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Date: Sun, 20 Apr 2008 00:03:12 +0200
From: Marcin Slusarz <marcin.slusarz@gmail.com>
To: Bob Copeland <me@bobcopeland.com>
Cc: akpm@linux-foundation.org, hch@infradead.org, alan@lxorguk.ukuu.org.uk,
       miklos@szeredi.hu, linux-kernel@vger.kernel.org,
       linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 6/8] omfs: add bitmap routines
Message-ID: <20080419220307.GB7888@joi>
References: <1208637457-24969-7-git-send-email-me@bobcopeland.com>
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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