diff options
Diffstat (limited to 'src/runtime/mpallocbits.go')
| -rw-r--r-- | src/runtime/mpallocbits.go | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/runtime/mpallocbits.go b/src/runtime/mpallocbits.go index a3cbc53a1b..b460c032bf 100644 --- a/src/runtime/mpallocbits.go +++ b/src/runtime/mpallocbits.go @@ -88,6 +88,26 @@ func (b *pageBits) clearAll() { } } +// popcntRange counts the number of set bits in the +// range [i, i+n). +func (b *pageBits) popcntRange(i, n uint) (s uint) { + if n == 1 { + return uint((b[i/64] >> (i % 64)) & 1) + } + _ = b[i/64] + j := i + n - 1 + if i/64 == j/64 { + return uint(bits.OnesCount64((b[i/64] >> (i % 64)) & ((1 << n) - 1))) + } + _ = b[j/64] + s += uint(bits.OnesCount64(b[i/64] >> (i % 64))) + for k := i/64 + 1; k < j/64; k++ { + s += uint(bits.OnesCount64(b[k])) + } + s += uint(bits.OnesCount64(b[j/64] & ((1 << (j%64 + 1)) - 1))) + return +} + // pallocBits is a bitmap that tracks page allocations for at most one // palloc chunk. // |