Re: [PATCH 1/3] quota: optimize mark_dirty logic

[Jan Kara <jack@suse.cz>]

  Hi,

On Sat 27-03-10 15:15:38, Dmitry Monakhov wrote:
> - Skipp locking if quota is dirty already.
> - Return old quota state to help fs-specciffic implementation to optimize
>   case where quota was dirty already.
> 
> Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
> ---
>  fs/quota/dquot.c |   13 +++++++++++--
>  1 files changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> index e0b870f..88a8ef2 100644
> --- a/fs/quota/dquot.c
> +++ b/fs/quota/dquot.c
> @@ -319,14 +319,23 @@ static inline int mark_dquot_dirty(struct dquot *dquot)
>  	return dquot->dq_sb->dq_op->mark_dirty(dquot);
>  }
>  
> +/* Mark dquot dirty in atomic meaner, and return it's old dirty flag state */
>  int dquot_mark_dquot_dirty(struct dquot *dquot)
>  {
> +	int ret = 1;
> +
> +	/* If quota is dirtly already we don't have to acquire dq_list_lock */
> +	if (test_bit(DQ_MOD_B, &dquot->dq_flags))
> +		return 1;
> +
>  	spin_lock(&dq_list_lock);
> -	if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
> +	if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) {
>  		list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
>  				info[dquot->dq_type].dqi_dirty_list);
> +		ret = 0;
> +	}
>  	spin_unlock(&dq_list_lock);
> -	return 0;
> +	return ret;
>  }
>  EXPORT_SYMBOL(dquot_mark_dquot_dirty);
  OK, this looks fine. Merged.

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR