From 214c889ef231aa3b3c29a8cbda6783ddfc064b47 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 11 Apr 2011 22:39:40 +0000 Subject: [PATCH] inetpeer: reduce stack usage BugLink: http://bugs.launchpad.net/bugs/793702 [ Upstream commit 66944e1c5797562cebe2d1857d46dff60bf9a69e ] 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 Cc: Scot Doyle Cc: Stephen Hemminger Cc: Hiroaki SHIMODA Reviewed-by: Hiroaki SHIMODA Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Tim Gardner --- net/ipv4/inetpeer.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index a96e656..14af1b4 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -366,7 +366,8 @@ static void inetpeer_free_rcu(struct rcu_head *head) } /* 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; @@ -380,7 +381,6 @@ 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. */ if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) { - struct inet_peer __rcu **stack[PEER_MAXDEPTH]; struct inet_peer __rcu ***stackptr, ***delp; if (lookup(&p->daddr, stack, base) != p) BUG(); @@ -435,7 +435,7 @@ static struct inet_peer_base *peer_to_base(struct inet_peer *p) } /* 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; @@ -467,7 +467,7 @@ static int cleanup_once(unsigned long ttl) * happen because of entry limits in route cache. */ return -1; - unlink_from_pool(p, peer_to_base(p)); + unlink_from_pool(p, peer_to_base(p), stack); return 0; } @@ -523,7 +523,7 @@ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create) if (base->total >= inet_peer_threshold) /* Remove one less-recently-used entry. */ - cleanup_once(0); + cleanup_once(0, stack); return p; } @@ -539,6 +539,7 @@ static void peer_check_expire(unsigned long dummy) { unsigned long now = jiffies; int ttl, total; + struct inet_peer __rcu **stack[PEER_MAXDEPTH]; total = compute_total(); if (total >= inet_peer_threshold) @@ -547,7 +548,7 @@ static void peer_check_expire(unsigned long dummy) ttl = inet_peer_maxttl - (inet_peer_maxttl - inet_peer_minttl) / HZ * total / inet_peer_threshold * HZ; - while (!cleanup_once(ttl)) { + while (!cleanup_once(ttl, stack)) { if (jiffies != now) break; } -- 1.7.10.4