* [PATCH] hpfs: Use hweight32
@ 2009-11-13 7:07 Akinobu Mita
2009-11-13 23:32 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Akinobu Mita @ 2009-11-13 7:07 UTC (permalink / raw)
To: akpm, linux-kernel; +Cc: Akinobu Mita, Mikulas Patocka, Al Viro
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;
}
--
1.6.5.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] hpfs: Use hweight32
2009-11-13 7:07 [PATCH] hpfs: Use hweight32 Akinobu Mita
@ 2009-11-13 23:32 ` Andrew Morton
2009-11-15 7:16 ` Mikulas Patocka
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2009-11-13 23:32 UTC (permalink / raw)
To: Akinobu Mita; +Cc: linux-kernel, Mikulas Patocka, Al Viro
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.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] hpfs: Use hweight32
2009-11-13 23:32 ` Andrew Morton
@ 2009-11-15 7:16 ` Mikulas Patocka
0 siblings, 0 replies; 3+ messages in thread
From: Mikulas Patocka @ 2009-11-15 7:16 UTC (permalink / raw)
To: Andrew Morton; +Cc: Akinobu Mita, linux-kernel, Al Viro
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
^ permalink raw reply [flat|nested] 3+ messages in thread
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2009-11-13 23:32 ` Andrew Morton
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