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Message-Id: <20240305183949.258473-1-thinker.li@gmail.com>
Date: Tue, 5 Mar 2024 10:39:49 -0800
From: Kui-Feng Lee <thinker.li@...il.com>
To: netdev@...r.kernel.org,
ast@...nel.org,
martin.lau@...ux.dev,
kernel-team@...a.com,
kuba@...nel.org,
davem@...emloft.net,
dsahern@...nel.org,
pabeni@...hat.com
Cc: sinquersw@...il.com,
kuifeng@...a.com,
Kui-Feng Lee <thinker.li@...il.com>
Subject: [PATCH net-next v3] selftests/net: fix waiting time for ipv6_gc test in fib_tests.sh.
ipv6_gc fails occasionally. According to the study, fib6_run_gc() using
jiffies_round() to round the GC interval could increase the waiting time up
to 750ms (3/4 seconds). The timer has a granularity of 512ms at the range
4s to 32s. That means a route with an expiration time E seconds can wait
for more than E * 2 + 1 seconds if the GC interval is also E seconds.
E * 2 + 2 seconds should be enough for waiting for removing routes.
Also remove a check immediately after replacing 5 routes since it is very
likely to remove some of routes before completing the last route with a
slow environment.
Signed-off-by: Kui-Feng Lee <thinker.li@...il.com>
---
I made the follow change to simulate the case that a route misses the first
GC, and the waiting time of the next GC is rounded up by round_jiffies())
adding 750ms extra waiting time.
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 6540d877d369..88479daa6ff7 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1487,8 +1487,10 @@ int fib6_add(struct fib6_node *root, struct fib6_info *rt,
list_add(&rt->nh_list, &rt->nh->f6i_list);
__fib6_update_sernum_upto_root(rt, fib6_new_sernum(info->nl_net));
- if (rt->fib6_flags & RTF_EXPIRES)
+ if (rt->fib6_flags & RTF_EXPIRES) {
+ printk(KERN_CRIT "fib6_add expires\n");
fib6_add_gc_list(rt);
+ }
fib6_start_gc(info->nl_net, rt);
}
@@ -2296,6 +2298,7 @@ static void fib6_flush_trees(struct net *net)
static int fib6_age(struct fib6_info *rt, struct fib6_gc_args *gc_args)
{
unsigned long now = jiffies;
+ static int expire_cnt = 0;
/*
* check addrconf expiration here.
@@ -2303,8 +2306,9 @@ static int fib6_age(struct fib6_info *rt, struct fib6_gc_args *gc_args)
*/
if (rt->fib6_flags & RTF_EXPIRES && rt->expires) {
- if (time_after(now, rt->expires)) {
+ if (time_after(now, rt->expires) && expire_cnt++) {
pr_debug("expiring %p\n", rt);
+ printk(KERN_CRIT "fib6_age expiring\n");
return -1;
}
gc_args->more++;
@@ -2376,8 +2380,7 @@ void fib6_run_gc(unsigned long expires, struct net *net, bool force)
if (gc_args.more)
mod_timer(&net->ipv6.ip6_fib_timer,
- round_jiffies(now
- + net->ipv6.sysctl.ip6_rt_gc_interval));
+ now + net->ipv6.sysctl.ip6_rt_gc_interval + HZ * 3 / 4);
else
del_timer(&net->ipv6.ip6_fib_timer);
spin_unlock_bh(&net->ipv6.fib6_gc_lock);
The following is the test case.
fib6_gc_test()
{
setup
echo
echo "Fib6 garbage collection test"
set -e
EXPIRE=5
# Check expiration of routes every $EXPIRE seconds (GC)
$NS_EXEC sysctl -wq net.ipv6.route.gc_interval=$EXPIRE
$IP link add dummy_10 type dummy
$IP link set dev dummy_10 up
$IP -6 address add 2001:10::1/64 dev dummy_10
$NS_EXEC sysctl -wq net.ipv6.route.flush=1
# Temporary routes
$IP -6 route add 2001:20::1 \
via 2001:10::2 dev dummy_10 expires $EXPIRE
sleep $(($EXPIRE * 4 + 1))
set +e
cleanup &> /dev/null
}
According to what I found from the kernel messages, the route waited
11.258s before being removed. It is longer than $EXPIRE * 2 + 1 seconds
where EXPIRE=5.
[ 8.674004] fib6_add expires
[ 19.932557] fib6_age expiring
Waiting for EXPIRE * 2 + 2 seconds should be enough for non-debug build.
Changes from v2:
- GC_WAIT_TIME to replace $(($EXPIRE * 2 + 2))
v2: https://lore.kernel.org/all/20240305013734.872968-1-thinker.li@gmail.com/
---
tools/testing/selftests/net/fib_tests.sh | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/net/fib_tests.sh b/tools/testing/selftests/net/fib_tests.sh
index 3ec1050e47a2..73895711cdf4 100755
--- a/tools/testing/selftests/net/fib_tests.sh
+++ b/tools/testing/selftests/net/fib_tests.sh
@@ -789,6 +789,7 @@ fib6_gc_test()
set -e
EXPIRE=5
+ GC_WAIT_TIME=$((EXPIRE * 2 + 2))
# Check expiration of routes every $EXPIRE seconds (GC)
$NS_EXEC sysctl -wq net.ipv6.route.gc_interval=$EXPIRE
@@ -805,7 +806,7 @@ fib6_gc_test()
$IP -6 route add 2001:20::$i \
via 2001:10::2 dev dummy_10 expires $EXPIRE
done
- sleep $(($EXPIRE * 2 + 1))
+ sleep $GC_WAIT_TIME
$NS_EXEC sysctl -wq net.ipv6.route.flush=1
check_rt_num 0 $($IP -6 route list |grep expires|wc -l)
log_test $ret 0 "ipv6 route garbage collection"
@@ -823,7 +824,8 @@ fib6_gc_test()
$IP -6 route add 2001:20::$i \
via 2001:10::2 dev dummy_10 expires $EXPIRE
done
- sleep $(($EXPIRE * 2 + 1))
+ # Wait for GC
+ sleep $GC_WAIT_TIME
check_rt_num 0 $($IP -6 route list |grep expires|wc -l)
log_test $ret 0 "ipv6 route garbage collection (with permanent routes)"
@@ -840,10 +842,8 @@ fib6_gc_test()
$IP -6 route replace 2001:20::$i \
via 2001:10::2 dev dummy_10 expires $EXPIRE
done
- check_rt_num_clean 5 $($IP -6 route list |grep expires|wc -l) || return
# Wait for GC
- sleep $(($EXPIRE * 2 + 1))
- $NS_EXEC sysctl -wq net.ipv6.route.flush=1
+ sleep $GC_WAIT_TIME
check_rt_num 0 $($IP -6 route list |grep expires|wc -l)
log_test $ret 0 "ipv6 route garbage collection (replace with expires)"
@@ -863,8 +863,7 @@ fib6_gc_test()
check_rt_num_clean 0 $($IP -6 route list |grep expires|wc -l) || return
# Wait for GC
- sleep $(($EXPIRE * 2 + 1))
-
+ sleep $GC_WAIT_TIME
check_rt_num 5 $($IP -6 route list |grep -v expires|grep 2001:20::|wc -l)
log_test $ret 0 "ipv6 route garbage collection (replace with permanent)"
@@ -901,9 +900,7 @@ fib6_gc_test()
check_rt_num_clean 1 $($IP -6 route list|grep expires|wc -l) || return
# Wait for GC
- sleep $(($EXPIRE * 2 + 1))
-
- $NS_EXEC sysctl -wq net.ipv6.route.flush=1
+ sleep $GC_WAIT_TIME
check_rt_num 0 $($IP -6 route list |grep expires|wc -l)
log_test $ret 0 "ipv6 route garbage collection (RA message)"
--
2.34.1
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