| Message ID | 538541A3.2060102@gmail.com |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
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@intel.com> > Signed-off-by: Niu Yawei <yawei.niu@intel.com> > --- > 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 > >
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, + * we check it without locking here to avoid unnecessary + * dqget()/dqput() calls. */ + if (inode->i_dquot[cnt]) + continue; + dq_get = 1; + 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;