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inetpeer: reduce stack usage

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On 64bit arches, we use 752 bytes of stack when cleanup_once() is called
from inet_getpeer().

Lets share the avl stack to save ~376 bytes.

Before patch :

# objdump -d net/ipv4/inetpeer.o | scripts/checkstack.pl

0x000006c3 unlink_from_pool [inetpeer.o]:		376
0x00000721 unlink_from_pool [inetpeer.o]:		376
0x00000cb1 inet_getpeer [inetpeer.o]:			376
0x00000e6d inet_getpeer [inetpeer.o]:			376
0x0004 inet_initpeers [inetpeer.o]:			112
# size net/ipv4/inetpeer.o
   text	   data	    bss	    dec	    hex	filename
   5320	    432	     21	   5773	   168d	net/ipv4/inetpeer.o

After patch :

objdump -d net/ipv4/inetpeer.o | scripts/checkstack.pl
0x00000c11 inet_getpeer [inetpeer.o]:			376
0x00000dcd inet_getpeer [inetpeer.o]:			376
0x00000ab9 peer_check_expire [inetpeer.o]:		328
0x00000b7f peer_check_expire [inetpeer.o]:		328
0x0004 inet_initpeers [inetpeer.o]:			112
# size net/ipv4/inetpeer.o
   text	   data	    bss	    dec	    hex	filename
   5163	    432	     21	   5616	   15f0	net/ipv4/inetpeer.o

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Scot Doyle <lkml@scotdoyle.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Reviewed-by: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2011-04-11 22:39:40 +00:00 • committed by David S. Miller
parent f8e9881c2a
commit 66944e1c57
1 changed files with 7 additions and 6 deletions
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13
net/ipv4/inetpeer.c
View file

@ -354,7 +354,8 @@ static void inetpeer_free_rcu(struct rcu_head *head)
} }
/* May be called with local BH enabled. */ /* May be called with local BH enabled. */
static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base) static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base,
struct inet_peer __rcu **stack[PEER_MAXDEPTH])
{ {
int do_free; int do_free;
@ -368,7 +369,6 @@ static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base)
* We use refcnt=-1 to alert lockless readers this entry is deleted. * We use refcnt=-1 to alert lockless readers this entry is deleted.
*/ */
if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) { if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) {
struct inet_peer __rcu **stack[PEER_MAXDEPTH];
struct inet_peer __rcu ***stackptr, ***delp; struct inet_peer __rcu ***stackptr, ***delp;
if (lookup(&p->daddr, stack, base) != p) if (lookup(&p->daddr, stack, base) != p)
BUG(); BUG();
@ -422,7 +422,7 @@ static struct inet_peer_base *peer_to_base(struct inet_peer *p)
} }
/* May be called with local BH enabled. */ /* May be called with local BH enabled. */
static int cleanup_once(unsigned long ttl) static int cleanup_once(unsigned long ttl, struct inet_peer __rcu **stack[PEER_MAXDEPTH])
{ {
struct inet_peer *p = NULL; struct inet_peer *p = NULL;
@ -454,7 +454,7 @@ static int cleanup_once(unsigned long ttl)
* happen because of entry limits in route cache. */ * happen because of entry limits in route cache. */
return -1; return -1;
unlink_from_pool(p, peer_to_base(p)); unlink_from_pool(p, peer_to_base(p), stack);
return 0; return 0;
} }
@ -524,7 +524,7 @@ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
if (base->total >= inet_peer_threshold) if (base->total >= inet_peer_threshold)
/* Remove one less-recently-used entry. */ /* Remove one less-recently-used entry. */
cleanup_once(0); cleanup_once(0, stack);
return p; return p;
} }
@ -540,6 +540,7 @@ static void peer_check_expire(unsigned long dummy)
{ {
unsigned long now = jiffies; unsigned long now = jiffies;
int ttl, total; int ttl, total;
struct inet_peer __rcu **stack[PEER_MAXDEPTH];
total = compute_total(); total = compute_total();
if (total >= inet_peer_threshold) if (total >= inet_peer_threshold)
@ -548,7 +549,7 @@ static void peer_check_expire(unsigned long dummy)
ttl = inet_peer_maxttl ttl = inet_peer_maxttl
- (inet_peer_maxttl - inet_peer_minttl) / HZ * - (inet_peer_maxttl - inet_peer_minttl) / HZ *
total / inet_peer_threshold * HZ; total / inet_peer_threshold * HZ;
while (!cleanup_once(ttl)) { while (!cleanup_once(ttl, stack)) {
if (jiffies != now) if (jiffies != now)
break; break;
} }