 +308,23 @@ bool __bitmap_intersects(const unsigned long *bitmap1, } EXPORT_SYMBOL(__bitmap_intersects); +bool __bitmap_intersects_and(const unsigned long *bitmap1, + const unsigned long *bitmap2, + const unsigned long *bitmap3, unsigned int bits) +{ + unsigned int k, lim = bits / BITS_PER_LONG; + + for (k = 0; k < lim; ++k) + if (bitmap1[k] & bitmap2[k] & bitmap3[k]) + return true; + + if (bits % BITS_PER_LONG) + if ((bitmap1[k] & bitmap2[k] & bitmap3[k]) & BITMAP_LAST_WORD_MASK(bits)) + return true; + return false; +} +EXPORT_SYMBOL(__bitmap_intersects_and); + bool __bitmap_subset(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { |