Re: [PATCH 6/8] omfs: add bitmap routines

From: Marcin Slusarz
Date: Sat Apr 19 2008 - 18:03:56 EST


On Sat, Apr 19, 2008 at 04:37:35PM -0400, Bob Copeland wrote:
> +unsigned long omfs_count_free(struct super_block *sb)
> +{
> + unsigned int i, j;
> + u64 *map;
> + unsigned long sum = 0;
> + struct omfs_sb_info *sbi = OMFS_SB(sb);
> +
> + for (i = 0; i < sbi->s_imap_size; i++) {
> + map = (u64 *) sbi->s_imap[i];
> + for (j = 0; j < sb->s_blocksize / 8; j++)
> + sum += hweight64(~map[j]);
> + }
> + return sum;
> +}
I think inner loop can be replaced with something like:
sum += sb->s_blocksize * 8 - bitmap_weight(map, sb->s_blocksize * 8);

Marcin
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