ipvs: Embed estimator object into stats object

There's no reason for dynamically allocating an estimator object for every
stats object. Directly embed an estimator object into every stats object and
switch to using the kernel-provided list implementation. This makes the code
much simpler and faster, as we do not need to traverse the list of all
estimators to find the one belonging to a stats object. There's no need to use
an rwlock, as we only have one reader. Also reorder the members of the
estimator structure slightly to avoid padding overhead. This can't be done
with the stats object as the members are currently copied to our user space
object via memcpy() and changing it would break ABI.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>

3 files changed, 65 insertions, 82 deletions

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index c8ee9b89b023..7312c3dd309f 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -140,8 +140,24 @@ struct ip_vs_seq {
 
 
 /*
- *      IPVS statistics object
+ *      IPVS statistics objects
  */
+struct ip_vs_estimator {
+        struct list_head        list;
+
+        u64                     last_inbytes;
+        u64                     last_outbytes;
+        u32                     last_conns;
+        u32                     last_inpkts;
+        u32                     last_outpkts;
+
+        u32                     cps;
+        u32                     inpps;
+        u32                     outpps;
+        u32                     inbps;
+        u32                     outbps;
+};
+
 struct ip_vs_stats
 {
         __u32                   conns;          /* connections scheduled */
@@ -156,7 +172,15 @@ struct ip_vs_stats
         __u32                   inbps;          /* current in byte rate */
         __u32                   outbps;         /* current out byte rate */
 
+        /*
+         * Don't add anything before the lock, because we use memcpy() to copy
+         * the members before the lock to struct ip_vs_stats_user in
+         * ip_vs_ctl.c.
+         */
+
         spinlock_t              lock;           /* spin lock */
+
+        struct ip_vs_estimator  est;            /* estimator */
 };
 
 struct dst_entry;
@@ -659,7 +683,7 @@ extern void ip_vs_sync_conn(struct ip_vs_conn *cp);
 /*
  *      IPVS rate estimator prototypes (from ip_vs_est.c)
  */
-extern int ip_vs_new_estimator(struct ip_vs_stats *stats);
+extern void ip_vs_new_estimator(struct ip_vs_stats *stats);
 extern void ip_vs_kill_estimator(struct ip_vs_stats *stats);
 extern void ip_vs_zero_estimator(struct ip_vs_stats *stats);
 
diff --git a/net/ipv4/ipvs/ip_vs_ctl.c b/net/ipv4/ipvs/ip_vs_ctl.c
index 999d884e8862..d651bce05493 100644
--- a/net/ipv4/ipvs/ip_vs_ctl.c
+++ b/net/ipv4/ipvs/ip_vs_ctl.c
@@ -684,8 +684,8 @@ ip_vs_zero_stats(struct ip_vs_stats *stats)
 {
         spin_lock_bh(&stats->lock);
         memset(stats, 0, (char *)&stats->lock - (char *)stats);
-        spin_unlock_bh(&stats->lock);
         ip_vs_zero_estimator(stats);
+        spin_unlock_bh(&stats->lock);
 }
 
 /*
diff --git a/net/ipv4/ipvs/ip_vs_est.c b/net/ipv4/ipvs/ip_vs_est.c
index 1d6e58e502fd..5a20f93bd7f9 100644
--- a/net/ipv4/ipvs/ip_vs_est.c
+++ b/net/ipv4/ipvs/ip_vs_est.c
@@ -17,6 +17,7 @@
 #include <linux/types.h>
 #include <linux/interrupt.h>
 #include <linux/sysctl.h>
+#include <linux/list.h>
 
 #include <net/ip_vs.h>
 
@@ -44,28 +45,11 @@
  */
 
 
-struct ip_vs_estimator
-{
-        struct ip_vs_estimator  *next;
-        struct ip_vs_stats      *stats;
-
-        u32                     last_conns;
-        u32                     last_inpkts;
-        u32                     last_outpkts;
-        u64                     last_inbytes;
-        u64                     last_outbytes;
-
-        u32                     cps;
-        u32                     inpps;
-        u32                     outpps;
-        u32                     inbps;
-        u32                     outbps;
-};
+static void estimation_timer(unsigned long arg);
 
-
-static struct ip_vs_estimator *est_list = NULL;
-static DEFINE_RWLOCK(est_lock);
-static struct timer_list est_timer;
+static LIST_HEAD(est_list);
+static DEFINE_SPINLOCK(est_lock);
+static DEFINE_TIMER(est_timer, estimation_timer, 0, 0);
 
 static void estimation_timer(unsigned long arg)
 {
@@ -76,9 +60,9 @@ static void estimation_timer(unsigned long arg)
         u64 n_inbytes, n_outbytes;
         u32 rate;
 
-        read_lock(&est_lock);
-        for (e = est_list; e; e = e->next) {
-                s = e->stats;
+        spin_lock(&est_lock);
+        list_for_each_entry(e, &est_list, list) {
+                s = container_of(e, struct ip_vs_stats, est);
 
                 spin_lock(&s->lock);
                 n_conns = s->conns;
@@ -114,19 +98,16 @@ static void estimation_timer(unsigned long arg)
                 s->outbps = (e->outbps+0xF)>>5;
                 spin_unlock(&s->lock);
         }
-        read_unlock(&est_lock);
+        spin_unlock(&est_lock);
         mod_timer(&est_timer, jiffies + 2*HZ);
 }
 
-int ip_vs_new_estimator(struct ip_vs_stats *stats)
+void ip_vs_new_estimator(struct ip_vs_stats *stats)
 {
-        struct ip_vs_estimator *est;
+        struct ip_vs_estimator *est = &stats->est;
 
-        est = kzalloc(sizeof(*est), GFP_KERNEL);
-        if (est == NULL)
-                return -ENOMEM;
+        INIT_LIST_HEAD(&est->list);
 
-        est->stats = stats;
         est->last_conns = stats->conns;
         est->cps = stats->cps<<10;
 
@@ -142,62 +123,40 @@ int ip_vs_new_estimator(struct ip_vs_stats *stats)
         est->last_outbytes = stats->outbytes;
         est->outbps = stats->outbps<<5;
 
-        write_lock_bh(&est_lock);
-        est->next = est_list;
-        if (est->next == NULL) {
-                setup_timer(&est_timer, estimation_timer, 0);
-                est_timer.expires = jiffies + 2*HZ;
-                add_timer(&est_timer);
-        }
-        est_list = est;
-        write_unlock_bh(&est_lock);
-        return 0;
+        spin_lock_bh(&est_lock);
+        if (list_empty(&est_list))
+                mod_timer(&est_timer, jiffies + 2 * HZ);
+        list_add(&est->list, &est_list);
+        spin_unlock_bh(&est_lock);
 }
 
 void ip_vs_kill_estimator(struct ip_vs_stats *stats)
 {
-        struct ip_vs_estimator *est, **pest;
-        int killed = 0;
-
-        write_lock_bh(&est_lock);
-        pest = &est_list;
-        while ((est=*pest) != NULL) {
-                if (est->stats != stats) {
-                        pest = &est->next;
-                        continue;
-                }
-                *pest = est->next;
-                kfree(est);
-                killed++;
-        }
-        while (killed && !est_list && try_to_del_timer_sync(&est_timer) < 0) {
-                write_unlock_bh(&est_lock);
+        struct ip_vs_estimator *est = &stats->est;
+
+        spin_lock_bh(&est_lock);
+        list_del(&est->list);
+        while (list_empty(&est_list) && try_to_del_timer_sync(&est_timer) < 0) {
+                spin_unlock_bh(&est_lock);
                 cpu_relax();
-                write_lock_bh(&est_lock);
+                spin_lock_bh(&est_lock);
         }
-        write_unlock_bh(&est_lock);
+        spin_unlock_bh(&est_lock);
 }
 
 void ip_vs_zero_estimator(struct ip_vs_stats *stats)
 {
-        struct ip_vs_estimator *e;
-
-        write_lock_bh(&est_lock);
-        for (e = est_list; e; e = e->next) {
-                if (e->stats != stats)
-                        continue;
-
-                /* set counters zero */
-                e->last_conns = 0;
-                e->last_inpkts = 0;
-                e->last_outpkts = 0;
-                e->last_inbytes = 0;
-                e->last_outbytes = 0;
-                e->cps = 0;
-                e->inpps = 0;
-                e->outpps = 0;
-                e->inbps = 0;
-                e->outbps = 0;
-        }
-        write_unlock_bh(&est_lock);
+        struct ip_vs_estimator *est = &stats->est;
+
+        /* set counters zero, caller must hold the stats->lock lock */
+        est->last_inbytes = 0;
+        est->last_outbytes = 0;
+        est->last_conns = 0;
+        est->last_inpkts = 0;
+        est->last_outpkts = 0;
+        est->cps = 0;
+        est->inpps = 0;
+        est->outpps = 0;
+        est->inbps = 0;
+        est->outbps = 0;
 }