From: Eric Dumazet <dada1@cosmosbay.com>
To: Andi Kleen <ak@suse.de>
Cc: netdev@vger.kernel.org, davem@davemloft.net
Subject: Re: [PATCH] Shrink struct dst_entry a bit
Date: Tue, 13 Mar 2007 15:58:10 +0100 [thread overview]
Message-ID: <200703131558.10596.dada1@cosmosbay.com> (raw)
In-Reply-To: <200703131544.57757.dada1@cosmosbay.com>
[-- Attachment #1: Type: text/plain, Size: 426 bytes --]
On Tuesday 13 March 2007 15:44, Eric Dumazet wrote:
> Also, 'lastuse' could use a u32 too, I even had a patch for this one...
Here is the patch I have here for lastuse u32 conversion, not for inclusion
yet because not yet tested (only compiled)
[PATCH] NET : abstract lastuse (from struct dst_entry) and convert it to u32
This saves 4 bytes (possibly 8) on 64 bit archs
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
[-- Attachment #2: lastuse.patch --]
[-- Type: text/plain, Size: 12548 bytes --]
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index c080f61..fb23951 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -89,7 +89,16 @@ static inline u64 get_jiffies_64(void)
return (u64)jiffies;
}
#endif
-
+/*
+ * On 64bit archs, storing timestamps in 'unsigned long' vars
+ * may consume unecessary memory. Using u32 is ok when deltas
+ * between current jiffie and past timestamps are known to
+ * fit in 32-1 bits. Even with HZ=1000, thats 24 days.
+ */
+static inline u32 get_jiffies_32(void)
+{
+ return (u32)jiffies;
+}
/*
* These inlines deal with timer wrapping correctly. You are
* strongly encouraged to use them
diff --git a/include/net/dst.h b/include/net/dst.h
index e12a8ce..70366b7 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -67,13 +67,13 @@ #define DST_BALANCED 0x10
int (*input)(struct sk_buff*);
int (*output)(struct sk_buff*);
+
+ struct dst_ops *ops;
#ifdef CONFIG_NET_CLS_ROUTE
__u32 tclassid;
#endif
-
- struct dst_ops *ops;
- unsigned long lastuse;
+ u32 __lastuse;
atomic_t __refcnt; /* client references */
int __use;
union {
@@ -103,11 +103,23 @@ struct dst_ops
int entry_size;
atomic_t entries;
- struct kmem_cache *kmem_cachep;
+ struct kmem_cache *kmem_cachep;
};
#ifdef __KERNEL__
+static inline void
+dst_lastuse_set(struct dst_entry *dst)
+{
+ dst->__lastuse = get_jiffies_32();
+}
+
+static inline unsigned long
+dst_lastuse_delta(const struct dst_entry *dst)
+{
+ return get_jiffies_32() - dst->__lastuse;
+}
+
static inline u32
dst_metric(const struct dst_entry *dst, int metric)
{
diff --git a/net/core/dst.c b/net/core/dst.c
index 764bccb..6c0a023 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -136,7 +136,7 @@ void * dst_alloc(struct dst_ops * ops)
return NULL;
atomic_set(&dst->__refcnt, 0);
dst->ops = ops;
- dst->lastuse = jiffies;
+ dst_lastuse_set(dst);
dst->path = dst;
dst->input = dst_discard_in;
dst->output = dst_discard_out;
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 6055074..c3f5264 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -215,7 +215,7 @@ int rtnl_put_cacheinfo(struct sk_buff *s
u32 ts, u32 tsage, long expires, u32 error)
{
struct rta_cacheinfo ci = {
- .rta_lastuse = jiffies_to_clock_t(jiffies - dst->lastuse),
+ .rta_lastuse = jiffies_to_clock_t(dst_lastuse_delta(dst)),
.rta_used = dst->__use,
.rta_clntref = atomic_read(&(dst->__refcnt)),
.rta_error = error,
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 32a7db3..3d5c46c 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -166,7 +166,7 @@ static void dn_dst_check_expire(unsigned
spin_lock(&dn_rt_hash_table[i].lock);
while((rt=*rtp) != NULL) {
if (atomic_read(&rt->u.dst.__refcnt) ||
- (now - rt->u.dst.lastuse) < expire) {
+ dst_lastuse_delta(&rt->u.dst) < expire) {
rtp = &rt->u.dst.dn_next;
continue;
}
@@ -187,7 +187,6 @@ static int dn_dst_gc(void)
{
struct dn_route *rt, **rtp;
int i;
- unsigned long now = jiffies;
unsigned long expire = 10 * HZ;
for(i = 0; i <= dn_rt_hash_mask; i++) {
@@ -197,7 +196,7 @@ static int dn_dst_gc(void)
while((rt=*rtp) != NULL) {
if (atomic_read(&rt->u.dst.__refcnt) ||
- (now - rt->u.dst.lastuse) < expire) {
+ dst_lastuse_delta(&rt->u.dst) < expire) {
rtp = &rt->u.dst.dn_next;
continue;
}
@@ -278,7 +277,6 @@ static inline int compare_keys(struct fl
static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
{
struct dn_route *rth, **rthp;
- unsigned long now = jiffies;
rthp = &dn_rt_hash_table[hash].chain;
@@ -293,7 +291,7 @@ static int dn_insert_route(struct dn_rou
rth->u.dst.__use++;
dst_hold(&rth->u.dst);
- rth->u.dst.lastuse = now;
+ dst_lastuse_set(&rth->u.dst);
spin_unlock_bh(&dn_rt_hash_table[hash].lock);
dnrt_drop(rt);
@@ -308,7 +306,7 @@ static int dn_insert_route(struct dn_rou
dst_hold(&rt->u.dst);
rt->u.dst.__use++;
- rt->u.dst.lastuse = now;
+ dst_lastuse_set(&rt->u.dst);
spin_unlock_bh(&dn_rt_hash_table[hash].lock);
*rp = rt;
return 0;
@@ -1119,7 +1117,7 @@ make_route:
rt->u.dst.neighbour = neigh;
neigh = NULL;
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
rt->u.dst.output = dn_output;
rt->u.dst.input = dn_rt_bug;
rt->rt_flags = flags;
@@ -1175,7 +1173,7 @@ static int __dn_route_output_key(struct
(flp->mark == rt->fl.mark) &&
(rt->fl.iif == 0) &&
(rt->fl.oif == flp->oif)) {
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
dst_hold(&rt->u.dst);
rt->u.dst.__use++;
rcu_read_unlock_bh();
@@ -1380,7 +1378,7 @@ make_route:
rt->u.dst.flags = DST_HOST;
rt->u.dst.neighbour = neigh;
rt->u.dst.dev = out_dev;
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
rt->u.dst.output = dn_rt_bug;
switch(res.type) {
case RTN_UNICAST:
@@ -1449,7 +1447,7 @@ int dn_route_input(struct sk_buff *skb)
(rt->fl.oif == 0) &&
(rt->fl.mark == skb->mark) &&
(rt->fl.iif == cb->iif)) {
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
dst_hold(&rt->u.dst);
rt->u.dst.__use++;
rcu_read_unlock();
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 2f44e61..6831897 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -343,7 +343,7 @@ static int cleanup_once(unsigned long tt
spin_lock_bh(&inet_peer_unused_lock);
p = inet_peer_unused_head;
if (p != NULL) {
- __u32 delta = (__u32)jiffies - p->dtime;
+ __u32 delta = get_jiffies_32() - p->dtime;
if (delta < ttl) {
/* Do not prune fresh entries. */
spin_unlock_bh(&inet_peer_unused_lock);
@@ -471,7 +471,7 @@ void inet_putpeer(struct inet_peer *p)
p->unused_next = NULL;
*inet_peer_unused_tailp = p;
inet_peer_unused_tailp = &p->unused_next;
- p->dtime = (__u32)jiffies;
+ p->dtime = get_jiffies_32();
}
spin_unlock_bh(&inet_peer_unused_lock);
}
diff --git a/net/ipv4/multipath_drr.c b/net/ipv4/multipath_drr.c
index 574c735..e318dbd 100644
--- a/net/ipv4/multipath_drr.c
+++ b/net/ipv4/multipath_drr.c
@@ -147,7 +147,7 @@ static void drr_select_route(const struc
multipath_comparekeys(&nh->fl, flp)) {
int nh_ifidx = nh->u.dst.dev->ifindex;
- nh->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&nh->u.dst);
nh->u.dst.__use++;
if (result != NULL)
continue;
diff --git a/net/ipv4/multipath_random.c b/net/ipv4/multipath_random.c
index c312785..5355593 100644
--- a/net/ipv4/multipath_random.c
+++ b/net/ipv4/multipath_random.c
@@ -78,7 +78,7 @@ static void random_select_route(const st
for (rt = first; rt; rt = rt->u.dst.rt_next) {
if ((rt->u.dst.flags & DST_BALANCED) != 0 &&
multipath_comparekeys(&rt->fl, flp)) {
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
if (i == candidate_no)
decision = rt;
diff --git a/net/ipv4/multipath_rr.c b/net/ipv4/multipath_rr.c
index 0ad2252..26a55bf 100644
--- a/net/ipv4/multipath_rr.c
+++ b/net/ipv4/multipath_rr.c
@@ -60,7 +60,7 @@ static void rr_select_route(const struct
nh = rcu_dereference(nh->u.dst.rt_next)) {
if ((nh->u.dst.flags & DST_BALANCED) != 0 &&
multipath_comparekeys(&nh->fl, flp)) {
- nh->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&nh->u.dst);
if (min_use == -1 || nh->u.dst.__use < min_use) {
min_use = nh->u.dst.__use;
diff --git a/net/ipv4/multipath_wrandom.c b/net/ipv4/multipath_wrandom.c
index 57c5036..30467d3 100644
--- a/net/ipv4/multipath_wrandom.c
+++ b/net/ipv4/multipath_wrandom.c
@@ -189,7 +189,7 @@ static void wrandom_select_route(const s
decision = first;
last_mpc = NULL;
for (mpc = first_mpc; mpc; mpc = mpc->next) {
- mpc->rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&mpc->rt->u.dst);
if (last_power <= selector && selector < mpc->power)
decision = mpc->rt;
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 5841739..cbd6337 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -533,7 +533,7 @@ static int rt_may_expire(struct rtable *
time_after_eq(jiffies, rth->u.dst.expires))
goto out;
- age = jiffies - rth->u.dst.lastuse;
+ age = dst_lastuse_delta(&rth->u.dst);
ret = 0;
if ((age <= tmo1 && !rt_fast_clean(rth)) ||
(age <= tmo2 && rt_valuable(rth)))
@@ -549,7 +549,7 @@ out: return ret;
*/
static inline u32 rt_score(struct rtable *rt)
{
- u32 score = jiffies - rt->u.dst.lastuse;
+ u32 score = dst_lastuse_delta(&rt->u.dst);
score = ~score & ~(3<<30);
@@ -922,7 +922,6 @@ out: return 0;
static int rt_intern_hash(unsigned hash, struct rtable *rt, struct rtable **rp)
{
struct rtable *rth, **rthp;
- unsigned long now;
struct rtable *cand, **candp;
u32 min_score;
int chain_length;
@@ -933,7 +932,6 @@ restart:
min_score = ~(u32)0;
cand = NULL;
candp = NULL;
- now = jiffies;
rthp = &rt_hash_table[hash].chain;
@@ -962,7 +960,7 @@ #endif
rth->u.dst.__use++;
dst_hold(&rth->u.dst);
- rth->u.dst.lastuse = now;
+ dst_lastuse_set(&rth->u.dst);
spin_unlock_bh(rt_hash_lock_addr(hash));
rt_drop(rt);
@@ -1198,7 +1196,7 @@ void ip_rt_redirect(__be32 old_gw, __be3
if (rt->idev)
in_dev_hold(rt->idev);
rt->u.dst.obsolete = 0;
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
rt->u.dst.path = &rt->u.dst;
rt->u.dst.neighbour = NULL;
rt->u.dst.hh = NULL;
@@ -2105,7 +2103,7 @@ int ip_route_input(struct sk_buff *skb,
rth->fl.oif == 0 &&
rth->fl.mark == skb->mark &&
rth->fl.fl4_tos == tos) {
- rth->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rth->u.dst);
dst_hold(&rth->u.dst);
rth->u.dst.__use++;
RT_CACHE_STAT_INC(in_hit);
@@ -2581,7 +2579,7 @@ int __ip_route_output_key(struct rtable
return 0;
}
- rth->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rth->u.dst);
dst_hold(&rth->u.dst);
rth->u.dst.__use++;
RT_CACHE_STAT_INC(out_hit);
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index f1c32ff..ecc8aa9 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -160,7 +160,7 @@ #endif
dev_hold(rt->u.dst.dev);
dst_prev->obsolete = -1;
dst_prev->flags |= DST_HOST;
- dst_prev->lastuse = jiffies;
+ dst_lastuse_set(dst_prev);
dst_prev->header_len = header_len;
dst_prev->nfheader_len = 0;
dst_prev->trailer_len = trailer_len;
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index f4d7be7..906cfed 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1425,7 +1425,7 @@ static int fib6_age(struct rt6_info *rt,
gc_args.more++;
} else if (rt->rt6i_flags & RTF_CACHE) {
if (atomic_read(&rt->u.dst.__refcnt) == 0 &&
- time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) {
+ dst_lastuse_delta(&rt->u.dst) >= gc_args.timeout) {
RT6_TRACE("aging clone %p\n", rt);
return -1;
} else if ((rt->rt6i_flags & RTF_GATEWAY) &&
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index bb2b508..bb7f203 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -528,7 +528,7 @@ out:
dst_hold(&rt->u.dst);
read_unlock_bh(&table->tb6_lock);
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
rt->u.dst.__use++;
return rt;
@@ -706,7 +706,7 @@ out:
dst_hold(&rt->u.dst);
read_unlock_bh(&table->tb6_lock);
out2:
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
rt->u.dst.__use++;
return rt;
@@ -801,7 +801,7 @@ out:
dst_hold(&rt->u.dst);
read_unlock_bh(&table->tb6_lock);
out2:
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
rt->u.dst.__use++;
return rt;
}
@@ -1560,7 +1560,7 @@ static struct rt6_info * ip6_rt_copy(str
rt->rt6i_idev = ort->rt6i_idev;
if (rt->rt6i_idev)
in6_dev_hold(rt->rt6i_idev);
- rt->u.dst.lastuse = jiffies;
+ dst_lastuse_set(&rt->u.dst);
rt->rt6i_expires = 0;
ipv6_addr_copy(&rt->rt6i_gateway, &ort->rt6i_gateway);
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index b93bfb8..f059cbe 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -223,7 +223,7 @@ __xfrm6_bundle_create(struct xfrm_policy
dev_hold(rt->u.dst.dev);
dst_prev->obsolete = -1;
dst_prev->flags |= DST_HOST;
- dst_prev->lastuse = jiffies;
+ dst_lastuse_set(dst_prev);
dst_prev->header_len = header_len;
dst_prev->nfheader_len = nfheader_len;
dst_prev->trailer_len = trailer_len;
prev parent reply other threads:[~2007-03-13 14:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-13 13:48 [PATCH] Shrink struct dst_entry a bit Andi Kleen
2007-03-13 14:10 ` Eric Dumazet
2007-03-13 14:31 ` Andi Kleen
2007-03-13 14:44 ` Eric Dumazet
2007-03-13 14:58 ` Eric Dumazet [this message]
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