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Commit 66944e1c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

inetpeer: reduce stack usage 



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: default avatarEric 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: default avatarHiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f8e9881c

net/ipv4/inetpeer.c

+7 −6
Original line number Original line Diff line number Diff line
@@ -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;

	}

	}