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[Qemu-devel] [RFC v2 02/33] bitmap: introduce bitmap_count_one()
From: |
Peter Xu |
Subject: |
[Qemu-devel] [RFC v2 02/33] bitmap: introduce bitmap_count_one() |
Date: |
Wed, 30 Aug 2017 16:31:59 +0800 |
Count how many bits set in the bitmap.
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
Signed-off-by: Peter Xu <address@hidden>
---
include/qemu/bitmap.h | 10 ++++++++++
util/bitmap.c | 15 +++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h
index c318da1..a13bd28 100644
--- a/include/qemu/bitmap.h
+++ b/include/qemu/bitmap.h
@@ -82,6 +82,7 @@ int slow_bitmap_andnot(unsigned long *dst, const unsigned
long *bitmap1,
const unsigned long *bitmap2, long bits);
int slow_bitmap_intersects(const unsigned long *bitmap1,
const unsigned long *bitmap2, long bits);
+long slow_bitmap_count_one(const unsigned long *bitmap, long nbits);
static inline unsigned long *bitmap_try_new(long nbits)
{
@@ -216,6 +217,15 @@ static inline int bitmap_intersects(const unsigned long
*src1,
}
}
+static inline long bitmap_count_one(const unsigned long *bitmap, long nbits)
+{
+ if (small_nbits(nbits)) {
+ return (ctpopl(*bitmap & BITMAP_LAST_WORD_MASK(nbits)));
+ } else {
+ return slow_bitmap_count_one(bitmap, nbits);
+ }
+}
+
void bitmap_set(unsigned long *map, long i, long len);
void bitmap_set_atomic(unsigned long *map, long i, long len);
void bitmap_clear(unsigned long *map, long start, long nr);
diff --git a/util/bitmap.c b/util/bitmap.c
index efced9a..3446d72 100644
--- a/util/bitmap.c
+++ b/util/bitmap.c
@@ -355,3 +355,18 @@ int slow_bitmap_intersects(const unsigned long *bitmap1,
}
return 0;
}
+
+long slow_bitmap_count_one(const unsigned long *bitmap, long nbits)
+{
+ long k, lim = nbits/BITS_PER_LONG, result = 0;
+
+ for (k = 0; k < lim; k++) {
+ result += ctpopl(bitmap[k]);
+ }
+
+ if (nbits % BITS_PER_LONG) {
+ result += ctpopl(bitmap[k] & BITMAP_LAST_WORD_MASK(nbits));
+ }
+
+ return result;
+}
--
2.7.4
- [Qemu-devel] [RFC v2 00/33] Migration: postcopy failure recovery, Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 01/33] bitmap: remove BITOP_WORD(), Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 02/33] bitmap: introduce bitmap_count_one(),
Peter Xu <=
- [Qemu-devel] [RFC v2 03/33] bitmap: provide to_le/from_le helpers, Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 04/33] migration: dump str in migrate_set_state trace, Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 05/33] migration: better error handling with QEMUFile, Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 06/33] migration: reuse mis->userfault_quit_fd, Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 07/33] migration: provide postcopy_fault_thread_notify(), Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 09/33] migration: implement "postcopy-pause" src logic, Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 08/33] migration: new postcopy-pause state, Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 10/33] migration: allow dst vm pause on postcopy, Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 11/33] migration: allow src return path to pause, Peter Xu, 2017/08/30
- [Qemu-devel] [RFC v2 12/33] migration: allow send_rq to fail, Peter Xu, 2017/08/30