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quota: optimize i_dquot access
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Remove redundant calls of i_dquot(), keep pointer in local variable.

add/remove: 0/0 grow/shrink: 3/7 up/down: 40/-278 (-238)
function                                     old     new   delta
__dquot_free_space                           734     750     +16
__dquot_alloc_space                          484     500     +16
dquot_free_inode                             324     332      +8
dquot_drop                                    82      69     -13
vfs_load_quota_inode                        1357    1341     -16
dquot_reclaim_space_nodirty                  348     316     -32
dquot_disable                               1980    1944     -36
dquot_claim_space_nodirty                    354     314     -40
__dquot_drop                                 125      83     -42
__dquot_initialize                           522     423     -99

Signed-off-by: Konstantin Khlebnikov <[email protected]>
Signed-off-by: Jan Kara <[email protected]>
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@koct9i @jankara
koct9i authored and jankara committed Mar 4, 2015
1 parent 023a600 commit 5bcd3b6
Showing 1 changed file with 39 additions and 24 deletions.
63 changes: 39 additions & 24 deletions fs/quota/dquot.c
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Original file line number Diff line number Diff line change
Expand Up @@ -900,14 +900,17 @@ static inline struct dquot **i_dquot(struct inode *inode)

static int dqinit_needed(struct inode *inode, int type)
{
struct dquot * const *dquots;
int cnt;

if (IS_NOQUOTA(inode))
return 0;

dquots = i_dquot(inode);
if (type != -1)
return !i_dquot(inode)[type];
return !dquots[type];
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (!i_dquot(inode)[cnt])
if (!dquots[cnt])
return 1;
return 0;
}
Expand Down Expand Up @@ -970,12 +973,13 @@ static void add_dquot_ref(struct super_block *sb, int type)
static void remove_inode_dquot_ref(struct inode *inode, int type,
struct list_head *tofree_head)
{
struct dquot *dquot = i_dquot(inode)[type];
struct dquot **dquots = i_dquot(inode);
struct dquot *dquot = dquots[type];

i_dquot(inode)[type] = NULL;
if (!dquot)
return;

dquots[type] = NULL;
if (list_empty(&dquot->dq_free)) {
/*
* The inode still has reference to dquot so it can't be in the
Expand Down Expand Up @@ -1389,13 +1393,15 @@ static int dquot_active(const struct inode *inode)
static void __dquot_initialize(struct inode *inode, int type)
{
int cnt, init_needed = 0;
struct dquot *got[MAXQUOTAS];
struct dquot **dquots, *got[MAXQUOTAS];
struct super_block *sb = inode->i_sb;
qsize_t rsv;

if (!dquot_active(inode))
return;

dquots = i_dquot(inode);

/* First get references to structures we might need. */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
struct kqid qid;
Expand All @@ -1407,7 +1413,7 @@ static void __dquot_initialize(struct inode *inode, int type)
* we check it without locking here to avoid unnecessary
* dqget()/dqput() calls.
*/
if (i_dquot(inode)[cnt])
if (dquots[cnt])
continue;
init_needed = 1;

Expand Down Expand Up @@ -1438,16 +1444,16 @@ static void __dquot_initialize(struct inode *inode, int type)
/* We could race with quotaon or dqget() could have failed */
if (!got[cnt])
continue;
if (!i_dquot(inode)[cnt]) {
i_dquot(inode)[cnt] = got[cnt];
if (!dquots[cnt]) {
dquots[cnt] = got[cnt];
got[cnt] = NULL;
/*
* Make quota reservation system happy if someone
* did a write before quota was turned on
*/
rsv = inode_get_rsv_space(inode);
if (unlikely(rsv))
dquot_resv_space(i_dquot(inode)[cnt], rsv);
dquot_resv_space(dquots[cnt], rsv);
}
}
out_err:
Expand All @@ -1473,19 +1479,21 @@ EXPORT_SYMBOL(dquot_initialize);
static void __dquot_drop(struct inode *inode)
{
int cnt;
struct dquot **dquots = i_dquot(inode);
struct dquot *put[MAXQUOTAS];

spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
put[cnt] = i_dquot(inode)[cnt];
i_dquot(inode)[cnt] = NULL;
put[cnt] = dquots[cnt];
dquots[cnt] = NULL;
}
spin_unlock(&dq_data_lock);
dqput_all(put);
}

void dquot_drop(struct inode *inode)
{
struct dquot * const *dquots;
int cnt;

if (IS_NOQUOTA(inode))
Expand All @@ -1498,8 +1506,9 @@ void dquot_drop(struct inode *inode)
* must assure that nobody can come after the DQUOT_DROP and
* add quota pointers back anyway.
*/
dquots = i_dquot(inode);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (i_dquot(inode)[cnt])
if (dquots[cnt])
break;
}

Expand Down Expand Up @@ -1600,8 +1609,8 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
{
int cnt, ret = 0, index;
struct dquot_warn warn[MAXQUOTAS];
struct dquot **dquots = i_dquot(inode);
int reserve = flags & DQUOT_SPACE_RESERVE;
struct dquot **dquots;

if (!dquot_active(inode)) {
inode_incr_space(inode, number, reserve);
Expand All @@ -1611,6 +1620,7 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
warn[cnt].w_type = QUOTA_NL_NOWARN;

dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
Expand Down Expand Up @@ -1652,13 +1662,14 @@ int dquot_alloc_inode(struct inode *inode)
{
int cnt, ret = 0, index;
struct dquot_warn warn[MAXQUOTAS];
struct dquot * const *dquots = i_dquot(inode);
struct dquot * const *dquots;

if (!dquot_active(inode))
return 0;
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
warn[cnt].w_type = QUOTA_NL_NOWARN;

dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
Expand Down Expand Up @@ -1690,25 +1701,26 @@ EXPORT_SYMBOL(dquot_alloc_inode);
*/
int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
{
struct dquot **dquots;
int cnt, index;

if (!dquot_active(inode)) {
inode_claim_rsv_space(inode, number);
return 0;
}

dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&dq_data_lock);
/* Claim reserved quotas to allocated quotas */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (i_dquot(inode)[cnt])
dquot_claim_reserved_space(i_dquot(inode)[cnt],
number);
if (dquots[cnt])
dquot_claim_reserved_space(dquots[cnt], number);
}
/* Update inode bytes */
inode_claim_rsv_space(inode, number);
spin_unlock(&dq_data_lock);
mark_all_dquot_dirty(i_dquot(inode));
mark_all_dquot_dirty(dquots);
srcu_read_unlock(&dquot_srcu, index);
return 0;
}
Expand All @@ -1719,25 +1731,26 @@ EXPORT_SYMBOL(dquot_claim_space_nodirty);
*/
void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
{
struct dquot **dquots;
int cnt, index;

if (!dquot_active(inode)) {
inode_reclaim_rsv_space(inode, number);
return;
}

dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&dq_data_lock);
/* Claim reserved quotas to allocated quotas */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (i_dquot(inode)[cnt])
dquot_reclaim_reserved_space(i_dquot(inode)[cnt],
number);
if (dquots[cnt])
dquot_reclaim_reserved_space(dquots[cnt], number);
}
/* Update inode bytes */
inode_reclaim_rsv_space(inode, number);
spin_unlock(&dq_data_lock);
mark_all_dquot_dirty(i_dquot(inode));
mark_all_dquot_dirty(dquots);
srcu_read_unlock(&dquot_srcu, index);
return;
}
Expand All @@ -1750,14 +1763,15 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
{
unsigned int cnt;
struct dquot_warn warn[MAXQUOTAS];
struct dquot **dquots = i_dquot(inode);
struct dquot **dquots;
int reserve = flags & DQUOT_SPACE_RESERVE, index;

if (!dquot_active(inode)) {
inode_decr_space(inode, number, reserve);
return;
}

dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
Expand Down Expand Up @@ -1793,12 +1807,13 @@ void dquot_free_inode(struct inode *inode)
{
unsigned int cnt;
struct dquot_warn warn[MAXQUOTAS];
struct dquot * const *dquots = i_dquot(inode);
struct dquot * const *dquots;
int index;

if (!dquot_active(inode))
return;

dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
Expand Down

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