Messages in this thread | | | Date | Sun, 15 Nov 2009 08:16:31 +0100 (CET) | From | Mikulas Patocka <> | Subject | Re: [PATCH] hpfs: Use hweight32 |
| |
On Fri, 13 Nov 2009, Andrew Morton wrote:
> On Fri, 13 Nov 2009 16:07:08 +0900 > Akinobu Mita <akinobu.mita@gmail.com> wrote: > > > Use hweight32 instead of counting for each bit > > > > Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> > > Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> > > Cc: Al Viro <viro@zeniv.linux.org.uk> > > --- > > fs/hpfs/super.c | 7 ++----- > > 1 files changed, 2 insertions(+), 5 deletions(-) > > > > diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c > > index f2feaa0..cf6fe4a 100644 > > --- a/fs/hpfs/super.c > > +++ b/fs/hpfs/super.c > > @@ -119,11 +119,8 @@ unsigned hpfs_count_one_bitmap(struct super_block *s, secno secno) > > unsigned i, count; > > if (!(bits = hpfs_map_4sectors(s, secno, &qbh, 4))) return 0; > > count = 0; > > - for (i = 0; i < 2048 / sizeof(unsigned); i++) { > > - unsigned b; > > - if (!bits[i]) continue; > > - for (b = bits[i]; b; b>>=1) count += b & 1; > > - } > > + for (i = 0; i < 2048 / sizeof(unsigned); i++) > > + count += hweight32(bits[i]); > > hpfs_brelse4(&qbh); > > return count; > > Could actualy use bitmap_weight() here. > > It's a bit naughty, because bitmap_weight() operates on long*'s, but it > will work OK. > > Shrug.
... and add support for popcnt, so that it's optimized on AMD CPUs.
Mikulas
| |