On Wed 28-05-14 09:53:39, Niu Yawei wrote:
> Avoid unnecessary dqget()/dqput() calls in __dquot_initialize(),
> that will introduce global lock contention otherwise.
The patch looks good. Just two minor nits below.
Honza
> Signed-off-by: Lai Siyao <lai.siyao@xxxxxxxxx>
> Signed-off-by: Niu Yawei <yawei.niu@xxxxxxxxx>
> ---
> fs/quota/dquot.c | 13 ++++++++++++-
> 1 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> index 9cd5f63..dc6f711 100644
> --- a/fs/quota/dquot.c
> +++ b/fs/quota/dquot.c
> @@ -1400,7 +1400,7 @@ static int dquot_active(const struct inode *inode)
> */
> static void __dquot_initialize(struct inode *inode, int type)
> {
> - int cnt;
> + int cnt, dq_get = 0;
> struct dquot *got[MAXQUOTAS];
> struct super_block *sb = inode->i_sb;
> qsize_t rsv;
> @@ -1416,6 +1416,13 @@ static void __dquot_initialize(struct inode *inode, int type)
> got[cnt] = NULL;
> if (type != -1 && cnt != type)
> continue;
> + /* the i_dquot should have been initialized in most case,
cases ^^^
> + * we check it without locking here to avoid unnecessary
> + * dqget()/dqput() calls. */
Please fix the comment style - scripts/checkpatch.pl is your friend.
> + if (inode->i_dquot[cnt])
> + continue;
> + dq_get = 1;
init_needed or something like that would be a better name I think.
> +
> switch (cnt) {
> case USRQUOTA:
> qid = make_kqid_uid(inode->i_uid);
> @@ -1427,6 +1434,10 @@ static void __dquot_initialize(struct inode *inode, int type)
> got[cnt] = dqget(sb, qid);
> }
>
> + /* all required i_dquot has been initialized */
> + if (!dq_get)
> + return;
> +
> down_write(&sb_dqopt(sb)->dqptr_sem);
> if (IS_NOQUOTA(inode))
> goto out_err;
> --
> 1.7.1
>
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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