[XFRM]: Kill excessive refcounting of xfrm_state objects.
The refcounting done for timers and hash table insertions
are just wasted cycles. We can eliminate all of this
refcounting because:
1) The implicit refcount when the xfrm_state object is active
will always be held while the object is in the hash tables.
We never kfree() the xfrm_state until long after we've made
sure that it has been unhashed.
2) Timers are even easier. Once we mark that x->km.state as
anything other than XFRM_STATE_VALID (__xfrm_state_delete
sets it to XFRM_STATE_DEAD), any timer that fires will
do nothing and return without rearming the timer.
Therefore we can defer the del_timer calls until when the
object is about to be freed up during GC. We have to use
del_timer_sync() and defer it to GC because we can't do
a del_timer_sync() while holding x->lock which all callers
of __xfrm_state_delete hold.
This makes SA changes even more light-weight.
Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
---
net/xfrm/xfrm_state.c | 54 +++++++++++++------------------------------------
1 files changed, 14 insertions(+), 40 deletions(-)
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index b1c0ae7..814e72e 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -229,10 +229,8 @@ void km_state_expired(struct xfrm_state
static void xfrm_state_gc_destroy(struct xfrm_state *x)
{
- if (del_timer(&x->timer))
- BUG();
- if (del_timer(&x->rtimer))
- BUG();
+ del_timer_sync(&x->timer);
+ del_timer_sync(&x->rtimer);
kfree(x->aalg);
kfree(x->ealg);
kfree(x->calg);
@@ -323,9 +321,9 @@ static void xfrm_timer_handler(unsigned
if (warn)
km_state_expired(x, 0, 0);
resched:
- if (next != LONG_MAX &&
- !mod_timer(&x->timer, jiffies + make_jiffies(next)))
- xfrm_state_hold(x);
+ if (next != LONG_MAX)
+ mod_timer(&x->timer, jiffies + make_jiffies(next));
+
goto out;
expired:
@@ -340,7 +338,6 @@ expired:
out:
spin_unlock(&x->lock);
- xfrm_state_put(x);
}
static void xfrm_replay_timer_handler(unsigned long data);
@@ -394,17 +391,10 @@ int __xfrm_state_delete(struct xfrm_stat
x->km.state = XFRM_STATE_DEAD;
spin_lock(&xfrm_state_lock);
hlist_del(&x->bydst);
- __xfrm_state_put(x);
- if (x->id.spi) {
+ if (x->id.spi)
hlist_del(&x->byspi);
- __xfrm_state_put(x);
- }
xfrm_state_num--;
spin_unlock(&xfrm_state_lock);
- if (del_timer(&x->timer))
- __xfrm_state_put(x);
- if (del_timer(&x->rtimer))
- __xfrm_state_put(x);
/* All xfrm_state objects are created by xfrm_state_alloc.
* The xfrm_state_alloc call gives a reference, and that
@@ -579,14 +569,11 @@ xfrm_state_find(xfrm_address_t *daddr, x
if (km_query(x, tmpl, pol) == 0) {
x->km.state = XFRM_STATE_ACQ;
hlist_add_head(&x->bydst, xfrm_state_bydst+h);
- xfrm_state_hold(x);
if (x->id.spi) {
h = xfrm_spi_hash(&x->id.daddr, x->id.spi,
x->id.proto, family);
hlist_add_head(&x->byspi, xfrm_state_byspi+h);
- xfrm_state_hold(x);
}
x->lft.hard_add_expires_seconds = XFRM_ACQ_EXPIRES;
- xfrm_state_hold(x);
x->timer.expires = jiffies + XFRM_ACQ_EXPIRES*HZ;
add_timer(&x->timer);
} else {
@@ -609,24 +596,17 @@ static void __xfrm_state_insert(struct x
{
unsigned int h;
- h = xfrm_dst_hash(&x->id.daddr, x->props.reqid, x->props.family);
-
x->genid = ++xfrm_state_genid;
+ h = xfrm_dst_hash(&x->id.daddr, x->props.reqid, x->props.family);
hlist_add_head(&x->bydst, xfrm_state_bydst+h);
- xfrm_state_hold(x);
h = xfrm_spi_hash(&x->id.daddr, x->id.spi, x->id.proto,
x->props.family);
-
hlist_add_head(&x->byspi, xfrm_state_byspi+h);
- xfrm_state_hold(x);
-
- if (!mod_timer(&x->timer, jiffies + HZ))
- xfrm_state_hold(x);
- if (x->replay_maxage &&
- !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
- xfrm_state_hold(x);
+ mod_timer(&x->timer, jiffies + HZ);
+ if (x->replay_maxage)
+ mod_timer(&x->rtimer, jiffies + x->replay_maxage);
wake_up(&km_waitq);
@@ -738,7 +718,6 @@ static struct xfrm_state *__find_acq_cor
xfrm_state_hold(x);
x->timer.expires = jiffies + XFRM_ACQ_EXPIRES*HZ;
add_timer(&x->timer);
- xfrm_state_hold(x);
hlist_add_head(&x->bydst, xfrm_state_bydst+h);
wake_up(&km_waitq);
}
@@ -840,8 +819,7 @@ out:
memcpy(&x1->lft, &x->lft, sizeof(x1->lft));
x1->km.dying = 0;
- if (!mod_timer(&x1->timer, jiffies + HZ))
- xfrm_state_hold(x1);
+ mod_timer(&x1->timer, jiffies + HZ);
if (x1->curlft.use_time)
xfrm_state_check_expire(x1);
@@ -866,8 +844,7 @@ int xfrm_state_check_expire(struct xfrm_
if (x->curlft.bytes >= x->lft.hard_byte_limit ||
x->curlft.packets >= x->lft.hard_packet_limit) {
x->km.state = XFRM_STATE_EXPIRED;
- if (!mod_timer(&x->timer, jiffies))
- xfrm_state_hold(x);
+ mod_timer(&x->timer, jiffies);
return -EINVAL;
}
@@ -1010,7 +987,6 @@ xfrm_alloc_spi(struct xfrm_state *x, u32
spin_lock_bh(&xfrm_state_lock);
h = xfrm_spi_hash(&x->id.daddr, x->id.spi, x->id.proto,
x->props.family);
hlist_add_head(&x->byspi, xfrm_state_byspi+h);
- xfrm_state_hold(x);
spin_unlock_bh(&xfrm_state_lock);
wake_up(&km_waitq);
}
@@ -1096,9 +1072,8 @@ void xfrm_replay_notify(struct xfrm_stat
c.data.aevent = event;
km_state_notify(x, &c);
- if (x->replay_maxage &&
- !mod_timer(&x->rtimer, jiffies + x->replay_maxage)) {
- xfrm_state_hold(x);
+ if (x->replay_maxage) {
+ mod_timer(&x->rtimer, jiffies + x->replay_maxage);
x->xflags &= ~XFRM_TIME_DEFER;
}
}
@@ -1118,7 +1093,6 @@ static void xfrm_replay_timer_handler(un
}
spin_unlock(&x->lock);
- xfrm_state_put(x);
}
int xfrm_replay_check(struct xfrm_state *x, u32 seq)
--
1.4.2.rc2.g3e042
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