leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

[XFRM]: Kill excessive refcounting of xfrm_state objects.

Browse Source 
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 <davem@davemloft.net>
This commit is contained in:
David S. Miller 2006-08-24 03:54:22 -07:00
parent 1c09539975
commit a47f0ce05a
1 changed files with 12 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
net/xfrm/xfrm_state.c
View File

@ -266,10 +266,8 @@ void km_state_expired(struct xfrm_state *x, int hard, u32 pid);
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);
@ -361,9 +359,9 @@ static void xfrm_timer_handler(unsigned long data)
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:
@ -378,7 +376,6 @@ expired:
out:
spin_unlock(&x->lock);
xfrm_state_put(x);
}
static void xfrm_replay_timer_handler(unsigned long data);
@ -433,19 +430,11 @@ int __xfrm_state_delete(struct xfrm_state *x)
x->km.state = XFRM_STATE_DEAD;
spin_lock(&xfrm_state_lock);
hlist_del(&x->bydst);
__xfrm_state_put(x);
hlist_del(&x->bysrc);
__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
@ -676,17 +665,13 @@ xfrm_state_find(xfrm_address_t *daddr, xfrm_address_t *saddr,
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);
h = xfrm_src_hash(saddr, family);
hlist_add_head(&x->bysrc, xfrm_state_bysrc+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 {
@ -713,26 +698,20 @@ static void __xfrm_state_insert(struct xfrm_state *x)
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_src_hash(&x->props.saddr, x->props.family);
hlist_add_head(&x->bysrc, xfrm_state_bysrc+h);
xfrm_state_hold(x);
if (xfrm_id_proto_match(x->id.proto, IPSEC_PROTO_ANY)) {
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);
@ -844,10 +823,8 @@ static struct xfrm_state *__find_acq_core(unsigned short family, u8 mode, u32 re
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);
h = xfrm_src_hash(saddr, family);
xfrm_state_hold(x);
hlist_add_head(&x->bysrc, xfrm_state_bysrc+h);
wake_up(&km_waitq);
}
@ -955,8 +932,7 @@ 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);
@ -981,8 +957,7 @@ int xfrm_state_check_expire(struct xfrm_state *x)
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;
}
@ -1177,7 +1152,6 @@ xfrm_alloc_spi(struct xfrm_state *x, u32 minspi, u32 maxspi)
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);
}
@ -1264,10 +1238,8 @@ void xfrm_replay_notify(struct xfrm_state *x, int event)
km_state_notify(x, &c);
if (x->replay_maxage &&
!mod_timer(&x->rtimer, jiffies + x->replay_maxage)) {
xfrm_state_hold(x);
!mod_timer(&x->rtimer, jiffies + x->replay_maxage))
x->xflags &= ~XFRM_TIME_DEFER;
}
}
EXPORT_SYMBOL(xfrm_replay_notify);
@ -1285,7 +1257,6 @@ static void xfrm_replay_timer_handler(unsigned long data)
}
spin_unlock(&x->lock);
xfrm_state_put(x);
}
int xfrm_replay_check(struct xfrm_state *x, u32 seq)